Mortality among the Residents of the Three Mile Island Accident Area: 1979-1992.The largest U.S. population exposed to low-level radioactivity radioactivity, spontaneous disintegration or decay of the nucleus of an atom by emission of particles, usually accompanied by electromagnetic radiation. The energy produced by radioactivity has important military and industrial applications. released by an accident at a nuclear power plant is composed of residents near the Three Mile Island (TMI TMI Too Much Information TMI Three Mile Island TMI TRMM Microwave Imager TMI Transactions on Medical Imaging TMI Texas Military Institute TMI Teen Missions International TMI Tauber Manufacturing Institute ) Plant on 28 March 1979. This paper (a collaboration of The University of Pittsburgh and the Pennsylvania Department of Health) reports on the mortality experience of the 32,135 members in this cohort cohort /co·hort/ (ko´hort) 1. in epidemiology, a group of individuals sharing a common characteristic and observed over time in the group. 2. for 1979-1992. We analyzed an·a·lyze tr.v. an·a·lyzed, an·a·lyz·ing, an·a·lyz·es 1. To examine methodically by separating into parts and studying their interrelations. 2. Chemistry To make a chemical analysis of. 3. standardized mortality ratios The standardized mortality ratio or SMR in epidemiology is the ratio of observed deaths to expected deaths according to a specific health outcome in a population and serves as an indirect means of adjusting a rate. (SMRs) using a local comparison population and performed relative risk regression modeling to assess overall mortality and specific cancer risks by confounding confounding when the effects of two, or more, processes on results cannot be separated, the results are said to be confounded, a cause of bias in disease studies. confounding factor factors and radiation-related exposure variables. Total mortality was significantly elevated for both men and women (SMRs = 109 and 118, respectively). All heart disease accounted for 43.3% of total deaths and demonstrated elevated SMRs for heart disease of 113 and 130 for men and women, respectively; however, when controlling for confounders and natural background radiation, these elevations in heart disease were no longer evident. Overall cancer mortality was similar in this cohort as compared to the local population (male SMR (Specialized Mobile Radio) The communications services used by police, ambulances, taxicabs, trucks and other delivery vehicles. Throughout the U.S., approximately 3,000 independent operators are licensed by the FCC to offer this service, which provides always-on = 100; female SMR = 101). In the relative risk modeling, there was a significant effect for all lymphatic lymphatic /lym·phat·ic/ (lim-fat´ik) 1. pertaining to lymph or to a lymphatic vessel. 2. a lymphatic vessel. lym·phat·ic adj. and hematopoietic hematopoietic /he·ma·to·poi·et·ic/ (-poi-et´ik) 1. pertaining to hematopoiesis. 2. an agent that promotes hematopoiesis. hematopoietic 1. pertaining to or affecting the formation of blood cells. tissue in males in relation to natural background exposure (p = 0.04). However, no trend was noted. We found a significant linear trend for female breast cancer risk in relation to increasing levels of TMI-related likely [Gamma]-exposure (p = 0.02). Although such a relationship has been noted in other investigations, emissions from the TMI incident were significantly lower than in other documented studies. Therefore, it is unlikely that this observed increase is related to radiation exposure on the day of the accident. The mortality surveillance of this cohort does not provide consistent evidence that radioactivity released during the TMI accident has a significant impact on the mortality experience of this cohort to date. However, continued follow-up of these individuals will provide a more comprehensive description of the morbidity and mortality Morbidity and Mortality can refer to:
n. High-energy radiation capable of producing ionization in substances through which it passes. Ionizing radiation , mortality, neoplasms, nuclear reactors List of nuclear reactors is a comprehensive annotated list of all the nuclear reactors of the world, sorted by country. This list excludes nuclear marine propulsion reactors, except those at land installations, and . . Environ en·vi·ron tr.v. en·vi·roned, en·vi·ron·ing, en·vi·rons To encircle; surround. See Synonyms at surround. [Middle English envirounen, from Old French environner Health Perspect 108:545-552 (2000). [Online 28 April 2000] http://ehpnet1.niehs.nih.gov/docs/2000/108p545-552talbott/abstract.html An incident at the Three Mile Island (TMI) nuclear power plant on 28 March 1979 produced a relatively small environmental release of radioactivity that consisted primarily of xenon xenon (zē`nŏn) [Gr.,=strange], gaseous chemical element; symbol Xe; at. no. 54; at. wt. 131.29; m.p. −111.9°C;; b.p. −107.1°C;; density 5.86 grams per liter at STP; valence usually 0. and iodine iodine (ī`ədīn, –dĭn) [Gr.,=violet], nonmetallic chemical element; symbol I; at. no. 53; at. wt. 126.9045; m.p. 113.5°C;; b.p. 184.35°C;; sp. gr. 4.93 at 20°C;; valence −1, +1, +3, +5, or +7. radioisotopes. Scientists computed individual maximum and likely [Gamma]- and [Beta]-radiation doses based on residential location and the amount of time each person spent in the 5-mile area during the 10 days after the accident (1). Gur et al. (1) determined that the average likely and maximum whole-body [Gamma]-doses for individuals in this area were 9 mrem (0.09 mSv) and 25 mrem (0.25 mSv), respectively. The radiation from the TMI nuclear accident was considered minimal as compared to the approximately 300 mrem (3 mSv) annual effective dose received by an individual in the United States United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and the fourth largest country in area. from natural background (2). Although it has been postulated pos·tu·late tr.v. pos·tu·lat·ed, pos·tu·lat·ing, pos·tu·lates 1. To make claim for; demand. 2. To assume or assert the truth, reality, or necessity of, especially as a basis of an argument. 3. that radiation from a nuclear accident and natural background radiation exposures act on the biologic system in the same way (3,4) and that the health effects produced by these types of radioactivity are indistinguishable, available human data are insufficient to confirm this hypothesis (5). In addition, the long-term consequences from low-dose radiation are clearly of recent concern to the public. Consequently, soon after the TMI incident, public health researchers began to monitor whether this brief low-dose radiation exposure exerted any effects on the health of those people living near the nuclear facility. Past research efforts included a survey conducted by the Pennsylvania Department of Health (PDoH; Harrisburg, PA) on the [is greater than] 35,000 people living near the TMI facility (1,6,7). The survey included a characterization A rather long and fancy word for analyzing a system or process and measuring its "characteristics." For example, a Web characterization would yield the number of current sites on the Web, types of sites, annual growth, etc. of the radiation exposure to local inhabitants
The game is based loosely on the concepts from SameGame. and a careful follow-up of the local inhabitants' mortality and cancer morbidity morbidity /mor·bid·i·ty/ (mor-bid´it-e) 1. a diseased condition or state. 2. the incidence or prevalence of a disease or of all diseases in a population. mor·bid·i·ty n. status over time (1,6,7). This population provides a unique opportunity to study the long-term health effects associated with low levels of radiation. Given this opportunity, it is important to assess whether the absence of increased physical health effects can be observed in this low-level radiation-exposed population to confirm the estimates of several scientific reports that such health consequences were unlikely (8). Within 2 months of the accident, the PDoH developed and implemented a TMI Population Registry to track possible health effects to the local population (9). This registry was a special population census conducted within a 5-mile radius of the TMI facility to ascertain the number and characteristics of the local residents, including sociodemographic information, medical history, cigarette smoking status, and previous radiation exposure history. It was estimated that 93-94% of the targeted population was interviewed, with [is less than] 4% of the canvassed households either refusing to respond or unobtainable for other reasons. The registry included 35,946 individuals living within the 5-mile radius of the TMI nuclear reactor nuclear reactor, device for producing controlled release of nuclear energy. Reactors can be used for research or for power production. A research reactor is designed to produce various beams of radiation for experimental application; the heat produced is a waste (9). An initial mortality follow-up study by the PDoH examined mortality from 1979 to 1985 (6). Age-adjusted standardized mortality ratios (SMRs) were calculated to determine if the number of observed deaths among the TMI cohort was greater than what would be expected in the TMI population. Regression modeling demonstrated that neither estimated maximum nor likely whole-body [Gamma]-doses were associated with all-cause, noncancer, or total cancer mortality when controlling for the confounding factors. The authors cautioned that the 6-year follow-up period was short when evaluating most cancers. In 1985, a separate study was initiated by Columbia University Columbia University, mainly in New York City; founded 1754 as King's College by grant of King George II; first college in New York City, fifth oldest in the United States; one of the eight Ivy League institutions. ; the study sought to ascertain cancer cases that occurred before and after the TMI accident (10,11). The study cohort included individuals who resided within a 10-mile radius of the TMI nuclear facility and encompassed nearly 160,000 persons. The study area was divided into 69 study tracts and cancer cases within each tract were ascertained as·cer·tain tr.v. as·cer·tained, as·cer·tain·ing, as·cer·tains 1. To discover with certainty, as through examination or experimentation. See Synonyms at discover. 