Effects of repeated freeze-thaw cycles on concentrations of cholesterol, micronutrients, and hormones in human plasma and serum.
Explore the source record for details and available documents.
Blood Donors↗
Biomedical subjects
S C Hoffman
Publications and source records attributed to S C Hoffman.
The repeatability of serum carotenoid, retinoid, and tocopherol concentrations in specimens of blood collected 15 years apart.
Community-wide programs to collect blood for a research serum bank were carried out in Washington County, Maryland in 1974 and 1989. Of the 8395 persons who participated in both programs, 64 were controls in a nested case-control study of the association of antioxidant micronutrients with subsequent breast cancer, and 30 and 166 were controls in similar studies of lung and prostate cancer. Assay results for five carotenoids, two retinoids, and two tocopherols in samples of blood collected 15 years apart were thus available for comparisons of micronutrient concentrations. The mean Spearman rank order correlation coefficient for all comparisons was 0.44, with two coefficients greater than 0.60 and two less than 0.30. Blood pressure readings at the two blood collections had a mean rank order correlation coefficient of 0.46. Because blood pressure readings in 1974 were shown to be significantly predictive of atherosclerosis 15-18 years later, the present results suggest that ranked concentrations of antioxidant micronutrients from a single sample are sufficiently representative to be used as predictors of subsequent concentrations and are thus suitable for assessment as risk factors for subsequent illnesses.
Aged↗
A prospective study of plasma ascorbic acid concentrations and breast cancer (United States).
OBJECTIVES: To investigate the association between prediagnostic plasma ascorbic acid concentrations and subsequent breast cancer risk in a nested case-control study. METHODS: Female volunteer residents of Washington County, MD, donated 14,625 non-fasting blood samples in 1989. Incident breast cancer cases (n = 115) and controls (n = 115) were matched by age, menopausal status at donation, and date and hour of blood donation. RESULTS: Median ascorbic acid concentrations were similar between cases and controls (1.44 mg/dl vs. 1.39 mg/dl. p = 0.78). There was no evidence for a dose-response relationship between higher plasma ascorbic acid concentrations and breast cancer risk [highest vs. lowest fifths: ORadjusted = 0.90, Ptrend = 0.98). CONCLUSIONS: Findings from this prospective study do not suggest a protective association between prediagnostic plasma ascorbic acid concentrations and breast cancer risk in the subsequent 5 years of follow-up.
Ascorbic Acid↗
Household exposure to passive cigarette smoking and serum micronutrient concentrations.
BACKGROUND: The associations observed between passive smoking and adverse health outcomes have generated controversy. In part, this could be because the diets of passive smokers, like those of active smokers, differ from those of persons who are not exposed to cigarette smoke, especially with regard to antioxidants. OBJECTIVE: Our objective was to assess the relation between household exposure to passive smoking and serum concentrations of retinol, tocopherols, and carotenoids. DESIGN: A cross-sectional study was conducted in Washington County, MD, to compare exposure to passive smoking at home, recorded in a private census of county residents in 1975, with micronutrient concentrations assayed in serum collected in 1974. This comparison was possible for 1590 control subjects in nested case-control studies conducted between 1986 and 1998. RESULTS: Among persons who were not current smokers, those who lived with smokers tended to have lower serum total carotenoid, alpha-carotene, ss-carotene, and cryptoxanthin concentrations than did those who lived in households with no smokers. There was little evidence that exposure to passive smoking was associated with reduced serum concentrations of lutein and zeaxanthin, lycopene, retinol, alpha-tocopherol, or gamma-tocopherol. CONCLUSIONS: Among nonsmokers, exposure to passive smoking tended to be associated with lower serum concentrations of the carotenoids most strongly associated with active smoking (total carotenoids, alpha-carotene, ss-carotene, and cryptoxanthin). The associations were weaker for passive smoking than for active smoking. The consistency of the associations observed for active and passive smoking indicates that exposure to passive smoking may result in decreased circulating concentrations of selected micronutrients.
Adult↗
Serum dehydroepiandrosterone and dehydroepiandrosterone sulfate and the subsequent risk of developing colon cancer.
