Chronic diseases and allergies are risk factors predictive of a history of Medial Tibial Stress Syndrome (MTSS) in distance runners: SAFER study XXIV.

Background: Medial Tibial Stress Syndrome (MTSS) is one of the most common causes of exercise-associated lower leg pain in distance runners.

Aim: To identify risk factors predictive of a history of MTSS in distance runners entering the Two Oceans Marathon races (21.1 km and 56 km).

Design: Cross-sectional study.

Setting: 2012 to 2015 Two Oceans Marathon races (21.1 km and 56 km).

Participants: Consenting race entrants.

Methods: 106,743 race entrants completed an online pre-race medical screening questionnaire. 76,654 consenting runners (71.8%) were studied. 558 verified MTSS injuries were reported in the previous 12 months. Risk factors predictive of a history of MTSS were explored using uni - & multivariate analyses: demographics (race distance, sex, and age groups), training/racing history, history of chronic diseases, allergies, and medication use.

Results: Independent risk factors predictive of a history of MTSS (adjusted for sex, age group, and race distance) were a higher chronic disease composite score (PR = 3.1 times increase risk for every two additional chronic diseases; p < 0.0001) and a history of allergies (PR = 1.9; p < 0.0001). Chronic diseases (PR > 2) predictive of a history of MTSS were: symptoms of CVD (PR = 4.2; p < 0.0001); GIT disease (PR = 3.3; p < 0.0001); kidney/bladder disease (PR = 3.3; p < 0.0001); nervous system/psychiatric disease (PR = 3.2; p < 0.0001); respiratory disease (PR = 2.9; p < 0.0001) a history of CVD (PR = 2.9; p < 0.0001); and risk factors of CVD (PR = 2.4; p < 0.0001) (univariate analysis). Average running speed was associated with higher risk of MTSS.

Conclusion: Novel independent risk factors predictive of a history of MTSS in distance runners (56 km, 21.1 km) were multiple chronic diseases and a history of allergies. Identifying athletes at higher risk for MTSS can guide healthcare professionals in their prevention and rehabilitation efforts.