Dietary patterns and hip fracture in the Adventist Health Study 2: combined vitamin D and calcium supplementation mitigate increased hip fracture risk among vegans

Am J Clin Nutr. 2021 Aug 2;114(2):488-495. doi: 10.1093/ajcn/nqab095.

Abstract

Background: Concerns regarding the adequacy of vegetarian diets with respect to fracture risk continue.

Objectives: We aimed to explore the influence of 5 previously defined dietary patterns on hip fracture risk and whether this association is modified by concomitant calcium and vitamin D supplementation.

Methods: The Adventist Health Study 2 is a prospective cohort study in which participants were enrolled during 2002-2007; proportional hazards regression analyses were used to estimate fracture risk. Participants reside throughout the United States and Canada. A total of 34,542 non-Hispanic white peri- and postmenopausal women and men 45 y and older responded to the biennial hospital history form and were followed for a median of 8.4 y.

Results: The study identified 679 incident hip fractures during 249,186 person-years of follow-up. Fracture risk varied according to dietary pattern, with a clear effect modification by concurrent supplementation with both vitamin D and calcium. In multivariable models, including adjustment for calcium and vitamin D supplementation, female vegans had 55% higher risk of hip fracture (HR: 1.55; 95% CI: 1.06, 2.26) than nonvegetarians (NVEGs), whereas there was no association between diet pattern and hip fracture risk in men. When further stratifying females on supplement use with both vitamin D and calcium, vegans taking both supplements were at no greater risk of hip fracture than the subjects with other dietary patterns including the NVEGs.

Conclusions: Without combined supplementation of both vitamin D and calcium, female vegans are at high risk of hip fracture. However, with supplementation the excessive risk associated with vegans disappeared. Further research is needed to confirm the adequacy of a vegan diet supplemented with calcium and vitamin D with respect to risk of fracture.

Keywords: Adventist Health Study; diet pattern; dietary nutrients; hip fracture; vegan.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Aged
  • Calcium / administration & dosage*
  • Diet / adverse effects*
  • Dietary Supplements*
  • Female
  • Hip Fractures / prevention & control*
  • Humans
  • Male
  • Middle Aged
  • Risk Factors
  • Vegans*
  • Vitamin D / administration & dosage*

Substances

  • Vitamin D
  • Calcium