Low levels of the vitamin during early life has previously been proposed as a risk factor for the disease but use of supplements to protect against it has not been investigated.
Schizophrenia is a biochemical disorder that affects one in 100 people. It usually manifests itself between the ages of 15 to 25 years. There is no known cure for the disease, which causes 10 per cent of those affected to commit suicide. In the UK alone the annual cost of schizophrenia is over £2.6 billion.
The Cambridge team measured vitamin D intake during the first year of life among subjects, just over 9,000, of the Northern Finland 1966 Birth Cohort.
Following up when subjects had reached the age of 31, they found that intake of at least 2000 IU of vitamin D was associated with a reduced risk (0.23) of schizophrenia in men compared to those on lower doses as infants.
There were no significant associations between either the frequency or dose of vitamin D supplements and schizophrenia in females however.
Nor did the vitamin affect outcome of nonpsychotic disorder or psychotic disorders other than schizophrenia in either sex, report the authors in the April issue of Schizophrenia Research (67(2-3):237-45).