This purpose of this study was to evaluate whether serum dehydroepiandrosterone (DHEA) and its sulfate conjugate, dehydroepiandrosterone sulfate (DHEAS), are associated with the likelihood of developing colon cancer. A nested case-control study was conducted using the serum bank and cancer registry in Washington County, Maryland. From a population of 20,305 county residents who donated blood in 1974, incident cases of colon cancer that occurred from 1975 to 1991 (n = 117) were matched to one cancer-free control by age, race, and sex. Serum specimens that were stored at -70 degrees C since 1974 were assayed for DHEA and DHEAS. Compared with the controls, the mean serum concentrations of cases were 3% lower for DHEA (P = 0.90) and 13% lower for DHEAS (P = 0.60). When DHEA levels were analyzed according to fourths, no noteworthy associations were observed. Compared with the lowest fourth, the highest fourth of serum DHEAS was nonsignificantly associated with a halving in the risk of colon cancer (odds ratio, 0.50; 95% confidence limits, 0.18, 1.37; Ptrend = 0.22), and further analyses showed the potential protective association was confined largely to males (highest-versus-lowest fourth odds ratio, 0.26; 95% confidence limits, 0.06, 1.16; Ptrend = 0.06). This prospective study does not provide strong evidence that circulating DHEA and DHEAS concentrations are associated with the risk of colon cancer. Among men, DHEAS was associated with a decreased risk of colon cancer, but the association was within the bounds of chance. Further studies are needed to either support or refute the potentially promising lead hinted at by the results for DHEAS.
Adult↗
Temperature variations in chest-type mechanical freezers.
Explore the source record for details and available documents.
Adult↗
A prospective study on folate, B12, and pyridoxal 5'-phosphate (B6) and breast cancer.
To investigate the incidence of breast cancer and prediagnostic serum levels of folate, B12, and pyridoxal 5'-phosphate (B6), we conducted a nested case-control study using resources from the Washington County (Maryland) serum bank. In 1974, 12,450 serum specimens were donated, and in 1989, 14,625 plasma specimens were donated by female residents of Washington County. One hundred ninety-five incident breast cancer cases and 195 controls were matched by age, race, menopausal status at donation, and cohort participation as well as by date of blood donation. In both cohorts and all menopausal subgroups, median B12 concentrations were lower among cases than controls. Differences reached statistical significance only among women who were postmenopausal at donation (1974 cohort, 413 versus 482 pg/ml, P = 0.03; 1989 cohort, 406 versus 452 pg/ml, P = 0.02). Among women postmenopausal at blood donation, observed associations of B12 suggested a threshold effect with increased risk of breast cancer in the lowest one-fifth compared to the higher four-fifths of the control distribution [lowest versus highest fifth: 1974 cohort, matched odds ratio = 4.00 (95% confidence interval = 1.05-15.20); 1989 cohort, matched odds ratio = 2.25 (95% confidence interval = 0.86-5.91)]. We found no evidence for an association between folate, B6, and homocysteine and breast cancer. Findings suggested a threshold effect for serum B12 with an increased risk of breast cancer among postmenopausal women in the lowest one-fifth compared to the higher four-fifths of the control distribution. These results should stimulate further investigations of potentially modifiable risk factors, such as these B-vitamins, for prevention of breast cancer.
Adolescent↗
Serum concentrations of organochlorine compounds and the subsequent development of breast cancer.
A nested case-control study was conducted to examine the association between serum concentrations of 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE), the primary metabolite of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT), and polychlorinated biphenyls (PCBs) and the development of breast cancer up to 20 years later. Cases (n = 346) and controls (n = 346) were selected from cohorts of women who donated blood in 1974, 1989, or both, and were matched on age, race, menopausal status, and month and year of blood donation. Analyses were stratified by cohort participation because median DDE and PCB concentrations among the controls were 59 and 147% higher in 1974 than 1989, respectively. Median concentrations of DDE were lower among cases than controls in both time periods [11.7% lower in 1974 (P = 0.06) and 8.6% lower in 1989 (P = 0.41)]. Median concentrations of PCBs were similar among cases and controls [P = 0.21 for 1974 and P = 0.37 for 1989 (Wilcoxon signed rank test)]. The risk of developing breast cancer among women with the highest concentrations of DDE was roughly half that among women with the lowest concentrations, whether based on concentrations in 1974 [odds ratio (OR), 0.50; 95% confidence interval (CI), 0.27-0.89; P(trend) = 0.02] or in 1989 (OR, 0.53; 95% CI, 0.24-1.17; P(trend) = 0.08). The associations between circulating concentrations of PCBs and breast cancer were less pronounced but still in the same direction (1974: OR, 0.68; 95% CI, 0.36-12.9; P(trend) = 0.2; and 1989: OR, 0.73; 95% CI, 0.37-1.46; P(trend) = 0.6). Adjustment for family history of breast cancer, body mass index, age at menarche or first birth, and months of lactation did not materially alter these associations. These associations remained consistent regardless of lactation history and length of the follow-up interval, with the strongest inverse association observed among women diagnosed 16-20 years after blood drawing. Results from this prospective, community-based nested case-control study are reassuring. Even after 20 years of follow-up, exposure to relatively high concentrations of DDE or PCBs showed no evidence of contributing to an increased risk of breast cancer.
