Effects of low-to-moderate alcohol supplementation on urinary estrogen metabolites in postmenopausal women in a controlled feeding study

Associations of established breast cancer risk factors with urinary estrogens in postmenopausal women

PURPOSE

Circulating estrogens are an established risk factor for postmenopausal breast cancer (BCa). We describe the distribution of urinary estrogens, their metabolites, and relevant metabolic pathway ratios among healthy postmenopausal women and examine associations of several known BCa factors with these estrogen measures.

METHODS

Eligible postmenopausal women (n = 167) had no history of hormone use (previous 6 months) and cancer/metabolic disorders and had a body mass index (BMI) ≤ 35 kg/m². Estrogens were quantified in spot urine samples with liquid chromatography-high-resolution mass spectrometry and corrected for creatinine. We assessed overall distributions of estrogens and associations of age, BMI, race/ethnicity, parity/age at first birth, age at menarche, alcohol, and smoking with log-transformed estrogen measures using multivariate regression.

RESULTS

BMI was positively associated with estrone (β per unit = 0.04, 95% Confidence Interval [CI] 0.00; 0.07), combined parent estrogens (β = 0.04, 95% CI 0.01; 0.07), and E2:total estrogens (β = 0.04, 95% CI 0.02; 0.06), and inversely associated with 4-MeOE1 (β = - 0.17, 95% CI - 0.33; - 0.02), E3:parent estrogens (β = - 0.04, 95% CI - 0.07; - 0.00), and 16-pathway:parent (β = - 0.04, 95% CI - 0.07; - 0.01). Being African American vs. white was associated with higher levels of 4-MeOE1 (β = 3.41, 95% CI 0.74; 6.08), 17-epiE3 (β = 1.19, 95% CI 0.07; 2.31), 2-pathway:parent (β = 0.54, 95% CI 0.04; 1.04), and lower levels of E2:total estrogens (β = - 0.48, 95% CI - 0.83; - 0.13). Having < 7 alcohol drinks/week vs. none was associated with higher levels of 16-ketoE2 (β = 1.32, 95% CI 0.36; 2.27), 16-epiE3 (β = 1.02, 95% CI 0.24; 1.79), and 17-epiE3 (β = 0.55, 95% CI 0.02; 1.08). Smoking was positively associated with E3:parent (β = 0.29, 95% CI 0.01; 0.57), 16-pathway:parent (β = 0.25, 95% CI 0.01; 0.49), and inversely associated with estradiol (β = - 0.52, 95% CI - 0.93; - 0.10). As compared to nulliparous, parous women with age at first birth ≥ 25 years had lower levels of estrone, combined parent estrogens, 2-OHE1, and 2-OHE2.

CONCLUSION

Our findings suggest that BMI, race/ethnicity, and some reproductive and lifestyle factors may contribute to postmenopausal BCa through their effects on circulating estrogens.

Epidemiology of Moderate Alcohol Consumption and Breast Cancer: Association or Causation?

Epidemiological studies have been used to show associations between modifiable lifestyle habits and the incidence of breast cancer. Among such factors, a history of alcohol use has been reported in multiple studies and meta-analyses over the past decades. However, associative epidemiological studies that were interpreted as evidence that even moderate alcohol consumption increases breast cancer incidence have been controversial. In this review, we consider the literature on the relationship between moderate or heavy alcohol use, both in possible biological mechanisms and in variations in susceptibility due to genetic or epigenetic factors. We argue that there is a need to incorporate additional approaches to move beyond the associations that are reported in traditional epidemiological analyses and incorporate information on molecular pathologic signatures as a requirement to posit causal inferences. In particular, we point to the efforts of the transdisciplinary field of molecular pathological epidemiology (MPE) to evaluate possible causal relationships, if any, of alcohol consumption and breast cancer. A wider application of the principles of MPE to this field would constitute a giant step that could enhance our understanding of breast cancer and multiple modifiable risk factors, a step that would be particularly suited to the era of "personalized medicine".

Effects of low-to-moderate alcohol supplementation on urinary estrogen metabolites in postmenopausal women in a controlled feeding study

Heavy alcohol drinking is associated with increased breast cancer risk, but associations with low‐to‐moderate alcohol consumption are less clear and the biological mechanisms are not well defined. The objective of this study was to evaluate the effects of 8 weeks of low (15 g/d) and moderate (30 g/d) alcohol ingestion on concentrations of 15 urinary estrogen metabolites (EMs) in postmenopausal women (n = 51) in a controlled feeding study with a randomized crossover design. Compared to no alcohol, 15 g/day for 8 weeks had no effect on urinary EMs. However, compared to no alcohol, 30 g/day for 8 weeks decreased urinary 2‐hydroestrone (2‐OHE1) by 3.3% (P = 0.055) and increased 16‐epiestriol (16‐EpiE3) by 26.6% (P = 0.037). Trends for reduced urinary 2‐OHE1 (P = 0.045), reduced ratio of 2‐OH:16OH pathways (P = 0.008), and increased 16‐EpiE3 (P = 0.035) were observed as alcohol ingestion increased from 0 g to 15 g to 30 g/d. Moderate alcohol consumption for 8 weeks had modest effects on urinary concentrations of 2‐OHE1 and 16‐EpiE3 among postmenopausal women in a carefully controlled feeding study.