Australian Study Indicates Physically Fit Women Have Stronger Hip Bones, Spines
Physically fit women have stronger spines and hip bones, indicating that moderate exercise could be a “safe” way to ward off thinning of the bones, a common cause for hip breaks among the elderly, an Australian researcher said Wednesday.
Dr. John Eisman, head of bone and mineral research at the Garvan Institute of Medical Research in Sydney, said that the study is the first to show the importance of physical fitness in determining the strength of hip bones.
Among post-menopausal women--who are especially vulnerable to osteoporosis, a bone-thinning disease--physical fitness was the most important factor in determining how strong and dense their hip bones were, Eisman told physicians gathered for the Endocrine Society’s international meeting at the Anaheim Convention Center.
More Physically Active
In an interview, Eisman said the data compiled on 81 women prompts him to conclude that people should “be more physically active . . . . Activities should be more attuned to the weight-bearing function, that is, walking and carrying instead of sitting and riding.”
The research implies, he said, “that if you change your fitness, you can change your bone mass.” Extreme exercise is not required or even necessarily suggested, he said, “just a moderate degree of fitness.”
The women studied in the research ranged in age from 20 to 70 and were neither frail nor the caliber of “Olympic athletes,” Eisman said. “They were your average, run-of-the-mill people.”
The study determined the women’s current physical fitness and linked it only to their current bone strength. The study did not show whether moderate exercise today leads to stronger bones tomorrow, he said.
However, a study Eisman is now performing on identical twins could show such a relationship. He said the study involves restricting the activity of one twin, so that the researchers can later measure whether there is a difference in bone strength between the active and non-active twin.
Still, it is unknown whether the study discussed Wednesday means that young women who exercise now will be less susceptible to osteoporosis and bone breaks when they are middle-aged or elderly, Eisman said.
“But I think if you can show that someone who is fit now, or becomes more fit now, results in an increase in bone mass now, then follow it up and show that they can maintain it (the bone mass), I think you can be optimistic,” Eisman added.
“But there’s no way you could say what you see now (in bone strength) will be the same in 30 years” without a 30-year study, he said.
81 Women in Study
For the study, Eisman and other Garvan Institute researchers measured the 81 women’s “threshold” for physical fitness with an exercise bike and measured their bone density at the hip, the spine and the wrist, the three places where breaks occur most often among people with brittle or thin bones. There was little difference noted in the strength of wrist bones, but there was a significant data recorded regarding hip bones and spines, he said.
“We found that the fitter the women were, the higher was their bone density in both of the sites measured. This was true even when the results were corrected for age, weight and height,” he said.
The data on hip bones is especially important, he said, because bone thinning is the major cause in hip breaks, a debilitating injury among the elderly.
Post-menopausal women are especially susceptible to osteoporosis because lack of estrogen contributes to bone thinning, according to researchers. Calcium deficiency likewise has been linked to osteoporosis.
Eisman said the researchers noted that genetics can influence bone strength, and the research does not imply that other factors, such as estrogen and calcium, “don’t also play a part.”
But walking and exercising more can’t hurt, and very possibly it could help build stronger bones, he said, adding: “Unless you are running on the freeway, exercise is a safe thing to suggest.”
