Association of lifestyle with mortality and the mediating role of aging among older adults in China

1) examine the association between lifestyle and mortality; 2) examine the association between two aging measures and mortality; 3) evaluate the mediating effect of the two aging measures on the association between lifestyle and mortality among older Chinese adults. We used data from 2039 older adults (≥ 65 years) from the 2011/2012 biomarker substudy of the Chinese Longitudinal Healthy Longevity Survey (CLHLS). We created a healthy lifestyle index based on 5 factors (exercise, smoking, drinking, diet, and BMI, range: 0–5). We calculated two aging measures, the Klemera and Doubal method-biological age (KDM-BA) and physiological dysregulation (PD), based on 10 blood-based biomarkers using algorithms developed previously. A Cox proportional hazards model, general linear regression model, and formal mediation analysis were performed. After adjustment for age and sex, compared to participants without any healthy lifestyle factors, those with 5 healthy lifestyle factors had an 85% lower risk of mortality (hazard ratio [HR] = 0.15, 95% confidence interval [CI]: 0.04, 0.60). PD, but not KDM-BA, was significantly associated with mortality (HR = 1.69, 95% CI: 1.25, 2.29). The healthy lifestyle index was negatively associated with PD (β = -0.021, P = 0.012). PD mediated 9% (95% CI: 1%, 52%, P = 0.043) of the total effect of the healthy lifestyle index on mortality. In the older Chinese population, healthy lifestyle reduces mortality risk and aging partially mediates this association. The findings highlight the importance of adherence to a healthy lifestyle for promoting phenotypic aging even in late life.