The intersectional role of social stress in fracture risk: results from the Women’s Health Initiative

BackgroundThe biological consequences of stress from the social environment pattern health outcomes. This study investigated whether social stress is prospectively associated with fracture incidence among racially and ethnically diverse, postmenopausal women.MethodsData from 160 709 postmenopausal women in the Women’s Health Initiative was analysed using Cox proportional hazards regression models to examine prospective associations of social stress with time to total and hip fracture incidence. Self-reported questionnaires measuring social strain, social functioning and social support were used to assess social stress.ResultsAge and race/ethnicity modified associations between social stress and total and hip fractures. HRs for the associations between higher social support (indicating lower social stress) and total fractures among those age 50–59 years were 0.92 (95% CI: 0.90 to 0.94); HR=0.94 (95% CI: 0.93 to 0.95) for those age 60–69 years and HR=0.96 (95% CI: 0.95 to 0.98) for those age 70–79 years. Higher social strain was associated with greater hip fracture incidence among Native American women (HR=1.84, 95% CI: 1.10 to 3.10), Asian women (HR=1.37, 95% CI: 1.01 to 1.86) and white women (HR=1.04, 95% CI: 1.01 to 1.08).ConclusionIdentifying population patterns of fracture incidence as biological expressions of social environments reveals how race/ethnic specific social environmental factors influence disparities in fractures.

Effects of changes in regular physical activity status on hip fracture: A nationwide population-based cohort study in Korea

Objective Hip fracture incidence is increasing with rapid aging of the population and regular physical activity (RPA) is an important modifiable protective factor for fracture. However, the association between the risk of hip fractures and changes in RPA status in the general population remains unknown. Thus, we explore the association between the risk of hip fracture and changes in RPA status. Methods We studied 4,984,144 individuals without fractures within a year whose data were registered in the Korean National Health Insurance Service database. Baseline physical activity level was assessed using a standardized self-reported questionnaire during two consecutive national health screening surveys performed in Korea from 2009 to 2012. The risk of hip fracture between 2013 and 2016 according to change in RPA was prospectively analyzed. Participants were divided into those who were always inactive, became inactive, became active, and were always active. Results Compared to participants who were always inactive, those who became inactive exhibited a 0.12/1,000 person-years (PY) reduction in hip fracture incidence rate (IR) [aHR: 0.865; 95% confidence interval (CI): 0.824–0.908]. Participants who became active, and those who were always active, exhibited a 0.24/1,000 PY reduction in IR (aHR: 0.827; 95% CI: 0.787–0.870) and a 0.39/1,000 PY reduction in IR (aHR: 0.691; 95% CI: 0.646–0.740), respectively. Conclusion Changes in RPA status were associated with the risk of hip fracture; consistent RPA was related to the maximum benefit for risk reduction in the general population.