Association between healthy lifestyle score changes and quality of life and health-related quality of life: a longitudinal analysis of South Korean panel data

OBJECTIVES: We aimed to determine the influence of changes in the aggregate score of healthy lifestyle factors on health-related quality of life (HRQOL) and overall quality of life (QOL) in the Korean older adult population. DESIGN: This study used a longitudinal design. SETTING AND PARTICIPANTS: Data on 9474 participants aged 45 years or older were extracted from the Korean Longitudinal Study on Aging for the period 2006–2016. A composite score of four lifestyle factors (smoking, drinking, physical activity and body mass index) was calculated, and biennial changes in aggregate score were computed. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcomes were HRQOL and QOL. RESULTS: Generalised estimating equation analysis results showed that those with healthy lifestyle score changes from ‘Low–High’ (β =−0.987, p=0.002; β =−1.288, p<0.0001), ‘High–Low’ (β =−1.281, p<0.0001; β =−1.952, p<0.0001) and ‘Low–Low’ (β =−1.552, p<0.0001; β =−2.398, p<0.0001) groups were more likely to be have lower HRQOL and QOL estimates than those in ‘High–High’ group. Female gender, older age and depression had a more negative impact on HRQOL, while male gender and younger age had a more negative impact on QOL, especially in the Low–Low group. The relationship between changes in scores and HRQOL and QOL varied across different elements of healthy lifestyle scores. Changes in physical activity, drinking and smoking status were significantly associated with lower HRQOL and QOL. CONCLUSION: The findings suggest an association between a low healthy lifestyle score and poor quality of life, in both general and health-related aspects. Strategies targeting the Korean ageing demographic to promote a healthier lifestyle should be encouraged.