Fig. 1

Percentages of participants with depressive symptoms by gender and vitamin D status. Differences in proportions were tested using Chi-square test. Overall prevalence of depressive symptoms was 32.2% (95% confidence interval, 29.1–35.1%). Females had higher prevalence of depressive symptoms than males (35.6% vs. 17.7%, P <  0.001). Participants with vitamin D deficiency had higher prevalence of depressive symptoms than those without (38.8% vs. 27.9%, P <  0.001)