Subsequent fracture risk in Norwegians and immigrants with an index forearm fracture: a cohort study

The current study investigated subsequent fracture risk following a forearm fracture in three country of birth categories: Norway, Europe and North America, and other countries. Subsequent fracture risk was modestly higher in Norwegian-born individuals compared to the two other groups. Secondary fracture prevention should be recommended regardless of country background.

Background: Fracture risk is higher in patients with a previous fracture, but whether subsequent fracture risk differs by origin of birth is unknown. This study explores subsequent fracture risk in patients with an index forearm fracture according to region of birth.

Methods: Nationwide data on forearm fractures in patients ≥ 18 years in 2008-2019 were obtained from the Norwegian Patient Registry and Statistics Norway. Index fractures were identified by ICD-10 code S52, whereas subsequent fractures included any ICD-10 fracture code. Data on country of birth were from Statistics Norway and included three regional categories: (1) Norway, (2) other Europe and North America and (3) other countries. Direct age standardization and Cox proportional hazard regression were used to analyse the data.

Results: Among 143,476 individuals with an index forearm fracture, 35,361 sustained a subsequent fracture. Norwegian-born forearm fracture patients had the highest subsequent fracture rates (516/10,000 person-years in women and 380 in men). People born outside Europe and North America had the lowest rates (278/10,000 person-years in women and 286 in men). Compared to Norwegian-born individuals, the hazard ratios (HRs) of subsequent fracture in individuals from Europe and North American were 0.93 (95% CI 0.88-0.98) in women and 0.85 (95% CI 0.79-0.92) in men. The corresponding HRs in individuals from other countries were 0.76 (95% CI 0.70-0.84) in women and 0.82 (95% CI 0.74-0.92) in men.

Conclusion: Individuals born outside Norway had a lower subsequent fracture risk than Norwegian-born individuals; however, subsequent fracture risk increased with age in all groups. Our results indicate that secondary fracture prevention should be recommended regardless of region of origin.