Associations of weight change with perceived stress and depression: a nationwide population-based study.

Purpose: Depression and perceived stress are prevalent mental health problems worldwide, closely associated with physical health. Prior studies have suggested that both weight gain and loss may increase the odds of depression and stress, highlighting the need for clarification using national data. Methods: Data from the Korea National Health and Nutrition Examination Survey in 2014, 2016, 2018, and 2020 were used. The final analytic sample included 21,599 adults aged ≥19 years. We identified weight change over the past year and categorized it into seven groups (≥10 kg loss, 6-<10 kg loss, 3-<6 kg loss, no weight change, 3-<6 kg gain, 6-<10 kg gain, and ≥10 kg gain). We analyzed the odds of depressive symptoms, self-reported physician diagnosis of depression, and perceived stress according to the change in weight. Results: Higher odds of depressive symptoms, self-reported physician diagnosis of depression, and perceived stress were observed at both substantial weight loss and weight gain. Compared with participants reporting no weight change, the adjusted odds ratios (95% CIs) for weight loss ≥10 kg were 3.51 (2.30-5.34), 1.99 (1.17-3.78), and 1.83 (1.34-2.48) for depressive symptoms, self-reported physician diagnosis of depression, and perceived stress, respectively. The corresponding estimates for weight gain ≥10 kg were 3.82 (2.72-5.36), 2.80 (1.89-4.14), and 2.28 (1.82-2.85), respectively. No significant interactions were observed between weight change and sex, age, body mass index, or weight control status. Conclusions: Substantial weight loss and weight gain were associated with elevated odds of adverse mental health outcomes.