Background: To protect against osteoporosis, keeping the vitamin D blood level (25[OH]D; VDBL) above 30 ng/mL is recommended. It is established that regular intake of vitamin D, calcium intake, and physical exercise contribute to maximizing bone mineral mass during childhood and adolescence. Recent articles suggest that patients with schizophrenia treated with antipsychotics have low VDBL and may have a higher risk of hip fractures in their later years than the general population.
Objectives: To evaluate whether adolescent psychiatric inpatient VDBL is lower than the 30-ng/mL optimal threshold and to document low-VDBL risk factors.
Method: We determined the VDBL of all consecutive inpatients from three adolescents units in 2009 (N = 136). Univariate analyses explored the influence on VDBL of (1) well-documented risk factors (e.g., age, gender, ethnic origin, body mass index, or season) and (2) suspected risk factors (e.g., disease type or antipsychotic treatment).
Results: All but six patients had a VDBL <30 ng/mL (mean [ ± SD]: 15.9 [ ± 8.4] ng/mL). VDBL was significantly lower for all patients during the first quarter of the year compared to the other three (all p < 0.01). VDBL was also lower for blacks/North Africans 12.8 (±7.0) than for Caucasians/Europeans 17.2 (±8.5): t = 2.62, p = 0.009. We found no differences between patients regarding disease category (K = 3.75, p = 0.154) or antipsychotic treatment (t = 0.127, df = 124, p = 0.89).
Conclusion: VDBL in an adolescent population with severe mental illness is lower than current recommendations of optimal level for bone health regardless of treatment or disease type. Because adolescence is a period of bone construction and could represent a critical window of opportunity for maximizing bone mass, especially among patients with severe mental illness, we recommend vitamin D supplementation.