Daily number of fractures is associated with road temperature in an urban area.

INTRODUCTION Different factors related to winter are known to influence the fracture incidence, but little is known about the effect of road surface temperature. This study examines the association between road surface temperature and the daily number of fractures in an urban area during two winters. MATERIAL AND METHODS Retrospective data collection was conducted on all patients treated at Bispebjerg Hospital, Denmark, for a humeral, ankle, distal radius or hip fracture during the periods October to April 2009/2010 and 2010/2011. Patients were grouped according to age into the following categories: < 15, 15-30, 30-45, 45-60 and > 60 years. Data on road surface temperature (Tp.) were obtained from The Danish Road Directorate and grouped into the following categories: Days with Tp. > 0 °C, Tp. < 0 °C, Tp. > -5 °C, Tp. < -5 °C and ice alert (IA). RESULTS A total of 4,892 patients (4,938 fractures) were treated during the study periods. The daily number of distal radius, humeral and ankle fractures increased significantly with decreasing road surface temperature and the presence of IA. For hip fractures no significant association was found. Decreasing temperature was associated with a significant decrease in the daily number of fractures for patients < 15 years, whereas patients > 30 years experienced a significant increase. CONCLUSION Decreasing road temperature results in increased numbers of all fractures except hip fractures. Low temperatures is a risk factor for patients > 30 years and a protective factor for patients < 15 years. FUNDING not relevant. TRIAL REGISTRATION not relevant.