Depressive state and subsequent weight gain in workers: A 4-year follow-up study.

Objective: It has been suggested that the presence of a depressive state is a predictor of increase of the body weight. However, to precisely understand the nature of this relationship, the data should be controlled for other factors that can also be associated with weight gain.

Methods And Participants: To test the hypothesis that the presence of a depressive state is associated with future weight gain, a 4-year prospective occupation-based cohort study was conducted in male adult workers (N=1730) at a railway company. Following the initial screening, follow-up information was obtained via a legally required annual health examination. The presence of a depressive state was identified using the Zung Self-Rating Depression Scale (SDS). The weight of each participant was measured to the nearest kilogram. Multiple logistic regression analysis was used to test the association between the depressive state and a weight gain of 4 kg or more over the 4-year study period after controlling for potentially confounding variables such as the age, smoking status, alcohol intake status, and physical activity.

Results: A weight gain of 4 kg or more over the 4-year study period was significantly associated with the depressive state, even after controlling for confounding variables (p< 0.05). Short-term longitudinal analysis also revealed an association between the depressive state and subsequent increase of the body weight.

Conclusion: Since the depressive state was demonstrated to be an important risk factor for increase of the body weight, further research on depression should be conducted with a view to providing effective health education.