RELATIONSHIPS AMONG BMI, ESTRADIOL, AND STRESS REACTIVITY IN WOMEN

PURPOSE: Research suggests that women are nearly twice as likely to develop mood and anxiety disorders, compared to men, and it has been suggested that reproductive-related hormones, such as estradiol (E2), may play a key role in increased susceptibility to mood and anxiety disorders in some women, perhaps via impacts on behavioral and physiological responses to psychosocial stressors. Additionally, body mass index (BMI) has been shown to be inversely associated with E2 levels in premenopausal women, and previous studies have also suggested that women who are overweight or obese are at higher risk for the development of mood and anxiety disorders. In order to examine potential causal mechanisms in these relationships, this study aimed to examine associations between BMI, E2, and behavioral and physiological responses to an acute psychosocial stressor in premenopausal women. METHODS: Following a two-tiered screening process, 27 healthy women (18-45y, mean age: 22.9y) who were medication-free and had regular menstrual cycles completed: (1) enrollment visit, (including anthropometrics, and measures of mood, resilience); (2) salivary E2 collection, and (3) a psychosocial stressor protocol for the assessment of affective and salivary cortisol responses to stress. Both E2 assessment and the psychosocial stressor protocol were conducted during the follicular phase of the menstrual cycle to control for ovarian cycle E2 fluctuations. RESULTS: Higher BMI was significantly associated with lower salivary E2 levels (r = -.43, p = 0.02), and lower E2 levels were significantly associated with increased levels of sadness and feeling overwhelmed during the psychosocial stressor protocol (r = -.40, p = 0.04 and r = -0.39, p = 0.04, respectively). Lower E2 levels were also associated with lower cortisol (r = 0.36, p = 0.06, trend) output across the acute psychosocial stressor. CONCLUSIONS: Our findings suggest that lower E2 levels may be associated with a more negative affective and hormonal response to acute stressors, and that there may be a modifying role of BMI in this relationship. Considering that regular physical activity is inversely associated with BMI, our findings suggest a potential protective role for PA in the pathophysiology of women’s mood and anxiety disorders, however more research is needed in this area. Leslie H. and Evelyn G. Garner Faculty Leadership Award and the Wells Fargo Student/Faculty Research Award