Relation between health-related quality of life and sleep quality with adjustment for comorbidity among the Korean elderly: Mixed-effects model with a 6-year follow-up study

It is an important public health problem to identify risk factors of health-related quality of life (HRQoL) among the elderly. We recruited subjects from Ansan, Korea, as a subset of the Korean Genome and Epidemiology Study (KoGES), which is an ongoing population study, and followed up their sleep quality for 6 years. Mixed effect models were used to estimate the association between sleep quality and HRQoL, and we found that overall HRQoL was significantly lower to the elderly having poor sleep quality with adjustment for significant covariates although sleep quality showed a significant interaction effect with time for the mental component summary of SF-12. In particular, the elderly having lack of quality sleep appeared to have good general health, but their functional performances were significantly poor.