Increased altitudes change sleep status among Chinese population

Sleep is integral to human health. Accumulating evidence has revealed that sleep characteristics could be influenced by altitudes. However, few studies explored what the trajectories of sleep status are along with the altitudes. Therefore, this study aims to find the relationship between altitudes and sleep status using data from CHARLS, a nationwide survey data from China. The generalized additive model and generalized additive mixed-effects model were used to explore the association between sleep status and altitudes. Age, gender, education level, and other common confounding factors were included in the models as covariates. The sleep duration showed a rapid increase trend after the altitude of 1600 m. The probabilities of long sleep duration were increased with the evaluation of altitudes (edf = 1.945, P = 0.004), while the similar statistically significant change was not observed for short sleep duration (edf = 2.204, P = 0.193). Gender, residence, and ethnicity were the main influencing factors for the increase in sleep duration as altitude increased. The high-altitude environment could have effects on the sleep status of individuals, especially on the sleep duration. Long sleep duration was found more prevalent among highlanders. This study shed light on the underlying relationship between altitudes and sleep status which could provide clues for further mechanism studies.