Is poor sleep associated with obesity in older adults? A narrative review of the literature

Introduction To address the worldwide epidemic of obesity, a sizable literature implicates sleep problems in the onset of obesity in younger populations. However, less is known about how this process may operate among older adults, which is of concern, given demographic shifts that have resulted in a much higher proportion of developed nations around the world reaching late life. Methods We offer a current review of the literature studying older adults and examining associations between sleep quality and obesity in this population. We consider both subjective and objectively measured sleep as well as both cross-sectional and longitudinal studies offering stronger causal inference. Results We discuss seemingly contradictory literature showing that shorter sleep duration as well as longer sleep duration are associated with obesity risk, then review studies that tested for non-linear relationships and reported a U-shape pattern, suggesting that too much or too little sleep is detrimental. Besides sleep duration, we discuss evidence showing that other forms of sleep dysfunction related to night-time awakenings, REM sleep, slow-wave sleep, and daytime sleepiness, which are indicators of sleep quality, are also linked to obesity. Specific psychological and physiological mediators and moderators, suggesting possible mechanisms whereby sleep problems may affect obesity in older adults, are described. Conclusion We conclude by discussing areas, where additional research could help clarify this association, considering such factors as medical comorbidities common in late life, and health-related behaviors that may stem from poor sleep (such as disordered eating behavior). Such insights will have great value for clinical practice.