Older women who keep physically active — even if that activity involves taking relatively slow daily walks — are less likely to fall and fracture a hip, according to a study published in the journal JAMA Network Open.
This isn’t the first study to link regular physical activity and a lower risk of hip fractures in older adults, but it is one of the biggest, according to its authors.
The topic is an important one. Currently, more than 300,000 Americans aged 65 and older are hospitalized with a hip fracture each year, according to the Centers for Disease Control and Prevention. Three-quarters of those fractures occur among women, and almost all (95 percent) are the result of falls.
Those numbers are expected to grow significantly in the coming years as the large baby boomer generation continues to age.
Hip fractures can be very serious, for they raise the risk of medical complications such as blood clots, infections and pneumonia. One in five older adults who break a hip die within a year of the injury. Hip fractures can also greatly affect quality of life, making it impossible for people to regain their previous levels of physical functioning.
How the study was done
For the current study, a team of researchers led by epidemiologist Michael LaMonte of the University of Buffalo, analyzed data collected from 77,206 women who were enrolled during the 1990s in the Women’s Health Initiative, a long-term national health study. The women were between the ages of 50 and 79 when they entered the study, and all were ambulatory (able to walk) at the start of the study.
The women filled out a detailed health questionnaire at the time of their enrollment, which included questions about both their recreational activities (such as walking, swimming, biking, dancing and golfing) and non-recreational activities (such vacuuming, gardening and shoveling snow). The questionnaire drilled down on the women’s walking habits in particular, asking specific questions about the length and speed of their walks.
LaMonte and his colleagues followed the women for an average of 14 years. During that time, about a third of the women (25,355) experienced some kind of fracture. Of these, 3,164 were hip fractures. Other common fractures included vertebral ones (4,056), as well as those involving the wrist or forearm (5,473), lower leg (4,140), foot (3,859) and upper arm (2,964).
The researchers then looked at the types and levels of physical activity reported by the women to see if they correlated with their risk of breaking a bone. After controlling for sedentary behavior (time the women spent sitting), they found that, on average, the women who engaged in the most physical activity — no matter what kind or how intense — were 18 percent less likely to have broken their hip than women who were inactive.
Walking was specifically found to be inversely related to hip fractures. The more walking women did each week — even at relatively slow speeds — the lower their risk of breaking a hip.
The women who exercised the most were also less likely to experience a vertebral fracture.
The analysis did reveal, however, that women who engaged in vigorous physical activity (defined as jogging, tennis, and other aerobics dancing) were at a slightly greater risk for wrist and forearm fractures, and the women who exercised the most overall were also at an increased risk of knee and elbow fractures.
Those higher risks may be because older women who are able to exercise at higher-intensity levels are “more functional and more likely to break a fall with outstretched hands,” LaPonte and his coauthors write.
Limitations and implications
The study comes with important caveats. It’s observational, so can’t prove a cause-and-effect relationship between exercise and the risk of fractures. In addition, the women self-reported their physical activity, and such reports are not always accurate.
Still, as LaMonte and his colleagues point out, the finding of an inverse relationship between physical activity and hip and vertebral fracture “is biologically plausible.”
“Physical activity could attenuate the age-related reduction in spine and hip [bone mineral density]” and “help improve balance, range of motion, and muscle strength, thereby reducing falls,” they explain.
“We were happy to see a strong relationship between walking and lower hip fracture risk,” LaMonte told HealthDay reporter Amy Norton “As we get older, we naturally do less-strenuous physical activity. This suggests that to lower your risk of hip fracture, you don’t need to do anything fancy. It can be as simple as walking.”
FMI: You can read the study in full on the JAMA Network Open website.