Prevalence of Vitamin D Deficiency in Adult Outpatients With Bipolar Disorder or Schizophrenia.
OBJECTIVE
Several studies show an association between schizophrenia and low levels of vitamin D. To date, there are only few studies about the prevalence of vitamin D deficiency in patients with bipolar disorder. We hypothesized that vitamin D deficiency is less common among patients with bipolar disorder than among patients with schizophrenia or schizoaffective disorder. A second hypothesis is that vitamin D deficiency is more prevalent among patients with schizophrenia, schizoaffective disorder, or bipolar disorders than among the general Dutch population.Most studies have been conducted with hospitalized patients; in this study, we only included outpatients.


METHODS
All outpatients of a center for bipolar disorders and all outpatients of 3 flexible assertive community treatment teams were asked to participate in this cross-sectional study.


RESULTS
We included 118 patients with bipolar disorder and 202 patients with schizophrenia or schizoaffective disorder. Vitamin D levels were deficient in 30.3% (95% confidence interval, 25.5-35.6) of the cases. The type of psychiatric disorder was not a predictor of vitamin D deficiency. The absolute difference in risk of deficiency between the study population and the Dutch Caucasian population was 23.8% (95% confidence interval, 18.3%-29.3%).


CONCLUSIONS
In this study, vitamin D deficiency was 4.7 times more common among outpatients with bipolar disorder, schizophrenia, or schizoaffective disorder than among the Dutch general population.Given the high prevalence of vitamin D deficiency, we believe that outpatients with bipolar disorder, schizophrenia, or schizoaffective disorder should be considered at risk of having low levels of vitamin D. Annual measurement of vitamin D levels in psychiatric outpatients with these disorders seems to be justified to maintain bone health, muscle strength, and to prevent osteoporosis.
From the *Department of Severe Mental Illnesses, Mental Health Care Organisation Noord-Holland-Noord, Alkmaar; †Department of Severe Mental Illnesses, Mental Health Care Organisation Noord-Holland-Noord, Heerhugowaard; ‡Centre for Bipolar Disorders, Mental Health Care Organisation Noord-Holland-Noord, Alkmaar; and §Department of Research & Monitoring, Mental Health Care Organisation Noord-Holland-Noord, Heerhugowaard, The Netherlands.
Remco
R
Boerman
Dan
D
Cohen
Peter F J
PF
Schulte
Annet
A
Nugter
D000328:Adult; D001714:Bipolar Disorder / Q000097:blood / Q000453:epidemiology*; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D010045:Outpatients; D015995:Prevalence; D011618:Psychotic Disorders / Q000097:blood / Q000453:epidemiology*; D012559:Schizophrenia / Q000097:blood / Q000453:epidemiology*; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology*