Strong relationship between vitamin D status and bone mineral density in anorexia nervosa

Bone. 2015 Sep;78:212-5. doi: 10.1016/j.bone.2015.05.014. Epub 2015 May 14.

Abstract

Background: Anorexia nervosa (AN) is associated with impaired bone health and low bone mineral density (BMD) as a consequence of an inadequate peak bone mass in adolescence and bone loss in young adulthood. The vitamin D status with its implications for bone health in patients affected by AN has only been examined previously in small studies.

Objective: To evaluate the prevalence of vitamin D deficiency and test the hypothesis that patients with AN and vitamin D deficiency might have worse bone metabolism and lower bone density as compared with AN with adequate vitamin D repletion.

Design: We analysed the vitamin D status and bone metabolism in a large cohort (n=89) of untreated patients affected by AN, with amenorrhoea.

Results: Vitamin D deficiency is widespread in untreated patients with AN: 16.9% had 25OH vitamin D levels below 12 ng/ml, 36% below 20 ng/ml and 58.4% below 30 ng/ml. PTH values were higher and BMD at both femoral sites were lower in patients with vitamin D<20 ng/ml. Progressively higher values of BMD were observed by 4 ranks of 25 OH vitamin D values (severe deficiency: <12 ng/ml, deficiency: ≥12 ng/ml and <20 ng/ml, insufficiency: ≥20 and <30 ng/ml and normal: ≥30 ng/ml). In patients with severe vitamin D deficiency BMD at the hip were significantly lower than that measured in groups with values over 20 ng/ml (p<0.001 for trend). The level of significance did not change for values adjusted for BMI or body weight.

Conclusion: We found a strong relationship between vitamin D status and hip BMD values with additional benefits for those with 25OHD levels above 20 ng/ml. Our results support the design of a randomized placebo-controlled clinical trial on the effect of vitamin D on BMD in patients with AN. The second point, whether 25OHD should be above 20 or 30 ng/ml remains a discussion point.

Keywords: 25 OH vitamin D; Anorexia nervosa; Bone mineral density; Vitamin D.

MeSH terms

  • Adolescent
  • Adult
  • Amenorrhea / blood
  • Amenorrhea / complications
  • Anorexia Nervosa / blood*
  • Anorexia Nervosa / complications
  • Body Mass Index
  • Bone Density*
  • Bone and Bones / pathology
  • Cohort Studies
  • Cross-Sectional Studies
  • Diet
  • Dietary Supplements
  • Female
  • Humans
  • Middle Aged
  • Prevalence
  • Vitamin D / analogs & derivatives*
  • Vitamin D / blood
  • Vitamin D Deficiency / blood
  • Vitamin D Deficiency / complications
  • Vitamin D Deficiency / epidemiology

Substances

  • Vitamin D
  • 25-hydroxyvitamin D