2. for the 1975-1985 period. Estimates of emissions delivered to these tracts were derived from mathematical dispersion dispersion, in chemistry dispersion, in chemistry, mixture in which fine particles of one substance are scattered throughout another substance. A dispersion is classed as a suspension, colloid, or solution. models; the model of accident emissions was validated val·i·date tr.v. val·i·dat·ed, val·i·dat·ing, val·i·dates 1. To declare or make legally valid. 2. To mark with an indication of official sanction. 3. by readings from off-site dosimeters. Pre- and postaccident trends in cancer rates for the 10-year time period were examined. Cancer rates were adjusted for population density, income, and education. Analyses were limited because personal risk factor information (i.e., smoking and education) was not collected. For accident emissions, the researchers failed to find definite effects of exposure on the cancer types and population subgroups studied. No association was seen for leukemia leukemia (l  kē`mēə), cancerous disorder of the blood-forming tissues (bone marrow, lymphatics, liver, spleen) characterized by excessive production of immature or mature in adults or for childhood cancers as
a group. However, non-Hodgkin lymphoma Non-Hodgkin lymphoma (NHL) describes a group of cancers arising from lymphocytes, a type of white blood cell. It is distinct from Hodgkin lymphoma in its pathologic features, epidemiology, common sites of involvement, clinical behavior, and treatment. showed elevated risks relative to
both accident and routine emissions; the odds ratios assuming a 5-year
latency (1) The time between initiating a request in the computer and receiving the answer. Data latency may refer to the time between a query and the results arriving at the screen or the time between initiating a transaction that modifies one or more databases and its completion. were 2.0 [95% confidence interval confidence interval,n a statistical device used to determine the range within which an acceptable datum would fall. Confidence intervals are usually expressed in percentages, typically 95% or 99%. (CI), 1.2-3.5] and 2.13 (CI, 1.29-3.51), respectively. The odds ratio for lung cancer lung cancer, cancer that originates in the tissues of the lungs. Lung cancer is the leading cause of cancer death in the United States in both men and women. Like other cancers, lung cancer occurs after repeated insults to the genetic material of the cell. and accident emissions was 1.75 (CI, 1.47-2.08); the odds ratio for lung cancer and routine emissions was 1.55 (CI, 1.18-2.03). Background [Gamma]-radiation also showed a slight trend in risk for lung cancer, with an odds ratio of 1.1 (CI, 0.9-1.4) (11). To further assess the effects of the accident, the University of Pittsburgh (Pittsburgh, PA), in collaboration with the PDoH, is continuing a mortality follow-up through the year 1999. We report here on the general and cause-specific mortality experience of this population (termed the UPitt/PDoH TMI cohort) during the 1979-1992 period. Methods A total of 35,946 residents were initially enrolled in the TMI census. Data collected included individual information on education, occupation, smoking status, residential history, medical history, previous radiation exposure (treatment or occupational), and daily travel in and out of the area during the 10 days after the accident (9). The final UPitt/PDoH TMI cohort consisted of 32,135 individuals after excluding people based on six criteria: a) individuals with unknown [Gamma]-and [Beta]-exposure levels, b) those living beyond the 5-mile radius, c) those born after 28 March 1979, d) those with unknown residential history, e) those who established residency A duration of stay required by state and local laws that entitles a person to the legal protection and benefits provided by applicable statutes. States have required state residency for a variety of rights, including the right to vote, the right to run for public office, the after 28 March 1979, and f) those who were duplicated in the TMI census. Gur et al. (1) computed individual estimated average likely and maximum whole-body [Gamma]-doses from the TMI accident radio-activity releases based on residential location and the amount of time each person spent in the 5-mile area during the 10 days after the accident. The present study assigned natural environmental background exposure estimates (not including TMI radioactivity releases) based on a direct measurement recorded with a scintillation scintillation /scin·til·la·tion/ (sin?ti-la´shun) 1. an emission of sparks. 2. a subjective visual sensation, as of seeing sparks. 3. detector detector: see particle detector. and associated instrumentation from a 1976 airborne radon survey (12). These data were applied to the portion of the Hatch Hatch may refer to: Actions and objects
System of postal-zone codes (zip stands for “zone improvement plan”) introduced in the U.S. in 1963 to improve mail delivery and exploit electronic reading and sorting capabilities. were then averaged and assigned a quartile Quartile A statistical term describing a division of observations into four defined intervals based upon the values of the data and how they compare to the entire set of observations. Notes: Each quartile contains 25% of the total observations. of exposure. SMRs. We examined the total and cause-specific mortality experiences of the UPitt/PDoH TMI cohort for the period of 28 March 1979 through 31 December 1992. We jointly classified the person-years at risk contributed by each cohort member by sex, race, age, and time periods using the modified life table technique of the Occupational Cohort Mortality Analysis Program (OCMAP-PLUS), created at the University of Pittsburgh (13). We computed expected counts of deaths by multiplying mul·ti·ply 1 v. mul·ti·plied, mul·ti·ply·ing, mul·ti·plies v.tr. 1. To increase the amount, number, or degree of. 2. Mathematics To perform multiplication on. average annual race-, sex-, age-, and time-specific mortality rates by the person-years at risk in the corresponding race-, sex-, age-, and time-specific intervals in the cohort. We computed the expected counts of death using three counties surrounding the TMI study area [defined as an aggregate of Dauphin Dauphin, town, Canada Dauphin (dô`fĭn), town (1991 pop. 8,453), SW Man., Canada, on the Vermilion River. It is the retail and distribution center for an agricultural, lumbering, and fishing area. , Lancaster, and York counties York County may refer to one of several counties:
Excess and deficit mortalities were expressed as SMRs. We identified statistically significant deviations of the SMR below and above 100, indicating deficit and excess mortality risks, respectively, using Poisson probabilities. No formal probability adjustments were made for the multiple statistical comparisons performed. Because of the small numbers of nonwhite non·white n. A person who is not white. non  white adj. cohort members, we based these analyses on white
cohort members only.Relative risk (RR) regression. We used RR regression to investigate the dependence of the internal cohort rates for six outcomes of interest, including all malignant malignant /ma·lig·nant/ (-nant) 1. tending to become worse and end in death. 2. having the properties of anaplasia, invasiveness, and metastasis; said of tumors. neoplasms; cancer of the bronchus bronchus: see lungs. , trachea trachea (trā`kēə) or windpipe, principal tube that carries air to and from the lungs. It is about 4 1-2 in. (11.4 cm) long and about 3-4 in. (1.9 cm) in diameter in the adult. , and lung (BTL BTL Between the Lines BTL Battle BTL Bottle BTL Buy To Let BTL Below The Line (advertising) BTL Biomass-to-Liquids BTL Bubba the Love Sponge BTL Between the Lions (PBS children's TV show) ); cancer of the breast (females only); cancer of the lymphatic and hematopoietic tissue excluding chronic lymphocytic leukemia chronic lymphocytic leukemia n. Abbr. CLL Lymphocytic leukemia occurring mainly in older adults, characterized by slow onset and gradual progression of symptoms. and Hodgkin disease Hodgkin disease or lymphoreticuloma Most common malignant lymphoma. It starts with local, painless swelling of lymph nodes and sometimes of the spleen, liver, or other organs, followed by weight loss and weakness. (LHT LHT Long Haul Trucker (bicycle) LHT Long Holding Time LHT Long Haul Transmission LHT Lord High Treasurer LHT Low Harmonic Technology (Siemens) LHT Long Haul Terminal (Alcatel) ); cancer of the central nervous system (CNS See Continuous net settlement. CNS See continuous net settlement (CNS). ); and all heart disease. We chose the four cancer sites because of their radiosensitive ra·di·o·sen·si·tive adj. Sensitive to the action of radiation. Used especially of living structures. ra nature (15). We excluded chronic lymphocytic leukemia and Hodgkin disease from further analysis in the all lymphatic and hematopoietic tissue