Association of Low Back Pain With Self-Reported Risk Factors Among Patients Seeking Physical Therapy Services.Key Words: Case-control study case-control study, n an investigation employing an epidemiologic approach in which previously existing incidents of a medical condition are used in lieu of gathering new information from a randomized population. , Cross-sectional study cross-sectional study n. See synchronic study. cross-sectional study, n the scientific method for the analysis of data gathered from two or more samples at one point in time. , Low back pain, Odds ratio, Risk factors. Identification of factors that might increase the risk for low back pain (LBP LBP In currencies, this is the abbreviation for the Lebanese Pound. Notes: The currency market, also known as the Foreign Exchange market, is the largest financial market in the world, with a daily average volume of over US $1 trillion. ) may offer a method to reduce LBP-related costs and disability. Some identified risk factors may be reduced or removed through environmental interventions or health education. For risk factors that cannot be removed, identification of groups at increased risk may allow for targeting patient education and back pain prevention programs. Investigators have reported evidence of increase risk of LBP with exposure to a variety of factors, including mechanical stresses such as heavy or frequent lifting,[1-5] prolonged pro·long tr.v. pro·longed, pro·long·ing, pro·longs 1. To lengthen in duration; protract. 2. To lengthen in extent. sitting or standing,[5-7] hours in a vehicle,[1,2,7-9] smoking,[1,2,10,11] vibration exposure,[1,2,4,9] activity level,[1,8,12] pregnancy,[2,8,13,14] and oral contraceptive oral contraceptive n. A pill, typically containing estrogen or progesterone, that prevents conception or pregnancy. Also called birth control pill. use.[15,16] Most of these investigators, however, did not include an estimate of the magnitude of association. Rather, they based their conclusions on significance testing (ie, whether a relationship existed). Among those investigators who included magnitudes of association, the values varied widely. Many researchers also used population-based samples in which subjects with LBP were identified as those with any recollection of LBP in the past year,[7,12] rather than subjects whose symptoms affected their life or work or who used health care dollars. The purpose of this study was to estimate, among a group of patients receiving physical therapy, the magnitude of association between LBP and self-reported factors thought to increase the risk of LBP (risk factors). A patient-based sample was chosen so that the impact of symptoms on health care costs could be seen. All subjects with LBP in this group were seeking medical attention for their LBP and were, therefore, incurring in·cur tr.v. in·curred, in·cur·ring, in·curs 1. To acquire or come into (something usually undesirable); sustain: incurred substantial losses during the stock market crash. 2. associated health care costs. They also incurred at least some time loss as a result of their LBP, which also affected other activities. A comparison group consisted of patients seeking physical therapy services for non-low back-related problems and, consequently, were similar to the subjects with LBP in willingness to seek services, access to services, and potential impact of their problem on health care costs and quality of life. The magnitudes of association were estimated because the magnitudes of association are particularly important as physical therapists attempt to understand the cost-benefit ratios Cost-benefit ratio The net present value of an investment divided by the investment's initial cost. Also called the profitability index. of education programs or the cost-benefit ratios of attempting to modify occupational stresses through ergonomic ergonomic - Concerning ergonomics or exhibitting good ergonimics. interventions. The sample and design used in this study allowed for 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 association between self-reported risk factors and LBP in the group most likely to use health care dollars and, therefore, likely to be the target of risk factor modification and cost-containment strategies. Method Subjects Subjects in this study were recruited as part of a larger study of the association between pelvic pelvic /pel·vic/ (pel´vik) pertaining to the pelvis. pel·vic adj. Of, relating to, or near the pelvis. asymmetry Asymmetry A lack of equivalence between two things, such as the unequal tax treatment of interest expense and dividend payments. and LBP.[17] A clinic-based sample of adult patients seeking physical therapy services was targeted. All subjects were recruited from the same facilities so that those with LBP and those without LBP would be as alike as possible on uncontrolled variables such as geographical distribution the natural arrangements of animals and plants in particular regions or districts. See under Distribution. See also: Distribution Geographic , socioeconomic so·ci·o·ec·o·nom·ic adj. Of or involving both social and economic factors. socioeconomic Adjective of or involving economic and social factors Adj. 1. group, health care access, and willingness to seek medical attention. All subjects were 21 to 50 years of age. Patients referred to physical therapists for treatment of LBP of no more than 1 year in duration were the "cases" in this cross-sectional cross section also cross-sec·tion n. 1. a. A section formed by a plane cutting through an object, usually at right angles to an axis. b. A piece so cut or a graphic representation of such a piece. 2. "case-control Case-control studies are one type of epidemiological study design. It is used to identify factors that may contribute to a medical condition by comparing a group of patients who have that condition with a group of patients that do not. " design. Patients experiencing their current LBP for more than 1 year were excluded because it is believed that the pain and disability experienced by people with LBP become increasingly dissociated dis·so·ci·ate v. dis·so·ci·at·ed, dis·so·ci·at·ing, dis·so·ci·ates v.tr. 1. To remove from association; separate: over time from the original physical basis of the problem.[18] Patients who were being treated by physical therapists for an upper-extremity problem that was not obviously neck- or back-related (eg, thoracic outlet syndrome Thoracic Outlet Syndrome Definition Thoracic outlet syndromes are a group of disorders that cause pain and abnormal nerve sensations in the neck, shoulder, arm, and/or hand. ) served as the comparison group. Patients who were eligible for the comparison group and who reported experiencing limiting LBP in the past year were excluded. Limiting low back pain was defined as LBP that limited activity for more than a few days or for which the patient sought medical care. Sample Size and Recruitment A sample size of 150 subjects with LBP and 150 comparison subjects was targeted. The number of subjects was estimated for the larger study to obtain a power of at least 80%.