Aging men commonly experience a gradual, mild loss in weight, which places them at greater risk for bone fractures. Such weight loss is also a risk factor for death and could be a sign of underlying disease. The competing risk of death makes it difficult to accurately estimate how much weight loss raises the chance of getting a major fracture. A new study by Adjunct Professor Kristine Ensrud sought to untangle the two factors by calculating the risk older men have in breaking the hip, spine, and pelvis with and without accounting for the competing risk of death.

The study was published in the Journal of Bone and Mineral Research.

“Disabling fractures like hip fractures and mortality share many common risk factors in older adults,” says Ensrud. “The sicker you are or if you smoke, the more likely you are to die or fall and get a hip fracture.”

The study found that as men age, weight loss increases their risk of fracture over time. On top of that, the researchers discovered that the probability of fractures and the association between weight loss and fractures can be overestimated if the competing risk of mortality is not accounted for.

Specifically, the study found that if mortality risk is not taken into account, the probability of a hip, spine, or pelvis fracture in aging men with gradual weight loss was approximately seven percent at five years and 17 percent at 10 years. When mortality risk was factored in, the fracture probability dropped to about six percent at five years and 10 percent at 10 years when calculated using a competing risk approach.

Ensrud said the overestimation gets worse over a longer period of time and had a greater impact on the 10-year probability than it did on the five-year probability of a fracture.

The results have big implications for how providers and patients think about their long-term health.

“When you see an older patient, you should communicate his or her 10-year probability for a specific serious health event like a hip fracture,” says Ensrud. “But doctors should also take into account the patient’s risk of mortality not related to the condition of interest, because your probability of a hip fracture is lower if you are at high risk of dying from something else.”

Researchers should also factor-in how individual patient mortality risk changes probabilities for specific adverse disease events in older adults.

“In research, when trying to estimate the lifetime risk of an adverse outcome, it’s important in older age groups to take into account the risk of death, because it’s more likely for them than younger populations,” says Ensrud.

The data for this study came from a larger studyEnsrud is conducting, called MrOS, which examines age-related conditions in a cohort of older, community-dwelling men.