cancer grouping because they rarely have been linked to radiation exposure (16). We analyzed these outcomes on combinations of the three exposure-related covariates and the potential confounding factors. Natural background radiation was considered a predictor variable Noun 1. predictor variable - a variable that can be used to predict the value of another variable (as in statistical regression) variable quantity, variable - a quantity that can assume any of a set of values as well as a confounding variable A confounding variable (also confounding factor, lurking variable, a confound, or confounder) is an extraneous variable in a statistical or research model that should have been experimentally controlled, but was not. in the maximum and likely [Gamma]-models. We performed the RR modeling separately for each of the six time-to-event outcomes. For each outcome, we constructed risk sets from the cohort data file, with age as the primary time dimension. A risk set consisted of a case (cause-specific outcome) and all other cohort members who were alive and at risk at the age that the case died. To adjust for birth cohort effects The term cohort effect is used in social science to describe variations in the characteristics of an area of study (such as the incidence of a characteristic or the age at onset) over time among individuals who are defined by some shared temporal experience or common life , we restricted the risk sets to include only individuals born within 1 month of the corresponding case. We constructed the risk sets using the RISK-SET module of the OCMAP-PLUS software (13). Multiplicative mul·ti·pli·ca·tive adj. 1. Tending to multiply or capable of multiplying or increasing. 2. Having to do with multiplication. mul RR models of the form [Lambda](t) = [[Lambda].sub.0](t) exp exp abbr. 1. exponent 2. exponential [x(t)[Beta]] were fit to the internal cohort rates. Mathematical details of the models are given elsewhere (17-19). In this model, [[Lambda].sub.0](t) is the hazard of an event at age t for an individual with baseline levels of all covariates; x(t) is a vector of covariates (exposures and/or confounders), and [Beta] is the corresponding parameter (1) Any value passed to a program by the user or by another program in order to customize the program for a particular purpose. A parameter may be anything; for example, a file name, a coordinate, a range of values, a money amount or a code of some kind. vector estimated by partial likelihood. We used the conditional logistic regression In statistics, logistic regression is a regression model for binomially distributed response/dependent variables. It is useful for modeling the probability of an event occurring as a function of other factors. program in STATA Stata (Statistics/Data Analysis) is a statistical program created in 1985 by Statacorp that is used by many businesses and academic institutions around the world. Most of its users work in research, especially in the fields of economics, sociology, political science, and (20) to estimate [Beta] from the explicitly constructed risk sets. The potential confounders considered included smoking (never or ever), education at the time of the accident ([is less than] 12 or [is greater than or equal to] 12 years), work in a radiation field (ever, never, or unknown), and external background radiation (low, low medium, or high). The radiation-related exposure variables included estimated maximum and likely [Gamma]-exposure during the 10 days after the accident (0-7, 8-20, 21-34, or [is greater than or equal to] 35 mrem and 0-2, 3-7, 8-15, or [is greater than or equal to] 16 mrem, respectively) and external background exposure (low, low medium, and high medium). We used the lowest category of each risk factor as a baseline for the estimated RR; that category always had an RR value of 1.00. Individual RR estimates were statistically significant if their CIs did not include 1.00. All models were based on white cohort members who were [is greater than or equal to] 18 years of age on the day of the accident. Potential confounders were screened by identifying variables that were individually significant before adding to a model as an adjustment factor. We assessed the statistical significance of each main effect with a likelihood ratio statistic statistic, n a value or number that describes a series of quantitative observations or measures; a value calculated from a sample. statistic a numerical value calculated from a number of observations in order to summarize them. . All tests were done at the 0.05 significance level and no adjustment was made for multiple comparisons. For the quantitative exposure variables that exhibited a monotonic monotonic - In domain theory, a function f : D -> C is monotonic (or monotone) if for all x,y in D, x <= y => f(x) <= f(y). ("<=" is written in LaTeX as \sqsubseteq). increasing or decreasing pattern in the parameter estimates, we conducted a test for linear trend (based on equally spaced scores). Results Age, race, sex, education levels, occupation, and smoking history. Table 1 shows a demographic summary of the UPitt/PDoH TMI cohort. The mean age at the time of census registration was 32.9 years. Approximately 97% of the cohort was white; 2.8% was of other races. A total of 5,150 (46.1%) males and 5,858 (50.0%) females [is greater than or equal to] 18 years of age graduated from high school. An additional 1,384 (12.4%) males and 850 (7.3%) females attained an advanced degree. Approx-imately 34% of those in the cohort [is greater than or equal to] 18 years of age were current or past smokers. A total of 768 (6.7%) men and 350 (3.0%) women reported working in radiation-related jobs (nuclear plant, other nuclear-related industry, or medical profession). Table 1. Demographic summary of the PDoH TMI cohort.
1979 cohort(a) 1992 cohort(a)
Persons (n) 32,135 28,456
Households (n) 11,832 10,320
Mean age (years) 32.9 41.5
Median age (years) 29.0 39.0
White (%) 97.2 97.2
Smokers (%) 33.8 28.0
(a) After exclusionary criteria were applied. Estimated radiation levels on the day of the accident. Figure 1 shows the maximum and likely [Gamma]-radiation levels for the UPitt/PDoH TMI cohort during the 10 days after the accident (4). Approximately 15% (5,032 individuals) were exposed to [is greater than] 40 mrem (0.4 mSv) maximum [Gamma]-radiation (the equivalent of approximately three chest X rays). The average likely [Gamma]-dose was 10.4 mrem (0.10 mSv), with 3,539 individuals (11.1%) exposed to [is greater than] 20 mrem (0.20 mSv). Less than 2.1% received the highest levels of estimated maximum or likely [Gamma]-radiation. [Figure 1 ILLUSTRATION OMITTED] Figure 2 presents the mean likely 10-day cumulative whole-body [Gamma]-dose in millirems within a 5-mile radius of the TMI area by civil division. The highest exposures were reported in Lower Swatara, Royalton, and Goldsboro. [Figure 2 ILLUSTRATION OMITTED] Natural background radiation exposure before the TMI accident. Figure 3 presents crude estimates of natural background radiation exposure for the TMI area. The quartiles of exposure for the UPitt/PDoH TMI cohort lie largely in the first three categories: low (5.7-7.2 [micro]R/hr), low medium (7.3-7.9 [micro]R/hr), and high medium (8.0-8.7 [micro]R/hr). The highest quartile (8.8-10.5 [micro]R/hr) is largely outside of the 5-mile radius, and the high-medium exposure area lies mainly in the northwest and southeast quadrants, which are not close in proximity to the TMI plant. The majority of the individuals in the UPitt/PDoH cohort resided in the lowest background exposure areas. [Figure 3 ILLUSTRATION OMITTED] General mortality patterns. We examined the general mortality experience of the UPitt/PDoH TMI cohort to assess relationships between mortality and exposure to radiation from the TMI accident. Table 2 shows observed deaths and SMRs for males and females during the 1979-1992 study period. There was a total of 1,934 male deaths, which resulted in slightly elevated overall mortality when compared to the general population of the three-county aggregate (SMR = 109, p [is less than] 0.05). Deaths due to heart disease were also significant (SMR = 116, p [is less than] 0.05). A total of 1,925 female deaths yielded a statistically significant excess in overall mortality (SMR = 118, p [is less than] 0.05). Females also exhibited an excess in all heart disease (SMR = 130, p [is less than] 0.05). Nonmalignant respiratory disease Noun 1. respiratory disease - a disease affecting the respiratory system respiratory disorder, respiratory illness adult respiratory distress syndrome, ARDS, wet lung, white lung - acute lung injury characterized by coughing and rales; inflammation of the was also significantly higher in females (SMR = 124, p [is less than] 0.05). Total and cause-specific mortality rates cause-specific mortality rate Epidemiology The mortality rate from a specified cause for a population; the numerator is the number of deaths attributed to a specific cause during a specified time interval; the denominator is the size of the population at the were also compared to the state of Pennsylvania as a whole and to a new state comparison that excluded Philadelphia County (data not shown). Similar results were found. Table 2. Observed (Obs) and [SMR.sub.c] (SMR based on corresponding county rates rates levied upon the county, and collected by the boards of guardians, for the purpose of defraying the expenses to which counties are liable, such as repairing bridges, jails, etc. See also: County ) for specific causes of death, PDoH TMI cohort, 1979-1992 for Pennsylvania three-county comparison, white males and females.