[17] The sample size estimate was based on a univariate univariate adjective Determined, produced, or caused by only one variable analysis, using the effect size (odds ratio) of 2.0. All subjects were recruited through outpatient outpatient /out·pa·tient/ (-pa-shent) a patient who comes to the hospital, clinic, or dispensary for diagnosis and/or treatment but does not occupy a bed. out·pa·tient n. physical therapy facilities in 7 hospitals and 32 private practices serving a range of inner-city inner city n. The usually older, central part of a city, especially when characterized by crowded neighborhoods in which low-income, often minority groups predominate. and suburban communities in the metropolitan Boston (Mass) area. In some facilities, daily referral information was used to identify potentially eligible subjects. In other facilities, volunteers were sought through study information brochures placed in the waiting room. Follow-up follow-up, n the process of monitoring the progress of a patient after a period of active treatment. follow-up subsequent. follow-up plan telephone calls were used to determine interest and eligibility. Data collection appointments were made at the participating facility most convenient to the subject. Subjects received $25 for their participation. Recruitment and enrollment were continued until the target sample size was reached. Data Collection At the time of data collection, informed consent was obtained and each subject completed a self-administered questionnaire. The questionnaire solicited information on descriptive characteristics and on factors found or suspected in other studies to be associated with LBP. These factors included age; height; weight; average number of hours per week spent sitting, standing, in a trunk A communications channel between two points. It generally refers to a high-bandwidth, fiber-optic line between telephone switching centers (central offices). Telephone "trunks" handle thousands of simultaneous voice and data signals, whereas telephone "lines" are the wires from the , in a car, or exposed to industrial vibration; activity level; smoking status; lifting habits; history of back pain over the past year; and, for female subjects, pregnancy history and oral contraceptive use. Calculation of Odds Ratios The associations between LBP and self-reported risk factors were obtained using an estimated odds ratio (OR) from 2 x 2 contingency tables contingency table n. A statistical table that shows the observed frequencies of data elements classified according to two variables, with the rows indicating one variable and the columns indicating the other variable. . An odds ratio estimates the association between 2 dichotomous di·chot·o·mous adj. 1. Divided or dividing into two parts or classifications. 2. Characterized by dichotomy. di·chot variables, typically with 1 variable being the "disease" (LBP) and 1 factor being an "exposure" (risk factor for LBP). The odds ratio (OR) is constructed as follows: OR = Odds of disease among exposed subjects/Odds of disease among unexposed subjects From this proportion, it can be seen that the odds ratio will be 1.0 if the odds of disease are similar among exposed and unexposed subjects. Odds ratios greater than 1.0 indicate an increased disease risk among exposed subjects, whereas odds ratios less than 1.0 indicate that the exposure reduces disease risk (ie, is "protective"). The Figure shows how the 2 x 2 contingency table is used to calculate the estimated odds ratio. [Figure ILLUSTRATION OMITTED] In this study, rather than dichotomizing the exposure and labeling people simply as exposed or not exposed to a given risk factor for LBP, each risk factor was categorized cat·e·go·rize tr.v. cat·e·go·rized, cat·e·go·riz·ing, cat·e·go·riz·es To put into a category or categories; classify. cat into 2, 3, or 4 levels, depending on the variable and the number of subjects per level. One odds ratio was then calculated to compare each higher level of the risk factor (exposure) with the lowest level of the risk factor (no exposure) among the subjects with LBP (those with the "disease") and the comparison subjects (those without the "disease"). Where there were 4 levels of a risk factor, 3 odds ratios were estimated, comparing 3 higher exposures with the lowest level of exposure. The lowest level of the risk factor was the no-exposure referent ref·er·ent n. A person or thing to which a linguistic expression refers. Noun 1. referent - something referred to; the object of a reference in all analyses except for activity level, where an activity level perceived as similar to others was compared with lower and higher levels of perceived activity. All odds ratios were calculated with 95% confidence intervals 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%. (CIs) using the general formula: exp exp abbr. 1. exponent 2. exponential [ln(OR) [+ or -] 1.96 (SD[lnOR])].[19] The 95% CI is an indication of the precision of the estimated odds ratio. A wide interval indicates a relatively imprecise im·pre·cise adj. Not precise. im  pre·cise ly adv. estimate. The 95% CI also
can be used to estimate statistical probability
"Statistical probability" is a term sometimes used informally as a synonym for frequency probability, which identifies probability with relative frequency over a long series of events or the . When the null value A value in a field or variable that indicates nothing was ever derived and stored in it. For example, in a decimal-based amount field, a null value might be all binary 0s (null characters), but not a decimal 0. for the odds ratio (1.0) lies within the 95% CI, the corresponding probability value for the odds ratio will be greater than .05. The more centrally the null value lies in the interval, the larger the corresponding probability value. If a person were simply to assess whether the null value were in. the 95% CI, there would be no benefit over probability values. The width of the CI, however, indicates how precise, or how "accurate," the estimate might be. An indication of precision of an estimate is not available through a probability value. Possible effect modification effect modification Epidemiology An interaction among multiple possible cause-and-effect relationships, where the estimate of the effect of one factor on a disease process depends on other factors in the study or 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 of the risk factor-LBP relationship by age group and sex was explored. Effect modification exists when subgroups (eg, 2 different age groups) differ on the studied association. Effect. modification, therefore, might be considered analogous analogous /anal·o·gous/ (ah-nal´ah-gus) resembling or similar in some respects, as in function or appearance, but not in origin or development. a·nal·o·gous adj. to an interaction in a factorial factorial For any whole number, the product of all the counting numbers up to and including itself. It is indicated with an exclamation point: 4! (read “four factorial”) is 1 × 2 × 3 × 4 = 24. analysis of variance The discrepancy between what a party to a lawsuit alleges will be proved in pleadings and what the party actually proves at trial. In Zoning law, an official permit to use property in a manner that departs from the way in which other property in the same locality . To explore possible effect modification, the estimated odds ratios for levels of the risk factor with LBP were computed separately for male and female subjects and separately for subjects aged 21 to 34 years and subjects aged 35 to 50 years. If there was effect modification by age group or by sex, the 2 stratum-specific estimates for comparable odds ratios would differ. In such an instance, the primary association would be more validly represented by the stratum-specific estimates. Confounding exists when an uncontrolled variable (eg, sex) is independently related to each of the 2 primary association variables under study (eg, LBP and the risk factor