Time trends in proximal humeral fractures from 1944 to 2020 - A cohort study in Malmö, Sweden.

Background: Most studies infer increasing incidence of proximal humeral fractures (PHF) from the 1950´s until the 1990´s. Recent time trends are less clear.

Objectives: Our primary objective was to identify time trends in the age- and sex-adjusted adult incidence of PHF in Malmö, Sweden, from year 1944 until 2020. Our secondary objectives were to describe the variation in incidence according to age, the monthly distribution, and to compare data from the two most recent decades with earlier.

Study Design And Methods: Malmö has one emergency hospital where acute fractures are treated. We identified PHF in adult patients (≥ 18 years) by reviewing relevant radiology examinations during 17 sample years from year 1944 to 2020. We used jointpoint analyses to estimate time trends.

Results: We identified 3 031 PHF during the study period (3 231 161 person years), 73% were sustained by women with mean age of 69 years (mean age in men 59). Joinpoint analyses indicated an increase in the age- and sex-adjusted incidence of PHF from year 1944 (52 per 100 000 person years) until 1977 (120 per 100 000) and thereafter a decrease until 2020 (85 per 100 000). A seasonal variation with more fractures during winter months, was apparent in earlier but not recent decades.

Conclusions: The age- and sex-adjusted incidence of PHF increased in Malmö, Sweden, from the 1940´s until year 1977 and thereafter decreased until 2020. More fractures were seen during winter months in earlier but not recent decades.