Total mortality
White males
(n = 15,539)(a)
Cause of death Obs [SMR.sub.c]
All causes of death 1,934 109(*)
All malignant neoplasm 423 100
Respiratory system cancer 151 106
Central nervous system cancer - -
Breast cancer 2 311
Thyroid cancer - -
Leukemia 19 115
All other lymphopoietic cancer 18 100
Nonmalignant respiratory disease 156 110
All heart disease 817 116(*)
All external causes 156 109
Total mortality
White females
(n = 15,707(b)
Cause of death Obs [SMR.sub.c]
All causes of death 1,925 118(*)
All malignant neoplasm 384 101
Respiratory system cancer 58 103
Central nervous system cancer - -
Breast cancer 78 102
Thyroid cancer - -
Leukemia 17 108
All other lymphopoietic cancer 24 125
Nonmalignant respiratory disease 126 124(*)
All heart disease 853 130(*)
All external causes 61 109
(a) 200,092.9 person-years. (b) 202,608.3 person-years. (*) p < 0.05. Mortality patterns by exposure variables. Tables 3-5 show sex-specific SMRs for the radiation exposure variables for those [is greater than or equal to] 18 years of age. The lowest exposure group in the maximum and likely [Gamma]-categories ([is less than] 8 and [is less than] 3 mrem, or [is less than] 0.08 and [is less than] 0.03 mSv, respectively) exhibited significant excesses in overall mortality for males and females [SMRs = 122.2 and 122.4; SMRs = 142.3 and 142.7 (p [is less than] 0.01)]. In women, individuals in the highest maximum and likely [Gamma]-exposure groups also showed an increased SMR [[is greater than or equal to] 35 and [is greater than or equal to] 16 mrem (0.35 and [is greater than or equal to] 0.16 mSv); SMR = 123.2 and 122.9, respectively (p [is less than] 0.01)]. Table 3. Observed (Obs) and SMRs for selected causes of death,(a) UPitt/PDoH TMI cohort, white males,(b) 1979-1992.
All causes
Risk factor Obs SMR CI
Background radiation
Low 660 108.2(*) 100.1-116.8
Low medium 860 107.2(*) 100.1-114.6
High medium 405 108.1(*) 97.8-119.1
Maximum gamma
< 8 mrem 558 122.2(*) 112.3-132.8
8-19 mrem 538 108.0(*) 99.1-117.5
20-34 mrem 406 95.3 86.2-105.0
[is greater than 432 105.0 95.4-115.4
or equal to] 35 mrem
Likely gamma
< 3 mrem 533 122.4(**) 112.2-133.2
3-7 mrem 432 104.0 94.4-114.2
8-15 mrem 501 99.2 90.7-108.3
[is greater than 468 107.4 97.9-117.6
or equal to] 16 mrem
All heart causes
Risk factor Obs SMR CI
Background radiation
Low 279 115.5(*) 102.4-129.9
Low medium 358 112.4(*) 101.0-124.7
High medium 177 122.1(*) 104.7-141.4
Maximum gamma
< 8 mrem 252 135.1(*) 118.9-152.9
8-19 mrem 221 114.5(*) 99.9-130.7
20-34 mrem 168 100.0 85.4-116.3
[is greater than 176 110.5 94.7-128.0
or equal to] 35 mrem
Likely gamma
< 3 mrem 233 131.9(**) 115.5-149.9
3-7 mrem 182 112.5 96.8-130.1
8-15 mrem 205 103.5 89.8-118.7
[is greater than 197 115.7(*) 100.1-133.0
or equal to] 16 mrem
All malignancies
Risk factor Obs SMR CI
Background radiation
Low 137 92.6 77.7-109.5
Low medium 188 101.4 87.4-117.0
High medium 96 106.3 86.1-129.9
Maximum gamma
< 8 mrem 116 116.4 96.2-139.6
8-19 mrem 114 91.9 75.8-110.4
20-34 mrem 98 96.5 78.3-117.6
[is greater than 95 95.5 77.3-116.8
or equal to] 35 mrem
Likely gamma
< 3 mrem 103 109.7 89.6-133.1
3-7 mrem 102 100.6 82.1-122.2
8-15 mrem 119 96.1 79.6-115.0
[is greater than 10 93.7 76.1-114.0
or equal to] 16 mrem
BTL cancer
Risk factor Obs SMR CI
Background radiation
Low 48 100.6 74.2-133.4
Low medium 56 96.6 72.9-125.4
High medium 43 146.9(*) 106.3-197.9
Maximum gamma
< 8 mrem 44 148.1(*) 107.6-198.8
8-19 mrem 37 90.2 63.5-124.3
20-34 mrem 35 108.0 75.2-150.2
[is greater than 31 96.2 65.4-136.6
or equal to] 35 mrem
Likely gamma
< 3 mrem 39 141.0(*) 100.3-192.8
3-7 mrem 31 93.8 63.7-133.1
8-15 mrem 42 104.0 74.9-140.6
[is greater than 35 102.2 71.2-142.1
or equal to] 16 mrem
All lymphatic and
hematopoetic
Risk factor Obs SMR CI
Background radiation
Low 10 69.7 33.4-128.3
Low medium 27 148.6 97.9-216.2
High medium 6 66.7 24.5-145.2
Maximum gamma
< 8 mrem 10 104.2 50.0-191.6
8-19 mrem 8 65.5 28.3-129.0
20-34 mrem 13 130.7 69.6-223.5
[is greater than 12 121.7 62.9-212.6
or equal to] 35 mrem
Likely gamma
< 3 mrem 9 98.4 45.0-186.7
3-7 mrem 10 100.2 48.0-184.2
8-15 mrem 15 124.0 69.4-204.5
[is greater than 9 86.5 39.6-164.3
or equal to] 16 mrem
CNS cancers
Risk factor Obs SMR CI
Background radiation
Low 2 59.3 7.2-214.2
Low medium 3 68.6 14.2-200.4
High medium 1 43.4 1.1-241.7
Maximum gamma
< 8 mrem 2 92.6 11.2-334.5
8-19 mrem 2 64.9 7.8-234.4
20-34 mrem 2 84.7 10.2-306.0
[is greater than 0 - -
or equal to] 35 mrem
Likely gamma
< 3 mrem 2 98.8 12.0-356.9
3-7 mrem 1 39.9 1.0-222.4
8-15 mrem 3 101.4 20.9-296.2
[is greater than 0 - -
or equal to] 16 mrem
(a) Adjusted by age. (b) As compared to the Pennsylvania three-county comparison. (*) p < 0.05. (**) p < 0.01. Table 4. Observed (Obs) and SMRs for selected causes of death,(a) UPitt/PDoH TMI cohort, white females,(b) 1979-1992.