under consideration). The relationship of the 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. to the 2 primary association variables, if uncontrolled, distorts the estimated relationship between the primary variables. If the association between the primary variables differs substantively when the potential confounding variable is controlled, the uncontrolled (referred to as the "crude") estimate is considered to be confounded or biased. In such an instance, the controlled estimate may be considered a more valid estimate of the true association between the primary variables. To control possible confounding of the LBP-risk factor association by age group or sex, a standardized standardized pertaining to data that have been submitted to standardization procedures. standardized morbidity rate see morbidity rate. standardized mortality rate see mortality rate. odds ratio (SOR) was computed across age group or sex strata for each association. If the summary measure (SOR) differs substantively from the crude (uncontrolled) association, confounding of the crude estimate must be considered. A standardized odds ratio standardizes the crude odds ratios to the distribution of sex or age group in the lowest level of the risk factor (calculated as SOR = [[Sigma SIGMA - A scientific visual programming environment from NASA. http://fi-www.arc.nasa.gov/fia/projects/sigma/. ] [a.sub.i][d.sub.i]/[c.sub.i]]/[[Sigma] [b.sub.i]]).[19] Most computations and statistical analyses were conducted using Statistix Analytic an·a·lyt·ic or an·a·lyt·i·cal adj. 1. Of or relating to analysis or analytics. 2. Expert in or using analysis, especially one who thinks in a logical manner. 3. Psychoanalytic. Software for Windows[20](*). and Microsoft Excel (tool) Microsoft Excel - A spreadsheet program from Microsoft, part of their Microsoft Office suite of productivity tools for Microsoft Windows and Macintosh. Excel is probably the most widely used spreadsheet in the world. Latest version: Excel 97, as of 1997-01-14. 7.0.[21]([dagger]) Results Sample A total sample of 150 subjects with LBP and 150 comparison subjects (subjects without LBP) was enrolled over a 27-month period. Data from 4 comparison subjects were discarded dis·card v. dis·card·ed, dis·card·ing, dis·cards v.tr. 1. To throw away; reject. 2. a. To throw out (a playing card) from one's hand. b. because of data recording omissions or incomplete entries. Eight comparison subjects who reported experiencing LBP on the day of testing were also dropped from the data set, yielding a final complement of 150 subjects with LBP and 138 comparison subjects. Descriptive data on the subjects are presented in Table 1. Table 1. Descriptive Statistics descriptive statistics see statistics. for Subject Demographic Characteristics
Subjects Subjects
With LBP(a) Without LBP
Characteristic (n = 150) (n = 138)
Mean age (y) 35.2 35.5
Sex (%)
Male 40.0 39.1
Female 60.0 60.9
Mean height (cm) 171.5 170.3
Mean weight (kg) 74.1 70.8
Acute LBP ([is less than or equal to] 3 59.7%
Chronic LBP (>3-12 mo) 40.3% NA(b)
Oswestry Low Back Pain Disability
Questionnaire score
0%-20% (minimal disability) 59.5% NA
22%-40% (moderate disability) 32.6%
40%-54% (severe disability) 6.8%
(a) LBP = low back pain. (b) NA = not applicable. Association of Low Back Pain and Smoking The crude, stratum-specific, and standardized estimated odds ratios and 95 % CIs for the LBP-smoking association are presented in Table 2. The odds ratios comparing current smokers with those who quit smoking less than 1 year previously, with those who quit smoking I to 2 years previously, and with those who never smoked were all similar. Consequently, only the categories of current smokers and current nonsmokers were retained for subsequent analyses. When current smokers were compared with current nonsmokers, the LBP-smoking association was 2.21 (CI=1.09, 4.46). When data were stratified stratified /strat·i·fied/ (strat´i-fid) formed or arranged in layers. strat·i·fied adj. Arranged in the form of layers or strata. by sex, the LBP-smoking associations were fairly similar. When data were stratified by age group, the associations again were not markedly different. There did not appear to be important effect modification, given the fairly similar stratum-specific estimates. The standardized odds ratios did not indicate any confounding of the LBP-smoking association by sex or age group. Table 2. Association of Low Back Pain With Levels of Self-Reported Risk Factors: Frequencies and Estimated Crude, Stratum-Specific, and Standardized Odds Ratios (OR) With 95% Confidence Intervals (CIs)
Subjects
Subjects Without
With Low
Low Back Back
Pain Pain
Risk Factor Exposure (n = 150) (n = 138)
Smoking status Nonsmoker 122 125
Current smoker 28 13
Male
Nonsmoker 47 49
Current smoker 13 5
Female
Nonsmoker 75 76
Current smoker 15 8
<35 years of age
Nonsmoker 58 55
Current smoker 14 5
35-50 years of age
Nonsmoker 59 69
Current smoker 13 8
Full-term No pregnancies(c) 41 58
vaginal 1 delivery 10 7
delivery 2 deliveries 18 5
[is greater than or
equal to]
3 deliveries 4 5
No pregnancies
vs [is greater
than or equal to] 1
vaginal delivery
<35 years of age
No pregnancies 32 35
[is greater than
or equal to] 1
vaginal delivery 11 4
35-50 years of age
No pregnancies 8 23
[is greater than or
equal to] 1
vaginal delivery 21 13
Vibration < 1 119 133
exposure(d) (h) [is greater than
or equal to] 1 14 3
Time spent <1 (low) 25 46
in a car (h) 1 (moderate) 55 33
>1 (high) 68 58
[is greater
than or
equal to] 1 123 91
Estimated Crude
or Stratum-
Specific OR(a)
Risk Factor Exposure (95% CI)
Smoking status Nonsmoker 2.21 (1.09, 4.46)
Current smoker
Male
Nonsmoker
Current smoker 2.71 (0.90, 8.19)
Female
Nonsmoker
Current smoker 1.90 (0.76, 4.74)
<35 years of age
Nonsmoker
Current smoker 2.66 (0.90, 7.86)
35-50 years of age
Nonsmoker
Current smoker 1.90 (0.74, 4.90)
Full-term No pregnancies(c) Referent
vaginal 1 delivery 2.02 (0.71, 5.75)
delivery 2 deliveries 5.09 (1.75, 14.81)
[is greater than or
equal to]
3 deliveries 1.13 (0.29, 4.47)
No pregnancies
vs [is greater
than or equal to] 1
vaginal delivery 2.66 (1.31,5.42)
<35 years of age
No pregnancies
[is greater than
or equal to] 1
vaginal delivery 3.01 (0.87, 10.39)
35-50 years of age
No pregnancies
[is greater than or
equal to] 1
vaginal delivery 4.64 (1.61, 13.41)
Vibration < 1 Referent
exposure(d) (h) [is greater than
or equal to] 1 5.22 (1.46, 18.59)
Time spent <1 (low) Referent
in a car (h) 1 (moderate) 3.07 (1.60, 5.88)
>1 (high) 2.16 (1.18, 3.93)
[is greater
than or
equal to] 1 2.49 (1.42, 4.34)
Standardized
OR(a)
Risk Factor Exposure (95% CI)
Smoking status Nonsmoker
Current smoker
Male
Nonsmoker
Current smoker 2.21 (1.09, 4.50)
Female
Nonsmoker
Current smoker
<35 years of age
Nonsmoker
Current smoker 2.27 (1.08, 4.78)
35-50 years of age
Nonsmoker
Current smoker
Full-term No pregnancies(c)
vaginal 1 delivery
delivery 2 deliveries
[is greater than or
equal to]
3 deliveries
No pregnancies
vs [is greater
than or equal to] 1
vaginal delivery
<35 years of age
No pregnancies
[is greater than
or equal to] 1
vaginal delivery 3.33 (1.30, 8.54)
35-50 years of age
No pregnancies
[is greater than or
equal to] 1
vaginal delivery
Vibration < 1
exposure(d) (h) [is greater than
or equal to] 1
Time spent <1 (low)
in a car (h) 1 (moderate)
>1 (high)
[is greater
than or
equal to] 1
