SYDNEY, Australia -- After an initial low-trauma fracture from a simple fall, both older men and women are equally likely to have a subsequent significant fracture, researchers here reported.
SYDNEY, Australia, Jan 23 -- After an initial low-trauma fracture from a simple fall, both older men and women are equally likely to have a subsequent significant fracture, found researchers here.
Nevertheless, they pointed out, less than 30% of women and 10% of men with a prior fracture are treated for osteoporosis to help lower this risk.
The reduced risk of an initial fracture associated with male sex was lost once a single low-trauma fracture occurred, reported Jaqueline Center, Ph.D., of the University of New South Wales, and colleagues, in the Jan. 24-31 issue of the Journal of the American Medical Association.
For men, the absolute risk of a subsequent fracture was similar to that of women and equivalent to or greater than the initial fracture risk of a woman 10 years older, they found. Women had nearly twice the risk of a subsequent re-fracture while men had more three times the re-fracture risk.
Their calculations of the absolute risk of refracture in both women and men came from an ongoing prospective cohort study (Osteoporosis Dubbo Epidemiology Study) of 2,245 community-dwelling women and 1,760 men, 60 or older, living in the city of Dubbo, 240 miles northwest of Sydney. The participants were followed up from July 1989 through April 2005.
Only low-trauma fractures caused by a fall from a standing height or less were included in the original analysis. Individuals with skull fractures or underlying disease that could predispose to a pathological fracture were excluded. Median follow-up from initial fracture to subsequent fracture, death, or the end of the study was 3.25 years among women and 2.13 years among men.
There were 905 women (mean age 78) and 337 men (mean age 77) with an initial fracture, of whom 253 women and 71 men had a subsequent fracture. The initial fracture risk increased with age and, as expected, was higher in women than in men.
Women had nearly twice the risk of a subsequent fracture (RR 1.95 (95% confidence interval [CI], 1.70-2.25), while men had 3.5 times the refracture risk (RR 3.47, CI 2.68-4.48). Although the initial fracture may have been minor, the subsequent fracture was a hip or other major break, the researchers said.
In terms of person-years, women and men, ages 60 to 69, had absolute refracture rates of 36/1,000 person-years (CI, 26-48/1000) and 37/1,000 person years (CI, 23-59/1000), respectively.
As a result, the absolute risk of a subsequent fracture was similar in women and men and at least as great as the initial fracture risk for a woman 10 years older, the researchers said.
The increase in the absolute fracture risk remained for up to 10 years, by which time 40% to 60% of surviving women and men experienced a subsequent fracture. The majority of the fractures occurred in the first five years after the initial fracture, and up to 10 years if the individual was still alive and had not experienced a subsequent fracture, the researchers said.
The researchers calculated that a 60-year-old woman with an initial fracture had an absolute refracture risk comparable to or greater than an initial fracture risk of a 70- to 79-year-old woman.
For men, the absolute risk of a subsequent fracture was similar to that of women and equivalent to or greater than the initial fracture risk of a woman 10 years older.
For example, a 60- to 69-year-old man's absolute refracture risk was equivalent to or greater than a 70- to 79-year-old woman's initial fracture risk and similar to the initial risk of a man at least 20 years older, the researchers said.
Thus, the investigators said, men no longer enjoyed their reduced risk of an initial fracture once a single low-trauma fracture occurred.
All initial fracture locations apart from rib (men) and ankle (women) resulted in increased subsequent fracture risk, with the highest risks following initial hip fractures (RR, 9.97; CI, 1.38-71.98) and clinical vertebral fractures in younger men (RR, 15.12, CI, 6.06-37.69).
In multivariate analyses, bone mineral density in the femoral neck, age, and smoking were predictors of subsequent fracture in women and bone mineral density in the femoral neck, physical activity, and calcium intake were predictors in men.
Among the study's limitations mentioned by the authors is that the population was almost 99% white, and the results therefore may not hold for other racial and ethnic groups.
Vertebral fractures were those that came to clinical attention, so the results may not be the same for morphometric vertebral fractures. Furthermore, it was not possible to examine individual fracture types for each age group, and peripheral fractures were analyzed together in upper or lower limbs or major or minor groupings. Thus, they said, individual fracture types may signal greater or lesser refracture risks.
Also, the investigators said, there were few individuals alive without refracture available for follow-up of more than 10 years.
Summing up, Dr. Center's team wrote, "The critical clinical relevance of these findings is that and incident low-trauma fracture is a signal for increased risk of all types of subsequent osteoporotic fractures, particularly in the next five to 10 years?"
Thus, virtually all low-trauma fractures indicate the clinical need for fracture-preventive therapy, and given the early peak of refracture, such preventive treatment should not be delayed. "The lack of consideration of osteoporosis and treatment initiatives by the medical profession and the public, particularly in relation to men, should be the focus of education initiatives," the investigators concluded.
Funding support for this study included unrestricted educational grants from Merck Sharp and Dohme, Eli Lilly, and GE Lunar Corporation.