All causes
Risk factor Obs SMR CI
Background radiation
Low 654 101.6 94.0-109.7
Low medium 908 128.6(**) 120.4-137.3
High medium 358 130.8(**) 117.6-145.0
Maximum gamma
< 8 mrem 682 142.3(**) 131.8-153.4
8-19 mrem 425 102.7 93.2-113.0
20-34 mrem 399 101.9 92.1-112.4
[is greater than 419 123.2(**) 111.7-135.6
or equal to] 35 mrem
Likely gamma
< 3 mrem 676 142.7(**) 132.2-153.9
3-7 mrem 306 102.0 90.9-114.1
8-15 mrem 496 101.7 93.0-111.1
[is greater than 447 122.9(**) 111.8-134.8
or equal to] 16 mrem
All heart causes
Risk factor Obs SMR CI
Background radiation
Low 288 111.6 99.1-125.3
Low medium 415 143.7(**) 130.2-158.2
High medium 148 144.7(**) 122.3-170.0
Maximum gamma
< 8 mrem 355 171.7(**) 154.3-190.5
8-19 mrem 163 103.7 88.4-120.9
20-34 mrem 167 107.6 91.9-125.2
[is greater than 168 128.7(**) 110.0-149.7
or equal to] 35 mrem
Likely gamma
< 3 mrem 358 174.6(**) 157.0-193.6
3-7 mrem 105 94.7 77.4-114.6
8-15 mrem 209 108.2 94.1-124.0
[is greater than 181 128.7(**) 110.6-148.9
or equal to] 16 mrem
All malignancies
Risk factor Obs SMR CI
Background radiation
Low 135 90.0 75.5-106.6
Low medium 172 111.1 80.3-128.3
High medium 74 102.2 95.1-129.0
Maximum gamma
< 8 mrem 99 107.0 86.9-130.2
8-19 mrem 102 96.0 78.3-116.5
20-34 mrem 91 98.2 79.1-120.6
[is greater than 92 106.8 86.1-131.0
or equal to] 35 mrem
Likely gamma
< 3 mrem 86 95.9 76.7-118.4
3-7 mrem 88 109.2 87.6-134.6
8-15 mrem 110 94.9 78.0-114.3
[is greater than 100 109.4 89.0-133.1
or equal to] 16 mrem
BTL cancer
Risk factor Obs SMR CI
Background radiation
Low 21 93.4 57.8-142.7
Low medium 22 100.3 62.8-151.8
High medium 12 106.9 55.2-186.8
Maximum gamma
< 8 mrem 14 114.6 62.7-192.3
8-19 mrem 17 103.1 60.1-165.1
20-34 mrem 9 65.0 29.7-123.4
[is greater than 16 121.3 69.3-197.0
or equal to] 35 mrem
Likely gamma
< 3 mrem 12 102.9 53.2-179.8
3-7 mrem 19 149.7 90.1-233.7
8-15 mrem 10 57.3 27.5-105.4
[is greater than 15 107.6 60.2-177.5
or equal to] 16 mrem
All lymphatic and
hematopoetic
Risk factor Obs SMR CI
Background radiation
Low 13 81.0 43.1-138.5
Low medium 23 140.2 88.9-210.3
High medium 11 146.4 73.1-261.9
Maximum gamma
< 8 mrem 15 149.9 83.9-247.2
8-19 mrem 13 116.7 62.1-199.5
20-34 mrem 13 131.9 70.2-225.5
[is greater than 7 77.7 31.2-160.0
or equal to] 35 mrem
Likely gamma
< 3 mrem 12 122.0 63.1-213.2
3-7 mrem 12 143.9 74.4-251.5
8-15 mrem 14 113.7 62.2-190.8
[is greater than 10 104.8 50.2-192.7
or equal to] 16 mrem
CNS cancers
Risk factor Obs SMR CI
Background radiation
Low 2 62.0 7.5-224.0
Low medium 7 198.2 79.7-408.4
High medium 3 166.2 34.3-485.6
Maximum gamma
<8 mrem 2 106.4 12.9-384.4
8-19 mrem 5 195.3 63.4-455.8
20-34 mrem 2 95.4 11.5-344.6
[is greater than 3 146.7 30.3-428.7
or equal to] 35 mrem
Likely gamma
< 3 mrem 2 108.5 13.1-392.0
3-7 mrem 4 199.4 54.3-510.6
8-15 mrem 3 115.8 23.9-338.4
[is greater than 3 140.1 28.9-409.4
or equal to] 16 mrem
(a) Adjusted by age. (b) As compared to the Pennsylvania three-county comparison. (**) p < 0.01. Table 5. SMRs for breast cancer,(a) PDoH TMI cohort, white females,(b) 1979-1992.
Breast cancer
Risk factor Obs SMR CI
Background radiation
Low 33 113.1 77.8-158.8
Low medium 31 98.5 66.9-139.9
High medium 14 92.5 50.6-155.0
Maximum gamma
< 8 mrem 16 88.2 50.4-143.2
8-19 mrem 22 101.3 63.5-153.3
20-34 mrem 19 103.0 62.0-160.8
[is greater than or 21 119.4 73.9-182.6
equal to] 35 mrem
Likely gamma
< 3 mrem 11 63.2 31.6-113.2
3-7 mrem 18 107.2 63.5-169.3
8-15 mrem 24 103.9 66.6-154.7
[is greater than or 25 134.2 86.9-198.1
equal to] 16 mrem
Obs, observed. (a) Adjusted by age. (b) As compared to the Pennsylvania three-county comparison. Although significantly elevated (p [is less than] 0.05), SMRs for all heart disease did not increase by natural background radiation level in males. Women in the low-medium and high-medium natural background exposure categories displayed significantly elevated SMRs for all heart disease (p [is less than] 0.01). No relationship was noted between increasing maximum and likely [Gamma]-exposure and increasing SMRs for both males and females. Males in the high-medium natural background area showed increases in SMRs for BTL cancers (SMR = 146.9, p [is less than] 0.05); the lowest maximum and likely [Gamma]-levels also showed increases in SMRs for BTL cancers [SMRs = 148.1 and 141.0 (p [is less than] 0.05)]. No significant relationship was observed in all malignancies, LHT cancers, and CNS cancers for men or women. RR regression. Tables 6 and 7 show the results from the RR regression modeling for males and females. The RRs and associated CIs are shown for each cause of interest, along with a global p-value and a trend p-value where appropriate. Univariate models for smoking and education were fit but are not shown. If the confounder con·found tr.v. con·found·ed, con·found·ing, con·founds 1. To cause to become confused or perplexed. See Synonyms at puzzle. 2. was a significant predictor of risk, multivariate The use of multiple variables in a forecasting model. models were fit adjusting for the confounder. Additionally, all maximum and likely [Gamma]-models were adjusted for level of background radiation exposure. Table 6. Summary of RR regression modeling, white males, 18+ years of age, 1979-1992.(a)
Background, RR (CI)
Cause of
death Low Low medium High medium
All malignant 1.00 1.14 1.14
neoplasm (0.90-1.45) (0.86-1.51)
G p = 0.49
All malignant 1.00 1.14 1.14
neoplasm(c) (0.89-1.44) (0.86-1.51)
G p = 0.52
BTL cancer 1.00 1.03 1.55
(0.69-1.55) (1.00-2.41)
G p = 0.10; T p = 0.06
BTL cancer(d) 1.00 1.01 1.42
(0.66-1.53) (0.90-2.21)
G p = 0.22; T p = 0.14
LHT cancer 1.00 2.41 0.83
(0.99-5.84) (0.24-2.89)
G p = 0.04
CNS cancer(e) 1.00 0.99 0.99
(0.11-12.22) (0.01-22.65)
G p = 0.9999
All heart 1.00 0.97 1.10
disease (0.82-1.16) (0.90-1.35)
G p = 0.47
All heart 1.00 0.91 1.05
disease(d) (0.76-1.08) (0.85-1.30)
G p = 0.30
Maximum [Gamma] (mrem),(b) RR (CI)
[is greater
Cause of than or
death < 8 8-19 20-34 equal to] 35
All malignant 1.00 0.76 0.89 0.78
neoplasm (0.56-1.03) (0.63-1.24) (0.57-1.05)
G p = 0.22
All malignant 1.00 0.8 0.93 0.80
neoplasm(m) (0.58-1.08) (0.66-1.31) (0.59-1.09)
G p = 0.34
BTL cancer 1.00 0.63 0.73 0.59
(0.38-1.04) (0.42-1.27) (0.36-0.97)
G p = 0.15
BTL cancer(d) 1.00 0.72 0.84 0.68
(0.43-1.21) (0.48-1.48) (0.41-1.14)
G p = 0.44
LHT cancer 1.00 1.55 3.40 2.71
(0.47-5.17) (1.06-10.92) (0.88-8.30)
G p = 0.12
CNS cancer(e) 1.00 1.15 1.46 --
(0.07-17.82) (0.06-32.66)
G p = 0.999; T p = 0.999
All heart 1.00 0.93 0.69 0.78
disease (0.74-1.17) (0.53-0.90) (0.62-0.99)
G p = 0.01
All heart 1.00 1.05 0.77 0.84
disease(d) (0.83-1.33) (0.59-1.01) (0.66-1.07)
G p = 0.04
Likely [Gamma] (mrem),(b) RR (CI)
[is greater
Cause of than or equal
death 3 3-7 8-15 to] 16
All malignant 1.00 0.85 0.88 0.79
neoplasm (0.63-1.14) (0.64-1.22) (0.58-1.08)
G p = 0.50
All malignant 1.00 0.87 0.92 0.81
neoplasm(m) (0.64-1.18) (0.66-1.2) (0.59-1.10)
G p = 0.56
BTL cancer 1.00 0.68 0.76 0.67
(0.41-1.14) (0.45-1.30) (0.41-1.09)
G p = 0.24
BTL cancer(d) 1.00 0.72 0.80 0.72
(0.43-1.21) (0.46-1.39) (0.44-1.18)
G p = 0.53
LHT cancer 1.00 0.91 2.18 1.30
(0.28-2.87) (0.75-6.29) (0.42-4.12)
G p = 0.88
CNS cancer(e) 1.00 0.71 1.67 --
(0.01-16.03) (0.12-28.97)
G p = 0.85
All heart 1.00 0.96 0.82 0.87
disease (0.77-1.20) (0.64-1.05) (0.69-1.09)
G p = 0.47
All heart 1.00 1.07 0.91 0.92
disease(d) (0.85-1.35) (0.71-1.17) (0.73-1.17)
G p = 0.50
Abbreviations: G, global; T, trend, (a) Risk sets were adjusted to include only individuals born within 1 month of the corresponding case. (b) Models for maximum and likely [Gamma] were adjusted for background. (c) Model adjusted by smoking status. (d) Model adjusted by smoking status and educational level. (e) Exact models used due to small numbers of observed deaths. Table 7. Summary of RR regression modeling, white females, 18+ years of age, 1979-1992.(a)
Background, RR (CI)
Cause of
death Low Low medium High medium
All malignant 1.00 1.26 1.15
neoplasm (0.99-1.60) (0.86-1.55)
G p = 0.16