(a) Association of low back pain and upper level(s) of risk factor compared with referent level at the risk factor. (b) Standardized odds ratios: stratum-specific estimates weighted by the product of the distribution of sex or age groups in the referent level of the risk factor and the rate in that group. (c) No pregnancies of 6 months' duration or longer. (d) Hours of exposure daily. Association of Low Back Pain and Vaginal vag·i·nal adj. 1. Of or relating to the vagina. 2. Relating to or resembling a sheath. vaginal pertaining to the vagina, the tunica vaginalis testis, or to any sheath. Delivery In order to consider whether number of pregnancies or number of vaginal deliveries was associated with LBP, 7 women who had a pregnancy of at least 6 months but less than 9 months in duration were eliminated from the analyses. The small number of such women did not permit control of the potentially confounding factor of number of months of pregnancy. The association between LBP and the number of full-term pregnancies or number of full-term vaginal deliveries was then examined, using those women who had not had a pregnancy of at least 6 months' duration as the referent group. The number of full-term vaginal deliveries was a slightly stronger risk factor than the number of full-term pregnancies (regardless of type of delivery). The crude, stratum-specific, and standardized estimated odds ratios and 95% CIs for the LBP-vaginal delivery association are presented in Table 2. The estimated odds ratio for LBP for the women with one full-term vaginal delivery (as compared with the women with no pregnancies of 6 months' duration or longer) was 2.02 (CI=0.71, 5.75). For women who delivered 2 children vaginally, the odds ratio was 5.09 (CI=1.75, 14.81). For women who delivered 3 or more children vaginally, the odds ratio was 1.13 (CI=0.29, 4.47). Given the wide CIs around these estimates, no conclusions about the presence or absence of a trend of increased risk with more pregnancies should be drawn. To examine the effect of age group and obtain estimates of reasonable precision, categories were collapsed. Women with I or more full-term vaginal deliveries were compared with women with no pregnancies of 6 months or more. The resulting crude odds ratio was 2.66 (CI=1.31, 5.42). Controlling for age group, the odds ratio for women aged 21 to 34 years was 3.01 (CI=0.87, 10.39), whereas the odds ratio for women aged 35 to 50 years was 4.64 (CI=1.61, 13.41). The standardized odds ratio was 3.33 (CI= 1.30, 8.54). There may be weak effect modification and confounding by age group, although the imprecision im·pre·cise adj. Not precise. im pre·cisely adv. of the estimates makes this difficult to assess. The slight
differences in association by age group may suggest that 1 or more
full-term vaginal delivery increases the odds of LBP slightly with
increasing age. The estimate of the association between LBP and vaginal
delivery status is slightly stronger when the age group is controlled.Association of Low Back Pain and Daily Vibration Exposure Subjects were asked to estimate the number of hours on an average day they spent sitting on, standing on, or holding equipment that vibrated heavily (including industrial tools, machines, equipment, chain saws, and mowers). When subjects with less than 1 hour of vibration exposure daily were compared with subjects with 1 hour or more of exposure (Tab. 2), the association of the exposure with LBP was 5.22 (CI=1.46, 18.59). Given the small number of comparison subjects who reported vibration exposure (n=3), stratified analyses were not done. Data for 4 subjects who reported vibration exposure and that they were currently not working or had a reduced workload The term workload can refer to a number of different yet related entities. An amount of labor While a precise definition of a workload is elusive, a commonly accepted definition is the hypothetical relationship between a group or individual human operator and task demands. due to their injury were removed from the analysis, and the odds ratio was recomputed. This analysis was done as the only available mechanism to explore whether the LBP-vibration association might be inflated by differential recall of those subjects with work-related injury claims. The odds ratio with the data for these people removed was 6.15 (CI=1.34, 28.30). Association of Low Back Pain and Hours Spent in a Car Daily The reported number of hours spent in a car daily was categorized into 3 levels (less than 1 hour, 1 hour, and more than 1 hour). The highest stratum stratum /stra·tum/ (strat´um) (stra´tum) pl. stra´ta [L.] a layer or lamina. stratum basa´le ([is greater than] 1 hour) contained 44% of the subjects, but the distribution of subjects precluded further stratification stratification (Lat.,=made in layers), layered structure formed by the deposition of sedimentary rocks. Changes between strata are interpreted as the result of fluctuations in the intensity and persistence of the depositional agent, e.g. . The association of LBP with hours spent in a car daily, using those subjects who spent less than 1 hour in a car daily as the referent group, is shown in Table 2. The estimated odds ratio for LBP among subjects who spent 1 hour in a car daily as compared with subjects who spent less than 1 hour in a car daily was 3.07 (CI=1.60, 5.88). For those subjects who spent more than 1 hour in a car daily, the odds ratio was 2.16 (CI= 1.18, 3.93). The data were then stratified by sex and age group, but no substantive differences in the odds ratios were found. That is, there was neither effect modification nor confounding of the association between LBP and time spent in a car by sex or age group. Because the estimated associations for subjects who spent 1 hour in a car daily and for subjects who spent more than 1 hour in a car daily were fairly similar and the differences in exposure not substantial, the 2 higher categories were collapsed. The resulting association between LBP and spending 1 or more hours in a car daily (as compared with less than 1 hour daily) was 2.49 (CI=1.42, 4.34). Association of Low Back Pain and Other Potential Risk Factors The associations of LBP with hours of sitting daily, hours of standing daily, daily lifting, activity level, and body mass index (BMI BMI body mass index. BMI abbr. body mass index Body mass index (BMI) A measurement that has replaced weight as the preferred determinant of obesity. ) were categorized into their respective quartiles. Odds ratios were computed using the lowest level of exposure as the referent group and are reported in Table 3. Although some of the odds ratios for hours of sitting daily and hours of standing daily were as high as 1.54, the wide CIs around the estimates across increasing levels of exposure appear to indicate that daily sitting and standing were not important risk factors for LBP in this sample. No evidence of either effect modification or confounding by sex or age group was found for either variable. Table 3. Association of Low Back Pain (LBP) With Levels of Self-Reported Risk Factors: Frequencies and Estimated Odds Ratios (OR) With 95% Confidence Intervals (CIs)
Subjects Subjects
With Without
Low Low
Back Back
Pain Pain
Risk Factor Exposure (n = 150) (n = 138)
Hours [is greater
of sitting than or equal to] 4 39 40
>4 [is greater
than or equal to] 6 45 30
>6 [is less
than or equal to] 8 29 42
[is greater
than or equal to] 9 36 26
Hours of standing [is less than
or equal to] 3 46 43
4-5 34 31
6-8 35 37
[is greater
than or equal to] 9 34 27
Daily lifting 10 lb(b) rarely 56 51
10 lb often 34 38
20 lb often 25 24
[is greater
than or equal
to] 35 lb often 34 24
10 lb rarely
Men 19 17
Women 37 34
[is greater than
or equal
to] 35 lb often
Men 18 18
