Trajectories of Body Mass Index and Their Associations with Mortality among Older Adults in Korea: Analysis of the Korean Longitudinal Study of Aging

Abstract

Weight change is an important risk factor for mortality. The association of weight change with mortality is frequently shown as a reverse J-shaped curve. 1,2) Weight loss in overweight or obese people and weight gain in underweight people have beneficial effects on health. 1) However studies have reported conflicting results depending on ethnicity and age groups. While some studies reported that weight loss and weight gain increased mortality, 3,4) others found no associations. 5) Instead of using baseline body mass index (BMI) as in previous Background: Weight change is a known risk factor for mortality. Previous Korean studies only considered mortality consequences of weight change between two time points over relatively short periods. This study investigated whether body mass index (BMI) trajectory patterns were associated with all cause-mortality based on continuous BMI observations during a 10-year follow-up period among Korean older adults. Method: This study analyzed data from the 2006-2016 Korean Longitudinal Study of Aging database. The participants included in this study were 3,478 people aged 65 years or older who have measured BMI more than once. A trajectory model was developed to classify different homogeneous trajectory subgroups according to BMI, and Cox proportional hazards models were used to investigate the association of BMI trajectory with allcause mortality. Result: We identified four trajectory groups: obese (OG); overweight (OWG); high normal weight (HNWG); and low normal weight (LNWG). The LNWG and HNWG experienced continuous weight loss during the study period. Trajectories with higher BMI were associated with lower mortality. The adjusted hazard ratios (95% confidence intervals) for all-cause mortality in the LNWG, HNWG, and OWG were 2.40 (1.69-3.40), 1.75 (1.26-2.45), and 1.38 (0.99-1.96), respectively, compared with those in the OG. Conclusion: We found that the lower the BMI of the weight trajectory group, the higher the mortality over 10 years in Korean older adults. This result suggested that baseline obesity status and degree of weight loss during follow-up contributed to mortality in later life.

Associations between body mass index and all‐cause mortality: A systematic review and meta‐analysis

“…There were 12 studies [47][48][49][50][51][52][53][54][55][56][57][58] (13 cohorts; 187,866 participants) with general populations (Table S3). Of these, seven cohorts were in East Asia, and three cohorts in each Europe and North America.…”

Gastrointestinal: Weight gain increases the risk of metachronous advanced colorectal neoplasm observed in post‐polypectomy surveillance colonoscopy

“…Furthermore, Korean cohort studies showed that Korean adults tended to lose weight with age during longitudinal follow-up. 24,28 Therefore, there may be a limitation to assess the association between weight loss and development of ACRN in this study.…”

Association of late-life body mass index with the risk of Alzheimer disease: a 10-year nationwide population-based cohort study

“…Fifth, the difference in AD risk according to late-life BMI may have been underestimated. In another study that followed 10-year mortality among Koreans aged 65 years or older, the lower the baseline BMI, the higher the mortality rate 43 which implied a higher chance of dying before AD develops. Finally, our study could not prove a causal relationship between late-life BMI and the incidence of AD because many possible confounding factors affecting the incidence of AD that cannot be identified in this database were not considered.…”