Body Composition Impact on Sleep in Young Adults: The Mediating Role of Sedentariness, Physical Activity, and Diet

The authors would like to express their gratitude to Imran Khan for the language and editing assistance.Obesity and sleep disturbances are both related to endocrine and metabolic alterations, cardiovascular disease, and impaired daytime functioning and mood. However, the bidirectional relationship between these conditions and the underlying mechanisms still remain unclear. This study aimed to investigate the potential association of anthropometric and body composition parameters with sleep in young adults, considering the mediating role of sedentariness, physical activity, and diet. A total of 187 adults aged 18–25 (35.29% men) participated in the study. Body mass index (BMI), waist–hip ratio, and waist–height ratio were calculated, and a dual-energy X-ray absorptiometry scanner was used to assess body composition. Sedentary time and physical activity, as well as sleep duration and quality, were objectively and subjectively measured using accelerometry and the Pittsburgh Sleep Quality Index. An inverse association was found between BMI and total sleep time (β = −0.165, p = 0.029). Waist–hip ratio and lean mass index were also negatively associated with total sleep time (β = −0.222, p = 0.007, and β = −0.219, p = 0.004) and sleep efficiency (β = −0.174, p = 0.037, and β = −0.188, p = 0.013). Sedentary time moderated by sex explained the association of BMI with total sleep time such that a high BMI was related to higher sedentariness in men which, in turn, was significantly associated with shorter sleep duration. Sedentary time is, therefore, a link/risk factor mediating the association of high BMI with short sleep duration in healthy young men.Spanish Ministry of Economy and Competitiveness via the Fondo de Investigacion Sanitaria del Instituto de Salud Carlos III PI13/01393Spanish Ministry of Economy and Competitiveness via Retos de la Sociedad DEP2016-79512-RSpanish Ministry of Economy and Competitiveness via European Regional Development Funds (ERDF)Spanish Government FPU16/01093Spanish Ministry of Education and Science (Red EXERNET) DEP2005-00046Fundacion Iberoamericana de Nutricion (FINUT)Redes Tematicas de Investigacion Cooperativa RETIC (Red SAMID) RD16/0022AstraZenecaUniversity of Granada Plan Propio de Investigacion 2016 Excellence actions: Unit of Excellence on Exercise and Health (UCEES)Junta de Andalucia, Consejeria de Conocimiento, Investigacion y Universidades (ERDF) SOMM17/6107/UG