A paper published this month in the New England Journal of Medicine presented new information about a novel new risk factor for hip fracture in older adults. The paper revealed a strong statistical association between elevated homocysteine levels in the blood and incidence of hip fracture. A paper appeared in the same issue that reported similar findings from another study conducted by researchers in the Netherlands.
Homocysteine is an amino acid found in the blood. Studies have suggested that higher than normal homocysteine levels are associated with cardiovascular disease, and even dementia. Homocystinura, a rare autosomal recessive biochemical abnormality, causes elevated concentrations of plasma homocysteine and severe occlusive vascular disease. Researchers speculate that the increased prevalence of osteoporosis among people with homocystinuria suggests that high serum homocysteine may weaken bone by interfering with collagen cross-linking, thereby increasing the risk of osteoporotic fracture. The authors of this paper examined the association between total homocysteine concentration and risk of hip fracture in men and women enrolled in the Framingham Heart Study.
The authors studied 825 men and 1174 women, ranging in age from 59 to 91 years, from whom blood samples had been obtained between 1979 and 1982. From the time of measurement of plasma total homocysteine concentrations the participants in the study were followed through June 1998 for incident hip fracture. Sex-specific, age adjusted incidence rates of hip fracture were calculated for quartiles of total homocysteine concentrations. Men and women in the highest quartile had a greater risk of hip fracture than those in the lowest quartile - the risk was almost four times as high for men and nearly double for women.
These findings suggest that the homocysteine concentration, which is easily modifiable by means of dietary intervention, is an important risk factor for hip fracture in older persons.