Women 16 6
Activity level Less active 25 18
(compared As active 50 50
with peers) More active 54 50
Much more active 19 20
Body mass <21.5 34 38
index 21.5-23.5 31 38
(kg/[m.sup.2]) 23.6-26.2 38 32
>26.2 44 27
(OR(a) for
LBP:Risk
Risk Factor Exposure Factor
Hours [is greater
of sitting than or equal to] 4 Referent
>4 [is greater
than or equal to] 6 1.54 (0.81, 2.91)
>6 [is less
than or equal to] 8 0.71 (0.37, 1.35)
[is greater
than or equal to] 9 1.42 (0.73, 2.78)
Hours of standing [is less than
or equal to] 3 Referent
4-5 1.03 (0.54, 1.94)
6-8 0.88 (0.47, 1.65)
[is greater
than or equal to] 9 1.18 (0.61, 2.25)
Daily lifting 10 lb(b) rarely Referent
10 lb often 0.81 (0.45, 1.48)
20 lb often 0.95 (0.48, 1.87)
[is greater
than or equal
to] 35 lb often 1.29 (0.68, 2.46)
10 lb rarely
Men Referent
Women
[is greater than
or equal
to] 35 lb often
Men 0.89 (0.35, 2.26)
Women 2.45 (0.86, 6.98)
Activity level Less active 1.39 (0.76, 2.74)
(compared As active Referent
with peers) More active 1.08 (0.74, 1.59)
Much more active 0.95 (0.51, 1.78)
Body mass <21.5 Referent
index 21.5-23.5 0.91 (0.47, 1.77)
(kg/[m.sup.2]) 23.6-26.2 1.33 (0.69, 2.57)
>26.2 1.82 (0.94, 3.55)
(a) Crude association between LBP and upper level(s) of risk factor compared with referent level of the risk factor. (b) 1 lb=0.4536 kg. Subjects were asked to identify their average daily lifting activities by checking off 1 of 5 possible categories. Very few people identified themselves as "lifting 50 lb([double dagger double dagger n. A reference mark (  ) used in printing and writing. Also called diesis.Noun 1. ]) often," so this category was collapsed with the category of "lifting 35 lb often," with the remaining 4 categories used to compute To perform mathematical operations or general computer processing. For an explanation of "The 3 C's," or how the computer processes data, see computer. the odds ratios. None of the estimates indicate that there was an important overall association between magnitude of daily lifting and LBP in this group. Although sex did not modify the LBP-lifting relationship at lower levels of lifting, some potential modification was evident between men and women lifting 35 lb or more often. For women, the odds ratio was 2.45 (CI=0.86, 6.98). The odds ratio for men in the same category was 0.89 (CI=0.35, 2.26). In spite of in opposition to all efforts of; in defiance or contempt of; notwithstanding. See also: Spite some apparent effect modification at the highest level of lifting, sex did not appear to confound 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. the estimates at any of the lifting levels. There was no apparent effect modification or confounding of the LBP-lifting association by age group. Subjects were asked to check off 1 of 4 categories that best described their work and recreational activity level in comparison with others of their age and sex. The category "as active as their peers" was used as the referent, and odds ratios were calculated. Although the odds ratio for LBP among subjects identifying themselves as less active than their peers (OR=1.39) was greater than for the higher activity levels (1.08 and 0.95, respectively), activity level did not appear to be an important risk factor in this sample. Sex and age group were neither modifiers nor confounders of the association. Body mass index was calculated as weight (in kilograms) divided by height (in meters squared). The highest levels of BMI showed a weak, but positive, association with LBP (OR=1.82 [CI=0.94, 3.55]) that declined across decreasing levels of BMI (OR= 1.33 and 0.91, respectively). Although there is some suggestion of a linear increase in risk with increased BMI, the estimates are too similar and the CIs are too wide to draw such a conclusion from these data. There was no evidence of effect modification or confounding of these associations by sex or age group. Multivariable Analyses Multivariable 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. was used to evaluate the independent effects of one risk factor controlling for other risk factors. There were only minor changes in estimates across a number of multivariable models. That is, the estimated odds of LBP with exposure to the studied factors appeared to be reasonably independent of each other. Discussion Smoking, 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. , motor vehicle driving, vibration exposure, and repetitive heavy lifting are among the limited number of factors that seem to be consistently considered in literature reviews as increasing the risk for LBP, although there is no consensus on role or magnitude of association.[1,3,7,11,14,22,23] This study provides estimates of association that support the role of smoking, parity, motor vehicle driving, and vibration exposure in increasing the odds of LBP. The calculated associations do not support the role of lifting or BMI as important risk factors for LBP. The determined associations for each of the risk factors, however, permit comparisons with the limited number of other investigations that cite magnitudes for these associations. For occupation-related risk factors, the magnitude of association may be reduced by the "healthy worker effect." That is, it may be that people with potentially problematic LBP reduce or eliminate exposure, whereas people with relatively healthier backs can sustain higher levels. This effect may be stronger for more avoidable exposures, such as heavy lifting, spending time "Spending Time" is the first single released by Christian artist Stellar Kart. The lyrics describe the band members desire to spend "more time with God". "Sometimes it’s a real struggle to spend time with God. in trucks, and industrial vibration. Where associations may be reduced by such self-selection Self-selection Consequence of a contract that induces only one group to participate. , identified magnitudes of association are still the most valid variables for understanding the potential impact to be made by education and risk factor modification. Smoking as a Risk Factor for Low Back Pain Both Skov and associates[7] and Leboeuf-Yde and associates[10] found odds ratios of 1.3 comparing current smokers and nonsmokers. The data from both studies yielded similar 95% CIs of approximately 0.9 and 1.8. These estimates are lower than the odds ratio of 2.21 (CI=1.09, 4.46) found in my study. Each of the other studies, however, was population-based and defined low back pain as any back symptoms in the past year (including tenderness or stiffness). When LeBoeuf-Yde and associates looked at the association of smoking with LBP lasting more than 30 days, the odds ratio increased to 2.3 (CI= 1.6, 3.2), an association very similar to that found in my study. Frymoyer and associates[1] found current smokers to be at higher risk for moderate back pain, with moderate pain defined as any symptoms from mild discomfort Discomfort may refer to pain, an unpleasant sensation, or to suffering, an unpleasant feeling or emotion. through distress. From the data presented by these investigators, odds ratios could be calculated for both subjects with moderate LBP and subjects with severe LBP. The odds ratios and 95% CIs calculated from their presented data were 1.34 (CI=1.05, 1.72) for current smoking with moderate LBP and 1.71 (CI=1.25, 2.34) for current smoking with severe LBP. Because 86.1% of the subjects with severe LBP in the study by Frymoyer et al reported seeking medical attention, these subjects might be considered more similar to the subjects with LBP in my study, all of whom