There may be a link between differences in finger length and motivation to exercise, suggests a study by American and Canadian researchers who analyzed differences in activity levels between normal mice and selectively bred, active mice.

Overall, the more active mice had a higher ratio of the length of the digit finger divided by the ring finger.

The results indicate a strong association between digit length, voluntary exercise and high levels of prenatal stress hormones, said the University of Alberta and University of California, Riverside researchers, United Press International reported.

They found that prenatal stress, rather than prenatal testosterone levels in the womb, plays a role in a natural desire for physical activity.

"The research shows a link, or relationship, between the brain, behavior and personality traits and the shape of the hand," lead researcher Peter Hurd, of the University of Alberta, said in a news release, UPI reported. "It opens the door to the notion that aspects of one's personality, in this case the desire to exercise, are fixed very early in life."

The study appears in the journal PLoS One.

In women with osteoporosis, the experimental bone drug denosumab reduced the risk of spinal fractures by 68 percent, the risk of hip fractures by 40 percent, and the risk of all fractures outside the spine by 20 percent, according to a study released Tuesday by drug maker Amgen.

The study of 7,800 postmenopausal women found that 2.3 percent of those who took the drug suffered a vertebral fracture, compared with 7.2 percent of those who took a placebo. That 68 percent relative risk reduction compares favorably with the 40 to 50 percent reductions achieved in clinical trials by drugs currently used to treat osteoporosis, The New York Times reported.

The 40 percent reduced risk of hip fracture noted in women who took denosumab is as good or better than that results seen with other drugs.

However, the study did find that 4.3 percent of women who took denosumab suffered serious infections, compared with 3.4 percent of those who took the placebo. While not statistically significant, the increased risk of infection could concern government regulators, The Times reported.

The study was presented at the annual meeting of the American Society for Bone and Mineral Research. It's expected Amgen will apply for U.S. Food and Drug Administration approval of denosumab by early next year.