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Low sun exposure and elevated serum prostate specific antigen in African American and Caucasian men.



Abstract: This study measured the association between sun exposure and abnormal prostate specific antigen PSA (Prostate specific antigen)
A tumor marker associated with prostate cancer.

Mentioned in: Tumor Markers
. This 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.
 was conducted in a community-based cohort of 685 men of whom 48% were African American African American Multiculture A person having origins in any of the black racial groups of Africa. See Race. . Most of the subjects, (85.5%) reported frequent exposure to the sun. Frequent sun exposure provided a 55% reduction in the odds for abnormal prostate specific antigen (PSA (Professional Services Automation) An information system designed to organize, track and manage all opportunities, work, resources, costs, revenues and invoices to improve the productivity and efficiency of the workforce. ) after adjustment for age, education, and income (OR=0.45; 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)=0.21-0.97). There were non-significant race differences. Frequent sun exposure among African American men was associated with a 40% reduction in the odds of abnormal PSA (OR = 0.59; 95% CI = 0.20-1.69). In contrast, among Caucasian men, a 68% reduction was observed (OR = 0.32; 95% CI= 0.10-1.01). Although not significant by race, the magnitude and direction of the observed differences are consistent with an hypothesis of melanin-mediated racial differences in the effects of ultraviolet exposure upon PSA levels. Further studies in African American men and Caucasian men are indicated with more exact measures of ultraviolet exposure, skin color or melanin melanin (mĕl`ənĭn), water-insoluble polymer of various compounds derived from the amino acid tyrosine. It is one of two pigments found in human skin and hair and adds brown to skin color; the other pigment is carotene, which contributes  content, and serum Vitamin D vitamin D

Any of a group of fat-soluble alcohols important in calcium metabolism in animals to form strong bones and teeth and prevent rickets and osteoporosis. It is formed by ultraviolet radiation (sunlight) of sterols (see steroid) present in the skin.
 levels.

**********

Prostate cancer prostate cancer, cancer originating in the prostate gland. Prostate cancer is the leading malignancy in men in the United States and is second only to lung cancer as a cause of cancer death in men.  is the most commonly diagnosed cancer 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.  (Boring, Squires, Tong, & Montgomery, 1994), and it is the second leading cancer-related cause of death among men (Carter & Coffey, 1988). Its distribution is far from uniform, however. The strongest determinant is age, with 80% of diagnosed cases being in men older than 65 (Boring, et al. 1994). Mortality rates vary greatly between countries. For example, rates in Japan are one fifteenth those in America, although rates among Japanese immigrants quadruple quad·ru·ple  
adj.
1. Consisting of four parts or members.

2. Four times as much in size, strength, number, or amount.

3. Music Having four beats to the measure.

n.
 after migration to the United States (Haenszel & Kurihara, 1968). Within the U.S., mortality rates in African Americans are twice those of white men, and these differences are not attributable to differences in socioeconomic class (Ernster, et al., 1977). Finally, mortality rates vary geographically, with rates between countries varying 10-fold (Zaridze, Boyle, & Smans, 1984). However, autopsy studies have found that the prevalence of latent prostate cancer does not vary greatly between countries (Yatani, et al., 1982), suggesting that the variation in mortality may be caused by factors affecting tumor tumor: see neoplasm.  growth (Dhom, et al. 1983).

Much of this variation fits with the hypothesis that vitamin D deficiency Vitamin D Deficiency Definition

