There is substantial interest in the health effects of coffee because it is the leading worldwide beverage after water. Existing literature on the connection between depression and coffee is scarce, and studies have yielded inconsistent results. The aim of this study was to examine the association between coffee consumption and depression in the Korean population.
We conducted a cross-sectional study in 10 177 Korean individuals aged 20-97 years who participated in the fifth Korean National Health and Nutrition Examination Survey. Consumption of coffee and depression were assessed using a questionnaire. Multiple logistic regression analysis was used to compute odds ratios (ORs) and 95% confidence intervals (CIs) for depression.
The lifetime prevalence of self-reported depression was 14.0% and that of self-reported clinical depression was 3.7%. After adjustment for potential confounders, the adjusted ORs for self-reported depression across coffee consumption categories were 1.00 (reference) for less than one cup/week, 0.84 (95% CI: 0.66, 1.07) for one to six cups/week, 0.63 (95% CI: 0.51, 0.79) for one cup/day, 0.69 (95% CI: 0.54, 0.88) for two cups/day and 0.58 (95% CI: 0.44, 0.76) for three or more cups/day (P for trend, <0.01). A similar association was observed for self-reported clinical depression, for which the multiple-adjusted ORs were 1.00 (reference) for less than one cup/week, 0.61 (95% CI: 0.40, 0.92) for one to six cups/week, 0.51 (95% CI: 0.34, 0.74) for one cup/day, 0.57 (95% CI: 0.39, 0.84) for two cups/day and 0.41 (95% CI: 0.24, 0.70) for three or more cups/day, respectively (P for trend, <0.01).
These findings support a possible protective effect of coffee on the risk of depression.