Assessing Body Mass Index as a Predictor of Running-Related Injuries: A Systematic Review and Meta- analysis

Background Understanding the causes of running-related injuries (RRIs) is essential for identifying high-risk runners and implementing preventive measures to reduce injury risk. This study aims to determine how body mass index (BMI) affects the occurrence of RRIs among runners, crucial for identifying high-risk individuals and implementing preventive measures. Methods We conducted a systematic review and meta-analysis following the 'PECOS' framework for observational studies and PRISMA protocols. We searched Scopus, Web of Science, PubMed, Science Direct, and SPORTDiscus databases until October 2023 for prospective studies on RRIs. Two independent reviewers assessed the methodological risk of bias in the included studies using the ROBINS-E tool. The extracted data included study details, sample characteristics, injury type, number of injuries, and follow-up period. The outcome of interest was RRIs sustained during the study, both overall and specific, and the mean ± standard deviation (SD) of BMI for runners who experienced RRIs and those who did not. Pooled odds ratios [95% confidence interval (CI)] were calculated using a random-effects model. Results In our analysis of 35 studies involving 14,025 runners (median 238; range 21 − 2,207; 57.4% women), we found that BMI significantly predicts RRIs (OR = 1.05, CI:1.02–1.09; P = 0.001), with individuals experiencing such injuries showing higher baseline BMIs (MD = 0.113kg/m², CI:0.031–0.194; P = 0.007). For specific injuries, no significant baseline BMI differences were found for runners with patellofemoral pain syndrome (PFPS) or Achilles tendinopathy (AT) compared to those without (MD = 0.14kg/m²,CI:-0.04-0.33; P = 0.13, and MD = 0.03kg/m²,CI:-0.19-0.25; P = 0.82, respectively). However, individuals with medial tibial stress syndrome (MTSS) had higher BMI (MD = 0.43kg/m²,CI:0.18–0.68;P = 0.001), and those with lower extremity stress fractures had lower BMI (MD=-0.28kg/m²,CI:-0.53-0.03;P = 0.03) compared to their counterparts. Conclusion Runners with RRIs generally have a higher baseline BMI, especially those with MTSS, while those with lower extremity stress fractures have a lower BMI, and BMI does not differentiate those with PFPS or AT.