Vitamin D deficiency exists when the concentration of 25-hydroxy-vitamin D (25-OH-D) in the blood serum occurs at 12 ng/ml (nanograms/milliliter), or less.
 increases the risk of prostate cancer (Schwartz & Hulka, 1990). Vitamin D is synthesized in the skin after exposure to UV radiation (Holick, 1989), so the sun is the major source of vitamin D (Holick, 1990). Ecological studies at both the state (Schwartz & Hulka, 1990) and national (Hanchette & Schwartz, 1992) have found an inverse association between UV exposure and prostate cancer mortality. The elderly tend to be exposed to less UV light (Lund & Sorenson, 1979) and have reduced ability to synthesize To create a whole or complete unit from parts or components. See synthesis.  Vitamin D (Baker, Peacock, & Nordin, 1980). Studies have also shown a high prevalence of vitamin D deficiency among older men worldwide (Weisman, Schen, Eisenberg, Edelstein, & Harrell, 1981; McKenna, Freany, Meade, & Muldowney, 1985). High melanin content reduces formation of pre-vitamin D (Clemens, Adams, Henderson, & Holick, 1982; Matsuoka, Wortsman, Haddad, Kolm, & Hollis, 1991), leading to decreased levels of vitamin D in people with increased skin pigmentation pigmentation, name for the coloring matter found in certain plant and animal cells and for the color produced thereby. Pigmentation occurs in nearly all living organisms.  (Matsuoka, et al. (1991); M'Buyamba-Kabangu, et al. 1987; Bell, et al. 1985; Reid, Cullen, Schooler, Livingston, & Evans, 1990). This is in accordance with the high rate of prostate cancer observed in African-Americans, although one study found that the differences in vitamin D level were due to socioeconomic class (Meier, et al., 1991). African-Americans have also been found to have equivalent levels of 1,25 dihydroxy vitamin D (1,25- OH-D) (Reid, et al. 1990; Meier, et al., 1991), which is the more biologically active form.

There is also biochemical evidence for vitamin D playing a role in prostate cancer. Vitamin D receptors have been found in prostate cells and many prostate cancer cell lines (Miller, et al., 1992; Skowronski, Peehl, & Feldman, 1993), and genetic variation in the receptor gene has recently been correlated with increased risk of prostate cancer (Ingles This article is about an American supermarket chain. For a town in Gran Canaria, see Playa del Inglés.

Ingles (NYSE: IMKTA) is a regional supermarket chain based in Asheville, North Carolina, where Robert "Bob" Ingle opened the first store in Asheville, NC in
, et al., 1997). Overall, there were no significant associations with vitamin D receptor polymorphisms with prostate cancer risk in 372 prostate cancer cases and 591 controls. However, among a subset of men with plasma 25-hydroxyvitamin D below the median, there was a 57% reduction in risk for men with the BB versus the bb genotype genotype (jēn`ətīp'): see genetics.
genotype

Genetic makeup of an organism. The genotype determines the hereditary potentials and limitations of an individual.
 (Ma, et al., 1998). In contrast, a cohort of over twenty thousand United States residents had no association between prostate cancer and prediagnostic levels of serum vitamin D metabolites Metabolites
Substances produced by metabolism or by a metabolic process.

Mentioned in: Interactions
 (Braun, Helzlsouer, Hollis, & Comstock, 1995). Ethnic differences, especially in African Americans, have been documented in the commonly used BsmI as a marker for the vitamin D receptor 3' untranslated region genotype. (Ingles et al, 1997).

Vitamin D inhibits the growth of many types of cancer cells cells once believed to be peculiar to cancers, but now know to be epithelial cells differing in no respect from those found elsewhere in the body, and distinguished only by peculiarity of location and grouping.

See also: Cancer
 in vitro in vitro /in vi·tro/ (in ve´tro) [L.] within a glass; observable in a test tube; in an artificial environment.

in vi·tro
adj.
In an artificial environment outside a living organism.
 and in vivo in vivo /in vi·vo/ (ve´vo) [L.] within the living body.

in vi·vo
adj.
Within a living organism.



in vivo adv.
 (Miller, et al., (1992); Skowronski, et al. (1993); Peehl, et al., (1994); Bahnson et al. (1993); Corder, et al. (1993); Getzengerg et al. (1997), and 1,25 OH vitamin D has been shown in vitro to inhibit normal and cancerous prostate cell growth while promoting cell differentiation Cell differentiation

The mechanism by which cells in a multicellular organism become specialized to perform specific functions in a variety of tissues and organs. Specialized cells are the product of differentiation.
 (Skowronski, et al., 1993; Peehl, et al., 1994).

The epidemiologic evidence is as yet inconclusive. One study found an association between low levels of 1,25 OH vitamin D and risk of prostate cancer (Braun, et al. (1995). This risk was most significant for men older than fifty-seven, and did not explain increased incidence among African-Americans. Two other studies have failed to reproduce this finding (Gann, et al., 1996; Mettlin, et al. 1997), although neither was able to rule out the possibility of a smaller effect. A recent prospective study found that men with increased calcium intake (which lowers 1,25-OH-D levels) were at greater risk for prostate cancer. In contrast, decreased fructose fructose (frŭk`tōs), levulose (lĕv`yəlōs'), or fruit sugar, simple sugar found in honey and in the fruit and other parts of plants.  consumption (which raises 1,25-OH-D levels by transiently lowering phosphorous phos·pho·rous
adj.
Of, relating to, or containing phosphorus, especially with a valence of 3 or a valence lower than that of a comparable phosphoric compound.
 levels) was associated with decreased risk (Giovannucci, et al., 1998).

