The association between neonatal vitamin D status and risk of schizophrenia

Clues from the epidemiology of schizophrenia, such as the increased risk in those born in winter/spring, have led to the hypothesis that prenatal vitamin D deficiency may increase the risk of later schizophrenia. We wish to explore this hypothesis in a large Danish case-control study (n = 2602). The concentration of 25 hydroxyvitamin D (25OHD) was assessed from neonatal dried blood samples. Incidence rate ratios (IRR) were calculated when examined for quintiles of 25OHD concentration. In addition, we examined statistical models that combined 25OHD concentration and the schizophrenia polygenic risk score (PRS) in a sample that combined the new sample with a previous study (total n = 3464; samples assayed and genotyped between 2008-2013). Compared to the reference (fourth) quintile, those in the lowest quintile (