0422 A Meta-Analysis of Associations between Insomnia and Obesity in Adults

Abstract

Introduction: Short sleep duration and sleep disturbances are associated with increased risk of obesity. No systematic reviews have evaluated the evidence on whether insomnia disorder and insomnia-specific symptoms are associated with obesity or body mass. The present study is a meta-analysis of associations between the diagnosis and symptoms of insomnia and obesity in adults. Methods: A systematic search of four databases was conducted using keywords, “sleep disorder,” “sleep initiation and maintenance disorders,” “insomnia,” “obesity,” and “body mass index (BMI).” 3985 unique items were identified from 1/1/2006 to 8/30/2016. Studies were included if they reported data on the association between insomnia symptoms (difficulty initiating/maintaining sleep or early waking) or diagnosis (having insomnia symptoms for 3+ times per week for 2+ weeks with impairments/distress) and BMI or weight status. We excluded studies in samples that were exclusively sleep apnea patients. Multilevel random effects models were used to calculate the averages and variability of effect sizes. Results: Sixty-seven studies met criteria for the study. We found no publication biases and high heterogeneity in effect sizes across studies. Having an insomnia diagnosis was not significantly associated with increased risk of obesity (odds ratio=.80 [.39, 1.67], p=.61). A small cross-sectional correlation (r=.06 [.01, .12], p=.03) was found between insomnia symptoms and BMI. Longitudinal data were limited. Based on three studies, odds of developing future insomnia symptoms among those who had obesity were not significantly greater than normal- weight individuals (odds ratio=1.07 [.91, 1.26], p=.40). Only two studies examined associations between insomnia symptoms and future obesity and findings were inconsistent. Metaregressions showed effect sizes were larger in studies conducted in North America, published earlier, and used validated measures of insomnia. Conclusion: The present findings suggest that an insomnia diagnosis is not associated with obesity. Insomnia symptoms are minimally associated with BMI. The lack of longitudinal studies present challenges in fully evaluating the dynamic associations between insomnia and obesity. Future longitudinal research and research on the mechanisms underlying the association between sleep and obesity are needed to better understand the relationship between insomnia and obesity.