Association between Weight Changes over a 4-Year Period and Health-Related Quality of Life in Middle-Aged and Older Adults in Korea: The Korean Genome and Epidemiology Study Cohort.

Background: The relationship between weight change and quality of life remains controversial. This study aimed to investigate whether changes in body weight among participants in different baseline body mass index categories are associated with physical and mental health functioning.

Methods: We conducted an analysis involving 5,106 adults who participated in the Korean Genome and Epidemiology Study, a cohort comprising Korean adults aged 40 to 69 years. We categorized participants into three groups based on body weight change, and physical and mental health were assessed using the 12-Item Short-Form Health Survey in year 4. We employed logistic regression analysis to assess the association between body weight change and poor functioning at year 4. We also utilized a generalized estimating equation to determine the relationship between weight changes and mental component summary (MCS) scores over the study period for each weight group.

Results: Weight gain in both the normal weight (odds ratio [OR], 1.88; 95% confidence interval [CI], 1.13-3.11; P=0.01) and overweight groups (OR, 1.75; 95% CI, 1.05-2.91; P=0.03) was associated with poor MCS. Normal weight weight-losers were associated with a greater increase (2.69 points; 95% CI, 0.50-4.88) in MCS compared to weightmaintainers. Significant differences in mean MCS were observed for overweight weight-losers, obese weight-gainers, and underweight weight-gainers when compared to weight maintainers in each respective weight group.

Conclusion: Different patterns of relationships between weight change and mental health-related quality of life were observed. Hence, it is crucial to focus on the mental health of middle-aged and older adults when assessing body weight changes.