Houghton LC, et al. - The association between estrogen metabolism in premenopausal women and early life body fatness was investigated. An inverse association of estimates of body fatness during early life with premenopausal levels of all estrogen metabolites (EM) combined, parent estrogens, and 2-pathway estrogen metabolites was shown. Adult body mass index (BMI) failed to completely explain these links.

Methods

• A validated 9-level pictogram was used by premenopausal women participating in the Nurses’ Health Study II to recall their body fatness at ages 5, 10, and 20 years.
• Using LC/MS-MS in luteal phase urines from 603 women ages 32–54 years, 15 estrogens and estrogen metabolites (EM) were measured.
• Linear mixed models were used to examine geometric means of individual EM, metabolic pathway groups, and pathway ratios by body fatness categories.

Results

• Body fatness at each age was found to be inversely related to adult concentrations of all EM combined, parent estrogens (estrone, estradiol), and the 2-hydroxylation pathway.
• Researchers found that women in the top (vs bottom) category of body fatness at age 10 had 21% lower levels of all EM (P_trend=0.003), 24% lower parent estrogens (P_trend=0.002), and 36% lower 2-pathway (P_trend=0.0003).
• Body fatness at age 10 was shown to be inversely related to 2-catechols (35% lower, P_trend=0.0004) and 2-methylated catechols (30% lower, P_trend=0.002).
• These links continued to be inverse but were attenuated after adjusting for premenopausal body mass index (BMI); only parent estrogens remained statistically significant (21% lower, P_trend=0.01).
• Body fatness at ages 5 and 20 were found to be similarly, but more weakly, related to estrogen pathways.