Prostate cancer screening Prostate cancer screening is an attempt to identify individuals with prostate cancer in a broad segment of the population—those for whom there is no reason to suspect prostate cancer.  consists of the prostate specific antigen (PSA) and the digital rectal examination Digital rectal examination
A routine screening test that is used to detect any lumps in the prostate gland or any hardening or other abnormality of the prostate tissue.
. The PSA is a blood test that screens for a glyco-protein that is detected only in the epithelial cells Epithelial cells
Cells that form a thin surface coating on the outside of a body structure.

Mentioned in: Corneal Transplantation
 of the prostate gland. PSA levels greater than 4ng./ml. suggest prostatic pathology (Catalona, 1996). About 80% of men with PSA levels greater than four will be found to have cancer of the prostate (Cahill, 1995). A recent study found that PSA velocity decreased in men taking 1,25-OH-D (Gross, Stamey, Hancock, & Feldman, 1998). Research on the environmental associations with elevated prostate specific antigen could provide critical early data on the etiology of prostate cancer.

METHODS

This study is a cross-sectional analysis Cross-sectional analysis

Assessment of relationships among a cross-section of firms, countries, or some other variable at one particular time.
 of baseline data from a community-based cohort of men participating in the South Carolina South Carolina, state of the SE United States. It is bordered by North Carolina (N), the Atlantic Ocean (SE), and Georgia (SW). Facts and Figures


Area, 31,055 sq mi (80,432 sq km). Pop. (2000) 4,012,012, a 15.
 Prostate Cancer Project (SCPCP), a study funded to test the effect of different educational interventions on participation in prostate cancer screening (Weinrich, Weinrich, Boyd, & Mettlin, 1998). In the original SCPCP cohort, there were 1151 African American men and Caucasian men aged 50-70 years. Among these men, 881 obtained a free prostate cancer examination, including a prostate specific antigen (PSA) assay. Subjects for the present analyses were 685 men (of the 811 men with PSA assays) who completed follow-up telephone interviews that included a self-report of sun exposure. Figure 1 shows details of the recruitment process.

In the initial stage, purposive pur·po·sive  
adj.
1. Having or serving a purpose.

2. Purposeful: purposive behavior.



pur
 sampling was used to recruit at-risk men from 11 counties at 216 community sites in central South Carolina. Community sites where men were recruited were distributed as follows: 57.5 % from work sites, 28.7% from churches, and 13.8% from other sources, including barber shops, meal sites, car dealerships This article is about car dealerships. For the indie pop band, see Dealership (band).

A car dealership or vehicle local distribution is a business that sells new cars and/or used cars at the retail level, based on a dealership contract with an automaker or
, National Association for Advancement of Colored not of the white race; - commonly meaning, esp. in the United States, of negro blood, pure or mixed.

See also: Color
 People (NAACP NAACP
 in full National Association for the Advancement of Colored People

Oldest and largest U.S. civil rights organization. It was founded in 1909 to secure political, educational, social, and economic equality for African Americans; W.E.B. Du Bois and Ida B.
) sites, and housing projects (Weinrich, Boyd, Greene, Mossa, & Weinrich, 1998). The sample included African American men aged 40-49 years that were excluded from the current analyses in order to avoid possible 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 race effects by age. Other inclusion criteria
For Wikipedia's inclusion criteria, see: What Wikipedia is not.


Inclusion criteria are a set of conditions that must be met in order to participate in a clinical trial.
 were no history of prostate cancer; not undergoing diagnostic studies to test for Prostate Cancer; and informed consent.

The men were recruited when they attended community sites where an educational program on prostate cancer was given. Refusal rates are not available for the men who chose to not come to the educational program on the day of the presentation. Almost all program attendees then completed the background questionnaire. There were only 53 refusals for the 216 sites where the programs were presented (an average of 0.2 refusals per site). The reasons given for refusing to complete the questionnaire were: already had exam (4), see a doctor normally (9), and no time (5); thirty-five men gave no reason. Eleven men indicating ethnicity other than African American or Caucasian were excluded from the analyses, resulting in 1,151 men in the initial interview.

