Figure 1. The Association between sleep–wake habits and the use of health care services. EE: Early-bed/Early-rise; EL: Early-bed/Late-rise; LE: Late-bed/ Early-rise; LL: Late-bed/Late-rise. The models for all participants adjusted for age, sex, educational attainment, and marital status, number of chronic diseases, smoking, passive smoking, drinking, and exercise. The stratified analysis adjusted for all the covariates except for the stratified variable.