0097 Sleep and Eating Rhythms are Associated with Metabolic Risk in Postmenopausal Women

Abstract Introduction Postmenopausal women are particularly vulnerable to metabolic dysfunction. Compelling evidence suggests that this is due to their lacking the protective effect of estrogens. We have shown that circulating estrogens regulate daily eating and sleep-activity rhythms in female mice and protect them from obesity and diabetes. However, few studies have investigated whether postmenopausal women have disrupted eating and sleep-activity rhythms that could contribute to their metabolic dysfunction. The purpose of this study was to investigate the relationship between eating rhythms, sleep, and metabolic risk in postmenopausal women. Methods During 7 days, we studied sedentary, postmenopausal women who were not taking hormones (estrogens ± progestin) and were metabolically unhealthy, defined as prediabetic or normal glucose tolerance with at least 1 feature of the metabolic syndrome. Women taking medications affecting sleep or eating were excluded. Sleep timing and quality were assessed by actigraphy and sleep logs. Times of first and last meals were collected from participants with a texting system. Body composition (DXA), body mass index (BMI), and waist circumference were collected as markers of obesity. Lipid metabolism and glycemic control were assessed by fasting lipid panel and HbA1c as well as oral glucose tolerance test. Results Eighteen postmenopausal women (mean ± SEM; 57.2 ± 1.1 years) participated in the study. Both sleep timing and quality were associated with metabolic risk in postmenopausal women. Specifically, later timing of sleep onset was associated with later meal timing and greater BMI and body fat percentage. Increased sleep fragmentation was associated with reduced HDL. In addition, both the timing and duration of eating were associated with worse metabolic measures. Longer eating duration was associated with larger waist circumference. Later eating time was associated with greater waist circumference and BMI. Conclusion We found that late timing and poor quality of sleep, as well as long eating duration, are associated with markers of metabolic risk in postmenopausal women. These data suggest that interventions that reduce eating duration and advance the timing of last meal and sleep onset may improve metabolic risk in postmenopausal women. Support (if any) This study is supported by NIH awards R01DK124774, T32 AG078110, and UL1TR001998.