In highly active individuals, high levels of coronary artery calcification do not appear to confer an elevated mortality risk, a large, observational study suggests.
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There was an increased risk of elevated levels of coronary artery calcification (CAC) in men with levels of exercise training comparable with that seen in master marathon runners, the study authors reported. However, elevated CAC in highly active men didn’t translate into a significant increase in all-cause or cardiovascular disease mortality risk in the study.
That result is contrary to the hypothesis that high activity levels would increase mortality risk in individuals with CAC, according to senior author Benjamin D. Levine, MD, of Texas Health Presbyterian Hospital in Dallas, and his coauthors.
“Our findings should reassure patients and their health care professionals that it appears these highly active individuals can safely continue their exercise programs,” Dr. Levine and his coauthors wrote in JAMA Cardiology.
The present analysis focused on 21,758 generally healthy men without prevalent cardiovascular disease. They were enrolled in the Cooper Center Longitudinal Study, a prospective, longitudinal study designed to assess linkages between physical activity, cardiorespiratory fitness, and health. The mean age of these men was 52 years at baseline; the mean duration of follow-up was 10.4 years.
Out of 21,758 male participants, 1,561 reported very high levels of physical activity, or at least 3,000 metabolic equivalent of task (MET) minutes per week, while 3,750 reported 1,500-2,999 MET minutes per week, and 16,477 reported low levels of physical activity, or less than 1,500 MET minutes per week.
The adjusted risk of elevated CAC, defined as at least 100 Agatston units, was 11% higher in the individuals reporting very high physical activity levels, the investigators found.
Presence of elevated CAC nearly doubled the risk of death in men with low levels of exercise, with a hazard ratio of 1.93 (95% confidence interval, 1.34-2.78), the investigators found. By contrast, there was no significant increase in all-cause mortality in the most active group (HR, 0.77; 95% CI, 0.52-1.15).
Taken together, these findings seem to provide evidence that high activity levels do not increase mortality risk, the investigators wrote, noting that the study is believed to have the “best available” mortality data in a large CAC population that includes measurement of physical activity.
The research was supported in partly through the National Space Biomedical Research Institute. One study author reported disclosures related to Abbott, AstraZeneca, and the American Heart Association.
SOURCE: Levine BD et al. JAMA Cardiol. 2019 Jan 30. doi: 10.1001/jamacardio.2018.4628.