The researchers from the Queensland Centre for Schizophrenia Research Australia, suggest that regular or irregular vitamin D supplementation during the first year of life is associated with a reduced risk of schizophrenia in males, conversely for females there appears to be no apparent association.
Known as the 'sunshine vitamin', vitamin D is made by the skin through exposure to sunlight. While vitamin D is known to play a vital role in metabolizing bone, ongoing research across the world is looking into other potential benefits.
A recent study found an association between a mother's intake of vitamin D during pregnancy and reduced risk of type 1 diabetes, caused by an autoimmune reaction, in her offspring. Scientists also reported last month that women who take vitamin D supplements through multivitamins are 40 per cent less likely to develop multiple sclerosis (MS) than women who do not take supplements.
Looking into the role the vitamin could play in reducing the risk of schizophrenia, the researchers studied male and female subjects from the Northern Finland 1966 Birth Cohort (n=9114). During the first year of life, data were collected about the frequency and dose of vitamin D supplementation.
They measured the primary outcomes of schizophrenia, psychotic disorders other than schizophrenia, and non psychotic disorders as diagnosed by age 31 years.
"In males, the use of at least 2000 IU of vitamin D was associated with a reduced risk of schizophrenia (RR=0.23, 95 per cent CI 0.06-0.95) compared to those on lower doses," reported the Australian researchers, adding that for females there was 'no significant association' between either the frequency or dose of vitamin D supplements and schizophrenia.
"Vitamin D supplementation during the first year of life is associated with a reduced risk of schizophrenia in males. Preventing hypovitaminosis D during early life may reduce the incidence of schizophrenia," concluded the researchers led by John McGrath.
Full findings of the paper 'Vitamin D supplementation during the first year of life and risk of schizophrenia: a Finnish birth cohort study,' by J. McGrath, K. Saari, H. Hakko, J. Jokelainen, P. Jones, M. R. Järvelin, D. Chant and M. Isohanni are published in the April 2004 issue of Schizophrenia Research (2004) 67:237-245.