Discussion
Traumatic injury is often thought to be predominantly unintentional and intentional thereby not occurring in any predictable pattern. However, previous studies have demonstrated an association between the number of trauma admissions and temperature, precipitation, hours of sunshine, day of the week, and time of day.7–9 14 The ability to predict the volume of total trauma admissions could enable better allocation of nondurable resources and personnel. However, in order to adjust staffing models a significant amount of lead-time may be required. According to the American Meteorological Society, ‘The current skill in forecasting daily weather conditions beyond 8 days is relatively low’.15 Furthermore, multiple factors including time of day, day of the week, temperature, rain or sunshine are at play, attempting to develop an equation to unify these into a clinically relevant resource needs assessment would be extremely difficult.
The intent of this study was to first determine if seasonal variation of specific trauma mechanisms exist in Western Massachusetts. In our location, an urban city with a population over 150 000, the winter temperature has a temperature range of 15°F–34°F (−9°C to 1°C), compared with the range of 33°F–56°F (0.5°C–13°C) and 55°F–78°F (13°C–26°C) in spring and summer.16 17 Our study found an increase in blunt trauma during summer and fall. While there are many postulated factors such as a sudden rise in temperature fostering more outdoor activity, there is likely a complex milieu of factors including social, economic, and weather factors that encompass a season and account for this variation. Although determining exact weather and temperature factors may be interesting, it may be too unpredictable to develop a targeted trauma prevention program. Instead, focusing on prevention leading up to and during seasons of increase incidence may lead to a reduction in traumatic injury mechanisms. Of course understanding patient demographics, socioeconomic factors, and environmental factors (eg, a particular road with increased rate of MVCs) is crucial to create any successful trauma prevention program.
Contrary to our hypothesis, there were higher rates of MVCs in fall and winter than in the spring. While most would predict that during summer months, the weather would allow more outdoor activity and increase motor vehicles on the road, which would lead to increase MVCs. Our data trended toward significance demonstrating a higher rate of MVCs in fall and winter. Although we did not evaluate specific weather trends in Western Massachusetts, it is known to have harsh weather conditions including heavy precipitation and snowfall in fall and winter months. Eisenberg et al demonstrated significant links between snowfall and fatal crashes.18 Similarly Saha et al described a high rate of adverse weather-related fatalities during months with high rain and wet conditions.19 Although there are multiple risk factors for MVCs including alcohol and drug use, road conditions, not using a seat belt, and so on, finding a higher rate of MVCs during specific seasons may be useful when devising a trauma prevention program regarding MVCs.
Nearly half of the MCCs occurred during summer. While most New Englanders would have predicted very few MCC during winter weather months due to the cold temperatures and the associated snow and ice, these data reinforce the need for a focused MCC prevention program leading up to and during spring and summer.
Falls were significantly more frequent during winter and close to significance in those greater than 65 years of age during winter in this study. A WHO report on falls prevention had a similar finding and cited potential reasons for this as slower reaction time triggered by hypothermia and/or slippery conditions related to ice.20 Given that falls during winter comprised nearly 30% of all trauma admissions, it would seem important to target prevention resources during this time.
While there are several limitations to this study (including its retrospective nature), one notable limitation is that this study was conducted at a single center located in a region with a highly variable climate. Although evaluating specific climates during seasons is beyond the scope of this project, Western Massachusetts is noted to be reliably cold with snow and ice in winter months and conversely hot and more humid in summer months. Studies in different climates would be required before any assertion of generalizability could be made. However, we believe the concept of identifying mechanisms of injury with seasonal variation may be important for all trauma centers. Potential benefits include a better understanding of institutional epidemiology and the ability to allocate preventative and treatment resources. Based on our institutions’ findings, future trauma prevention programs geared toward the prevention of blunt trauma, falls, and MCCs will be adapted to seasonal variation. For example, targeting MCCs in the spring and peaking in the summer with the hope of demonstrating a significant reduction of these injuries. Future directions include educating the public regarding these seasonal trends and focusing hospital resources to improve outcomes related to these traumatic injuries.