Vitamin K intake and hip fractures in women: a prospective study

Am J Clin Nutr. 1999 Jan;69(1):74-9. doi: 10.1093/ajcn/69.1.74.

Abstract

Background: Vitamin K mediates the gamma-carboxylation of glutamyl residues on several bone proteins, notably osteocalcin. High serum concentrations of undercarboxylated osteocalcin and low serum concentrations of vitamin K are associated with lower bone mineral density and increased risk of hip fracture. However, data are limited on the effects of dietary vitamin K.

Objective: We investigated the hypothesis that high intakes of vitamin K are associated with a lower risk of hip fracture in women.

Design: We conducted a prospective analysis within the Nurses' Health Study cohort. Diet was assessed in 72327 women aged 38-63 y with a food-frequency questionnaire in 1984 (baseline). During the subsequent 10 y of follow-up, 270 hip fractures resulting from low or moderate trauma were reported.

Results: Women in quintiles 2-5 of vitamin K intake had a significantly lower age-adjusted relative risk (RR: 0.70; 95% CI: 0.53, 0.93) of hip fracture than women in the lowest quintile (< 109 microg/d). Risk did not decrease between quintiles 2 and 5 and risk estimates were not altered when other risk factors for osteoporosis, including calcium and vitamin D intakes, were added to the models. Risk of hip fracture was also inversely associated with lettuce consumption (RR: 0.55; 95% CI: 0.40, 0.78) for one or more servings per day compared with one or fewer servings per week), the food that contributed the most to dietary vitamin K intakes.

Conclusions: Low intakes of vitamin K may increase the risk of hip fracture in women. The data support the suggestion for a reassessment of the vitamin K requirements that are based on bone health and blood coagulation.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Analysis of Variance
  • Body Mass Index
  • Cohort Studies
  • Diet*
  • Female
  • Hip Fractures / prevention & control*
  • Humans
  • Massachusetts
  • Middle Aged
  • Prospective Studies
  • Surveys and Questionnaires
  • Vitamin K / administration & dosage*
  • Vitamin K / therapeutic use

Substances

  • Vitamin K