Association between change in lifestyle and cognitive functions among elderly Koreans: findings from the Korean longitudinal study of aging (2006-2016).

Background: South Korea is an aged society that continues to age rapidly. Therefore, the purpose of this study was to investigate the association between changes in lifestyle and cognitive functions in the South Korean elderly using a nationally representative survey.

Methods: We analyzed data from the Korean Longitudinal Study of Aging (KLoSA) 2006-2016, a biannual panel survey. Multiple linear regression analysis was performed with repeated measurements data to examine the association between lifestyle change and cognitive functions over 2 years. Lifestyle combined the scores of four factors (smoking status, alcohol drinking status, body weight, and exercise), and then categorized them into four groups (Good→Good, Bad→Good, Good→Bad, and Bad→Bad) according to the two-year change. Cognitive functions were set according to the scores measured through the Korean Mini-Mental State Examination (K-MMSE).

Results: Among females, the K-MMSE score was the highest in the Bad→Good group compared to the reference group, Bad→Bad (β = 0.914; SD = 3.744; p < .0001). The next highest scores were in the Good→Good group (β = 0.813; SD = 4.654; p = 0.0005) and the Good→Bad group (β = 0.475; SD = 4.542; p = 0.0481). Among males, only the K-MMSE of the Good→Good group was statistically significant (β = 0.509; SD = 3.245; p = 0.0077). The results of subgroup analysis showed that the K-MMSE scores of females who did not participate in any social activities were more affected by their lifestyle (Good-Good: β = 1.614; SD = 4.270; p = 0.0017, Bad-Good: β = 1.817; SD = 3.945; p < .0001). Subgroup analysis showed that females who started drinking more than a moderate amount of alcohol had lower K-MMSE scores (Good-Bad: β = - 2.636; SD = 2.915; p = 0.0011). Additionally, in both sexes, exercising, among the four lifestyle options, had a strong and significant association with higher K-MMSE scores.

Conclusions: Following a healthy lifestyle or improving an unhealthy lifestyle can help people prevent or slow down cognitive decline. Regularly engaging in an adequate amount of exercise can help the cognitive function of the elderly. Females, specifically, can experience positive effects on their cognitive function if they participate in social activities while maintaining healthy lifestyles, in particular not drinking too much alcohol.