In the second stage, men went to see a physician of their own choice for free Prostate Cancer screening, which included a digital rectal examination (DRE DRE
Digital rectal examination.

Mentioned in: Rectal Examination
) and a serum prostate-specific antigen prostate-specific antigen
n. Abbr. PSA
A protease secreted by the epithelial cells of the prostate gland. Serum levels are elevated in patients with benign prostatic hyperplasia and prostate cancer.
 (PSA) assay. Out of the cohort of 1,151 men ages 50 to 70 years old, 811 (70.5%) obtained PSA assays.

The third stage of recruitment entailed contacting the 811 men about 15 months after their date of PSA screening, in order to assess sun exposure. One hundred twenty-six men from the 811 men were excluded from analyses for the following reasons: unable to contact (71), refused (11), no telephone (32), deceased (2), and contacted, but unable to answer sun exposure question (10). Data were analyzed for the remaining 685 men.

Established protocols that were followed for the first two stages of recruitment: initial and the second stage which involved prostate cancer screening have been published previously (Weinrich, Weinrich, Boyd, & Mettlin, in press). For the third stage of recruitment, all men were called by telephone 15 months after they received the Prostate Cancer screening and asked a series of questions which included the sun exposure question.

The analyses combined data from the initial questionnaire, the serum PSA level, and the sun exposure telephone interview. Seventy five percent of the prostate specific antigen (PSA) results were obtained from SmithKline Beecham Clinical Laboratories, 14% were obtained from Lab Corp, and the rest of the results (11%) from other laboratories.

The question to measure sun exposure was developed by the investigators. The sun exposure question was pilot tested with 40 men and minor changes in the wording made to enhance comprehension. The final question was, "How many days/week do you get outside in the sunlight for at least half an hour?". The four response options were: (1) None, (2) 1-2 times/ week, (3) 3-5 times/week, (4) Over 5 times/week. To avoid small cell sizes, the four possible responses were dichotomized: infrequent sun exposure (0 to 2 times/ week) or frequent sun exposure (3 or more times/week).

A simple 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.  model was used to calculate the crude odds ratio (OR) for the association of sun exposure categories of PSA (normal/abnormal based on ? 4 ng/ml or > 4 ng/ml). The crude OR in this simple model was compared to the adjusted OR in a model to which one potential 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.
 (race, age, education, marital status marital status,
n the legal standing of a person in regard to his or her marriage state.
, income, living arrangements, previous screening history, urinary symptoms, or pain in the lower back and groin) had been added. A change in the adjusted OR often percent or more compared to the crude OR was interpreted as evidence of data-based confounding by the added variable (Rothman, & Greenland, 1998).

Race was considered a potential effect modifier (programming) modifier - An operation that alters the state of an object. Modifiers often have names that begin with "set" and corresponding selector functions whose names begin with "get".  for the low sun exposure-abnormal PSA association. A model containing sun exposure, race, and their interaction was therefore examined using the likelihood ratio test (LRT LRT Light-Rail Transit
LRT Likelihood Ratio Test
LRT Light Rapid Transit
LRT Lower Respiratory Tract
LRT Lehrstuhl für Raumfahrttechnik
LRT Long Range Transportation
LRT Light Railway Transit
LRT London Regional Transport
LRT Loving Relationships Training
). Although the interaction between sun exposure and race was not statistically significant (p=0.53), melanin-mediated racial differences in the effects of sun exposure upon PSA levels are plausible. Consequently, separate multiple logistic regression models for Caucasians and African Americans were used to investigate further the association between low sun exposure and abnormal PSA levels.

RESULTS

Description of the cohort. African American men represented 47.6% of the sample (Table 1). The three levels of education were roughly equally represented, each with about one third of the sample. Low income men were represented with 19.7% of the men having incomes below $9,600 per year. Most of the men were married (85.1%), and most of the men lived with someone (88.6%).

Most of the men (78.1%) reported a history of previous prostate cancer screening (usually digital rectal examination) at the initial interview. Only 34.2% of the men had ever had a PSA assay and fewer than half of those had obtained a PSA test within the last year. About one-fourth of the sample described urinary symptoms (28.5%) and/or pain in the lower back or groin (29.1%) (Table 1).

