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

• Published in: The American journal of clinical nutrition 1999, Vol.69 (1), p.74-79
• Main Authors: Feskanich, D, Weber, P, Willett, W.C, Rockett, H, Booth, S.L, Colditz, G.A
• Format: Article
• Language: English
• Subjects: Adult; Analysis of Variance; Biological and medical sciences; Body Mass Index; bone fractures; Cohort Studies; Diet; Diseases of the osteoarticular system; estrogens; Female; food intake; foods; Fractures; Hip Fractures - prevention & control; Hip joint; hormone supplements; Humans; Massachusetts; Medical sciences; Middle Aged; nurses health study; nutrient intake; Osteoporosis; Osteoporosis. Osteomalacia. Paget disease; Prospective Studies; risk; Surveys and Questionnaires; vitamin K; Vitamin K - administration & dosage; Vitamin K - therapeutic use; Vitamins; Women
• ISSN: 0002-9165; 1938-3207
• DOI: 10.1093/ajcn/69.1.74

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 microgram/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.