Vitamin D deficiency in patients with intellectual disabilities: prevalence, risk factors and management strategies.

BACKGROUND: People with intellectual disabilities have a high risk of osteoporosis and fractures, which could partly be as a result of vitamin D deficiency. AIMS: To compare the serum vitamin D (25(OH)D) levels of 155 patients with intellectual disabilities under psychiatric care and 192 controls, investigate potential risk factors for vitamin D deficiency in people with intellectual disabilities and assess available treatments. METHOD: Cross-sectional observational study followed by treatment evaluation. Results Almost twice as many patients with intellectual disabilities had vitamin D deficiency (25(OH)D <50 nmol/l) compared with controls (77.3% v. 39.6%, P<0.0001). In the intellectual disabilities group, winter season (P<0.0001), dark skin pigmentation (P<0.0001), impaired mobility (P = 0.002) and obesity (P = 0.001) were independently associated with lower serum 25(OH)D. In most patients, 800 IU colecalciferol daily normalised 25(OH)D levels. CONCLUSIONS: Vitamin D deficiency is highly prevalent in people with intellectual disabilities, partly because of insufficient exposure to sunlight. Screening and treatment strategies, aiming to reduce these patients' high fracture risk, should be introduced. Similar strategies may be required in other psychiatric populations at risk for fractures and with a tendency to spend excessive time indoors.