Abstract
BACKGROUND: An alarming bidirectional relationship exists between prolonged sleep duration and obesity. However, obesity exhibits metabolic heterogeneity, and the cardiometabolic index (CMI) serves as a potential indicator of visceral fat distribution and function. The relationship of metabolic heterogeneity of obesity, CMI and sleep trajectory remain unclear. METHODS: A total 6359 participants from the China Health and Retirement Longitudinal Study were included. Metabolic heterogeneity of obesity was evaluated based on four obesity and metabolic phenotypes as metabolically healthy normal weight (MHNW), metabolically unhealthy normal weight (MUNW), metabolically healthy overweight/obesity (MHOO), and metabolically unhealthy overweight/obesity (MUOO). CMI was calculated using the established formula: (TG/HDL-C) × WHtR, where WHtR indicates waist-to-height ratio. Sleep duration trajectories from 2011 to 2020 were identified using group-based trajectory modeling. RESULTS: Four trajectories were identified in the total sleep duration: the decreasing (8.5%), the short stable (36.8%), the normal stable (49.1%) and the increasing (5.6%). In the increasing sleep group, individuals with MUOO (OR = 1.594, 95%CI: 1.163 ~ 2.161, P = 0.003) or higher CMI (OR = 1.495, 95%CI: 1.159 ~ 1.930, P = 0.002) exhibited a significantly higher risk of increasing sleep duration trajectory over time in the comparison with normal stable sleep group. Compared to normal stable sleep trajectory, MUOO in the both decreasing and short sleep group demonstrated attenuated progression toward shortened sleep duration over time. CONCLUSION: High CMI level and metabolically unhealthy overweight/obesity promoted the progression toward longer sleep duration. Our finding highlighted that greater attention be given to metabolism status and visceral fat for improving sleep quality.