We already know that if one of your parents had a hip fracture, it increases your risk for developing osteoporosis. But Swedish researchers have identified a new fracture risk factor: hip fractures in grandfathers may mean that their grandsons will have bone health issues, as well.

The study, which was published in the Journal of Clinical Endocrinology & Metabolism, was led by associate professor Mattias Lorentzon of the University of Gothenburg, Sweden. The research team studied 3688 grandparents and their 1015 grandsons. Not all the grandparents had experienced a hip fracture.

The team measured the subjects' bone mineral density (BMD) and cortical bone size (cortical bone is the outer layer of bone).

Of the total grandsons tested, 269 had low bone density—and every one of them had a grandparent who had a hip fracture.

The researchers then divided those 269 men into two groups—those who had a grandmother who had a hip fracture and those with a grandfather who had a hip fracture. They found that the men with a grandfather who had a fracture had less bone density and smaller bones than those with a female relative who had a hip fracture.

The fact that the grandsons had smaller bones, along with reduced bone density, put them at a higher risk for developing osteoporosis. The researchers also took other osteoporosis risk factors into account, such as smoking, exercise, and calcium intake.

Why These Findings Matters
Though the study focused on hip fractures, the research highlights the genetic implications associated with low bone mass and osteoporosis risk. And that affects the prevalence of spinal compression fractures as well.

"This new risk factor may be significant for the diagnosis of low bone mass and suggests possible mechanisms for the inheritance of low bone mass and fracture risk," says Dr. Lorentzon. "It's important for health professionals to ask whether grandparents have had hip fractures."

Moreover, the study focuses on men's risk for developing osteoporosis. Many people believe osteoporosis is solely a woman's disease—and it's not. Though the majority of osteoporosis sufferers are women, men can also develop osteoporosis.

To learn more, you can read the abstract of this study here.