Subclinical Myocardial Damage in Obesity May Be Mitigated by Physical Activity
The highest rates of heart failure were seen in individuals with poor physical activity.
According to a recent study published in JACC Heart Failure, physical activity is inversely associated with chronic subclinical myocardial damage.1
Obesity is widely known to be a risk factor for heart failure.2 Physical activity has been associated with a lower risk of heart failure in people with obesity, although pathophysiological mechanisms remain unknown.2,3
Using a non-concurrent cross-sectional prospective design, researchers analyzed the participants in the Atherosclerosis Risk in Community (ARIC) Study4 through 4 visits that occurred approximately every 3 years and a fifth follow-up visit that occurred about a decade later.
Assessing for physical activity, obesity status, and high-sensitivity cardiac troponin T (hs-cTnT) levels as a surrogate marker for myocardial damage, subjects were evaluated for physical activity level at visit 3 through a modified Baecke questionnaire later converted into a Metabolic Equivalent of Task (MET) and cross referenced with the American Heart Association (AHA) definitions of physical activity.1
Measurements of hs-cTnT were drawn at visit 4. Individuals with self-reported cardiovascular disease (CVD), a CVD clinical event, including coronary heart disease, heart failure, or coronary revascularization procedures, and patients with a silent myocardial infarction were excluded from analyses. Individuals with body mass index <18.5 were also excluded from analyses, as were individuals not of black or white race.1
Of the 9427 individuals included in the analyses, 7.2% had elevated hs-cTnT at visit 4. Of note, the prevalence of elevated hs-cTnT was greater in individuals with lower physical activity levels (7.7% of individuals with poor activity levels vs 6.8% of individuals with the AHA recommended activity levels). After adjusting for CVD mediators in multivariate models, individuals with poor physical activity were more likely to have an elevated hs-cTnT (odds ratio [OR], 1.31; 95% CI, 1.08-1.59; P =.001).1
In analyses that stratified data by obesity status using the non-obese and recommended activity level group as the reference, individuals with poor physical activity and obesity were the most likely to have elevated hs-cTnT (OR, 2.46; 95% CI, 1.91-3.19; P =.01), while there was a weaker association between individuals with obesity and the recommended activity level with elevated hs-cTnT (OR, 1.68; 95% CI, 1.28-2.21; P <.01).
During a median of 15 years of follow-up, the highest rates of heart failure were seen in the obese and poor activity group (HR, 2.55; 95% CI, 2.14-3.04). Furthermore, within each cross-category of physical activity level and obesity, elevated hs-cTnT was strongly associated with a higher incidence of heart failure (P for interaction <.001) over time.1
Given the many implications of their results, the researchers noted that “further studies should explore whether hs-cTnT might be used as a marker of cardiovascular health in association with changes in physical activity,” especially people with obesity.1
- Self-reported activity levels are likely associated with misclassification and are not entirely representative of the cumulative effects of regular physical activity on myocardial activity.
- Hs-cTnT was measured from stored blood samples and degradation of the samples could have affected the true value of the marker.
- It is difficult to establish the temporality of the observed associations of physical activity with myocardial damage in the study.
Dr Schrack is a consultant for EMD Serono Research & Development Institute, Inc. Dr Nambi has served as an event adjudicator for a study sponsored by Siemens to evaluate a new high-sensitivity troponin assay. Drs Selvin and Ballantyne have served on an advisory board for Roche Diagnostics. Drs Ballantyne and Nambi, along with Roche and Baylor College of Medicine have filed a provisional patent entitled “Biomarkers to Improve Prediction of Heart Failure Risk.”
- Florido R, Ndumele CE, Kwak L, et al. Physical activity, obesity, and subclinical myocardial damage. JACC Heart Failure. 2017;5(5):377-384. doi:10.1016/j.jchf.2017.02.002
- Hu G, Jousilahti P, Antikainen R, et al. Joint effects of physical activity, body mass index, waist circumference, and waist-to-hip ratio on the risk of heart failure. Circulation. 2010;121:237-244.
- Abel ED, Litwin SE, Sweeney G. Cardiac remodeling in obesity. Physiology Review. 2008;88:389-419.
- The ARIC Investigators. The Atherosclerosis Risk in Communities (ARIC) study: design and objectives. Am J of Epidemiol. 1989;129:687-702.