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The Role of Psychosocial Stress in the Etiology of Exercise-Associated Menstrual Disturbances
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Etter, Clara V
Master of Science
Date of Defense:
November 08, 2017
Nancy Williams, Thesis Advisor
Mary Jane De Souza, Committee Member
Lorah D Dorn, Committee Member
Abstract Background: Low energy availability and psychosocial stress have been shown to suppress reproductive function in mammals independently and in combination. The unique contributions of psychosocial stress on the severity of exercise associated menstrual dysfunction have not been identified and there are few prospective studies that demonstrate such effects. Objectives: To determine the contribution of psychosocial stress to the induction of menstrual disturbances in response to a diet and exercise program that induced modest weight loss. We tested the hypothesis that increases in psychosocial stress were associated with the induction of menstrual disturbances during the original intervention. Design: A secondary analysis was performed on data collected during a prior randomized controlled trial designed to assess the impact of three months of low (8 ± 2%), moderate (22 ± 3%), or high (42 ± 3%) levels of an energy deficit created through varying combinations of controlled caloric restriction and supervised exercise on menstrual function in ovulatory, sedentary women. We tested the hypothesis that increases in psychosocial stress were associated with the induction of menstrual disturbances during the original intervention. Methods: In the original trial, 36 women (age 18-24 yrs, BMI 21-29 kg/m2) were studied during a Baseline menstrual cycle followed by three successive menstrual cycles during which they exercised 5 d/wk, 50-85% VO2max for 20-75 min and all food was provided to participants according to study group assignment. Metabolic and anthropometric measures were repeated throughout the intervention. Menstrual disturbances (luteal cycle defects, oligomenorrhea, and anovulation) were detected using daily measures of urinary estrone-1-glucuronide (E1G), pregnanediol glucuronide (PdG), mid-cycle luteinizing hormone (LH) and menstrual calendars. Perceived stress was measured every two weeks with the 14-item Perceived Stress Scale (Cohen, 1983). For the secondary analysis, logistic regression and chi-square analyses were performed to test the association between perceived stress and menstrual disturbances induced during the intervention. For some analyses, participants were divided into tertiles based on their change in perceived stress across the intervention: Low Stress -12.5 to 0.5 (n = 13), Moderate Stress 1.0 to 4.5 (n = 11), and High Stress 5.0 to 36.5 (n = 12). ANOVA was used to detect group differences in reproductive hormone secretion and other measures. Baseline anthropometrics, age, aerobic fitness, scores for depression and eating attitudes, and reproductive factors were investigated as possible contributors to the change in perceived stress. Results: The intervention caused moderate weight loss (-2.57 ± 0.35 kg) and increases in aerobic fitness (p < 0.01). The change in perceived stress was a significant predictor of anovulatory cycles during the intervention such that each unit increase in change in perceived stress was associated with a 23% increase (odds ratio 1.23, 1.03 - 1.47, 95% CI) in the odds of an anovulatory cycle occurring during the intervention (p = 0.021). Changes in perceived stress were associated with Baseline luteal phase PdG AUC (r = -0.39, p = 0.02) and the change in BMI (r = 0.42, p = 0.01) such that higher Baseline PdG concentrations and greater reductions in BMI were associated with smaller increases in perceived stress. Conclusions: The study suggests that the severity of menstrual disturbances in the context of energy deficiency is related to increased psychosocial stress. Moreover, susceptibility to increases in psychosocial stress and thus more severe menstrual disturbances may be associated with suppressed baseline luteal phase progesterone and less than expected declines in BMI in untrained women who participate in programs with the goal of improving fitness and losing weight.
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