All malignant 1.00 1.29 1.16
neoplasm(c) (1.01-1.64) (0.86-1.56)
G p = 0.11
BTL cancer 1.00 1.24 1.31
(0.66-2.31) (0.63-2.72)
G p = 0.71; T p = 0.43
BTL cancer(c) 1.00 1.24 1.18
(0.66-2.33) (0.56-2.52)
G p = 0.78
LHT cancer(d) 1.00 2.15 2.04
(0.99-4.92) (0.76-5.36)
G p = 0.09
CNS cancer(e) 1.00 4.24 1.23
(0.76-48.87) (0.08-18.12)
G p = 0.10
Breast cancer 1.00 0.74 0.83
(0.44-1.25) (0.43-1.60)
G p = 0.53
All heart 1.00 1.23 1.30
disease (1.04-1.46) (1.05-1.61)
G p = 0.02; T p = 0.007
All heart 1.00 1.07 1.21
disease(f) (0.89-1.28) (0.97-1.50)
G p = 0.24; T p = 0.10
Maximum [Gamma] (mrem),(b) RR (CI)
[is less
Cause of than or
death < 8 8-19 20-34 equal to] 35
All malignant 1.00 0.84 0.93 1.05
neoplasm (0.60-1.16) (0.65-1.32) (0.76-1.44)
G p = 0.54
All malignant 1.00 0.84 0.94 1.05
neoplasm(m) (0.60-1.16) (0.66-1.34) (0.76-1.44)
G p = 0.53
BTL cancer 1.00 0.78 0.46 1.00
(0.34-1.80) (0.17-1.17) (0.45-2.20)
G p = 0.25
BTL cancer(c) 1.00 0.81 0.49 0.92
(0.35-1.88) (0.18-1.31) (0.40-2.10)
G p = 0.44
LHT cancer(d) 1.00 1.00 1.52 0.56
(0.40-2.45) (0.58-3.99) (0.20-1.57)
G p = 0.31
CNS cancer(e) 1.00 1.82 1.48 2.24
(0.23-22.53) (0.08-25.75) (0.24-28.01)
G p = 0.84
Breast cancer 1.00 1.02 1.20 1.40
(0.47-2.20) (0.53-2.71) (0.67-2.93)
G p = 0.77; T p = 0.30
All heart 1.00 0.59 0.55 0.69
disease (0.46-0.75) (0.42-0.71) (0.55-0.86)
G (p < 0.001)
All heart 1.00 0.67 0.64 0.75
disease(d) (0.52-0.86) (0.49-0.84) (0.60-0.95)
G (p = 0.005)
Likely [Gamma] (mrem),(b) RR (CI)
[is greater
Cause of than or equal
death 3 3-7 8-15 to] 16
All malignant 1.00 1.14 1.08 1.25
neoplasm (0.82-1.58) (0.76-1.52) (0.90-1.73)
G p = 0.55
All malignant 1.00 1.14 1.10 1.27
neoplasm(m) (0.82-1.60) (0.78-1.56) (0.92-1.76)
G p = 0.53
BTL cancer 1.00 1.45 0.44 1.00
(0.66-3.16) (0.17-1.13) (0.46-2.62)
G p = 0.03
BTL cancer(c) 1.00 1.73 0.52 1.09
(0.77-3.92) (0.20-1.34) (0.46-2.62)
G p = 0.03
LHT cancer(d) 1.00 1.20 1.32 0.91
(0.49-2.96) (0.50-3.52) (0.35-2.39)
G p = 0.88
CNS cancer(e) 1.00 3.62 3.64 3.75
(0.34- (0.25- (0.29-204.09)
186.92 213.62)
G p = 0.55; T p = 0.02
Breast cancer 1.00 1.76 1.76 2.42
(0.76-4.08) (0.73-4.22) (1.07-5.46)
G p = 0.17; T p = 0.02
All heart 1.00 0.49 0.59 0.66
disease (0.38-0.63) (0.46-0.75) (0.53-0.82)
G p < 0.001
All heart 1.00 0.54 0.68 0.72
disease(d) (0.42-0.70) (0.53-0.87) (0.58-0.90)
G p < 0.001
Abbreviations: G, global; T, trend. (a) Risk sets were adjusted to include only individuals born within 1 month of the corresponding case. (b) Models for maximum and likely [Gamma] were adjusted for background. (c) Model adjusted by smoking status. (d) Model adjusted by education status. (e) Exact models used due to small numbers of observed deaths. (f) Model adjusted by smoking status and educational level. As shown in Table 6, even though background exposure was not a significant predictor of male cancer risk, the RRs for the low-medium and high-medium groups were elevated (RRs = 1.00, 1.14, and 1.14, respectively). Neither maximum [Gamma]-exposure nor likely [Gamma]-exposures were significant predictors of cancer risk with RRs [is less than] 1. Because smoking was a significant individual predictor of cancer mortality, the models adjusting for smoking were also fit for the three exposure-related risk factors. No significant predictors were noted after adjusting for smoking, although the individual RRs for external background exposure (with adjustment for smoking) were still elevated (RRs = 1.00, 1.14, and 1.14). Although not shown, both smoking and education were univariate significant predictors of risk (p [is less than] 0.001 and p = 0.03, respectively) for male BTL cancer. The individual RRs for natural background level of exposure exhibited an increasing trend (RRs = 1.00, 1.03, and 1.55; p = 0.06). This trend in the estimates for background exposure was further attenuated Attenuated Alive but weakened; an attenuated microorganism can no longer produce disease. Mentioned in: Tuberculin Skin Test attenuated having undergone a process of attenuation. after controlling for smoking and education (p = 0.14). After adjustment for smoking, education, and background radiation level, neither maximum nor likely [Gamma]-radiation levels were significant predictors of male BTL cancer. The RR models for all cancer of LHT in males show that only natural background exposure was a significant predictor of risk (p = 0.04), with no apparent trend with increasing levels of exposure. Some levels of maximum [Gamma]-exposure were elevated but not statistically significant after adjustment for background radiation exposure. The RR models for cancer of the CNS in males (Table 6) were fit using the exact logistic regression module in LogXact (21) (because of the small number of cases, n = 6). None of the variables was a statistically significant predictor of risk, although some levels of maximum [Gamma]-and likely [Gamma]-exposure were elevated. The CIs on the individual estimates are extremely wide because of data sparseness sparse adj. spars·er, spars·est Occurring, growing, or settled at widely spaced intervals; not thick or dense. [Latin sparsus, past participle of spargere, to scatter. . The RRs for maximum [Gamma]-exposures were suggestive of suggestive of Decision making adjective Referring to a pattern by LM or imaging, that the interpreter associates with a particular–usually malignant lesion. See Aunt Millie approach, Defensive medicine. a protective effect for heart disease in males. Because both smoking and education were significant predictors of heart disease (p [is less than] 0.001), models for the exposure variables were fit controlling for both factors. After adjustment for these confounders as well as for natural background radiation, maximum [Gamma]-radiation remained significant (p = 0.04), but there was no apparent trend. As shown in Table 7, the results for all malignant neoplasms for females show no statistically significant predictors after control for smoking. The results for BTL cancer for females show both the smoking (results not shown) and likely [Gamma]-exposure were significant predictors. Likely gamma exposure remained statistically significant after controlling for smoking and background radiation (p = 0.03). For the models for all LHT in females, only education was a statistically significant predictor of risk (results not shown). Natural background exposure was borderline borderline /bor·der·line/ (-lin) of a phenomenon, straddling the dividing line between two categories. borderline statistically significant (p = 0.09). There were also data sparseness problems with the modeling of CNS cancer in females (Table 7). No individual variables were significant predictors of risk. There were no potential confounders or exposure variables that were statistically significant for female breast cancer. However, there were elevated RRs for both maximum [Gamma]-exposure and likely [Gamma]-exposure that exhibited increasing trends with level of exposure (RRs = 1.00, 1.20, and 1.40; RRs = 1.76, 1.76, and 2.42, maximum and likely, respectively). Only the trend for likely [Gamma]-exposure was statistically significant. For heart disease in females (Table 7), all risk factors were individually statistically significant. Risk estimates for background exposure were elevated with a statistically significant trend apparent (estimated risk ratios were 1.00, 1.23, and 1.30, respectively; trend p = 0.007). After controlling for smoking and education, this association was attenuated and no longer significant. Maximum [Gamma]- and likely [Gamma]-exposures both exhibited a significant negative association with all heart disease when environmental background was included as a confounder. These relationships remained significantly negative after additional control for education and smoking (p = 0.005; p [is less than] 0.001, respectively). Discussion The current study presents the most extensive follow-up of the mortality experience of the 32,135 individuals living within