Newborns with vitamin D deficiency have an increased risk of schizophrenia later in life, researchers from Aarhus University and the University of Queensland report. The discovery could prevent some cases of the disease, and shows that neonatal vitamin D deficiency could possibly account for about 8% of all schizophrenia cases in Denmark.

The study, led by Professor John McGrath from Aarhus University and the University of Queensland, found that newborns with vitamin D deficiency had a 44% increased risk of being diagnosed with schizophrenia as adults, compared to those with normal Vitamin D levels.

Professor McGrath, says the new study is based on 2,602 individuals. The study confirms a previous study that also found an association between neonatal vitamin D deficiency and an increased risk of schizophrenia. The findings support the hypothesis that the risk of schizophrenia could be reduced with the treatment of vitamin D deficiency during the earliest stages of life.

"Schizophrenia is a group of poorly understood brain disorders characterised by symptoms such as hallucinations, delusions and cognitive impairment," he says.

Professor McGrath Is part of the Danish research-project, iPSYCH and has a Niels Bohr Professorship at the National Centre for Register-based Research at Aarhus University

"As the developing fetus is totally reliant on 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."

The team made the discovery by analysing vitamin D concentration in blood samples taken from Danish newborns between 1981 and 2000 who had gone on to develop schizophrenia as young adults.

The researchers compared these samples to those of people matched by sex and date of birth who had not developed schizophrenia.

The research was published in Scientific Reports.

According to John McGrath, schizophrenia is associated with many different risk factors, both genetic and environmental, but the new research suggests that neonatal vitamin D deficiency could possibly account for about 8% of schizophrenia cases in Denmark.

"Much of the attention in schizophrenia research has been focused on modifiable factors early in life with the goal of reducing the burden of this disease. Previous research identified an increased risk of schizophrenia associated with being born in winter or spring and living in a high-latitude country, such as Denmark," he says.

"We hypothesised that low vitamin D levels in pregnant women due to a lack of sun exposure during winter months might underlie this risk, and investigated the association between vitamin D deficiency and risk of schizophrenia."

Professor McGrath also led a Dutch 2016 study that found a link between prenatal vitamin D deficiency and increased risk of childhood autism traits.

"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"