The prevalence of obesity has rapidly increased in the US since the late 1970s, which has serious population health and economic ramifications. Over this same period, the US population has also exhibited shorter average sleep duration and increased prevalence of sleep-disruptive disorders. The concomitant timing of these trends suggests that they may be related?a theory supported by several observational and short-term experimental studies indicating that short sleep promotes weight gain and obesity. However, there is no consensus regarding the impact of sleep on body habitus among adults because extant research has produced a range of findings (e.g., linear, U-shaped, or null associations). There are also unexplored questions about the relative importance of sleep duration versus sleep quality with respect to weight gain and obesity. Furthermore, there is scant longitudinal evidence that links short or disrupted sleep to long-term alterations in body habitus through specific physiological mechanisms (e.g., appetite-regulating hormones). To address these limitations, our investigation will address the following study aims:
Aim 1 : Comprehensively characterize the longitudinal associations of sleep duration and sleep quality with body habitus trajectories.
Aim 2 : Determine how the longitudinal associations between sleep parameters and body habitus trajectories characterized in the investigations of Aim 1 are mediated by several neuroendocrine hormones. To achieve these aims, we will conduct sophisticated longitudinal analyses of data from the population-based Wisconsin Sleep Cohort Study (WSCS). The WSCS has collected self- reported and objective measures of sleep duration, sleep quality, and body habitus on >1,100 adult subjects for nearly three decades. In addition, we will assay stored blood from WSCS participants?collected at the time participants had sleep and body habitus assessments. These assays will produce longitudinal neuroendocrine hormone data, providing us with an unparalleled data resource to examine the long-term associations among sleep, neuroendocrine hormones and body habitus.
Public Health Significance Findings from the proposed study Long-term trajectories of subjectively- and polysomnographically-assessed sleep patterns as predictors of neuroendocrine dysfunction and weight gain in adults?a continuing investigation of the Wisconsin Sleep Cohort Study (WSCS)?will contribute new knowledge of public health significance regarding the impact of short sleep duration and poor sleep quality on cumulative adverse changes in body habitus over middle age and older adulthood. The clarification of sleep-body habitus associations through longitudinal analyses of WSCS data will provide a stronger basis for clinical recommendations and public health initiatives with respect to sleep duration and sleep quality in the U.S. adult population.
