Usefulness of body mass index as a sufficient adiposity measurement for sex hormone concentration associations in postmenopausal women.

BACKGROUND: Both obesity and sex hormones are known risk factors for postmenopausal breast cancer. Although adiposity and sex hormones have been studied in the past, previous reports in postmenopausal women have not been conducted under carefully controlled dietary conditions. In this study, we investigated the usefulness of body mass index (BMI) as a sufficient adiposity measurement to assess associations with sex hormone levels. METHODS: This study was conducted as a cross-sectional analysis within the control segment (0 g alcohol group) of a randomized, crossover design, in which 51 postmenopausal women consumed 0 (control), 15 (one drink), and 30 (two drinks) g alcohol (ethanol)/d for 8 weeks each as part of a controlled diet. Dual-energy X-ray absorptiometry scans were administered to the women during the control (0 g alcohol) segment, and a blood sample was drawn at the end of that diet period for hormone analysis. RESULTS: In multivariate analysis (adjusted for age, race, family history of breast cancer, parity, and menarche <12 years), women who were overweight or obese had significantly higher serum concentrations of estradiol, bioavailable estradiol, estrone, and estrone sulfate and lower sex hormone-binding globulin than normal weight women (all P < 0.05). In models adjusted for BMI and the covariates above, none of the dual-energy X-ray absorptiometry adiposity measures added further information (all P > 0.10) for these five analytes beyond that of BMI alone. CONCLUSIONS: In this population of postmenopausal women, under carefully controlled dietary conditions, we confirmed previous findings that higher levels of adiposity were associated with higher concentrations of estrogens and lower sex hormone-binding globulin, and we found that the use of the epidemiology-friendly BMI seems sufficient to assess associations with these hormone levels.

Comparison of energy expenditure estimates from 4 physical activity questionnaires with doubly labeled water estimates in postmenopausal women.

BACKGROUND: Physical activity energy expenditure (EE) is an important determinant of health, and epidemiologists have used various methods, such as physical activity and energy intake recalls and records, to estimate energy cost. However, most epidemiologic studies have not validated these methods against the doubly labeled water (DLW) technique for measuring EE. OBJECTIVE: The aim was to compare EE estimated by 4 physical activity questionnaires with that obtained with the DLW technique in free-living postmenopausal women. DESIGN: We measured EE in kcal/d using the DLW method, the Harvard Alumni questionnaire, the Five City Project questionnaire, the Cross-Cultural Activity Participation Study (CAPS) Four Week Activity Recall, and the CAPS Typical Week Activity Survey in 65 healthy postmenopausal women. RESULTS: Compared with DLW, the Harvard Alumni questionnaire, the Five City Project questionnaire, and the CAPS Four Week Activity Recall overestimated (P < 0.05) daily EE by 62%, 16%, and 11%, respectively, whereas the CAPS Typical Week Activity Recall underestimated (P < 0.05) EE by 31%. Both the Harvard Alumni and Five City Project questionnaires overestimated EE in obese and overweight women. CONCLUSIONS: When using 3 of the 4 questionnaire methods, postmenopausal women overestimated EEs. Of all women, obese women overestimated daily EE the most.

Effects of alcohol on insulin-like growth factor I and insulin-like growth factor binding protein 3 in postmenopausal women.

