A prospective study of the association between lifestyle and the risk of depressive symptoms

Background: Few studies have prospectively, comprehensively, and by sex, examined the relationship between lifestyle and depressive symptoms. This study aimed to longitudinally examine which lifestyle factors are associated with depressive symptoms in a large cohort of Japanese participants stratified by sex.

Methods: Among 9087 office and community-based residents who attended a health measurement course at the Osaka Medical Center for Health Science and Promotion between 2001 and 2002, 6629 individuals (3962 men and 2667 women) without prior depressive symptoms were followed until the end of March 2012 to observe the associations between lifestyle factors and the development of new depressive symptoms.

Results: During the 5.06-year follow-up, 913 participants (517 men and 397 women) developed new depressive symptoms. Lifestyle factors such as very low physical activity, short sleep duration, smoking, skipping breakfast, and consuming a high-fat, high‑sodium diet, were associated with increased hazard ratios for depressive symptoms. Conversely, regular exercise, stress-coping methods, and diets rich in fish and fruit were associated with a reduced risk of depressive symptoms. In men, the risk was increased by very low physical activity, smoking, and diets including sugar-sweetened drinks, fatty meats, noodle soups, and highly seasoned dishes. In women, the risk was increased by long working hours and decreased by diets including seafood and fruits.

Conclusions: Sex-specific differences were observed in the relationship between lifestyle and the onset of depressive symptoms. Alongside shared factors, such as sleep and stress management, sex-specific strategies could enhance prevention.