had back pain for which they sought medical attention. When considering all of these findings, there is evidence that the association between smoking and LBP may be stronger among people with more severe symptoms or with symptoms of longer duration. That is, smoking may be a relevant risk factor for LBP among those people who are most likely to experience activity or work restrictions and to use health care dollars. Parity as a Risk Factor for Low Back Pain Women in this study who had one or more full-term children delivered vaginally had a 3-fold increase in odds of LBP as compared with women who had not had a pregnancy of at least 6 months' duration (crude OR=2.66 [CI=1.33, 5.42], standardized OR controlling for age group=3.33 [CI=1.30, 8.54]). As noted earlier, however, the wide CIs indicate that these estimates are relatively imprecise. Although other recent studies[13,16,24] have demonstrated a positive association between LBP and parity, only one other study[14] could be found that identified the magnitude of the studied association. Silman and associates[14] reported the odds ratios for the association of LBP with number of live births among a sample of married women. Adjusting for age at first birth, the authors identified a linear trend of increased risk with a greater number of children. They reported an odds ratio of 1.01 (CI=0.84, 1.52) for women with one child as compared with none, up through an odds ratio of 1.52 (CI=1.07, 2.16) for women with 4 or more live-born children. The associations reported by Silman and associates are substantially lower than those found in my study. Silman and associates, however, defined low back pain as any LBP ever that lasted more than 24 hours. Given such a broad definition, it is somewhat surprising that even weak associations were found in their sample. The data from my study indicate that women who have had one or more vaginal deliveries are at increased risk for LBP and that the risk may increase slightly with age. Although pregnancy and delivery are not risk factors that necessarily can be modified, targeted back pain prevention programs might be more effective in reducing disability and health care costs in this potentially high-risk group high-risk group Epidemiology A group of people in the community with a higher-than-expected risk for developing a particular disease, which may be defined on a measurable parameter–eg, an inherited genetic defect, physical attribute, lifestyle, habit, . Time Spent in a Car as a Risk Factor for Low Back Pain Subjects in this study who spent an hour or more in a car on an average day had more than twice the odds of LBP than did subjects who spent less than 1 hour in a car daily (OR=2.49 [CI=1.42, 4.34]). This association is similar to those of most of the studies in which magnitudes of association were identified. Skov and associates[7] found odds ratios of 2.23 (CI=1.29, 3.85) for active salespersons driving 15,000 to 30,000 km annually and up to 2.79 (CI=1.54, 5.07) among those driving more than 50,000 km annually. They defined low back pain as any symptoms in the last 12 months. Magnusson and associates[4] found an increased risk among male American occupational drivers as compared with sedentary sedentary /sed·en·tary/ (sed´en-tar?e) 1. sitting habitually; of inactive habits. 2. pertaining to a sitting posture. sedentary of inactive habits; pertaining to a fat, castrated or confined animal. workers (OR=1.79 [CI=1.16, 2.75]). No definition of LBP was given. Masset and Malchaire[9] (using the definition of any LBP problems in the past 12 months) cited a risk of 1.17 for "each twofold increase of duration" of vehicle driving among male steelworkers younger than 40 years of age. They noted that their results were statistically significant (P [is less than] .001), but they failed to include CIs around their estimates of association. In contrast to these studies, Macfarlane MacFarlane or Macfarlane is a surname shared by:
a chronological study in epidemiology which attempts to establish a relationship between an antecedent cause and a subsequent effect. See also cohort study. . Using any low back symptoms in the past year that lasted more than 24 hours as their definition, the age-adjusted odds ratio for male subjects driving 4 hours or more was 1.3 (CI=0.7, 2.4). The effect was similar among female subjects. The association was not markedly different for people who consulted physicians for their LBP, but the number of such individuals was quite small (22 men and 37 women). From data presented by Frymoyer and associates,[1] the odds ratio for the risk of LBP among men spending time in cars could be calculated (no duration of time spent in cars was given). For subjects with severe LBP (as compared with no pain), the odds ratio was 1.45 (CI=0.90, 2.33). For subjects reporting any LBP symptoms, the odds ratio was 1.71 (CI=0.92, 1.88). There does not appear to be consistency in the literature as to the role of time spent in a car as a risk factor for LBP. There appears to be a building consensus around fairly similar data, however, that time spent in a car does increase the risk of LBP. This consensus would argue that time spent in a car may be an appropriate target for design intervention A procedure used in a lawsuit by which the court allows a third person who was not originally a party to the suit to become a party, by joining with either the plaintiff or the defendant. and education in reducing disability and medical costs from LBP. Vibration Exposure as a Risk Factor for Low Back Pain Exposure to an hour or more of vibration daily among subjects in this study increased the odds of LBP approximately 5 times as compared with less than 1 hour of such exposure. Subjects were asked, "About how many hours on an average day do you spend sitting on, standing on, or holding equipment that vibrates heavily (eg, industrial tools, machines, equipment, chain saws, mowers)?" Subjects were asked separately about hours spent in a big truck. Although there appears to be consensus that vibration exposure is a risk for LBP or degenerative de·gen·er·a·tive adj. Of, relating to, causing, or characterized by degeneration. Degenerative Degenerative disorders involve progressive impairment of both the structure and function of part of the body. changes in the spine, the magnitude of association was found in only one other study that examined LBP. Magnusson and associates[4] reported that long-term Long-term Three or more years. In the context of accounting, more than 1 year. long-term 1. Of or relating to a gain or loss in the value of a security that has been held over a specific length of time. Compare short-term. vibration exposure (using a measured daily exposure extrapolated to years of employment) yielded an odds ratio of 2.0 (CI=0.98, 4.1) for LBP. They concluded that daily vibration exposure "did not relate to the reporting of low back pain." The authors, however, were not clear about how data were dichotomized for the analysis or who served as the referent group (sedentary workers or drivers with lower levels of exposure). The magnitude of association found in this study was substantially higher than those reported previously. It may be that the broad definition of vibration exposure to which subjects responded included more potential sources of exposure than considered elsewhere. Data in this study also were not subject to the "healthy worker effect" that may exist in job-based samples. That is, the association of vibration exposure to LBP may be reduced in an occupation-based