Sex- and ethnic-specific patterns in the incidence of hip fracture among older US Asian and non-Hispanic White adults

Background: Asian and Pacific Islander (Asian/PI) adults have lower hip fracture incidence than non-Hispanic White (NHW) adults, but data regarding Asian/PI subgroups are limited. We compared hip fracture incidence among older US Asian/PI and NHW populations, including ethnic subgroup differences. Methods: Using observational data from a California healthcare system, we identified Asian/PI and NHW adults aged ≥50 years (2000–2019) and followed subjects to 2021 for hip fracture determined by principal/primary hospital diagnosis or by secondary hospital diagnosis with hip/femur procedure codes. Age-adjusted hip fracture incidence was calculated with 95% confidence intervals (CIs). Log-Poisson regression was used to determine fracture incidence rate ratios (IRRs, [CI]; NHW or Chinese as reference) adjusting for age and year. Results: Among 215,359 Asian/PI and 776,839 NHW women, hip fracture incidence was 1.34 (1.28–1.40) and 2.97 (2.94–3.01) per 1000 person-years, respectively, with IRR 0.45 (0.43–0.47). Among 188,328 Asian/PI and 697,046 NHW men, hip fracture incidence was 0.62 (0.58–0.67) and 1.81 (1.78–1.84) per 1000 person-years, respectively, with IRR 0.34 (0.32–0.37). For the four largest Asian/PI subgroups, Filipina women (IRR 0.85 [0.75–0.96]) had lower, and Japanese (IRR 1.36 [1.20–1.54]) and South Asian (IRR 1.36 [1.07–1.72]) women had higher hip fracture incidence compared to Chinese women. Hip fracture incidence was only higher among South Asian (IRR 1.61 [1.21–2.14]) compared to Chinese men. Conclusion: Hip fracture incidence among US Asian/PI adults was 55% (women) and 66% (men) lower than NHW adults, but incidence varied by Asian/PI subgroup. The heterogeneity among Asian/PI adults highlights the importance of examining fracture risk by ethnic subgroup.