Objective: Previous studies in northern Europe and Australia have indicated that vitamin D deficiency is common in psychiatric patients. This study aimed to determine the prevalence of vitamin D deficiency among psychiatric inpatients in a large North American city. The association of vitamin D status with clinical characteristics was also explored, and subgroups of patients that are more vulnerable to vitamin D deficiency were identified.
Method: This descriptive study looked at 107 unselected consecutive admissions to a psychiatric inpatient service in New York City between September and early December 2010. All patients were aged 18 years and older. Psychiatric diagnoses were established by attending psychiatrists as part of the routine assessment using criteria from the DSM-IV. Serum levels of 25-hydroxyvitamin D were measured by high-performance liquid chromatography, tandem mass spectrometry. A vitamin D-deficient state was defined as serum 25-hydroxyvitamin D level ≤ 20 ng/mL.
Results: Fifty-six (52.3%) patients were classified as deficient in vitamin D. Age and 25-hydroxyvitamin D level were significantly correlated (P = .001). Seventy-one percent of patients from age 18 to 34 years were deficient in vitamin D; this rate was significantly higher than the rate of deficiency in older patients (P = .017). No significant relationships were found between 25-hydroxyvitamin D level and gender, race/ethnicity, glycosylated hemoglobin, body mass index, and major psychiatric diagnostic categories.
Conclusions: A high percentage of psychiatric inpatients are deficient in vitamin D. Younger patients were more at risk for deficiency. Screening for vitamin D deficiency should be part of the health assessment of patients with major psychiatric illnesses.