By Dr Ananya Mandal, MD
Researchers at Queensland Brain Institute have found that babies born with low vitamin D levels are twice as likely to develop schizophrenia later in life. This could mean that it may be possible to prevent schizophrenia, which affects almost 200,000 Australians.
According to Professor John McGrath from the Queensland Brain Institute there has been suggestions for some time that there may be a link between sunlight, vitamin D and brain development. He explained, “For the babies who had very low vitamin D, their risk was about twice as high as those babies who had optimal vitamin D…But the amazing thing was that the study that was based in Denmark, where low vitamin D is quite common, we found that if vitamin D is linked to schizophrenia our statistics suggest that it could explain about 40% of all schizophrenias…That's a much bigger effect than we're used to seeing in schizophrenia research.”
A little more time in sunlight could gather enough vitamin D for children. It however remains unclear whether there are fewer cases of schizophrenia in a country like Australia which sees a lot more sunlight. “We don't have high-quality data on that, but some statistics suggest we do have slightly lower incidences and prevalence of schizophrenia…Like many other diseases, like multiple sclerosis, schizophrenia tends to be more common in places further away from the equator…And if you're born in winter and spring you tend to have a slightly increased risk of schizophrenia also, and that was one of the original pieces of the jigsaw puzzle that led us to wonder maybe vitamin D could be implicated,” said Professor McGrath.
Professor Ian Hickie from the Brain and Mind Research Institute in Sydney is not surprised with these findings but he said more research is necessary. He said, “So the real acid test is going to be trying to lift vitamin D levels in pregnant women and newborns and see whether there's an effect on later schizophrenia…Or even in fact, looking at providing higher levels of vitamin D by vitamin D supplementation in other ways later in life and particularly childhood and the teenage years, to see whether you might reduce the risk of onset of schizophrenia.”
According to Professor McGrath, “Because the treatment and the outcome can be separated by about 20, 30 years, we need to treat pregnant women and then wait for their offspring to develop schizophrenia…It will be a very challenging study to do…” He said that it may be decades before scientists could be sure of the link. “But medical research tends to move at a steady pace. I think the other thing is that there are many other studies suggesting that vitamin D is good for baby's bone health…So it may well be that recommendations will be made to women to increase their vitamin D status for more obvious outcomes, like baby's rickets for example. If that happened then it may well be that schizophrenia would start to fall in decades to come,” he added.
On the flip side Dr. Hickie warned that too much sun exposure could increase the risk of skin cancer. He said, “Rates of melanoma and skin cancer are obviously very high in our country and directly related to sun exposure, particularly in childhood…So on the one hand we need to be careful about over exposure to sunlight, on the other hand it may well be that in some places, or in some individuals, low levels of vitamin D may constitute a risk factor, particularly in pregnancy and therefore affecting the rates of vitamin D in newborn children….So this is one of the issues that we're going to need to look at clearly. I don't think it means that everyone should be rushing out into the sun and necessarily putting themselves at risk of other sun-related cancers.”
Schizophrenia, said both doctors, is genetic and chemical imbalances in the brain may be responsible and stressful events are often thought to play a role in the onset of the schizophrenia. Vitamin D or lack of it could not be the only precipitating factor.
The report appeared in the Archive of General Psychiatry.