Adult↗
Controlled trial of the effect of length, incentives, and follow-up techniques on response to a mailed questionnaire.
Mailed questionnaires are an economical method of data collection for epidemiologic studies, but response tends to be lower than for telephone or personal interviews. As part of a follow-up study of volunteers who provided a brief health history and blood sample for a blood specimen bank in 1989, the authors conducted a controlled trial of the effect of length, incentives, and follow-up techniques on response to a mailed questionnaire. Interventions tested included variations on length of the questionnaire, effect of a monetary incentive, and effect of a postcard reminder versus a letter accompanied by a second questionnaire. Response was similar for the short (16-item, 4-page) and long (76-item, 16-page) questionnaire groups. The non-monetary [corrected] incentive did not improve the frequency of response. The second mailing of a questionnaire was significantly better than a postcard reminder in improving responses (23% vs. 10%). It is important to systematically test marketing principles to determine which techniques are effective in increasing response to mailed questionnaires for epidemiologic studies.
Adolescent↗
Serum concentrations of alpha tocopherol, beta carotene, and retinol preceding the diagnosis of rheumatoid arthritis and systemic lupus erythematosus.
OBJECTIVES: Because oxidative damage has been implicated in the pathogenesis of rheumatoid arthritis and systemic lupus erythematosus, this study was designed to see if serum concentrations of alpha tocopherol, beta carotene, and retinol, substances believed to be involved in the prevention or repair of oxidative damage, might be lower among persons who develop rheumatoid arthritis or systemic lupus erythematosus than among those who do not. METHODS: For this prospective case-control study, persons with rheumatoid arthritis and systemic lupus erythematosus that developed two to 15 years after donating blood for a serum bank in 1974 were designated as cases. For each case, four controls were selected from the serum bank donors, matched for race, sex, and age. Stored serum samples from cases and controls were assayed for alpha tocopherol, beta carotene, and retinol. RESULTS: Cases of both diseases had lower serum concentrations of alpha tocopherol, beta carotene, and retinol in 1974 than their matched controls. For rheumatoid arthritis, the difference for beta carotene (-29%) was statistically significant. CONCLUSIONS: These findings support those of a previous study that low antioxidant status is a risk factor for rheumatoid arthritis. They suggest a similar association for systemic lupus erythematosus.
Adult↗
The risk of developing lung cancer associated with antioxidants in the blood: ascorbic acid, carotenoids, alpha-tocopherol, selenium, and total peroxyl radical absorbing capacity.
Lung cancer cases diagnosed during the period 1975 through 1993 and matched controls were identified in the rosters of Washington County, Maryland residents who had donated blood for a serum bank in 1974 or 1989. Plasma from participants in the 1989 project was assayed for ascorbic acid; serum or plasma was assayed for participants in either project for alpha- and beta-carotene, cryptoxanthin, lutein/zeaxanthin, lycopene, alpha-tocopherol, selenium, and peroxyl radical absorption capacity. Among the total group of 258 cases and 515 controls, serum/plasma concentrations were significantly lower among cases than controls for cryptoxanthin, beta-carotene, and lutein/zeaxanthin with case-control differences of -25.5, -17.1, and -10.1%, respectively. Modest nonsignificant case-control differences in a protective direction were noted for alpha-carotene and ascorbic acid. There were only trivial differences for lycopene, alpha-tocopherol, selenium, and peroxyl radical absorption capacity. Findings are reported for males and females and for persons who had never smoked cigarettes, former smokers, and current smokers at baseline. These results and those from previous studies suggest that beta-carotene is a marker for some protective factor(s) against lung cancer; that cryptoxanthin, alpha-carotene, and ascorbic acid need to be investigated further as potentially protective factors or associates of a protective factor; and that lycopene, alpha-tocopherol, selenium, and peroxyl radical absorption capacity are unlikely to be associated with lung cancer risk. Until specific preventive factors are identified, the best protection against lung cancer is still the avoidance of airborne carcinogens, especially tobacco smoke; second best is the consumption of a diet rich in fruits and vegetables.