Sun exposure and Prostate Specific Antigen (PSA). Of the 685 subjects, 586 (85.6%) reported frequent exposure to the sun (half an hour or more, three or more times per week). The distribution of study variables by sun exposure

status is shown in Table 1. There was an inverse association between sun exposure and abnormal PSA. Only 6.1% of men with frequent sun exposure had an abnormal PSA, versus 10.1% of men with infrequent sun exposure; The corresponding (crude) odds ratio was 0.58. Younger, more educated, and higher income men obtained sun exposure less frequently (p<0.05). Race, age, marital status, living arrangements, previous screening history; urinary symptoms, and pain did not differ significantly with respect to sun exposure.

Potential confounders with PSA. Race, age, education, marital status, and living arrangements as well as previous screening history, urinary symptoms, and pain were considered as potential confounders (Table 2). When considered as potential confounders, only age, education, and income changed the resulting crude OR by ten percent or more, and were therefore included as confounders in the multiple logistic regressions. The other variables were dropped from consideration.

Logistic regression for sun exposure. Results for the multiple logistic regression model, including all subjects and adjusted for age, education, and income, is shown in Table 3. Frequent sun exposure was associated with a 50% lower odds ratio (OR) for an abnormal serum PSA level after adjustment for age, education, and income (OR=0.45; 95% Confidence Interval (CI)=0.21-0.97). Because of the hypothesis that high melanin levels decrease formation of pre-vitamin D(16),(17), separate models of sun exposure and abnormal PSA for African American and Caucasian men were constructed and are also presented in Table 4. Among African American men, frequent sun exposure was associated with a 40% lower odds ratio for an abnormal PSA when adjusted for age, education, and income (from OR=1.00 to OR=0.59; 95% CI=0.20-1.69). The inverse association was even stronger among Caucasian men (OR=0.32; 95% CI=0.10-1.01).

There was no statistically significant difference between African Americans and Caucasian men in the association of sun exposure with PSA level (p=0.8). However, the direction was still consistent with the hypothesis that sun exposure may have a stronger protective effect in Caucasian men than in African American men due to biological differences in sun exposure from different skin pigmentation.

Prostate Cancer. Abnormal PSA was used as the outcome variable because of its biological relevance and because there were too few prostate cancer cases (n=22) to use prostate cancer as an outcome. Three (0.4%) prostate cancer cases were exposed to sun infrequently as defined as 0-2 times per week. In contrast, 19 (2.8%) prostate cancer cases were exposed to sun frequently (3 or more times per week). When the analysis was restricted to men without prostate cancer, the reduction of the odds of abnormal PSA with frequent sun exposure was stronger (adjusted OR=0.28; 95% CI=0.12-0.70, p=0.006).

DISCUSSION

This cross-sectional study suggests an association between sun exposure and serum prostate specific antigen levels that may vary by race in a community-based cohort of 685 men. Frequent sun exposure was associated with a 50% lower odds ratio for abnormal serum PSA level after adjustment for age, education, and income. Among African American men, frequent sun exposure was associated with a 40% lower odds ratio for abnormal PSA when adjusted for age, education, and income. The association was even stronger, 60%, among Caucasian men. There are no previously published literature that uses PSA as an outcome to which to compare the results. This data supports the hypothesis of increased sun exposure and decreased risk for prostate cancer with the limitation that elevated PSA is not equivalent to prostate cancer. The stronger odds ratio for Caucasian men (60%) verus African American men (40%) supports the increased risk hypothesis due to decreased levels of vitamin D in people with increased skin pigmentation.

Results can be generalized only to populations similar to this southern community-based 6sample. An important limitation of the study is that only one question measured sun exposure. In addition, the outcome variable, elevated PSA, can be an indicator of benign prostatic hyperplasia benign prostatic hyperplasia
n. Abbr. BPH
A nonmalignant enlargement of the prostate gland commonly occurring in men after the age of 50, and sometimes leading to compression of the urethra and obstruction of the flow of urine.
 or prostatitis prostatitis (prŏs'tətī`tĭs), inflammation of the prostate gland. Acute prostatitis is usually a result of infection in the urinary tract or infection carried by the blood; in many cases the infection spreads from the urethra and is  as well as prostate cancer.

