The purpose of this systematic review was to obtain a comprehensive understanding of the implications of environmental and climate factors on sport-related concussion incidence in outdoor contact sports.

Data Sources

MEDLINE (via OVID), EMBASE (via Elsevier), CINAHL Complete (via EBSCOhost), SPORTDiscus (via EBSCOhost) Scopus (via Elsevier)

Study Selection

Studies that report incidence of sport-related concussion, assess data of athletes of outdoor contact sports, report on one or more climate/environmental factors, and diagnosis of concussion performed by a licensed medical professional were included. Reasons for exclusion included no report on extrinsic or environmental factors, no data on sport-related concussion incidence, and self-report of concussion diagnosis.

Data Extraction

Systematic Review was conducted utilizing Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines employing 2 reviewers at each phase and a third reviewer for conflict resolution.

Data Synthesis

7558 articles were reviewed and 20 met the inclusion criteria. There was moderate to strong strength of evidence concluding no difference between surface type (grass versus artificial) on sport-related concussion risk. Moderate to strong strength of evidence was found supporting no difference in sport-related concussion incidence based on game location (home versus away). There was no consensus on the effects of altitude or temperature on sport-related concussion incidence. One high quality study found a decreased risk of sport-related concussion when playing in wet conditions versus dry conditions. Heterogenous populations and data collection methods prevented extraction and meta-analysis.


Although consensus on specific environmental and climate factors that influence sport-related concussion incidence was limited, the majority of studies were of high quality and give insight into opportunity for future investigation. Administrators of large injury surveillance databases should consider including specific environmental and climate factors to provide investigators with robust data sets to better understand potential association with sport-related concussion.