Low maternal vitamin D as a risk factor for schizophrenia: A pilot study using banked sera

Objective: Evidence from epidemiology suggests that low maternal vitamin D may be a risk factor for schizophrenia. Method: Based on sera taken during the third trimester, we compared the level of 25 hydroxyvitamin D₃ in mothers of individuals with schizophrenia or schizoaffective disorders versus mothers of unaffected controls. For each case, we selected two controls matched on race, gender and date of birth of the offspring. Results: There was no significant difference in third trimester maternal vitamin D in the entire sample (cases=26, controls=51). Within the subgroup of black individuals (n=21), there was a trend level difference in the predicted direction. Conclusions: Maternal vitamin D does not operate as a continuous graded risk factor for schizophrenia, however, the results in the black subgroup raise the possibility that below a certain critical threshold, low levels of maternal vitamin D may be associated with an increased risk of schizophrenia.