a 5-mile radius of the TMI reactor Reactor (electricity) A device for introducing an inductive reactance into a circuit. Inductive reactance x is a function of the product of frequency f and inductance L; thus, x = 2πfL. facility at the time of the accident. In 1992, the lost-to-follow-up of this cohort was negligible  This article or section is written like a personal reflection or and may require .Please [ improve this article] by rewriting this article or section in an . (n = 121). The overall mortality experience from all causes for the UPitt/PDoH TMI cohort was significantly higher than the mortality experience of the surrounding three-county area. However, the largest contributor to overall mortality was all heart disease, accounting for 1,670 of the 3,859 total deaths (43.3%). There was no elevation elevation, vertical distance from a datum plane, usually mean sea level to a point above the earth. Often used synonymously with altitude, elevation is the height on the earth's surface and altitude, the height in space above the surface. in mortality due to all malignant neoplasm neoplasm or tumor, tissue composed of cells that grow in an abnormal way. Normal tissue is growth-limited, i.e., cell reproduction is equal to cell death. for males or females in the UPitt/PDoH TMI cohort (SMR = 100 and 101, respectively). The SMR for heart disease was significantly elevated for both males and females. SMRs were not adjusted for any of the confounding factors. An earlier PDoH mortality study (6) also reported an increase for all heart disease deaths. No control was made for confounding factors in that investigation. Only 20% of the UPitt/PDoH TMI cohort who were [is greater than or equal] 18 years of age at the time of the accident had some education beyond high school, as compared to 34% in the three-county comparison group (22). There are known increases in cardiovascular disease Cardiovascular disease Disease that affects the heart and blood vessels. Mentioned in: Lipoproteins Test cardiovascular disease risk factors (such as smoking, obesity obesity, condition resulting from excessive storage of fat in the body. Obesity has been defined as a weight more than 20% above what is considered normal according to standard age, height, and weight tables, or by a complex formula known as the body mass index. , alcohol, etc.) by education level that may account for some of this increase. When controlling for confounders and radiation factors in the current RR regression analysis In statistics, a mathematical method of modeling the relationships among three or more variables. It is used to predict the value of one variable given the values of the others. For example, a model might estimate sales based on age and gender. for all heart disease, the elevations in risk were no longer apparent. We selected the four specific cancer sites (cancers of the BTL, lymph lymph Pale fluid that bathes tissues, maintaining fluid balance and removing bacteria. It enters the blood system at a vein under the collarbone that it reaches via channels and ducts, being driven through them mainly by surrounding muscle activity. and hematopoetic tissue, CNS, and breast) for further examination because of previously documented increases in mortality in other studies of low-level radiation exposure (15). Cancer of the thyroid thyroid /thy·roid/ (thi´roid) 1. the thyroid gland; see under gland. 2. pertaining to the thyroid gland. 3. scutiform. 4. was also initially chosen because of its radiosensitive nature (23-26). However, there were no deaths from thyroid cancer Thyroid Cancer Definition Thyroid cancer is a disease in which the cells of the thyroid gland become abnormal, grow uncontrollably, and form a mass of cells called a tumor. in this cohort. There was a significant overall effect for natural background radiation exposure in the low--medium category (RR = 2.41) for cancers of the LHT in males. However, there is no dose--response relationship of LHT and increased background levels. Hence, this relationship is probably due to other confounders or risk factors not accounted for in this analysis. We observed a borderline significant increasing trend in risk with increasing natural background radiation for lung cancer in males, which is similar to the findings of Hatch et al. (10). After adjusting for smoking status and education level in our study, this trend was further attenuated (p = 0.14). Higher mean levels of indoor radon exposure have been documented in the TMI geographic area (27). It has been suggested that indoor radon concentrations, a known risk factor for lung cancer (15,16), may be correlated cor·re·late v. cor·re·lat·ed, cor·re·lat·ing, cor·re·lates v.tr. 1. To put or bring into causal, complementary, parallel, or reciprocal relation. 2. with natural background radiation (28). Thus, it is conceivable con·ceive v. con·ceived, con·ceiv·ing, con·ceives v.tr. 1. To become pregnant with (offspring). 2. that the observed increase in risk may be associated with indoor radon exposure. A significant overall relationship between likely [Gamma]-exposure and BTL cancer was observed in females even after controlling for background radiation exposure, education, and smoking status. However, there was not a consistent dose--response trend in this relationship. Although there was no overall significant effect of likely [Gamma]-exposure to the risk of breast cancer in women, an intriguing in·trigue n. 1. a. A secret or underhand scheme; a plot. b. The practice of or involvement in such schemes. 2. A clandestine love affair. v. finding of this study was a significant linear trend in the RR regression for day-of-the-accident likely [Gamma]-exposure and breast cancer mortality (p = 0.02) and a nonsignificant non·sig·nif·i·cant adj. 1. Not significant. 2. Having, producing, or being a value obtained from a statistical test that lies within the limits for being of random occurrence. trend for maximum [Gamma]-exposure (p = 0.30). There is a well-established relationship of ionizing radiation and breast cancer risk that has been demonstrated in numerous studies, (15,16,29-32). However, all of these studies reflect considerably higher absorbed doses ab·sorbed dose n. The quantity of radiation energy, expressed in rads, that is administered or absorbed per unit mass of target. absorbed dose than those in the present study. The precise levels of risk associated with low doses and low-dose rates remain uncertain (15,16,29). In addition, the current study did not gather information on parity parity or space parity, in physics, quantity that refers to the relationship between an object or process and the image that it can produce in a mirror. , age at menarche menarche /me·nar·che/ (me-nahr´ke) establishment or beginning of the menstrual function.menar´cheal me·nar·che n. The first menstrual period, usually during puberty. , radiation therapy, and family history of breast cancer, which are all well known breast cancer risk factors. Additional follow-up studies such as a nested case--control design may be warranted if the present trend of an increase in breast cancer risk with accident emissions continues over time. Additional radioactivity exposure from the TMI accident included a [Beta]-radiation dose of the released noble gases to the skin and the internal dose from the inhaled in·hale v. in·haled, in·hal·ing, in·hales v.tr. 1. To draw (air or smoke, for example) into the lungs by breathing; inspire. 2. and digested radionuclides, [Beta]-Radiation is less penetrative pen·e·tra·tive adj. 1. Tending to penetrate; penetrant. 