Further studies in African American men and Caucasian men are indicated with more exact measures of ultraviolet exposure, skin color or melanin content, serum Vitamin D levels, and measurement of vitamin D receptor genotype. Future research should be undertaken in a larger sample, in order to confirm the association between limited sun exposure and higher serum PSA levels, and to examine the manner in which the strength of that association may depend on skin pigmentation. More precise measures of sun exposure are needed, as well as better measures of skin pigmentation than the simple dichotomization di·chot·o·mize  
v. di·chot·o·mized, di·chot·o·miz·ing, di·chot·o·miz·es

v.tr.
To separate into two parts or classifications.

v.intr.
To be or become divided into parts or branches; fork.
 into Caucasians and African Americans considered here. This research needs to be conducted as it may answer some of the questions associated with increased prostate cancer mortality in African American men.

It is premature to recommend preventive health education of increased sun exposure. However, health educators should begin considering the potential dilemmas associated with conflicting sun preventive measures for prostate cancer and skin cancer. IF additional studies document an association between increased sun exposure and decreased prostate cancer, research would be needed to weigh the risk of increased skin cancer against the decreased risk of prostate cancer. Changing a preventive health care message from decreased sun exposure (for skin cancer) to increased sun exposure (for prostate cancer) should not be undertaken lightly. The impact of changing health care messages from one message to another message needs to be researched. When health messages are changed, there is the potential for a negative impact and/or a public response of "It will change anyway; why should I concern myself?"
Table 1. Distribution of Study Variables by Sun Exposure (N=685)

                               Frequent     Infrequent
                                 Sun           Sun
Variable                       Exposure *   Exposure *     Total

                               N     (%)      N    (%)    N     (%)
PSA
   Normal                     550   93.9     89   89.9   639   93.3
   Abnormal                    36    6.1     10   10.1    46    6.7
Demographics
Race
   African-American           286   48.8     40   40.4   326   47.6
   Caucasian                  300   51.2     59   59.6   359   52.4
Age(+)
   50-59 Years                380   64.8     76   76.8   456   66.6
   60-70 Years                206   35.2     23   23.2   229   33.4
Education (+)
   Less than HS               200   34.1     21   21.2   221   32.3
   High School                197   33.6     29   29.3   226   33.0
   College                    189   32.3     49   49.5   238   34.7
Marital Status
   Married                    495   84.5     88   88.9   583   85.1
   Not Married                 91   15.5     11   11.1   102   14.9
Income (+)
   $600                       123   21.0     12   12.1   135   19.7
   $9601-$25,020              220   37.5     28   28.3   248   36.2
   >25020                     243   41.5     59   59.6   302   44.1
Living Arrangements
   Alone                       67   11.4      7    7.1    74   10.8
   With Someone               516   88.1     91   91.9   607   88.6
   Missing                      3    0.5      1    1.0     4    0.6
Screening History
   Yes screen-past year        78   13.3     14   14.1    92   13.4
   Yes screen-year ago        374   63.8     69   69.7   443   64.7
   No screen                  134   22.9     16   16.2   150   21.9
PSA Screen History
   Yes screen-past year        91   15.5     15   15.2   106   15.5
   Yes screen-year ago        110   18.8     18   18.2   128   18.7
   No screen                  385   65.7     66   66.7   451   65.8
DRE Screen History
   Yes screen-past year       157   26.8     32   32.3   189   27.6
   Yes screen-year ago        285   48.6     50   50.5   335   48.9
   No screen                  144   24.6     17   17.2   161   23.5
Urinary Symptoms              169   28.8     26   26.3   195   28.5
Pain in groin, back, upper
legs, testicles               174   29.7     25   25.3   199   29.1

* Frequent sun exposure =>3 times/week;
infrequent sun exposure =<2 times/week
Table 2. The Effects of Potential Confounders on the Association
Between Frequent Sun Exposure and Abnormal Serum PSA Levels (N=685).

                              Adjusted Odds Ratio
                             for effect of Frequent
Adjustment Variable               Sun Exposure         95% CI

None                            0.58 (crude OR)       0.28-1.22
Race                            0.55                  0.26-1.16
Age                             0.50 *                0.24-1.07
Education                       0.52 *                0.25-1.11
Marital Status                  0.58                  0.28-1.20
Income                          0.49 *                0.23-1.05
Living Arrangements"            0.56                  0.27-1.17
Previous Screening History      0.58                  0.28-1.22
Urinary Symptoms                0.58                  0.28-1.20
Pain                            0.58                  0.28-1.21

* Data-based confounder of the Sun Exposure-Abnormal
PSA relationship: adjusted OR differs by more than
10% from crude OR.

