By Mark Cowen News Medical-Net June 27, 2012
The findings suggest that psychiatric inpatients may benefit from vitamin D supplementation, say the researchers.
David Menkes (Waikato Clinical School, Hamilton) and team found that 91% of the 102 inpatients studied had blood levels of 25-hydroxy vitamin D3 below 75 nM, which is considered suboptimal.
Furthermore, 74% had vitamin D levels below 50 nM, indicating at least mild deficiency, and 19% were severely deficient, with levels below 25 nM.
Vitamin D levels were also found to vary by diagnosis, with schizophrenia patients (n=38) showing the lowest mean levels, at 34.5 nM, and bipolar disorder patients (n=19) the highest, at 49.4 nM.
Furthermore, patients with schizophrenia-spectrum disorders (schizophrenia and schizoaffective disorder, n=49) were significantly more likely to be severely vitamin D deficient than those with other disorders, at 34% versus 9%.
Although patients with schizophrenia-spectrum disorders had spent more days hospitalized than those with other diagnoses, and had therefore spent more time indoors, "this difference was not significant and cannot account for the striking association of diagnosis with vitamin D," say the researchers.
The team also found that patients of Maori descent (n=51) had significantly lower mean vitamin D levels than non-Maori patients, at 37.8 versus 47.5 nM. And 14 Maori patients were severely deficient compared with just five non-Maori patients.
Menkes and team conclude in BMC Psychiatry: "The observed prevalence of vitamin D deficiency in our psychiatric inpatient population supports the idea that supplementation should be more generally available, and perhaps routinely prescribed, given its low cost, lack of adverse effects and multiple potential benefits."
They add: "Supplementation may be of particular benefit to Maori and to patients with schizophrenia; both groups have characteristically poor physical health outcomes and were found in this study to have exceptionally low vitamin D levels."