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Vitamin K May Play a Role in Hip Fracture Incidence in Japanese Population
By Sarah Madden, April 14th, 2008, abstracted from “Association of hip fracture incidence and intake of calcium, magnesium, vitamin D, and vitamin K”, Journal of European Epidemiology, April 1, 2008
Hip fractures are a common problem among the ever-aging US population1. Almost all hip fractures in adults 65 years and older are caused by falls1. In 2003, over 300 000 hospitalization visits occurred due to hip fractures and it is estimated that this number will surpass 500 000 by 2040, however this is most likely reflective of the aging population. Falls among older individuals, 65 years and older, is the leading cause of death from injury in this population2. The estimated cost of falls in older individuals was over $19 billion in the year 20003. Calcium is the most studied nutrient in association to bone health and is well known for this role among the public and scientific community4. Vitamin D and magnesium are known to play roles in calcium and bone metabolism, however the mechanisms behind these roles may not be well understood(4, 5). Recently, vitamin K has been acquiring attention for its possible role in bone maintenance and health6. Vitamin K is a fat soluble vitamin that has been traditionally acknowledged for its role in blood clotting yet is now receiving attention for its function in bone metabolism4. There are 2 forms of vitamin K, K1 and K2. K1 is present in higher plants and algae and K2 is produced by commonly found bacteria. It is believed that K2 plays a larger role in bone metabolism than K14. A survey-based study conducted in the Japanese population assessed hip fracture incidence with intakes of vitamin D, calcium, magnesium and vitamin K4. The country was categorized into 12 geographical areas. There were significant correlations found for intakes of all nutrients and hip fracture incidence, however vitamin K demonstrated the strongest correlations for both men and women after adjusting for age. A linear relationship was observed in relation to vitamin K consumption and hip break scores. In the eastern areas of Japan, where vitamin K is consumed in higher concentrations, lower hip break scores were recorded as opposed to the western areas where lower vitamin K was consumed and higher hip break scores were observed. In addition, the same observation was noted to natto consumption and lower hip break scores. Natto is a term used for fermented soybeans and it is high in vitamin K. These observations demonstrate a possible role of vitamin K in relation to bone maintenance4. The authors note that the Japanese population has very diverse eating habits ranging over different geographical patterns. This is important to note because observations were seen with respect to vitamin K intake and hip break scores despite different dietary habits. The data presented is observational and as a result no cause and effect relationship may be determined. Future studies should directly look for causal relationships and possible mechanisms attributing the role of vitamin K to bone maintenance. Furthermore, intakes of vitamin K in elderly populations should be evaluated to optimize bone health. Older individuals may need special attention with respect to this nutrient, therefore addressing this need may be a possible way to address the problems related to hip fractures in this population. Sarah Madden is an MSc Candidate, in the Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON
References:
1 Department of Health and Human Services; Centers for Disease Control and Prevention. Hip Fractures Among Older Adults. http://www.cdc.gov/ncipc/factsheets/adulthipfx.htm
2 Department of Health and Human Services; Centers for Disease Control and Prevention. Falls Have Become the Leading Cause of Injury Deaths for Seniors 3 http://www.cdc.gov/od/oc/media/pressrel/r061116.htm?s_cid=mediarel_r061116_x
3. Department of Health and Human Services; Centers for Disease Control and Prevention. Cost of Falls Among Older Adults 4 http://www.cdc.gov/ncipc/factsheets/fallcost.htm
4. Yaegashi Y, Onoda T, Tanno K, Kuribayashi T, Sakata K & Orimo H. Association of hip fracture incidence and intake of calcium, magnesium, vitamin D, and vitamin K. European Journal of Epidemiology. 2008; 23: 219-233
5 Dawson-Hughes B & Bischoff-Ferrari HA. Therapy of Osteoporosis With Calcium and Vitamin D. Journal of Bone and Mineral Research. 2007; 22(S#2)
6 Bolton-Smith C, McMurdo MET, Paterson CR, Mole PA, Harvey JM, Fenton ST, Prynne CJ, Mishra GD,& Shearer MJ. Two-Year Randomized Controlled Trial of Vitamin K1 (Phylloquinone) and Vitamin D3 Plus Calcium on the Bone Health of Older Women