Vitamin D deficiency in newborns linked to risk of schizophrenia, says study

People in northern regions often hear about risks associated with a lack of vitamin D, or the sunshine vitamin, such as depression and muscle weakness. Now new research suggests that for newborn babies, a lack of vitamin D could also mean a greater risk of developing schizophrenia later in life.

The study published in Scientific Reports found that newborns with vitamin D deficiency in Denmark had a 44 per cent greater risk of being diagnosed with schizophrenia as adults when compared with people of the same age and sex born with regular vitamin D levels.

Lead author John McGrath, a psychiatrist and professor at Aarhus University in Denmark and the University of Queensland in Australia, noted that while the study found an association between vitamin D deficiency and schizophrenia, it doesn't prove cause and effect. 

"Schizophrenia is a pretty serious group of disorders, it's very poorly understood and affects about one in 100 people," he said.

McGrath explained there are a number of possible causes of schizophrenia, including genetic and environmental factors.

The study's results indicate that a vitamin D deficiency could account for around eight per cent of all schizophrenia cases in Denmark.

McGrath said researchers looked at vitamin D as a risk factor because previous research has shown that people born in the winter or spring, and those living in northern countries, particularly dark-skinned migrants, have an increased risk of schizophrenia.

"They were the clues, the pieces of the jigsaw puzzle, that made us follow up this line of research."

The study's findings were based on analysis of random blood samples taken from 2,602 Danish babies born between 1981 and 2000. 

The large scale case-control study builds on a smaller one done in 2010 that also found a link between vitamin D deficiency and schizophrenia. McGrath said they are now planning on replicating the study with 80,000 neonatal blood samples from Denmark, which he expects to be complete in about two years.

Vitamin D supplements

McGrath says the findings imply that some cases of schizophrenia could be prevented through vitamin D supplementation. He noted that supplements have been effective at preventing other disorders like folate acid for spina bifida.

"This is an example where a safe simple cheap vitamin supplement has been able to prevent a very serious disorder of brain development."

Dr. Kami Kandola, chief public health officer for the Northwest Territories, says vitamin D supplements have been recommended for nursing pregnant mothers and young children in the territory since November 2014.

"We have a lot more risk factors in the North to put us at risk of vitamin D deficiency, so this is a talk that health care providers should be having with their pregnant moms and also nursing moms," she said.

Kandola recommends that all nursing mothers and children under three years of age in the territory take a daily vitamin D supplement of 800 IU (international units).

The one exception to this, Kandola said, are babies who are formula-fed as vitamin D is added to infant formula. She recommends that children who drink formula  take a daily vitamin D supplement of 400 IU.

Vitamin D supplements are covered under the territory's Non-Insured Health Benefits program.