Vitamin D status in anorexia nervosa: A meta-analysis

ObjectiveIn anorexia nervosa (AN), osteoporosis and osteopenia are common, which have been associated with low circulating levels of vitamin D (VitD) in other settings. We aimed to meta-analyze cross-sectional studies reporting on VitD parameters in patients with AN and healthy controls (HCs). MethodElectronic PubMed search from database inception until December 31, 2013 and meta-analysis of cross-sectional studies comparing serum levels of 25-hydroxyvitamin D (25OH-D), 1,25-dihydroxyvitamin D (1,25OH-D) and dietary VitD between patients with AN and HCs, before or after VitD supplementation. We calculated random effects standardized mean differences (SMDs) 95% confidence intervals (CIs) as effect size measures. ResultsOut of 1,739 initial hits, 15 studies with a total of 927 participants (AN=408 and HCs=519) were meta-analyzed. In the unsupplemented state, both serum 25OH-D (studies=4; n=168; SMD=-0.43; 95%CI: -0.83 to -0.03; p=.03) and 1,25OH-D levels (studies=4; n=113; SMD=-1.06; 95%CI: -1.47 to -0.66; p<.00001) were significantly lower in AN than HCs. In AN patients treated with cholecalciferol supplementation, serum 25OH-D levels were significantly higher than in HCs (studies=5; n=449; SMD=0.66; 95%CI: 0.01-1.31; p=.05). Paradoxically, despite lower 25OH-D and 1,25OH-D levels, AN patients reported similar intake of VitD compared to HCs (studies=6; n=314; SMD=0.33; 95%CI: -0.16, 0.81; p=.19). DiscussionAlthough AN patients reported similar dietary VitD intake compared to HCs, AN patients had significantly lower 25OH-D and 1,25OH-D levels without supplementation. Conversely, supplementation with cholecalciferol fully normalized VitD serum levels. Future studies are needed to clarify the role of VitD supplementation in AN for improving bone health. (c) 2014 Wiley Periodicals, Inc. (Int J Eat Disord 2015; 48:803-813)