sample when workers who have vibration-induced LBP leave the job and are not part of the studied sample. The number of subjects in my study who reported vibration exposure was quite small, resulting in wide CIs around the estimate of association. The small number of exposed subjects also precluded examination of other risk factors as potential confounding variables. Repetitive Heavy Lifting as a Risk Factor for Low Back Pain Macfarlane and associates[5] found that women who frequently lifted 25 lb or more were twice as likely to seek medical attention for LBP (OR=2.3 [CI=1.1, 5.0]). Data in my study showed a similar point estimate for women lifting 35 lb or more, but the CI was wider (OR=2.45 [CI=0.86, 6.98]). The parallel relation for men in the study by Macfarlane et al was a lower odds ratio of 1.2 (CI=0.5, 3.0). Data from my study indicated an inverse (mathematics) inverse - Given a function, f : D -> C, a function g : C -> D is called a left inverse for f if for all d in D, g (f d) = d and a right inverse if, for all c in C, f (g c) = c and an inverse if both conditions hold. association for men (OR=0.89 [CI=0.35, 2.26]). LeBoeuf-Yde and associates[12] found an odds ratio of 3.4 (CI=2.3, 5.1) for LBP lasting more than a month when subjects who performed heavy physical activity at work (lifting was not specified or quantified) were compared with subjects in sedentary jobs. Effect modification by sex was not 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. . When any LBP was included (regardless of duration), the association dropped to 1.3 (CI=0.8, 1.9). Magnusson and associates[4] found an odds ratio of 2.06 (CI=1.3, 3.3) for LBP when frequent and heavy lifting were combined as risk factors. Their subjects, however, were occupational drivers and sedentary workers. The effect of lifting adjusted for driving status was not reported. Repetitive heavy lifting did not appear to be as important a risk for LBP as other factors investigated in my study. There was some indication, however, that the risk may be increased among women. Limitations to the Study Elimination from the comparison group of subjects with limiting LBP within the past 12 months was intended to draw a clear line between the subjects with LBP and the comparison subjects. The effect, however, may have been to inflate inflate - deflate estimates of association between risk factors and LBP. If a risk factor is positively associated with LBP, excluding subjects from the comparison group who experienced limiting LBP may have reduced the number of comparison subjects with the risk behavior. Inflation of estimated associations, however, would occur only in the presence of an otherwise positive relation between the risk factor and LBP. Conclusion Among the studied group of patients seeking physical therapy services, this study determined the magnitude of the associations between LBP and self-reported risk factors for LBP. The data indicate increased odds of LBP among subjects who were smokers, subjects who were exposed to heavy vibration daily, subjects who spent an hour or more in a car daily, and women who had one or more children delivered vaginally. Estimates of the magnitudes of association in this physical therapy patient-based sample may permit comparisons with other risk factor studies and should facilitate consideration of the cost-effectiveness cost-effectiveness pertaining to cost-effective. cost-effectiveness analysis a comparison of the relative cost-efficiencies of two or more ways of performing a task or achieving an objective. of risk factor intervention, education, and back pain prevention programs among physical therapy clients with higher risk factor profiles. Acknowledgments I thank the clinicians in participating physical therapy facilities throughout the Boston area and my research assistants, without whom this study could not have been done. I also acknowledge the support of Dr Ken Rothman
n. A lengthy, formal treatise, especially one written by a candidate for the doctoral degree at a university; a thesis. dissertation Noun 1. process helped bring this study to a successful conclusion. (*) Analytical Software Analytical software is software that is designed specifically for and development of a particular environment or object. Co, PO Box 12185, Tallahassee, FL 32317. ([dagger]) Microsoft Carp, 1 Microsoft Way, Redmond, VA 98052. ([double dagger]) lb = 0.4536 kg. References [1] Frymoyer JW, Pope MH, Clements JH, et al. Risk factors in low-back pain: an epidemiological epidemiological emanating from or pertaining to epidemiology. epidemiological associations the associative relationships between the frequency of occurrence of a disease and its determinants, its predisposing and precipitating survey. J Bone Joint Surg Am. 1983;65:213-218. [2] Frymoyer JW, Pope MH, Costanza MC, et al. Epidemiologic studies epidemiologic study A study that compares 2 groups of people who are alike except for one factor, such as exposure to a chemical or the presence of a health effect; the investigators try to determine if any factor is associated with the health effect of low-back pain. Spine. 1980;5:419-423. [3] Garg A, Moore Moore, city (1990 pop. 40,761), Cleveland co., central Okla., a suburb of Oklahoma City; inc. 1887. Its manufactures include lightning- and surge-protection equipment, packaging for foods, and auto parts. JS. Epidemiology epidemiology, field of medicine concerned with the study of epidemics, outbreaks of disease that affect large numbers of people. Epidemiologists, using sophisticated statistical analyses, field investigations, and complex laboratory techniques, investigate the cause of low-back pain in industry. Occup Med. 1992;7:593-608. [4] Magnusson ML, Pope MH, Wilder DG, Areskoug B. Are occupational drivers at an increased risk for developing musculoskeletal disorders Musculoskeletal disorders (MSDs) can affect the body's muscles, joints, tendons, ligaments and nerves. Most-work related MSDs develop over time and are caused either by the work itself or by the employees' working environment. ? Spine. 1996;21:710-717. [5] Macfarlane GJ, Thomas (language) Thomas - A language compatible with the language Dylan(TM). Thomas is NOT Dylan(TM). The first public release of a translator to Scheme by Matt Birkholz, Jim Miller, and Ron Weiss, written at Digital Equipment Corporation's Cambridge Research Laboratory runs E, Papageorgiou AC, et al. Employment and physical work activities as predictors of future low back pain. Spine. 1997;22:1143-1149. [6] Clark WL, Haldeman S Haldeman may refer to:
