Vitamin C Intake May Reduce Fracture Risk
By Alison Palkhivala CME Author: Désirée Lie, MD, MSEd
From American Society for Bone and Mineral Research (ASBMR) 30th Annual Meeting.
September 15, 2008 (Montreal) — Total and supplemental use of vitamin C — but not dietary vitamin C intake — are associated with a reduced risk for hip and nonvertebral fracture, according to research presented here on September 14 at the American Society for Bone and Mineral Research 30th Annual Meeting.
Here are just two interesting paragraphs from the article:
"Basically, people who had higher levels of vitamin C intake had half the rate of hip fractures as people who had the lowest vitamin C [levels]," said Dr. Hannan. "Similarly, people who took supplemental vitamin C again had roughly half the amount of hip fractures as people who did not take any supplemental vitamin C."
"We want to look at modifiable risk factors [for osteoporosis], and diet is so modifiable," coauthor and presenter Marian T. Hannan, DSc, MPH, told Medscape Diabetes & Endocrinology.
"Vitamin C [intake] is highly modifiable. It's a water-soluble vitamin that's easily digested and easily absorbed.... [In addition,] there's a pathway for antioxidants inhibiting bone resorption. There's [also] a collagen effect that's directly related to vitamin C."
Dr. Hannan is a senior scientist and codirector of musculoskeletal research at the Institute for Aging Research at Hebrew Senior Life, Boston, Massachusetts. She is also an associate professor of medicine at Harvard Medical School in Boston
To read the complete article, just click on: http://www.medscape.com/viewarticle/580518?src=mp&spon=22&uac=13078CJ
Vitamin C may influence bone health by reducing oxidative stress and subsequent bone resorption, and by playing a role in collagen formation. Therefore, we evaluated associations of vitamin C intake (total, dietary and supplemental) with incident hip fracture and non-vertebral osteoporotic fracture, over 15 to 17-y of follow-up in the Framingham Osteoporosis Study.
366 men and 592 women completed a food frequency questionnaire in 1988-89 and were followed for non-vertebral fracture until 2003 and hip fracture until 2005. Tertiles or categories of vitamin C intake (each for total, dietary and supplemental) were created, adjusting for total energy intake (residual method).
Hazard ratios (HR) were estimated using Cox-proportional hazards regression adjusting for sex, age, BMI, height, smoking, physical activity index, total energy intake, alcohol intake, multivitamin use and current estrogen use (in women only). Supplemental and dietary vitamin C intakes were adjusted for each other. Final models were examined for attenuation by adding femoral bone mineral density (FN-BMD).
Mean age was 75 y ± 5.0. Over follow-up, 100 hip fractures and 180 non-vertebral fractures. Subjects in the highest tertile of total vitamin C intake had significantly fewer hip fractures or non-vertebral fractures compared to subjects in the lowest tertile.
Subjects in the highest category of supplemental vitamin C intake had significantly lower risk of hip and non-vertebral fracture compared to non-supplement users. Dietary vitamin C intake was not associated with risk of fracture (all P >0.17). The associations for hip fracture did not change after adjustment for baseline FN-BMD.
These results suggest that vitamin C may reduce the risk of fracture by 50% or more in elderly men and women, especially when vitamin C supplements are used. The observation that the risk for fracture may be independent of BMD suggests the possibility of effects on the bone matrix, muscle or other risk factors.
Intake of total and of supplemental — but not dietary — vitamin C in tertile 2 in older patients is associated with 27% and 50% reduction, respectively, in the rate of hip fractures, whereas in tertile 3, the rate was 54% and 69%, respectively.
Daily intake of total vitamin C in the lowest and highest tertiles is 97 and 305 mg/day, respectively, and daily intake of supplemental vitamin C ranges from 0 to 260 mg/day.
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