Adult↗
Prospective study of serum micronutrients and ovarian cancer.
BACKGROUND: Antioxidant micronutrients, such as alpha-tocopherol (vitamin E), the carotenoids, and selenium, may protect against the development of cancer by preventing free radical damage at the cellular level. PURPOSE: A nested case--control study was conducted among donors to a serum bank to examine the association between levels of serum micronutrients and/or cholesterol and the development of ovarian cancer. METHODS: In 1974, sera were collected from 20,305 residents of Washington County, MD, over a 4-month period and stored at -70 degrees C. Serum micronutrient concentrations of women who developed ovarian cancer (case subjects, n = 35) were compared with those of women who remained free of cancer and who were matched to case subjects on age and menopausal status (control subjects, n = 67). Serum levels of retinol (vitamin A), alpha- and beta-carotene (the major provitamin A), lycopene (a carotenoid), and alpha- and gamma-tocopherol were measured using high-performance liquid chromatography. Serum selenium was measured by neutron activation analysis. Cholesterol was measured by enzymatic assay. The data were categorized into thirds and conditional logistic regression analyses were performed to determine the association between prediagnostic serum cholesterol and micronutrient levels and the development of ovarian cancer; matched odds ratios (ORs) were determined from these regression analyses. P values for trend and for interaction were calculated with the use of two-sided likelihood ratio tests. RESULTS: Higher serum alpha-tocopherol levels were associated with an increased risk of ovarian cancer (P for trend = .04); however, this association diminished after adjustment for cholesterol. Women with higher serum cholesterol levels had an increased risk of ovarian cancer compared with women in the lowest third of cholesterol levels (OR = 3.2; 95% confidence interval = 0.9-11.3). The association between serum cholesterol levels and the risk of ovarian cancer was examined, stratifying by micronutrient level. The general pattern observed was an increased risk of ovarian cancer associated with cholesterol levels greater than 200 mg/dL, regardless of the micronutrient level. Serum selenium was associated with a decreased risk of ovarian cancer only among case participants diagnosed 4 or more years after blood collections (P for trend = .02). Concentrations of carotenoids and retinol were not associated with the development of ovarian cancer. CONCLUSIONS: Selenium may have a protective role against the development of ovarian cancer. Higher serum cholesterol levels were associated with an increased risk of developing ovarian cancer; an association that persisted regardless of serum micronutrient level. IMPLICATIONS: Given the small size of this study and the inconsistency of results among the few prospective studies of ovarian cancer conducted to test these associations, replications of these findings are highly desirable.
Carotenoids↗
Serum gonadotropins and steroid hormones and the development of ovarian cancer.
OBJECTIVE: To prospectively examine the association between endogenous hormones and development of ovarian cancer. DESIGN: Nested case-control study. SETTING: A population-based serum bank in Washington County, Maryland. PARTICIPANTS: Serum samples were collected in 1974 from 20305 county residents and stored at -70 degrees C. From 1975 through 1989, a total of 31 cases of ovarian cancer were identified in women who were not taking hormones at the time of blood collection. These cases were matched to 62 controls on age, menopausal status, and, for premenopausal women, number of days from the beginning of the last menstrual period. MAIN OUTCOME MEASURE: Prediagnostic endogenous hormone levels of cases and controls were compared. RESULTS: Mean follicle-stimulating hormone levels were lower among cases (43.3 IU/L) compared with controls (54.4 IU/L) (P = .04), and increasing levels were associated with significantly lower risk (P for trend = .01), particularly among postmenopausal women. Luteinizing hormone levels were 9% lower among cases than controls, but the difference was not statistically significant (P = .39). Compared with controls, cases had higher androstenedione levels (4.5 nmol/L vs 3.3 nmol; P = .03) and higher dehydroepiandrosterone (DHEA) levels (15.9 nmol/L vs 9.7 nmol/L; P = .02). The risk of ovarian cancer increased with higher levels of androstenedione and DHEA sulfate (P for trend = .008 and .11, respectively). These associations were not materially different between premenopausal and postmenopausal women. CONCLUSION: The results suggest that women with low serum gonadotropin levels or high androgen levels have an increased risk of ovarian cancer. These findings do not support the hypothesis that pituitary gonadotropins increase the risk of ovarian cancer. Replication of the study in other populations is highly desirable.
