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

Abstract

Objectives: 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.

Methods: 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.

Results: 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.

Conclusions: 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.

Keywords: Aging; Lifestyle; Mediation analysis; Mortality; Older adults.