A higher lifestyle score, indicating a less healthy lifestyle, was associated with reduced life expectancy, particularly among individuals with multimorbidity.
Key Findings
Results
A higher weighted lifestyle score (indicating a less healthy lifestyle) was associated with a 21% increase in mortality risk among participants with multimorbidity.
The weighted lifestyle score (WLS) was derived from five lifestyle factors: smoking (pack-years), alcohol intake (g/day), physical activity (MET-hours/day), sleep duration (hours/day), and diet quality assessed using the Korean Diet Quality Index.
Regression coefficients were positive for high-risk behaviors and negative for protective behaviors, then summed to generate the WLS.
Hazard ratios were estimated per standard deviation (SD) increase in WLS, stratified by morbidity status.
The 21% increase in mortality risk per SD increase in WLS was specific to the multimorbidity subgroup.
The study followed 111,537 Korean adults aged 40-69 years from the Health Examinee cohort (2004-2020) with a median follow-up of 10.6 years, during which 3,366 deaths occurred.
Results
The association between unhealthy lifestyle (T3 vs. T1 WLS tertile) and mortality risk was present across all morbidity strata but varied in magnitude.
HR for T3 vs. T1 among participants with no disease: 1.40 (95% CI: 1.13-1.74).
HR for T3 vs. T1 among participants with 1 disease: 1.68 (95% CI: 1.39-2.03).
HR for T3 vs. T1 among participants with multimorbidity: 1.62 (95% CI: 1.31-2.01).
T1 represented the healthiest lifestyle tertile and T3 the least healthy lifestyle tertile.
The association was strongest among those with 1 disease condition based on point estimates.
Results
Associations between unhealthy lifestyle and mortality were stronger among women with multimorbidity compared to men with multimorbidity.
Sex-stratified analyses were conducted within each morbidity subgroup.
The stronger association in women with multimorbidity was a notable finding highlighted in the results.
The study population consisted of Korean adults aged 40-69 years from the Health Examinee cohort.
Results
An unhealthy lifestyle (T3 vs. T1) was associated with substantial years of life lost (YLL) among individuals with multimorbidity.
At age 40 years, T3 was associated with YLL of 4.9 years in men with multimorbidity.
At age 40 years, T3 was associated with YLL of 4.3 years in women with multimorbidity.
YLL was estimated stratified by morbidity status (none, 1 condition, or multimorbidity).
These estimates reflect the potential life expectancy difference between the least healthy and healthiest lifestyle tertiles.
Methods
The study analyzed five lifestyle factors in 111,537 Korean adults to generate a weighted lifestyle score for examining mortality associations stratified by morbidity.
Participants were aged 40-69 years from the Health Examinee cohort (2004-2020).
Morbidity was categorized as none, 1 condition, or multimorbidity (2 or more conditions).
The five lifestyle factors were smoking (pack-years), alcohol intake (g/day), physical activity (MET-hours/day), sleep duration (hours/day), and diet quality.
Diet quality was assessed using the Korean Diet Quality Index.
Standardized regression coefficients were used to weight each lifestyle factor before summing into the composite WLS.
What This Means
This research suggests that having an unhealthy lifestyle — including heavy smoking, high alcohol consumption, low physical activity, poor sleep, and a low-quality diet — is linked to a significantly higher risk of death, particularly among Korean adults who already have multiple chronic health conditions (multimorbidity). The study followed over 111,000 Korean adults between the ages of 40 and 69 for about 10 years and found that people with the least healthy lifestyles had roughly 40–68% higher mortality risk compared to those with the healthiest lifestyles, depending on how many chronic conditions they had. Among people with multimorbidity specifically, those with the unhealthiest lifestyles faced around a 62% higher risk of death compared to those with the healthiest lifestyles.
The research also found that the impact of an unhealthy lifestyle was particularly pronounced in women with multiple chronic conditions, and that an unhealthy lifestyle was associated with losing nearly 5 years of life by age 40 in men and 4.3 years in women with multimorbidity. This suggests that lifestyle choices have measurable consequences for how long people live, even after accounting for pre-existing disease burden.
These findings matter because they highlight that lifestyle improvements may offer meaningful health benefits even for people who already have chronic diseases — a population that is sometimes overlooked in public health messaging. This research suggests that efforts to promote healthier behaviors such as quitting smoking, reducing alcohol, increasing physical activity, improving sleep, and eating a better diet could be especially valuable for individuals managing multiple health conditions.
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Abraham Kaggwa, Anthony Kityo, Sang-Ah Lee. (2026). Effect of morbidity on the association between lifestyle and mortality in the Health Examinee cohort.. Epidemiology and Health. https://doi.org/10.4178/epih.e2026022