Adult↗
Conducting an assessment of health needs and resources in a racial/ethnic minority community.
This article examines strategies and methodologic issues for researchers to consider when conducting community-based research within a racial/ethnic minority community. Members of minority communities have considerable skepticism about the health care system and researchers who work under its auspices. To facilitate quality research, it is necessary to build a mutually beneficial partnership between the community and researchers. Suggested strategies for accomplishing this goal, such as seeking out information on the social and political forces shaping the community and developing the community's capacity to undertake research of this type, are described. Methodologic issues include the importance of community input in defining the minority population group and its leadership, the benefits and limitations of conducting comparative analysis, and the need for measurement tools and techniques that are culturally and socially appropriate. Minority and nonminority researchers must make a concerted effort to gain knowledge of and respect for a community whose culture, values, and beliefs may differ from their own.
Community Participation↗
The Washington County Training Center: an exemplar of public health research in the field.
Explore the source record for details and available documents.
Baltimore↗
Effects of instructions and rating scales on item selection for the BSRI scales.
Walkup and Abbott (1978) stated that Edwards and Ashworth's (1977) failure to replicate Bem's (1974) selection of items for the Masculinity and Femininity Scales of the Bern Sex Role Inventory (BSRI) may be attributed to differences in the instructions and anchored rating scales used in the two studies. The present study tested the hypothesis that presence of various interaction effects involving instructions and rating scales would influence the acceptability of items for the BSRI Masculinity and Femininity Scales. Results based on the evaluation of individual items by Bem's item selection criteria in each of the four experimental conditions obtained by systematically manipulating two instructions (Bem's and Edwards' instructions) and two rating scales (Bem's and Edwards' rating scales) and also those based on the analysis of variance of item mean desirability ratings from the four experimental conditions supported the hypothesis.
Journal Article↗
Serum dehydroepiandrosterone and dehydroepiandrosterone sulfate and risk of melanoma or squamous cell carcinoma of the skin.
BACKGROUND: Dehydroepiandrosterone (DHEA) and its analogs have potent chemoprotective actions in mouse skin tumorigenesis models. To assess this association in humans, we investigated the relationship of prediagnostic serum concentrations of DHEA and dehydroepiandrosterone sulfate (DHEAS) to the subsequent risk of developing malignant melanoma and squamous cell carcinoma of the skin in residents of Washington County, Maryland, USA. PATIENTS AND METHODS: In a nested case-control study, serum that had been stored in 1974 was thawed and assayed for DHEA and DHEAS for 23 cases of malignant melanoma and 28 cases of squamous cell carcinoma and 1-2 matched controls per case. RESULTS: The mean serum concentrations of DHEA or DHEAS were similar in cases and controls. There were no statistically significant trends in the risk of developing malignant melanoma or squamous cell skin cancer by concentration of either steroid (all p-for-trends >0.30). CONCLUSION: The results of this study do not support the hypothesis that physiological concentrations of DHEA or DHEAS protect against skin cancer in humans.
Adult↗
A cross-sectional study of vitamin C and cognitive function in older adults: the differential effects of gender.
Previous studies have suggested that vitamin C status may be associated with cognitive function in community-dwelling populations. However, this has not been consistent across all studies due to methodological differences. This cross-sectional study assessed the association between vitamin C and cognitive function in 544 community-dwelling older adults aged 65 or older who participated in both the Cardiovascular Health Study (CHS) and the CLUE II study in 1989. Three percent of the subjects had low plasma vitamin C concentrations (< 40 mg/dL) and 15% had low total vitamin C intake (< 60 mg/day). Most participants (96.7 percent) had normal cognitive function. In the unadjusted analyses, the highest fifth of plasma vitamin C concentration was associated with better Digit Symbol Substitution Test (DSST) scores and marginally associated with Mini-Mental State Examination (MMSE) compared to the lowest fifth. Total vitamin C intake, measured by Block's food frequency questionnaire, was generally associated with higher MMSE scores, though it was not significant. Adjusting for numerous factors did not substantially change results. In a stratified analysis by gender, higher plasma concentrations or intake were associated with higher MMSE scores for men but not for women. These mixed results do not provide strong evidence of an association between vitamin C concentrations or intake and cognitive function.
Aged↗