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

Abstract

Background: Vitamin K mediates the ␥-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 72 327 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 g/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.Am J Clin Nutr 1999;69:74-9.

Phylloquinone intake as a marker for coronary heart disease risk but not stroke in women

“…In contrast, plasma phylloquinone reaches a plateau when dietary intakes of phylloquinone estimated by this FFQ exceed 200 mg/day (McKeown et al, 2002). Current data are, however, limited and while this FFQ appears to be appropriate for ranking individuals across the entire range of intake, there could be limitations in estimating high phylloquinone intakes (Feskanich et al, 1999;McKeown et al, 2002), which may have attenuated any linear trends.…”

“…More than half of the women in the lowest quintile category reported usual phylloquinone intakes below the adequate intake (AI), 90 mg/day for women (Food and Nutrition Board, Institute of Medicine, 2001). Because this FFQ may overestimate absolute phylloquinone intakes (Feskanich et al, 1999), it is plausible that the majority of women in this quintile category had usual intakes below the AI. Metabolic data suggest that intakes o100 mg/day do not maximally support carboxylation of osteocalcin, which is a sensitive marker of phylloquinone status .…”

“…Use of multivitamin and oil supplements was estimated based on questions in the FFQ. This FFQ has been validated for phylloquinone intake using diet records (Feskanich et al, 1999) and serum phylloquinone concentrations (McKeown et al, 2002). The phylloquinone contents of food items on the FFQ were obtained from the Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University (Booth et al, 1993(Booth et al, , 1995.…”

“…These vitamin K-dependent proteins are involved in several biological functions, including blood coagulation, vascular calcification, and bone metabolism (Ferland, 1998). Phylloquinone intakes are inversely associated with the risk of developing age-related chronic disorders, such as calcification of the abdominal aorta (Jie et al, 1995) and hip fracture (Feskanich et al, 1999;Booth et al, 2000).…”

A stable isotope method for the simultaneous measurement of vitamin K1 (phylloquinone) kinetics and absorption

“…VKD proteins were originally discovered as crucial in the control and regulation of blood coagulation (for example, prothrombin, factors II, VII, IX and X, and proteins C and S), but more recent evidence suggests a wider role for vitamin K in human health. In particular, low vitamin K intake has been associated with low bone mineral density (Booth et al, 2003a) and an increased fracture risk (Feskanich et al, 1999;Booth et al, 2000) and low plasma vitamin K status has been associated with an increased prevalence of osteoarthritis (Neogi et al, 2006). Evidence is also emerging for a benefit of increased vitamin K intake and status in reducing vascular calcification via the VKD protein, matrix Gla protein (Jie et al, 1995;Schurgers et al, 2001;Berkner and Runge, 2004).…”