Regular physical activity, including lighter intensity activities such as walking, is associated with reduced risk of hip and total fracture in post-menopausal women, according to new research from the University at Buffalo. The study is the most comprehensive evaluation of physical activity and fracture incidence in older women.
The study included more than 77,000 participants in the Women's Health Initiative, who were followed up over 14 years. During follow-up, 33% of participants reported experiencing at least one fracture.
The women who did the highest amount of physical activity – which was approximately 35 minutes or more of daily recreational and household activities – had an 18% lower risk of hip fracture and 6% lower risk of total fracture.
The study is one more among several papers – all using data from the Women's Health Initiative – published by UB researchers within the past few years that highlights the health benefits of being active, even at levels that are lower than the current physical activity guidelines.
"These findings provide evidence that fracture reduction is among the many positive attributes of regular physical activity in older women," said Dr Jean Wactawski-Wende, study co-author and dean of the University at Buffalo School of Public Health and Health Professions.
"Fracture is very common in postmenopausal women, and is associated with loss of independence, physical limitations and increased mortality," Wactawski-Wende said. In fact, the researchers note, approximately 1.5m fractures occur in US women each year, creating $12.7bn in health care costs. About 14% of these fractures are in the hip. Mortality after a hip fracture is as high as 20%.
"Modest activities, including walking, can significantly reduce the risk of fracture, which can, in turn, lower the risk of death," Wactawski-Wende said.
Non-recreation physical activity – examples include yardwork and household chores such as sweeping the floors or folding laundry – also was inversely associated with several types of fracture.
The research has important implications for public health, considering that these lighter intensity activities are common among older adults.
The main message, says study first author Dr Michael LaMonte, research associate professor of epidemiology and environmental health at UB, is "sit less, move more, and every movement counts."
Abstract
Importance: Physical activity is inversely associated with hip fracture risk in older women. However, the association of physical activity with fracture at other sites and the role of sedentary behavior remain unclear.
Objective: To assess the associations of physical activity and sedentary behavior with fracture incidence among postmenopausal women.
Design, Setting, and Participants: The Women’s Health Initiative prospective cohort study enrolled 77 206 postmenopausal women aged 50 to 79 years between October 1993 and December 1998 at 40 US clinical centers. Participants were observed for outcomes through September 2015, with data analysis conducted from June 2017 to August 2019.
Exposures: Self-reported physical activity and sedentary time.
Main Outcomes and Measures: Hazard ratios (HRs) and 95% CIs for total and site-specific fracture incidence.
Results: During a mean (SD) follow-up period of 14.0 (5.2) years among 77 206 women (mean [SD] age, 63.4 [7.3] years; 66 072 [85.6%] white), 25 516 (33.1%) reported a first incident fracture. Total physical activity was inversely associated with the multivariable-adjusted risk of hip fracture (>17.7 metabolic equivalent [MET] h/wk vs none: HR, 0.82; 95% CI, 0.72-0.95; P for trend < .001). Inverse associations with hip fracture were also observed for walking (>7.5 MET h/wk vs none: HR, 0.88; 95% CI, 0.78-0.98; P for trend = .01), mild activity (HR, 0.82; 95% CI, 0.73-0.93; P for trend = .003), moderate to vigorous activity (HR, 0.88; 95% CI, 0.81-0.96; P for trend = .002), and yard work (HR, 0.90; 95% CI, 0.82-0.99; P for trend = .04). Total activity was positively associated with knee fracture (>17.7 MET h/wk vs none: HR, 1.26; 95% CI, 1.05-1.50; P for trend = .08). Mild activity was associated with lower risks of clinical vertebral fracture (HR, 0.87; 95% CI, 0.78-0.96; P for trend = .006) and total fractures (HR, 0.91; 95% CI, 0.87-0.94; P for trend < .001). Moderate to vigorous activity was positively associated with wrist or forearm fracture (HR, 1.09; 95% CI, 1.03-1.15; P for trend = .004). After controlling for covariates and total physical activity, sedentary time was positively associated with total fracture risk (>9.5 h/d vs <6.5 h/d: HR, 1.04; 95% CI, 1.01-1.07; P for trend = .01). When analyzed jointly, higher total activity mitigated some of the total fracture risk associated with sedentary behavior. Analysis of time-varying exposures resulted in somewhat stronger associations for total physical activity, whereas those for sedentary time were materially unchanged.
Conclusions and Relevance: In older ambulatory women, higher total physical activity was associated with lower total and hip fracture risk but higher knee fracture risk. Mild activity and walking were associated with lower hip fracture risk, a finding with important public health implications because these activities are common in older adults. The positive association between sedentary time and total fracture risk requires further investigation.
Authors
Michael J LaMonte, Jean Wactawski-Wende, Joseph C Larson, Xiaodan Mai, John A Robbins, Meryl S LeBoff, Zhao Chen, Rebecca D Jackson, Andrea Z LaCroix, Judith K Ockene, Kathleen M Hovey, Jane A Cauley
[link url="https://www.sciencedaily.com/releases/2019/11/191106120430.htm"]University at Buffalo[/link]
[link url="https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2753526"]JAMA Network Open abstract[/link]