Prevalent CAC common in high-volume endurance activity athletes, but no long-term risk for mortality
Men who participate in high-volume endurance activity — equivalent to running approximately 6.5 km per day or 250 to 300 minutes per week — were likely to have prevalent coronary artery calcification, but no increased risk for all-cause or CVD mortality at long-term follow-up, according to new data published in JAMA Cardiology.
“The key question addressed in the present study was whether the presence of high CAC associated with high levels of exercise training as typically practiced by masters marathon runners is associated with greater mortality. For this question, the answer is clearly no,” Laura F. DeFina, MD, president, CEO and chief science officer of The Cooper Institute in Dallas, and colleagues wrote.
Physical activity in men
Researchers analyzed data from 21,758 men (mean age, 52 years) who were treated at the Cooper Clinic in Dallas from 1998 to 2013. Women were not included in this assessment due to an insufficient number of deaths, which was the study’s primary outcome of interest.
A thorough history questionnaire was conducted at baseline to collect medical and physical activity information, in addition to prescription medications that the men were taking. Measurements were also taken such as weight, BMI and seated resting BP. Electron beam tomography scans were used to assess CAC. Cardiorespiratory fitness was measured, which was then used to estimate metabolic equivalent of task (MET) levels.
Clinicians reviewed information collected from the physical activity questionnaire with the patient for accuracy. In this questionnaire, patients were asked to define their participation in activities, including jogging or running, walking, bicycling, treadmill, swimming, stationary cycle, aerobic dance or floor exercise, and vigorous activity. Researchers then categorized physical activity based on MET levels: at least 3,000 MET-minutes per week; 1,500 MET-minutes per week to 2,999 MET-minutes per week; and less than 1,500 MET-minutes per week.
Compared with men who accumulated lesser amounts of physical activity, those with at least 3,000 MET-minutes per week were more likely to have at least 100 Agatston units (AU) of prevalent CAC (RR = 1.11; 95% CI, 1.03-1.2). Men with high amounts of physical activity and at least 100 AU of CAC had a mean CAC level of 807 AU, according to the study.
There were 759 deaths, including 180 CVD deaths, during a mean follow-up of 10.4 years. In men with at least 3,000 MET-minutes per week, there were 40 all-cause deaths and 10 CVD deaths.
CAC and physical activity
Men with CAC less than 100 AU and at least 3,000 MET-minutes per week were less likely to die vs. those with less than 1,500 MET-minutes per week (HR = 0.52; 95% CI, 0.29-0.91). In addition, a significant increase in all-cause mortality was not seen in men with at least 100 AU of CAC and at least 3,000 MET-minutes per week vs. those who performed physical activity less than 1,500 MET-minutes per week (HR = 0.77; 95% CI, 0.52-1.15), the researchers wrote.
Men who were less active and had at least 100 AU of CAC were more likely to die vs. those with less than 100 AU of CAC (HR = 1.93; 95% CI, 1.34-2.78).
“Despite the fact that this type of high-volume physical activity and exercise may promote calcific coronary atherosclerosis, it appears to still be associated with safety and possibly lower mortality risks,” Carl J. Lavie, MD, from Ochsner Heart and Vascular Institute and University of Queensland School of Medicine; Ulrik Wisløff, PhD, from Norwegian University of Science and Technology in Trondheim, Norway; and Roger S. Blumenthal, MD, from Johns Hopkins Ciccarone Center for the Prevention of Cardiovascular Disease and Cardiology Today Editorial Board Member, wrote in a related editorial.
“We would like to emphasize that CAC testing appears to retain its utility in high-volume exercisers, and along with cardiorespiratory fitness is a very important predictor associated with survival,” they wrote. “High CAC scores were still associated with higher risk at any given physical activity level in this study, which is why CAC assessment is being promoted to help risk assessment and intensify preventive therapies such as vigorous lipid treatment.” – by Darlene Dobkowski
Disclosures: DeFina reports no relevant financial disclosures. Lavie reports he was a paid consultant and speaker for Mio Global Canada. Wisløff reports he is the inventor of PAI and acts as a paid advisor to PAI Health Inc. Blumenthal reports no relevant financial disclosures. Please see the study and editorial for all other authors’ relevant financial disclosures.