1. A reduction in a company's stated capital. 2. The total capital that is less than the par value of the company's capital stock. Notes: 1. This is usually reduced because of poorly estimated losses or gains. 2. and disability determination: another attempt at objective, reliable rating, Spine. 1988;13:332-341. [7] Skov T, Borg V, Orhede E. Psychosocial psychosocial /psy·cho·so·cial/ (si?ko-so´shul) pertaining to or involving both psychic and social aspects. psy·cho·so·cial adj. Involving aspects of both social and psychological behavior. and physical risk factors for musculoskeletal disorders of the neck, shoulders, and lower back in salespeople sales·peo·ple pl.n. Persons who are employed to sell merchandise in a store or in a designated territory. . Occup 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 Med. 1996;53:351-356. [8] Kelsey JL, White AA III. Epidemiology and impact of low-back pain. Spine. 1980;5:133-142. [9] Masset D, Malchaire J. Low back pain: epidemiologic ep·i·de·mi·ol·o·gy n. The branch of medicine that deals with the study of the causes, distribution, and control of disease in populations. [Medieval Latin epid aspects and work-related factors in the steel industry. Spine. 1994;19:143-146. [10] Leboeuf-Yde C, Yashin A, Lauritzen T. Does smoking cause low back pain? Results from a population-based study. J Manipulative ma·nip·u·la·tive adj. Serving, tending, or having the power to manipulate. n. Any of various objects designed to be moved or arranged by hand as a means of developing motor skills or understanding abstractions, especially in Physiol Ther. 1996;19:99-108. [11] Boshuizen HC, Verbeek JH, Broersen JP, Weel a. & adv. 1. Well. n. 1. A whirlpool. 1. A kind of trap or snare for fish, made of twigs. AN. Do smokers get more back pain? Spine. 1993;18:35-40. [12] Leboeuf-Yde C, Lauritsen JM, Lauritzen T. Why has the search for causes of low back pain largely been nonconclusive? Spine. 1997;22: 877-881. [13] Harreby M, Kjer J, Hesselsoe G, Neergaard K. Epidemiological aspects and risk factors for low back pain in 38-year-old men and women: a 25-year prospective cohort study A cohort study is a form of longitudinal study used in medicine and social science. It is one type of study design. In medicine, it is usually undertaken to obtain evidence to try to refute the existence of a suspected association between cause and disease; failure to refute of 640 school children. Eur Spine J. 1996;5:312-318. [14] Silman AJ, Ferry S, Papageorgiou AC, et al. Number of children as a risk factor for low back pain in men and women. Arthritis arthritis, painful inflammation of a joint or joints of the body, usually producing heat and redness. There are many kinds of arthritis. In its various forms, arthritis disables more people than any other chronic disorder. Rheum rheum (rldbomacm) any watery or catarrhal discharge. rheum n. A watery or thin mucous discharge from the eyes or nose. rheum any watery or catarrhal discharge. . 1995;38:1232-1235. [15] Grieve grieve v. grieved, griev·ing, grieves v.tr. 1. To cause to be sorrowful; distress: It grieves me to see you in such pain. 2. GP. Common Vertebral ver·te·bral adj. 1. Of, relating to, or of the nature of a vertebra. 2. Having or consisting of vertebrae. 3. Having a spinal column. Joint Problems. 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 , NY: Churchill Livingstone Imprint of a medical publishing company owned by Elsevier Ltd, but previously owned by Harcourt and Pearsons. Originally formed from Livingstone, Edinburgh, Scotland, and J & A Churchill, London, UK, and subsequently with an office in New York, but now integrated with the rest of Inc; 1981. [16] Wreje U, Isacsson D, Aberg H. Oral contraceptives Oral Contraceptives Definition Oral contraceptives are medicines taken by mouth to help prevent pregnancy. They are also known as the Pill, OCs, or birth control pills. and back pain in women in a Swedish community. Int J Epidemiol. 1997;26:71-74. [17] Levangie PK. The association of static pelvic asymmetry and low back pain. Spine. In press. [18] Waddell G. A new clinical model for the treatment of low-back pain. Spine. 1987;12:632-644. [19] Rothman KJ. Modern Epidemiology. Boston, Mass: Little, Brown & Co Inc; 1986. [20] Statistix for Windows. Tallahassee, Fla: Analytical Software Co; 1996. [21] Excel A full-featured spreadsheet for Windows and the Macintosh from Microsoft. It can link many spreadsheets for consolidation and provides a wide variety of business graphics and charts for creating presentation materials. for Microsoft Office Microsoft's primary desktop applications for Windows and Mac. Depending on the package, it includes some combination of Word, Excel, PowerPoint, Access and Outlook along with various Internet and other utilities. 97, 7.0 Edition. Redmond, Wash: Microsoft Corp; 1995-1996. [22] Riihimaki H. Epidemiology and pathogenesis pathogenesis /patho·gen·e·sis/ (path?ah-jen´e-sis) the development of morbid conditions or of disease; more specifically the cellular events and reactions and other pathologic mechanisms occurring in the development of disease. of non-specific low back pain: What does the epidemiology tell us? Bull Hosp Jt Dis. 1996;55:197-198. [23] Frank JW, Kerr MS, Brooker AS, et al. Disability resulting from occupational low back pain, part I: What do we know about primary prevention? A review of the scientific evidence on prevention before disability begins. Spine. 1996;21:2908-2917. [24] Svensson H, Andersson G, Hagstad A, Jansson PO. The relationship of low-back pain to pregnancy and gynecologic gynecologic /gy·ne·co·log·ic/ (gi?ne-) (jin?e-kah-loj´ik) pertaining to the female reproductive tract or to gynecology. factors. Spine. 1990;15: 371-375. PK Levangie, DSc, PT, is Associate Professor, Physical Therapy Program, Sacred Heart University Anthony J. Cernera, Ph.D., has been president of Sacred Heart University for 18 years. Sacred Heart University is known for its strong musical roots, and is well known for the Pioneer Bands. SHU is the second largest Catholic university in New England. , 5151 Park Ave AVE Avenue AVE Average AVE Alta Velocidad Espanola (train between Madrid and Seville) AVE Alta Velocidad Española (Spanish: High Speed Train) AVE Audio Video Entertainment AVE Advertising Value Equivalent , Fairfield, CT 06432-1000 (levangiep@sacredheart.edu). This research was completed in partial fulfillment ful·fill also ful·fil tr.v. ful·filled, ful·fill·ing, ful·fills also ful·fils 1. To bring into actuality; effect: fulfilled their promises. 2. of the requirements for her Doctor of Science degree in epidemiology at Boston University's School of Public Health, Boston, Mass. Dr Levangie was on the faculty of the Physical Therapy Program at Boston University Boston University, at Boston, Mass.; coeducational; founded 1839, chartered 1869, first baccalaureate granted 1871. It is composed of 16 schools and colleges. during the period of data collection. Levangie wrote the manuscript manuscript, a handwritten work as distinguished from printing. The oldest manuscripts, those found in Egyptian tombs, were written on papyrus; the earliest dates from c.3500 B.C. , with guidance from Dr Nancy Watts and Dr Ken Rothman; Levangie and Rothman provided data analysis; Levangie and research assistants managed the project and collected the data; and Levangie and the personnel of Beth Israel Hospital See:
As the state's first free-standing hospital dedicated to women, the Women's Hospital of Greensboro is a 134-bed hospital is dedicated to providing state-of-the-art, compassionate and personalized care to women provided subjects. Levangie provided the concept and research design; procured funds; and provided facilities and equipment, institutional liaisons, and clerical/secretarial support. This study was approved by the Charles River Charles River River, eastern Massachusetts, U.S. The longest river wholly in the state, it flows into Boston Bay after a course of about 80 mi (130 km). Navigable for about 7 mi (11 km), its estuary separates the cities of Boston and Cambridge. Campus Institutional Review Board of Boston University and by the institutional review boards of the 7 hospitals from which subjects were recruited. This study was supported in part by Sargent College of Allied Health Professions, Boston University, and by funding from the Foundation for Physical Therapy Inc. This article was submitted October 13, 1998, and accepted May 6, 1999.3 |
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