Low prevalence of vitamin D deficiency among adolescents with anorexia nervosa

Fifty adolescents with AN and 200 healthy girls underwent vitamin D screening. Girls with AN reported exceptional compliance with vitamin D supplementation and PTH concentrations were lower. Vitamin D deficiency was less common in the group with AN, but when race was considered, the trend was no longer significant. Introduction The objective of this study was to determine whether patients with anorexia nervosa (AN) are more compliant with supplementation and have a lower prevalence of vitamin D deficiency than healthy controls. Methods Fifty adolescents with AN and 200 controls were compared using anthropometric and lifestyle data, serum 25-hydroxyvitamin D (25OHD) and parathyroid hormone (PTH) concentrations, and prevalence of vitamin D deficiency. Results The prevalence of deficiency (< 20 ng/mL) was 2% in the AN group vs. 24% among controls (p=0.003). 25OHD was similar among white participants with AN and white controls (39.5 vs. 36.0 ng/mL, p=0.20), but higher than in non-white controls (20.6 ng/mL). Significantly more girls with AN reported vitamin D supplementation (86%) than the full control (14%) or white subgroup (27%) (p < 0.001). Participants with AN had lower PTH concentrations than controls, (27.8 vs. 47.4 pg/mL, p=0.009), a trend that lost significance after age and race adjustment (41.7 pg/mL, p=0.12). Conclusions Compared to healthy controls, adolescents with AN had a lower prevalence of vitamin D deficiency and PTH concentration. However, 25OHD and PTH concentrations were similar after adjustment for race and age. The trend of lower PTH levels in adolescents with AN, accompanied by exceptional compliance with supplementation, may have bone health implications for these patients.