Assessment of Coronary Atherosclerosis Using Calcium Scores in Short- and Long-Distance Runners

Objective: To determine whether there is a "dose-dependent" relationship between coronary atherosclerosis and the burden of exercise.

Background: Recent data have suggested there may be negative consequences related to strenuous exercise. Previous studies evaluating the presence of coronary atherosclerosis as assessed by coronary calcium scores have been confounded by the presence of other cardiovascular risk factors. We aimed to assess whether there was a relationship between the burden of coronary calcium and the amount of running in a local cohort.

Patients and methods: Eighty-five runners were screened on the basis of an exercise questionnaire that was later used to determine the experimental groups from January 2016 through October 2016. Twenty-nine individuals were excluded from the study because of the presence of preexisting cardiovascular risk factors. Runners were divided into 3 categories: Group A comprised runners who had competed in at least 10 ultramarathons and/or Ironman competitions in 10 years. Group B included runners who had participated in more than 9 marathons over 10 years. Group C comprised runners who had competed in more than 9 shorter races over 10 years. Coronary artery calcium (CAC) scores were assessed by computed tomography. Statistical analysis was performed using chi-square analyses. Logistic regression models were used to assess the relationship between runner groups and calcium score greater than 100, calcium score percentile, and calcium score greater than 0.

Results: There were no differences between groups A and B for CAC scores greater than 0 or greater than 100, and a similar percentage of group A and B athletes had scores greater than the 50th percentile. Groups A and B were combined for further analysis. Among those runners participating in extreme distance running (groups A and B), 73% of runners had CAC scores greater than 0 whereas only 21% of group C runners had CAC scores greater than 0 (P=.0002). Moreover, 70% of group A + B athletes ranked above the 50th percentile of their age and sex as assessed by a national database (Hoff JA, Chomka EV, Krainik AJ, Daviglus M, Rich S, Kondos GT. Age and gender distributions of coronary artery calcium detected by electron beam tomography in 35,246 adults. Am J Cardiol. 2001;87(12):1335-1339), whereas only 19% of group C runners were ranked above the 50th percentile (P=.0001). One-third of runners in group A + B had CAC scores greater than 100 as compared with only 12% of runners in group C (P=.05). When controlling for age, sex, and number of years running, the study group was not a significant predictor of CAC greater than 100 (P=.12). In contrast, group A + B was 10 times more likely than group C to have CAC scores in the 50th percentile or greater (P=.02) and 8.8 times more likely to have a abnormal calcium score when controlling for covariates (P=.03).

Conclusion: A significantly higher rate of coronary artery calcification existed in long-term marathon, ultramarathon, and extreme runners than in submarathon runners. Marathoners and ultramarathoners also had a higher incidence of calcification, as well as higher average plaque burden, as compared to a standard database. Marathoners and ultramarathoners also had above-average coronary calcium scores as compared to a national database.