BACKGROUND: Increased circulating insulin-like growth factor I (IGF-I) concentrations, frequently adjusted for IGF binding protein 3 (IGFBP-3), have been associated with increased risk of several types of cancer, including colon, prostate, and breast. Studies have suggested that alcohol may affect IGF-I or IGFBP-3; however, controlled feeding studies to assess alcohol's effects on IGF-I or IGFBP-3 have not been conducted. OBJECTIVE: To determine whether chronic, moderate alcohol intake affects serum IGF-I or IGFBP-3 concentrations, we performed a controlled, crossover feeding study. DESIGN: Fifty-three postmenopausal women were randomly assigned to consume 0 g (control), 15 g (one drink), or 30 g (2 drinks) alcohol daily for 8 wk and were rotated through the other 2 intake levels in random order. All foods and beverages were provided during the intervention. Individuals were monitored and calories adjusted to maintain constant weight, and serum was collected at the end of each diet period. RESULTS: Compared with the effects of 0 g alcohol/d, IGF-I concentrations were nearly unchanged by 15 g alcohol/d (0.8%; 95% CI: -3.2%, 3.5%) but decreased significantly by 4.9% (95% CI: -8.0%, -1.6%) with 30 g alcohol/d. IGFBP-3 concentrations significantly increased by 3.0% (95% CI: 0.4%, 5.6%) with 15 g alcohol/d but did not increase significantly with 30 g/d (1.8%; 95% CI: -0.9%, 4.5%). CONCLUSIONS: To our knowledge, this is the first published controlled diet study to find that in postmenopausal women, when weight is kept constant, alcohol consumption reduces the amount of serum IGF-I potentially available for receptor binding. These findings suggest that the effect of alcohol intake should be considered in studies of IGF-I, IGFBP-3, and cancer in postmenopausal women.

Effects of alcohol and menstrual cycle on insulin-like growth factor-I and insulin-like growth factor binding protein-3.

Alcohol ingestion and insulin-like growth factor-I (IGF-I) have been associated with increased breast cancer risk, the latter primarily in premenopausal women. We investigated whether alcohol ingestion altered IGF-I or its major binding protein (BP), IGFBP-3, in a controlled feeding study in premenopausal women. We also determined whether IGF-I or IGFBP-3 was affected by menstrual cycle phase. Serum was collected from 31 individuals who were randomly assigned to consume either 0 or 30 g (two drinks) of alcohol daily for three menstrual cycles and who then crossed over to the other alcohol level for three cycles. All calories were provided and weight was maintained during the study. For both alcohol levels, serum was collected during the final cycle at early follicular, periovulatory, and luteal phases. Relative to the follicular phase, IGF-I levels increased by 3.3% and 7.6% in the periovulatory and luteal phases, respectively (P for trend = 0.004). Although alcohol ingestion did not affect this increase, it significantly reduced IGF-I concentrations at all phases (9.5%; P < 0.001), whereas IGFBP-3 was unaffected by either menstrual phase or alcohol. This is the first controlled diet study to show that alcohol decreases serum IGF-I in premenopausal women and that IGF-I significantly increases over the course of the menstrual cycle whether or not alcohol is present.

Relationship between serum leptin levels and alcohol consumption in a controlled feeding and alcohol ingestion study.

We examined serum leptin levels in a controlled feeding and alcohol ingestion study to elucidate potential mechanisms by which alcohol may affect cancer and immunologically related health risks. A total of 53 healthy, nonsmoking postmenopausal women completed a random-order, three-period crossover design study in which each woman received zero (0 g of alcohol), one (15 g of alcohol), or two (30 g alcohol) drinks per day. After accounting for differences in body mass index, women who consumed 15 or 30 g of alcohol per day had 7.3% (95% confidence interval [CI] = 3.0% to 15.1%) and 8.9% (95% CI = 1.6% to 16.7%) higher serum leptin levels, respectively (P(trend) =.018), than women who consumed 0 g of alcohol per day. Younger women (i.e., 49-54 years) demonstrated a statistically significantly larger association of alcohol consumption level with the increase in serum leptin levels than older women (i.e., 55-79 years) (24.4%, 95% CI = 9.3% to 42.0% versus 3.7%, 95% CI = -4.1% to 12.1% increase in serum leptin levels for 30 g of alcohol per day relative to 0 g of alcohol per day for the lowest age quartile compared with the three highest age quartiles combined; P =.022). These results indicate that moderate alcohol consumption (15-30 g of alcohol per day) increases serum leptin levels in postmenopausal women and may predispose moderate drinkers to the morbidities associated with chronic elevations of this hormone including cancer.

Effects of moderate alcohol intake on fasting insulin and glucose concentrations and insulin sensitivity in postmenopausal women: a randomized controlled trial.

