Epidemiology and seasonal variation of distal radius fractures in Oulu, Finland

Summary The purpose of this study was to assess changes in epidemiology and reasons for wintertime excess of distal radius fractures in Oulu, Finland. Our results showed that age-specific incidence of distal radius fractures in elderly women in Finland has increased compared with a previous study. Slippery pavement surfaces assessed by a new meteorological model partly explained wintertime excess of fractures, but factors beyond weather are contributing to seasonality. Introduction In this report, we describe the epidemiology and seasonal variation of distal radius fractures in Oulu, Finland, with a focus on the effect of weather and slippery pavement conditions. Methods Records of patients aged .16 years living in Oulu with a distal radius fracture during the year 2008 were reviewed. Demographic data and details of the injury were assessed from medical records, and fractures were classified according to AO classification. Population data for Oulu during the year 2008 were used to calculate crude incidence as well as sex- and age-specific incidence rates. The number of wintertime fractures was compared with those related to pavement surface slipperiness using a unique weather and pavement condition model of the Finnish Meteorological Institute. Results The crude incidence was 258/100,000 personyears. Sex- and age-specific incidence rates rose to 1,107/ 100,000 person-years for females and 466/100,000 personyears for males aged .80 years. Poisson regression analysis showed that the number of fractures was 2.5 (95% confidence interval (CI), 1.6 to 4.0; P<0.001) times greater on slippery winter days compared with non-winter days whereas on normal winter days fractures were 1.4 (95% CI, 1.1 to 1.9; P=0.01) times greater. Both low- and highenergy injuries resulted in similar fracture patterns by AO classification. Conclusions Our results suggest that the epidemiology of distal radius fractures in elderly women in Finland has changed compared with a previous study. Weather analysis showed that the slipperiness of the pavement could partly explain the wintertime excess of distal radius fractures.