Your weight may affect your risk for developing osteoporotic fractures—and this risk exists whether you are overweight or underweight, according to the results of a new study.

The study, “Overweight/obesity and underweight are both risk factors for osteoporotic fractures at different sites in Japanese postmenopausal women,” was conducted by researchers at Kyoto University in Japan. It was published online ahead of print in November 2012 and appears in the journal Osteoporosis International.

Keep reading to learn about the results of this study; then, read our Causes of Osteoporosis article to learn more about how your weight (and other factors) influences your risk of osteoporosis and related complications.

A study published in 2012 showed that your weight can affect your risk for osteoporotic vertebral fractures (spinal fractures related to lone bone density). But the big surprise from this study was that being underweight can also negatively impact your risk—most people would assume it's just being overweight that would impact your fracture risk.

How the Study Was Conducted
The researchers looked at a group of 1,614 women in Japan over the course of 6.7 years. They examined the women’s risk of fractures at different points in the body, including in the spine, and they collected data on the women’s age, bone mineral density, and other factors.

What the Researchers Found
The rate of vertebral fractures in women who were overweight or obese was significantly higher than it was in women who were underweight or of normal weight. However, the study results showed that being underweight influenced other parts of the body—the rate of femoral neck (upper thigh bone) and long-bone fractures (bones in your arms in and legs) in underweight women was higher than it was in overweight or obese women.

The study authors concluded that women who were overweight or obese, and women who were underweight, had a heightened risk for osteoporotic fractures on different parts of the body. They argue that physicians can help patients assess their risk of fractures by taking their body mass index into account.

What This Study Means for You
A healthy weight is important for your overall health, including your risk of developing osteoporosis and its related complications. While you may know that it is important to shed excess pounds to help protect your bones, it is important for people who are underweight to take steps to protect their bones, too.

Talk to your doctor about healthy lifestyle modifications, such as diet and exercise, that can help you achieve a healthy weight. To learn about how to manage your weight while building bone strength, read our Bone-building Exercise Tips for Osteoporosis article.