2. Displaying keen insight; acute. Adj. 1. penetrative than [Gamma]-radiation and has a shorter range in air (30 inches for xenon-133). Considering shelter, clothing, and other shielding factors, the health impact from [Beta]-radiation was substantially reduced to an unknown extent (33). The internal dose was estimated to constitute no more than 0.4-9.4% of the total whole-body dose whole-body dose Radiation oncology Radiation exposure to gamma rays from outside the body, which irradiates the entire body; each organ receives about the same dose. See Dosimetry. (34). Regardless of the uncertainties of estimating, we did not observe any significant health impacts on the population in TMI in the present study. There was one thyroid cancer death among the cohort during this 13-year period. However, the overall SMR was not [is greater than] 1.0 (35). Cancer morbidity patterns may be quite different from mortality patterns. Thus, a continuous surveillance of cancer mortality and morbidity rates morbidity rate n. The proportion of patients with a particular disease during a given year per given unit of population. morbidity rate Epidemiology The number of cases of a particular disease in a unit of population , including thyroid cancer, is currently being conducted among this UPitt/PDoH TMI cohort. In conclusion, the mortality surveillance of this cohort to date does not provide consistent evidence that low-dose radiation releases during the TMI accident had any measurable impact on the mortality experience. Most notably, the increased risk of mortality for heart disease in males and in females, observed overall, was no longer apparent after controlling for confounders and natural external background radiation. However, because the latency period latency period n. In psychoanalytic theory, the fourth stage of psychosexual development, extending from about age 5 to puberty, when a child apparently represses sexual urges and prefers to associate with members of the same sex. for most cancers is 15 years or more, continued follow-up will provide a more comprehensive description of the mortality experience of the people residing in the TMI area at the time of the accident (15). In addition, the PDoH cancer registry A cancer registry is a systematic collection of data about cancer and tumor diseases. The data is collected by Cancer Registrars. Cancer Registrars capture a complete summary of patient history, diagnosis, treatment, and status for every cancer patient in the United States, and will be an invaluable resource in assessing whether the cancer incidence experience of this cohort mirrors the mortality risks seen in the surrounding three-county area. REFERENCES AND NOTES (1.) Gur D, Good WF, Tokuhata GK, Goldhaber MK, Rosen JC, Roa GR. 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Estimation estimation In mathematics, use of a function or formula to derive a solution or make a prediction. Unlike approximation, it has precise connotations. In statistics, for example, it connotes the careful selection and testing of a function called an estimator. of the dose to the thyroid and pituitary glands pituitary gland, small oval endocrine gland that lies at the base of the brain. It is sometimes called the master gland of the body because all the other endocrine glands depend on its secretions for stimulation (see endocrine system). and other structures of the head and neck. Phys Med Biol 632-642 (1976). (27.) Cohen cohen or kohen (Hebrew: “priest”) Jewish priest descended from Zadok (a descendant of Aaron), priest at the First Temple of Jerusalem. The biblical priesthood was hereditary and male. B. Compilation and integration of studies of radon levels in U.S. homes by states and counties. Crit Rev Environ Control 22:243-364 (1992). (28.) Fujimoto K. Correlation between indoor radon concentration and dose rate in air from terrestrial Dealing with the earth. See terrestrial link. gamma radiation gamma radiation, high-energy photons emitted as one of the three types of radiation resulting from natural radioactivity. It is the most energetic form of electromagnetic radiation, with a very short wavelength (high frequency). in Japan. Health Phys 75:291-296 (1998). (29.) Boice JD Jr. Ionizing radiation. Cancer Epidemiology and Prevention. 2nd ed (Schottenfeld D, Fraumeni JF, eds. New York New York, state, United States New York, Middle Atlantic state of the United States. It is bordered by Vermont, Massachusetts, Connecticut, and the Atlantic Ocean (E), New Jersey and Pennsylvania (S), Lakes Erie and Ontario and the Canadian province of :Oxford University Press, 1996;319-354. (30.) Darby SC, Nakashima E, Kato H. A parallel analysis of cancer mortality among atomic bomb atomic bomb or A-bomb, weapon deriving its explosive force from the release of atomic energy through the fission (splitting) of heavy nuclei (see nuclear energy). The first atomic bomb was produced at the Los Alamos, N.Mex. survivors and patients with ankylosing spondylitis Ankylosing Spondylitis Definition Ankylosing spondylitis (AS) refers to inflammation of the joints in the spine. AS is also known as rheumatoid spondylitis or Marie-Strümpell disease (among other names). . J Natl Cancer Inst 75(1):1-21 (1985). (31.) Mackenzie I. Breast cancer following multiple fluoroscopies. Br J Cancer 19:1-19 (1965). (32.) Miller AB, Howe GR, Sherman GJ, Lindsay JP, Yaffe MJ, Dinner PA, Risch HA, Preston DL. Mortality from breast cancer after irradiation during fluoroscopic Fluoroscopic (fluoroscopy) An x-ray procedure that produces immediate images and motion on a screen. The images look like those seen at airport baggage security stations. Mentioned in: Hypotonic Duodenography examination in patients being treated for tuberculosis tuberculosis (TB), contagious, wasting disease caused by any of several mycobacteria. The most common form of the disease is tuberculosis of the lungs (pulmonary consumption, or phthisis), but the intestines, bones and joints, the skin, and the genitourinary, . N Engl J Med 321(19):1285-1289 (1989). (33.) Battist L, Buchanan J, Congel F, Nelson C, Nelson M, Paterson H, Rosenstein M. Population Dose and Health Impact of the Accident at the Three Mile Island Nuclear Station. Preliminary Estimates for the Period March 28 through April, 1979. Washington, DC:U.S. Nuclear Regulatory Commission Nuclear Regulatory Commission (NRC), an independent U.S. government commission, created by the Energy Reorganization Act of 1974 and charged with licensing and regulating civilian use of nuclear energy to protect the public and the environment. , 1979. (34.) Kemeny JG, Babbitt B, Haggerty PE, Lewis C, Marks PA, Marrett CB, McBride L, McPherson HC, Peterson RW, Pigford TH, et al. Report of the President's Commission on the Accident at Three Mile Island. Washington, DC:U.S. Government Printing Office, 1979. (35.) Talbott EO, Engberg RA, Murphy, Youk AO, Shire Shire or Shiré (both: shē`rā), river, c.250 mi (400 km) long, flowing from the southern end of Lake Nyasa, Malawi, SE Africa, to the Zambezi River in central Mozambique. It is navigable to Nsanje. J, McHugh KP. Unpublished data. Evelyn O. Talbott,(1) Ada O. Youk,(2) Kathleen P. McHugh,(1) Jeffrey D. Shire,(1) Aimin Zhang,(3) Brian P. Murphy,(1) and Richard A. Engberg(1) (1) Department of Epimediology, (2) Department of Biostatistics, (3) Department of Environmental and Occupation Health, Graduate School of Public Health, University of Pittsburg Pennsylvania, USA Address correspondence to E.O. Talbott, Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, 507 Parran Hall Parran Hall is an academic building on the campus of the University of Pittsburgh on Fifth Avenue in Pittsburgh, Pennsylvania, United States. Parran Hall was completed in 1957, designed by Eggers & Higgins, architects of the Dirksen Senate Office Building,[1] , Pittsburgh, PA 15261 USA. Telephone: (412) 624-3074. Fax: (412) 624-7397. E-mail: eotl+@pop.pitt.edu We thank N. Wald for guidance in the preparation of this manuscript. We also thank K. Ramaswamy and J. Bratz for their early contributions and continuing support of this project. This research was supported by a grant from the Three Mile Island Public Health Fund. Received 30 September 1999; accepted 28 December 1999. |
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