Predictors of breast discomfort among women initiating menopausal hormone therapy

The aim of this study was to analyze the determinants of breast discomfort among postmenopausal women initiating menopausal hormone therapy (HT).

We analyzed questionnaire, anthropometric, and serum estrone data from the Postmenopausal Estrogen/Progestin Interventions (PEPI) Trial, a randomized trial comparing placebo, conjugated equine estrogens (CEE) alone, or CEE with a progestogen (continuous or cyclical medroxyprogesterone acetate or cyclical micronized progesterone) among postmenopausal women. HT users could join the PEPI Trial after stopping HT for 2 months. We modeled the relation between smoking, body weight, alcohol consumption, age, quitting HT for the PEPI Trial, physical activity, and alpha-tocopherol consumption and new-onset breast discomfort at the 12-month follow-up among 662 participants without baseline breast discomfort.

The associations of new-onset breast discomfort with weight and with strenuous exercise varied by treatment assignment. Among women assigned to CEE + progestogen, strenuous exercise was associated with a 49% lower odds of new-onset breast discomfort (odds ratio, 0.51; 95% CI, 0.29-0.89; P = 0.02), whereas among women assigned to placebo or CEE alone, strenuous exercise was not significantly associated with new-onset breast discomfort. Surprisingly, among women taking CEE alone, each kilogram higher weight was associated with a 6% lower odds of new-onset breast discomfort (P = 0.04), whereas among women taking placebo, the association was in the opposite direction (P = 0.04). Adjustment for estrone level had negligible effects on odds ratios. alpha-Tocopherol intake, age, smoking, and alcohol intake were not significantly associated with new-onset breast discomfort in adjusted analyses.

Strenuous exercise and higher body weight may decrease the odds of new-onset breast discomfort among postmenopausal women initiating HT.