Examining the relationship between circulating estradiol and physical health in postmenopausal breast cancer survivors.
The Women's Healthy Eating and Living (WHEL) Study was a randomized controlled trial to examine the effect of a high-vegetable, low-fat diet on breast cancer recurrence and mortality among breast cancer survivors. Among WHEL Study participants, poorer physical health, as defined by an SF-36 Health Survey score in the 40th percentile or lower, was associated with higher risk of additional breast cancer events and all-cause mortality estradiol was also positively related to breast cancer recurrence. In the current analysis, we hypothesized that higher estradiol was associated with poor physical health. Therefore, in a population of 1,027 WHEL Study postmenopausal breast cancer survivors, we examined the relationship between circulating estradiol concentrations at enrollment and poor physical health. Using multivariate logistic regression modeling, higher estradiol levels were associated with risk of poorer physical health. However, these elevated levels appeared to be a marker for larger body size : after adjusting for body mass index (BMI), the association between estradiol and poorer physical health disappeared. This suggests that estradiol and BMI are not independent risk factors for poor physical health estradiol may instead be in the mechanistic pathway between obesity and poor physical health.