July 22, 2014 | The Endocrine Society
Since schizophrenia is more prevalent in high latitudes and cold climates, researchers have theorised vitamin D may be connected to the disorder. “This is the first comprehensive meta-analysis to study the relationship between the 2 conditions,” said Ahmad Esmaillzadeh, PhD, Isfahan University of Medical Sciences, Isfahan, Iran. “When we examined the findings of several observational studies on vitamin D and schizophrenia, we found people with schizophrenia have lower vitamin D levels than healthy people. Vitamin D deficiency is quite common among people with schizophrenia.”
The researchers reviewed the findings of 19 observational studies that assessed the link between vitamin D and schizophrenia. Combined, the studies looked at vitamin D levels and the mental health of 2,804 adult participants. The studies used blood tests to determine each participant’s vitamin D levels.
The meta-analysis found that people with schizophrenia had significantly lower levels of vitamin D in the blood compared with the control groups. The average difference in vitamin D levels between patients with schizophrenia and control participants was -5.91 ng/ml.
People with vitamin D deficiency were 2.16 times more likely to have schizophrenia than those with sufficient vitamin D in their bloodstreams. In addition, 65% of the participants who had schizophrenia also were vitamin D deficient.
“There is a growing trend in the nutrition science field to consider vitamin D and its relationship to conditions such as diabetes, cancer, heart disease and depression,” said Dr. Esmaillzadeh. “Our findings support the theory that vitamin D may have a significant impact on psychiatric health. More research is needed to determine how the growing problem of vitamin D deficiency may be affecting our overall health.”