Associations between meteorological factors and emergency department visits for unintentional falls during Ontario winters

Introduction: Unintentional falls are a leading cause of injury-related hospital visits among Canadians, especially seniors. While certain meteorological conditions are sus-pected risk factors for fall-related injuries, few studies have quantified these associa-tions across a wider range of age groups and with population-based datasets. Methods: We applied a time-stratified case-crossover study design to characterize asso-ciations of highly-spatially-resolved meteorological factors and emergency department (ED) visits for falls, in Ontario, among those aged 5 years and older during the winter months (November to March) between 2011 and 2015. Conditional logistic models were used to estimate the odds ratios (ORs) and their 95% confidence intervals (CIs) for these visits in relation to daily snowfall accumulation, including single-day lags of up to one week before the visit, and daily mean temperature on the day of the visit. Analyses were stratified by age and sex. Results: We identified 761 853 fall-related ED visits. The odds for these visits was increased for most days up to a week after a snowfall of 0.2 cm or greater (OR = 1.05-1.08) com-pared to days with no snowfall. This association was strongest among adults aged 30 to 64 years (OR = 1.16-1.19). The OR for fall-related ED visits on cold days (less than -9.4 degrees C) was reduced by 0.05 relative to days with an average daily temperature of 3.0 degrees C or higher (OR = 0.95; 95% CI: 0.94, 0.96), and this pattern was evident across all ages. There were no substantive differences in the strength of this association by sex. Conclusion: Snowfall and warmer winter temperatures were associated with an increased risk of fall-related ED visits during Ontario winters. These findings are rele-vant for developing falls prevention strategies and ensuring timely treatment.