Tanya Agurs-Collins

Measurement Characteristics of the Women’s Health Initiative Food Frequency Questionnaire

PURPOSE The Womens Health Initiative (WHI) is the largest research program ever initiated in the United States with a focus on diet and health. Therefore, it is important to understand and document the measurement characteristics of the key dietary assessment instrument: the WHI food frequency questionnaire (FFQ). METHODS Data are from 113 women screened for participation in the WHI in 1995. We assessed bias and precision of the FFQ by comparing the intake of 30 nutrients estimated from the FFQ with means from four 24-hour dietary recalls and a 4-day food record. RESULTS For most nutrients, means estimated by the FFQ were within 10% of the records or recalls. Precision, defined as the correlation between the FFQ and the records and recalls, was similar to other FFQs. Energy adjusted correlation coefficients ranged from 0.2 (vitamin B12) to 0.7 (magnesium) with a mean of 0.5. The correlation for percentage energy from fat (a key measure in WHI) was 0.6. Vitamin supplement use was common. For example, almost half of total vitamin E intake was obtained from supplements. Including supplemental vitamins and minerals increased micronutrient correlation coefficients, which ranged from 0.2 (thiamin) to 0.8 (vitamin E) with a mean of 0.6. CONCLUSIONS The WHI FFQ produced nutrient estimate, that were similar to those obtained from short-term dietary recall and recording methods. Comparison of WHI FFQ nutrient intake measures to independent and unbiased measures, such as doubly labeled water estimates of energy expenditure, are needed to help address the validity of the FFQ in this population.

A Randomized Controlled Trial of Weight Reduction and Exercise for Diabetes Management in Older African-American Subjects

OBJECTIVE To evaluate a weight loss and exercise program designed to improve diabetes management in older African-Americans. RESEARCH DESIGN AND METHODS Overweight African-Americans (n = 64) ages 55–79 years with NIDDM were randomized to either an intervention (12 weekly group sessions, 1 individual session, and 6 biweekly group sessions) or usual care (1 class and 2 informational mailings). Clinical and behavioral variables were assessed at 0, 3, and 6 months of treatment. RESULTS Significant net differences in the intervention versus usual care were observed for weight (−2.0 kg, P = 0.006), physical activity, and dietary intake of fat, saturated fat, cholesterol, and nutrition knowledge at 3 months (all P < 0.05) and for weight at 6 months (−2.4 kg; P = 0.006) and mean HbA1c values at 3 and 6 months (respectively, −1.6 and −2.4%, both P < 0.01). After the adjustment for changes in weight and activity, the intervention participants were ∼ twice as likely to have a one unit decrease in HbA1c value as those in usual care. Blood pressure increase sin usual care participants resulted in net differences (intervention minus control) at 3 and 6 months of −3.3 (P = 0.09) and −4.0 (P = 0.05) mmHg diastolic, respectively, and −8.4 (P = 0.06) and −5.9 (P > 0.10) mmHg systolic, respectively. Blood lipid profiles improved more in intervention than usual care participants, but not significantly. CONCLUSIONS The intervention program was effective in improving glycemic and blood pressure control. The decrease in HbA1c values was generally independent of the relatively modest changes in dietary intake, weight, and activity and may reflect indirect program effects on other aspects of self-care.

Dietary patterns and breast cancer risk in women participating in the Black Women’s Health Study

BACKGROUND No studies have examined dietary patterns and breast cancer risk in a large cohort of African American women. OBJECTIVE We investigated the association between dietary patterns and breast cancer risk in the Black Womens Health Study. DESIGN This is a prospective cohort study of 50,778 participants followed biennially from 1995 through 2007. During 443,742 person-years of follow-up, 1094 incident cases of breast cancer were identified. Factor analysis was used to derive food patterns based on 69 food variables. We used Cox regression models to obtain incident rate ratios (IRRs) for breast cancer in relation to quintiles of each of the 2 dietary patterns, with adjustment for other breast cancer risk factors. RESULTS Through factor analysis, we identified 2 dietary patterns: Western (refined grains, processed meat, and sweets) and prudent (whole grains, vegetables, fruit, and fish). The prudent diet was weakly associated with lower breast cancer risk overall; P for trend = 0.06. In analyses stratified by body mass index (BMI; in kg/m(2)), the prudent dietary pattern was associated with a significantly lower risk of breast cancer in women with a BMI <25 (IRR: 0.64; 95% CI: 0.43, 0.93; P for trend = 0.01). The prudent dietary pattern was also associated with a significantly lower risk of breast cancer in premenopausal women (IRR: 0.70; 95% CI: 0.52, 0.96; P for trend = 0.01), and we found a significant inverse association for the prudent dietary pattern and estrogen receptor-negative breast cancer (IRR: 0.52; 95% CI: 0.28, 0.94; P for trend <0.01). CONCLUSION Our findings suggest that the prudent dietary pattern may protect against breast cancer in some black women.

