A population-based study of seasonal variation in children's fractures

INTRODUCTION Few Scandinavian studies have studied seasonal variations in paediatric fractures, and the studies that have focused on individual fracture sites. Furthermore, their findings do not coincide as they have described peaks in different seasons. Therefore, we described seasonal variation in the incidence rate (IR) of all paediatric fractures in the 1996-2019 period within a Danish population. METHODS We extracted data from the existing emergency room register at Odense University Hospital and included all fractures sustained by children aged 0-14 years and living in Odense Municipality. Seasonal and monthly IR were calculated using population counts stratified by age, gender and fracture site. RESULTS We recorded a significant increase in IR in spring and summer, except for a drop in July. For boys, the IR ranged from 206 in December to 404 per 10,000 person-years in June. For girls, the incidence ranged from 156 in December to 317 in May. Fractures were more frequent in the upper extremities and were up to six-fold more frequent in the epiphysis and metaphysis than in the shafts. All fracture sites showed a peak in spring and summer, suggesting that all fracture sites are subject to seasonal variation, especially the ones near the epiphysis. CONCLUSIONS The fracture peak observed in spring and summer corresponds to an increase in physical activity. The low incidence registered in July corresponds to a low level of sport activities during the summer vacations and families going on vacation in the countryside or travelling abroad. This study gives useful information for coordinating the right resources at hospitals.