Abstract
BACKGROUND: Declines in health, physical, cognitive, and mental function with age suggest a lower level of health-related quality of life (HRQoL) in late life; however, previous studies found that the associations were weak and varied, depending on the study designs and cohort characteristics. METHODS: The present study examined the paradox of aging in an East Asian context by regressing the age patterns of objective health indicators (physical, cognitive, and mental function), and subjective HRQoL (12-item Short Form, SF-12), on the independent and interactive effects of age and physical function in a cohort study of 5022 community-dwelling adults aged 55 and older in Taiwan. RESULTS: Age patterns differed across measures. The SF-12 mental health score (MCS) showed a slight positive association with age and this effect remained stable after controlling for various age-related covariates. The SF-12 physical health score (PCS), in turn, was negatively associated with age. Age differences in PCS were fully explained by age decrements in objective physical health. However, consistent with the so-called paradox of aging, the association between objective and subjective physical health weakened with age. CONCLUSION: These findings add to prior evidence indicating that - in spite of objective health decrements - subjective HRQoL is maintained in later life among Asian Chinese. Also, these paradoxical patterns appear to vary for mental and physical components of HRQoL, and future research is needed to explore the underlying mechanism. TRIAL REGISTRATION: Healthy Aging Longitudinal Study in Taiwan (HALST) is retrospectively registered at ClinicalTrials.gov on January 24, 2016 with trial registration number NCT02677831.