CONTEXT: Epidemiologic data demonstrate that moderate alcohol intake is associated with improved insulin sensitivity in nondiabetic individuals. No controlled-diet studies have addressed the effects of daily moderate alcohol consumption on fasting insulin and glucose concentrations and insulin sensitivity. OBJECTIVE: To determine whether daily consumption of low to moderate amounts of alcohol influences fasting insulin and glucose concentrations and insulin sensitivity in nondiabetic postmenopausal women. DESIGN, SETTING, AND PARTICIPANTS: Randomized controlled crossover trial of 63 healthy postmenopausal women, conducted at a clinical research center in Maryland between 1998 and 1999. INTERVENTIONS: Participants were randomly assigned to consume 0, 15, or 30 g/d of alcohol for 8 weeks each as part of a controlled diet. All foods and beverages were provided during the intervention. An isocaloric beverage was provided in the 0-g/d arm. Energy intake was adjusted to maintain constant body weight. MAIN OUTCOME MEASURES: Fasting insulin, triglyceride, and glucose concentrations, measured at the end of each dietary period; insulin sensitivity, estimated with a published index of glucose disposal rate corrected for fat-free mass based on fasting insulin and fasting triglyceride concentrations, compared among treatments with a mixed-model analysis of variance. RESULTS: A complete set of plasma samples was collected and analyzed for 51 women who completed all diet treatments. Consumption of 30 g/d of alcohol compared with 0 g/d reduced fasting insulin concentration by 19.2% (P =.004) and triglyceride concentration by 10.3% (P =.001), and increased insulin sensitivity by 7.2% (P =.002). Normal-weight, overweight, and obese individuals responded similarly. Only fasting triglyceride concentration was significantly reduced when comparing 0 and 15 g/d of alcohol (7.8%; P =.03), and no difference was found between consumption of 15 and 30 g/d of alcohol; however, there was a significant linear trend (P =.001). Fasting glucose concentrations were not different across treatments. CONCLUSIONS: Consumption of 30 g/d of alcohol (2 drinks per day) has beneficial effects on insulin and triglyceride concentrations and insulin sensitivity in nondiabetic postmenopausal women.

Moderate alcohol consumption lowers risk factors for cardiovascular disease in postmenopausal women fed a controlled diet.

BACKGROUND: Moderate alcohol consumption (1-2 drinks/d) may decrease cardiovascular disease risk in postmenopausal women by improving lipid profiles. OBJECTIVE: We measured the effect of moderate alcohol consumption on lipids and lipoproteins in postmenopausal women. DESIGN: Postmenopausal women (n = 51) consumed 0 (control), 15 (1 drink), and 30 (2 drinks) g alcohol (ethanol)/d for 8 wk each as part of a controlled diet in a randomized crossover design. The control diet provided approximately 15%, 53%, and 32% of energy from protein, carbohydrate, and fat, respectively. The energy provided from alcohol in the 15- and 30-g alcohol diets was replaced with energy from carbohydrate. RESULTS: Compared with concentrations after the control diet, plasma LDL cholesterol decreased from 3.45 to 3.34 mmol/L (P = 0.04) and triacylglycerol from 1.43 to 1.34 mmol/L (P = 0.05) after 15 g alcohol/d. There were no additional significant decreases in either lipid after an increase in alcohol intake from 15 to 30 g/d. Compared with concentrations after the control diet, plasma HDL cholesterol increased nonsignificantly from 1.40 to 1.43 mmol/L after 15 g alcohol/d but increased to 1.48 mmol/L after 30 g alcohol/d (P = 0.02). Apolipoprotein A-I increased significantly and apolipoprotein B decreased significantly after 30 g alcohol/d relative to the concentration after the control diet. CONCLUSIONS: Consumption of 15-30 g alcohol/d by postmenopausal women apparently decreases cardiovascular disease risk by improving lipid profiles. Plasma LDL-cholesterol and triacylglycerol concentrations improve after 15 g alcohol/d; plasma HDL cholesterol improves only after 30 g alcohol/d.