Sleep duration and apolipoprotein B in metabolically healthy and unhealthy overweight/obese phenotypes: a cross-sectional study in Chinese adults.

Objectives Short sleep duration is independently associated with an increased risk of developing cardiovascular disease; however, the association has not yet been examined in obese populations. We assessed the associations between sleep duration, metabolic phenotype and apolipoprotein variables in a nationally representative Chinese population with overweight/obesity. Study design Cross-sectional study. Settings The study conducted in nine provinces of China that vary substantially in geography and economic development. Patients Data were obtained from 4149 adults with overweight/obesity aged 18 to 94 years from the 2009 China Health and Nutrition Survey. Sleep duration was categorised as <= 6, 7-8 or >= 9 hour. Phenotypes were determined based on body mass index and metabolic health status and categorised as metabolically healthy overweight/obesity (MHOO) and metabolically unhealthy overweight/obesity (MUOO). Main outcome measure The outcome variables were elevated apolipoproteins. Results Compared with MHOO phenotype, MUOO phenotypes were more likely to report shorter sleep duration (12.2% vs9%). In the MUOO group, the multivariate-adjusted OR (95% CI) for elevated apolipoprotein B (apoB) was 1.66 (1.23 to 2.23) for those with <= 6 hours of sleep and 1.12 (0.86 to 1.45) for those with >= 9 hours of sleep, using 7-8 hours of sleep as a reference. Similar results were obtained in the subgroup of subjects who were >= 45 or < 45 years old, but shorter sleep duration was more strongly associated with elevated apoB in those <45 years (p interaction=0.023). However, no association was observed in the MHOO phenotype. Conclusions The high prevalence of short sleep duration and its strong association with elevated apoB in adults who are metabolically unhealthy overweight/obese suggest an increased risk of cardiovascular disease in this population. The differences in sleep sufficiency among obese phenotypes may account for the disparities in their cardiovascular outcomes.