Correlates of serum lycopene in older women

Abstract: Experimental and epidemiological evidence suggests that lycopene, a predominant carotenoid found in human serum, may reduce the risk of certain cancers. We examined the association of dietary, physiological, and other factors with serum lycopene concentrations in a subsample of 946 postmenopausal women participating in the Womens Health Initiative. Pearson partial correlation coefficients and linear regression coefficients were calculated after adjustment for age, ethnicity, and serum low-density-lipoprotein (LDL) cholesterol. Serum lycopene was correlated with serum LDL cholesterol (r = 0.23) and dietary lycopene (r = 0.17, both p < 0.001). Individual food items found to be correlated with serum lycopene after adjustment included fresh tomatoes or tomato juice (r = 0.11), cooked tomatoes, tomato sauce, or salsa (r = 0.17), and spaghetti with meat sauce (r = 0.19, all p < 0.01). Age and body mass index were negatively associated with serum lycopene levels (both p < 0.001). Serum lycopene levels were highest in the summer and highest for those living in the northeastern United States. If we postulate that high serum lycopene levels reduce cancer risk, it becomes apparent that we have limited ability to detect this association from studies of lycopene intake. An understanding of factors associated with serum lycopene levels can be useful for the interpretation of studies of dietary lycopene and disease risk.

Antioxidant supplement use in Women’s Health Initiative participants

BACKGROUND Although antioxidant supplements are widely available and commonly used in the United States, there is a lack of detailed information on their use, including types of supplements used, doses, duration of use, and changes in use over time. METHODS Antioxidant supplement use was assessed in participants in the Clinical Trial (n = 68,133) and Observational Study (n = 93,676) of the Womens Health Initiative. In-person interviews and a computerized inventory procedure were used to collect data on supplement use during baseline clinic visits from 1993 through 1998. RESULTS Antioxidant supplements were widely consumed. For example, 55.5% of participants reported taking supplemental vitamin C in some form. Supplement use was positively associated with age, education, and physical activity. Most antioxidants were consumed through multivitamins. However, high doses were commonly consumed from single supplements, with 43.9% using single vitamin C supplements taking >500 mg and 86.1% using single vitamin E supplements taking >200 IU daily. Except for beta-carotene, there were increases in the use of all supplements from 1993 to 1998. CONCLUSIONS This report demonstrates the feasibility of collecting comprehensive dietary supplement use data in large studies. These data may aid in the design of supplement use questionnaires, which could help to prevent misclassification error in epidemiologic studies of diet and disease.

Plasma lipid alterations in African-American women with breast cancer

Abstract The purpose of this study was to examine the relationship between plasma lipid and lipoprotein levels, stage of disease and breast cancer risk in African-American women. The study population comprised 163 African-American women: patients (n= 58) and controls (n= 105), with mean ages of 57.2 years and 47.7 years respectively. Approximately 71% and 56% of the women with breast cancer and the control population, respectively, were postmenopausal. Those with cancer had significantly higher education levels, P≤ 0.01, and higher triglyceride levels compared to the controls, P≤ 0.001, but lower body mass index (BMI) levels, P≤ 0.01. There were no statistically significant differences observed in total cholesterol, high-density-lipoprotein-containing cholesterol and low-density-lipoprotein-containing cholesterol between the patients and controls. After adjustments for age, education, BMI, and menopausal status, triglycerides remained significantly and positively associated with breast cancer risk. The significant correlation between the high levels of triglycerides and breast cancer risk (odds ratio = 5.12) may be attributed to differences in lipid metabolism between the women with breast cancer and controls, or to the consequences of breast cancer.

