Despite its other health downsides, increased weight has previously been linked with higher bone density and lower risk of fracture. A study from Cambridge, U.K., has looked at body fat percentage and linked lower levels of it with increased risk of bone breaks, particularly in women.
As part of the European Prospective Investigation into Cancer and Nutrition (EPIC), researchers looked at 14,789 participants people in the U.K. county of Norfolk to check their risk of fractures. Of the people studied, 556 had a fracture, including 184 people who had a hip fracture. The risk of a broken hip decreased as the percentage of body fat increased, but this relationship wasn't seen in men.
According to the researchers: "The percentage of body fat appears to predict hip fracture risk in women with an effect size comparable to that of bone density as measured by heel ultrasound."
Reduced levels of body fat could be as effective as a heel ultrasound to help doctors pick out those women most likely to break bones and monitor them more closely, and to offer them advice on diet and exercise to maintain healthy levels of body fat.