A new study has investigated the link between low vitamin D levels and schizophrenia risk.
Symptoms such as hallucinations, delusions, and cognitive problems characterize schizophrenia.
So far, however, researchers have been unable to find out exactly what causes this condition.
That being said, they have identified some likely risk factors — such as the presence of certain sets of genes, or exposure to some viruses.
Due to older research suggesting that schizophrenia might be more prevalent in regions with less sun, some scientists have hypothesized that vitamin D deficiency may also be a risk factor for this condition.
A recent study led by teams from Aarhus University in Denmark and the University of Queensland in Brisbane, Australia, has found that newborn babies with low vitamin D levels are more at risk of developing schizophrenia later on.
"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," says lead study author Prof. John McGrath.
"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."
Prof. John McGrath
In the study paper, which appears in the journal Scientific Reports, the authors report that vitamin D deficiency in newborn babies may be responsible for approximately 8 percent of all schizophrenia cases in Denmark.
A 44 percent increase in risk
The new study assessed the data of 2,602 people in Denmark. The researchers analyzed vitamin D levels in blood samples from babies born in Denmark in 1981–2000. All of these eventually developed schizophrenia in early adulthood.
Prof. McGrath and his team compared these samples with additional ones from schizophrenia-free individuals whom scientists had matched by date of birth and biological sex to those in the initial cohort.
The team discovered that those born with a vitamin D deficiency had a 44 percent higher risk of developing schizophrenia later in life. Also, this deficiency in newborns could account for about 8 percent of all schizophrenia diagnoses in Denmark, the authors suggest.
"We hypothesized," explains Prof. McGrath, "that low vitamin D levels in pregnant women due to a lack of sun exposure during winter months might underlie this risk, and [we] investigated the association between vitamin D deficiency and risk of schizophrenia."
Preventing vitamin D deficiency in women who are pregnant, he says, may therefore also prevent childrens' later risk of schizophrenia.
According to Prof. McGrath, "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 [with] the role [that] folate supplementation has played in the prevention of spina bifida."
In the future, the researchers aim to organize a clinical trial assessing whether or not administering vitamin D supplements to women who are pregnant could effectively protect their children from exposure to neurodevelopmental conditions.
"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 [conditions] such as autism and schizophrenia," says Prof. McGrath.