Dietary Patterns and the Risk of Colorectal Adenomas: the Black Women's Health Study

Background: Colorectal adenomas are benign lesions that may be precursors to colorectal cancer. No studies of African American women have investigated dietary patterns and the risk of developing colorectal adenomas. We examined data from the Black Womens Health Study to determine whether dietary patterns are associated with the risk of developing colorectal adenomas. Methods: This is a prospective cohort study of 59,000 participants followed biennially since 1995. During 155,414 person-years of follow-up from 1997 to 2007 among women who had had at least one screening colonoscopy, 620 incident cases of colorectal adenomas were identified. By using Cox regression models, we obtained incidence rate ratios (IRR) for colorectal adenoma in relation to quintiles of each of two dietary patterns, adjusting for other colorectal adenoma risk factors. Results: Two dietary patterns, Western and prudent, were utilized to assess the association between dietary intake and adenoma risk. The highest quintile of prudent diet, relative to the lowest quintile, was significantly associated with 34% lower colorectal adenoma risk overall (IRR = 0.66; 95% CI, 0.50–0.88; Ptrend < 0.01). Higher scores on the Western pattern were associated with a higher risk of developing colorectal adenoma (IRR = 1.42; 95% CI, 1.09–1.85 for the highest quintile relative to the lowest; Ptrend = 0.01). Conclusion: Our findings suggest that African American women may be able to reduce their risk of developing colorectal adenomas by following a prudent dietary pattern and avoiding a more Western pattern. Impact: A dietary modification could have a strong impact in colorectal adenoma prevention in African American women. Cancer Epidemiol Biomarkers Prev; 20(5); 818–25. ©2011 AACR.

Abstract A78: Associations between IGF-axis, testosterone and nutrients in healthy African American and Caucasian men at increased risk for prostate cancer

Introduction: African American men have the highest incidence and death rates from prostate cancer in the United States. The insulinlike growth factor (IGF) axis has been implicated in the carcinogenesis of prostate cancer. Several epidemiological studies have shown increased serum concentrations of IGF-1 and alterations of the associated binding proteins-IGFBP-2 and IGFBP-3, as strong risk factors for prostate cancer. This study examined racial differences in risk factors for prostate cancer in a healthy high risk screening population of African American and Caucasian males. The associations between IGF-1, IGFBP-2, IGFBP-3, prostate-specific antigen (PSA), testosterone, body mass index (BMI) and specific dietary macronutrients were examined. Methods: Serum was collected from 461 African American and Caucasian men aged ≥25 years who participated in prostate cancer screening programs located at two university hospitals in Washington, DC. Serum concentrations of IGF-1, IGFBP-2, IGFBP-3, PSA, and testosterone were analyzed using immunoassays from Diagnostic Systems Laboratories (Webster, TX). Height and weight were used to create BMI, which was calculated as weight/height2 (kg/m2). A food-frequency questionnaire was administered over the telephone to 128 study participants who consented. Wilcoxon rank sums test and chi square test examined mean differences and associations with other risk factors. Multiple linear regression analysis was used to examine racial differences in IGF-1, IGFBP-3, IGFBP-2, testosterone, PSA and specific macronutrients, adjusted for covariates such as age and BMI. Results: African American men had significantly lower concentrations of IGFBP-2 (p=0.035), and significantly higher concentrations of IGFBP-3 and testosterone when compared to Caucasian men, p=0.031 and p=0.033 respectively. There were no significant differences found for concentrations of IGF-1 by race. Levels of IGFBP-2 exhibited a significant inverse association with BMI for both races and a positive association with age for Caucasians. African American men had higher mean intakes of total calories, total fat, protein and carbohydrate, but only dietary fat intake was significantly higher when compared to intakes in Caucasian men (p=0.026). Multiple regression analysis revealed no significant relationships between nutrient intake and concentrations of IGF-1, IGFBP-3, IGFBP-2, PSA and testosterone by race. Finally, IGFBP-2 exhibited a significant univariate negative correlation with total calories, protein and total fat, with a somewhat stronger association among Caucasian than African American men. Conclusion: We provide evidence of racial variation in concentrations of IGFBP-2, IGFBP-3 and testosterone, but not for IGF-1. In this sample, African American men had a significantly higher consumption of total dietary fat intake than Caucasians. Further work is needed to determine whether these observations may explain the racial disparity in prostate cancer incidence and mortality in the U.S. Funded by: Department of Defense DAMD17-00-1-0024 Citation Information: Cancer Epidemiol Biomarkers Prev 2010;19(10 Suppl):A78.