Abstract
BACKGROUND: Whether healthy lifestyles mediate the association of socioeconomic status (SES) with mortality in older people is largely unknown. METHODS: A total of 22,093 older participants (age ≥ 65 years) from 5 waves (2002-2014) of Chinese Longitudinal Healthy Longevity Survey cohort were included for analysis. Mediation analysis of lifestyles on the association of SES with all-cause mortality was conducted. RESULTS: During a mean follow-up period of 4.92 ± 4.03 years, 15,721 (71.76%) deaths occurred. Compared with high SES, medium SES increased the risk of mortality by 13.5% (HR [total effect]: 1.135, 95% CI 1.067-1.205, p < 0.001), and the total effect was not mediated by healthy lifestyles (mediation proportion: - 0.1%, 95% CI - 3.8 to 3.3%, p = 0.936). The total effect when participants of low SES were compared with participants of high SES was HR = 1.161 (95% CI 1.088-1.229, p < 0.001) for mortality, and the total effect was modestly mediated through healthy lifestyles (mediation proportion: - 8.9%, 95% CI - 16.6 to - 5.1%, p < 0.001). Stratification analyses by sex, age and comorbidities, as well as a series of sensitivity analyses indicated similar results. In addition, mortality risk showed a downward trend with increased number of healthy lifestyles within each SES level (all p for trend < 0.050). CONCLUSION: Promotion of healthy lifestyles alone can only reduce a small proportion of socioeconomic inequity-related mortality risk in older Chinese people. Even so, healthy lifestyles are important in reducing the overall mortality risk within each SES level.