Association of Serum Vitamin D Levels with the Risk of Suicidal Behavior in Ilam, Iran: A Brief Report

There are conflicting reports on the effect of serum vitamin D (VD) levels on the development of suicidal behavior. VD deficiency is prevalent in Ilam province, and this region has the highest suicide mortality rate in Iran. The present study aimed to evaluate a possible association between serum VD levels and the risk of suicide among the inhabitants of Ilam province. A total of 157 suicide attempters (case group) and 314 age- and sex-matched individuals (control group) without a history of suicide attempts were recruited into the study. Suicide attempters were admitted to the Emergency Department of Ilam Shahid Mostafa Khomeini Hospital (Ilam, Iran) between March 2018 and March 2019. The individuals in the control group were randomly selected from those referred to various medical laboratories in Ilam during the same period. The participants in both groups were aged 18-35 years, and none had a history of kidney, liver, or endocrine diseases. Serum VD levels were measured using the enzyme-linked immunosorbent assay method. Categorical and continuous variables were compared using the Chi square test and independent samples t test, respectively. Serum VD level in the control group (31.5 +/- 0.2 ng/mL) was significantly lower than in the case group (43.1 +/- 0.1 ng/mL) (P<0.001). The results of logistic regression analysis showed that an increase in serum VD score was associated with an increase in the likelihood of suicide attempts (OR=1.05, 95% CI=1.03-1.06, P<0.001). Our findings confirmed the role of VD deficiency in the development of suicidal behavior. However, it is not a significant factor in its pathogenesis.