SAN DIEGO — Long-term cancer survivors who complied with physical activity guidelines had a lower risk of frailty-related fractures than those who did less exercise, based on data from more than 100,000 individuals.
“Fractures associated with fragility are more than just a broken bone,” Erica Reis-Bonia, MD, MPH, of the American Cancer Society in Atlanta, Georgia, said in a presentation at the annual meeting of the American College of Sports Medicine.
Older adults are at an increased risk of death for at least 10 years after a fracture, Reiss-Bonia said.
Cancer and cancer treatments are associated with an increased risk of fragility-related bone fractures; However, the role of factors such as physical activity to modulate fracture risk in cancer survivors remains unclear, as previous studies were small and limited to certain types of cancer, she noted.
In the current study, Rees-Punia and colleagues reviewed data from participants in the Cancer Prevention Study II and correlated it with Medicare claims data from 1999-2017. The study population included 101,543 participants, of whom 14,159 were cancer survivors. At baseline in 1999, the average age of participants was 69.5 years, 55% were women, and 97.9% were white.
Participants were divided into three categories: short-term survivors (1-5 years after diagnosis), long-term survivors (5 or more years after diagnosis) and no history of cancer. Reese Bonya said the first year after diagnosis was excluded from the analysis to account for the potential effects of cancer treatment.
The researchers used regression analysis to estimate the hazard ratios for total fracture risk and the effect of both weight training and moderate to vigorous aerobic physical activity (MVPA). MVPA was defined as moderate to brisk walking, or equivalent.
During the study period, researchers identified 14,196 fractures associated with fragility, including pelvic, radial, and vertebral fractures. Short-term cancer survivors had a 28% higher risk of total fracture-related fracture compared to individuals without cancer, and long-term cancer survivors had an 8% higher risk of fracture. Both increases were statistically significant.
When broken down by site-specific fractures, short-term cancer survivors also had a 24% increased risk of pelvic fractures and a 33% increased risk of radial fractures compared to individuals without cancer. Those were statistically significant as well.
However, long-term cancer survivors who met the MVPA guidelines and weight training had a lower risk of total fractures (hazard ratio). [HR] 0.88 for MVPA and HR 0.86 for weight training) compared with those who did not meet the MVPA guidelines. There was no significant reduction in fracture risk associated with either MVPA or weight training (HR, 0.95 for both) in the short-term survivors.
Res-Bonia said the results were limited by several factors, including the study’s predominantly white population. Other limitations included the challenge of separating the roles of cancer type, stage, and time since diagnosis and treatment.
“Those with late-stage disease or certain types of cancer are more likely to receive chemotherapy,” which has been linked to an increased risk of fractures, she added.
However, the results were reinforced by the large population and long-term follow-up, and by stratification over time since diagnosis.
Most of the participants used walking for the MVPA, but more research is needed to study the type of activity (swimming, cycling, walking, strength training) and intensity to better determine the role of exercise in fracture prevention, said Reiss-Bonia.
“Future research will explore the role of physical activity throughout the lifespan,” said Res-Bonia. It concluded that, in the meantime, “clinical guidelines for fracture prevention for survivors may include referrals for physical activity” to clinicians who specialize in exercise for cancer patients.
Consider activity levels to reduce fracture risk
“As we age, fractures become a major concern, especially as a result of falls. Falls are among the 20 most costly medical conditions, and the leading cause of traumatic brain injury for those age 65 and older,” Lee Stoner, Ph.D., said MPH, Director of The CardioMetabolic Lab (CML) at the University of North Carolina, Chapel Hill, for Medscape.
Stoner, who was not involved in this research, said previous research shows fracture risk can be reduced through exercise, so the results of the current study were not surprising.
“Surprisingly, this has received limited attention in cancer survivors, especially given the persistently high 5-year survival rates for many cancers,” he said.
The main message for clinicians, Stoner said, is an increased risk of fragility-related fractures in short-term cancer survivors compared to individuals without cancer. He stressed, “This risk drops to 8% 5 years after diagnosis. We know that both aerobic and resistance exercise reduce fracture risk in the general population, and this risk reduction is equally effective for cancer survivors.”
The authors did not mention the age of the participants, or whether [they made] Adjustment for age,” said Stoner. In future research, “it would be useful to elicit how much risk can be attributed to age versus cancer, and how much risk can be attributed to lifestyle before and during cancer treatment.”
The study did not receive any external funding. Reese Bona and Stoner reported no related financial relationships.
American College of Sports Medicine 2022 Annual Meeting and World Conference: Abstract 355. Filed June 1, 2022.
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