A new study has revealed an intriguing link between babies born with a vitamin D deficiency and an increased risk of developing schizophrenia later in life. Although the discovery stems from observational research, the scientists suggest vitamin D plays a major role in fetal brain development.

The initial hypothesis arose through a study of epidemiological research finding an increased risk of schizophrenia in people living in urban versus rural settings, residents of high altitude locations, dark-skinned ethnic groups, and those born across winter and spring. A common factor that the researchers could map over all those individual risk factors is higher levels of vitamin D deficiencies.

Over 2,600 adult subjects with diagnosed schizophrenia were subsequently selected to examine vitamin D levels from blood samples taken when they were born. The results were incredibly convincing, finding newborns with a vitamin D deficiency were 44 percent more likely to develop schizophrenia compared to a control group of healthy adults born with normal vitamin D levels.

"As the developing fetus is totally reliant on the mother's vitamin D stores, our findings suggest that ensuring pregnant women have adequate levels of vitamin D may result in the prevention of some schizophrenia cases, in a manner comparable to the role folate supplementation has played in the prevention of spina bifida," says John McGrath, lead on the new study.

While it is appropriate to be mildly hesitant when interpreting results that only suggest a correlation and not a causation, there is a body of evidence that backs up the hypothesis that prenatal vitamin D deficiency could increase schizophrenia risk. A variety of animal studies have demonstrated the tendency for transient prenatal vitamin D deficiency to disrupt everything from brain volume to gene and protein expression.

Vitamin D deficiency during pregnancy has also been recently linked to the development of autistic traits in young children. In addition to this, a recent study revealed intriguing molecular similarities in gene expression between autism and schizophrenia.

Despite this well-conceived new study, much still remains unclear. The results were only generated from a single blood sample taken at birth so it is not known whether extended vitamin D deficiency across the first few years of life influences schizophrenia risk. Maternal behaviors during pregnancy that could influence vitamin D levels are also unclear in relation to the child's ultimate schizophrenia risk.

"The next step is to conduct randomized clinical trials of vitamin D supplements in pregnant women who are vitamin D deficient, in order to examine the impact on child brain development and risk of neurodevelopmental disorders such as autism and schizophrenia," explains McGrath on the path moving forward.

The new research was published in the journal Scientific Reports.