Social isolation and depression as risk factors for weight loss of 5kg or more among older Korean adults.

Given a well-known overlapping prevalence of social isolation with loneliness and depression among older adults, this study aimed to contextually investigate the relationship of these constructs with weight loss of more than 5kg in a year, with a special focus on the intersection of living alone and marital dissolution as key dimensions of isolation. The data were obtained from the Korean Longitudinal Study of Aging (KLoSA) from 2006, 2008, 2010, 2012, 2014, 2016, and 2018, with an adult sample of those aged 65 and older (n = 5,481). The study evaluated several critical dimensions of social isolation: living alone, transition to living alone, infrequent social contact with children or friends, and infrequent social participation. These dimensions were examined individually and as a composite scale, along with loneliness and depressive symptoms, to determine their association with weight loss of 5kg or greater among older men and women. Generalized Estimating Equation (GEE) regression models enabled investigation of whether socially isolated men and women tended to lose 5kg or more in weight, given other confounding factors. Surprisingly, the results showed no evidence of such a trend. However, significant associations were found between weight loss and changes in living alone and marital status. For older men, transitioning to living alone without a change in marital status was linked to significant weight loss. For older women, transitioning to living alone following widowhood or divorce was the risk factor. These relationships remained significant even after adjusting for depression and a wide range of covariates. Additional analysis testing a cumulative effect revealed that only depression was a risk factor for being underweight at the last observation. Therefore, to prevent a clinically risky extent of weight loss, health policies for older Koreans should focus on those who transition to living alone, especially due to spousal bereavement or divorce (among women) and separation from living with children (among men).