Is this D vitamin to worry about? Vitamin D insufficiency in an inpatient sample

Objective: The aim of the present study was to investigate the relationship between reduced serum vitamin D levels and psychiatric illness.

Method: This study was an audit of serum 25-hydroxyvitamin D (25-OHD) levels measured routinely in a sample of 53 inpatients in a private psychiatric clinic. These levels were compared with those of controls without psychiatric illness.

Results: The median levels of serum 25-OHD were 43.0 nmol L⁻¹ (range 20–102 nmol L⁻¹) in the patient population, 46.0 nmol L⁻¹ (range 20–102 nmol L⁻¹) in female patients (n =33) and 41.5 nmol L⁻¹ (range 22–97 nmol L⁻¹) in male patients (n =20). The proportion of vitamin D insufficiency (serum 25-OHD ≤50 nmol L⁻¹) in this patient population was 58%. Furthermore, 11% had moderate deficiency (serum 25-OHD ≤25 nmol L⁻¹). There was a 29% difference between mean levels in the patient population and control sample (geometric mean age- and season-adjusted levels: 46.4 nmol L⁻¹ (95% confidence interval (CI) =38.6–54.9 nmol L⁻¹) vs 65.3 nmol L⁻¹ (95%CI =63.2–67.4 nmol L⁻¹), p <0.001).

Conclusion: Low levels of serum 25-OHD were found in this patient population. These data add to the literature suggesting an association between vitamin D insufficiency and psychiatric illness, and suggest that routine monitoring of vitamin D levels may be of benefit given the high yield of clinically relevant findings.