"N=681 for this variable.
Table 3. Multivariate-Adjusted Associations of Abnormal Serum
PSA and Sun Exposure and Other Selected Exposures (Confounding
Variables).

Variable                         Odds Ratio    95% CI

Sun Exposure                       0.45 *     0.21-0.97
Age
        50-59 years                1.00
        60-70 years                2.32 *     1.24-4.34
Education
        Less than High School      1.08       0.44-2.64
        High School                1.19       0.52-2.72
        Some College and above     1.00
Income
        $9600                      2.02       0.94-4.32
        $9600-$25020               1.00
        >$25020                    0.77       0.34-1.74

* p<0.05
Table 4. Separate Multivariate-Adjusted Associations of Abnormal
Serum PSA and Sun Exposure and Other Selected Exposures (Confounding
Variables) in African-American and Caucasian Men Aged 50-70 Years.

                                African-American       Caucasian

                                Odds               Odds
Variable                        Ratio   95% CI    Ratio      95% CI

Sun Exposure                    0.59   0.20-1.69   0.32    0.10-1.01
Age
        50-59 years             1.00               1.00
        60-70 years             1.68   0.74-3.83   4.52 *  1.56-13.05
Education
        Less than High School   1.36   0.41-4.42   0.74    0.17-3.22
        High School             1.30   0.39-4.34   1.16    0.37-3.69
        Some College and above  1.00               1.00
Income
        $9600                   2.49   0.95-6.53   0.93    0.17-4.94
        $9600-$25020            1.00               1.00
        >$25020                 1.30   0.38-4.47   0.57    0.19-1.72

 * p<0.05


REFERENCES

Bahnson, R.R., Oeler, T., Trump, D., Smith, D., Schwartz, G.G. (1993). Inhibition of human prostatic carcinoma cell lines by 1,25 dihydroxyvitamin D3 and vitamin D analogs. J Urol, 149(Suppl), 417a.

Baker, M.R., Peacock, M., Nordin, B.E. (1980). The decline in Vitamin D status with age. Age & Aging, 9, 249-252.

Bell, N.H., Greene, A., Epstein, S., Oexmann, M.J., Shaw, S., Shary, J. (1985). Evidence for alteration of the vitamin D endocrine system endocrine system (ĕn`dəkrĭn), body control system composed of a group of glands that maintain a stable internal environment by producing chemical regulatory substances called hormones.  in blacks. J Clin Invest, 76, 470-473.

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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
: Plenum In a building, the space between the real ceiling and the dropped ceiling, which is often used as an air duct for heating and air conditioning. It is also filled with electrical, telephone and network wires. See plenum cable.  Publishing Corp, pp. 1-7.

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Medical specialty dealing with the urinary system and male reproductive organs. It traces its origin to medieval lithologists, itinerant healers who specialized in surgical removal of bladder stones.
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Of, relating to, or affecting the skin.


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Sally Weinrich, Ph.D., R.N., is with the School of Nursing at the University of Louisville See also
  • The University of Louisville Cardinal Singers
  • The University of Louisville Collegiate Chorale
  • History of Louisville, Kentucky
  • McConnell Center
References

1. ^ [1]
2. ^ [2] URL accessed on June 8 2006
3.
. Gary Ellison, M.P.H., is with the National Cancer Institute. Martin Weinrich, Ph.D., is with the School of Medicine at the University of Louisville. Kevin S. Ross is with the University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill is a public, coeducational, research university located in Chapel Hill, North Carolina, United States. Also known as The University of North Carolina, Carolina, North Carolina, or simply UNC  and Carol Reis-Starr, Ph.D., is in the Divison of Geriatric Medicine & Gerontology gerontology: see geriatrics.  at Emory University Emory University (ĕm`ərē), near Atlanta, Ga.; coeducational; United Methodist; chartered as Emory College 1836, opened 1837 at Oxford. It became Emory Univ. in 1915 and in 1919 moved to Atlanta. . Address all correspondence to Dr. Weinrich at: School of Nursing; University of Louisville; Louisville, Kentucky

“Louisville” redirects here. For other uses, see Louisville (disambiguation).
, 40292; Phone: 502.852.8782; FAX: 502.852.8783; e-mail: sally.weinrich@louisville.edu.

This research was supported by the National Cancer Institute, R01 CA60561-01. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the National Cancer Institute.
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