Abstract

OBJECTIVES
Healthy lifestyles are associated with lower mortality risk, but evidence among Asian populations with multimorbidity remains limited. We examined the association between lifestyle and all-cause mortality, stratified by morbidity status.
METHODS
We analysed 111,537 Korean adults aged 40–69 years from the Health Examinee cohort (2004–2020). Five lifestyle factors—smoking (pack-years), alcohol intake (g/day), physical activity (MET-hr/day), sleep duration (hr/day), and diet quality, assessed using the Korean Diet Quality Index—were standardised and regressed on mortality. Regression coefficients were positive for high-risk behaviours and negative for protective behaviours; these coefficients were summed to generate a weighted lifestyle score (WLS), with higher values indicating a less healthy lifestyle. We estimated hazard ratios (HRs) per standard deviation (SD) increase in WLS and across WLS tertiles (T1=healthiest, T3=least healthy), as well as years of life lost (YLL), stratified by morbidity status (none, 1 condition, or multimorbidity).
RESULTS
During a median follow-up of 10.6 years, 3,366 deaths occurred. A higher WLS was associated with a 21% increase in mortality risk among participants with multimorbidity. HRs and 95% confidence intervals (CIs) for T3 versus T1 were 1.40 (95% CI, 1.13 to 1.74) among participants with no disease, 1.68 (95% CI, 1.39 to 2.03) among those with 1 disease, and 1.62 (95% CI, 1.31 to 2.01) among those with multimorbidity. Associations were stronger among females with multimorbidity. At age 40 years, T3 was associated with YLL of 4.9 years in males and 4.3 years in females with multimorbidity.
CONCLUSIONS
A higher lifestyle score, indicating a less healthy lifestyle, was associated with reduced life expectancy, particularly among individuals with multimorbidity. These findings highlight the potential benefits of adopting a healthy lifestyle in this population subgroup.

• Keywords: Multimorbidity; Life style; Mortality; Life expectancy; Cohort studies