Objectives: Novel findings indicate links between unhealthy lifestyles and depression based on active inflammatory processes. Thus, identifying participants with poor habits could reveal differences in trends of incident depression. This study aimed to examine the association between an objective lifestyle assessment, as measured by the Lifestyle and Well-Being Index (LWB-I), and incident depression in healthy participants of a Spanish cohort.
Study design: This was a longitudinal analysis of a subsample of 10,063 participants from the Seguimiento Universidad de Navarra cohort study.
Methods: Group comparisons and Cox proportional hazard models were conducted using the LWB-I, which categorizes the sample into groups with healthy and unhealthy lifestyles and well-being. The main outcome was incident depression as well as secondary outcomes.
Results: Those classified to the transition category of LWB-I were associated with a hazard ratio of 0.67 (95% confidence interval: 0.52-0.87), and those in the excellent category showed a hazard ratio of 0.44 (95% confidence interval: 0.33-0.58), which in both groups reflects a significantly lower risk of incident depression compared with the group including those classified in the poor LWB-I level. Moreover, the available sensitivity analyses concerning time of depression diagnosis or antidepressant treatment further supported the role of nutrition and physical activity on incident depression. Interestingly, throughout the follow-up, incident depression was inversely related to healthier daily habits as measured by the LWB-I.
Conclusions: A global assessment of lifestyles such as the LWB-I provides valuable insight into the complex relationship between lifestyle factors and their link to depression risk.