Change in Physical Activity and Cardiac Structure over 10 Years: The Multi-Ethnic Study of Atherosclerosis

Introduction Physical activity (PA) is inversely associated with risk of heart failure and cardiovascular disease (CVD), whereas increased left ventricular (LV) mass and mass to volume (m:v) ratio are unfavorable CVD risk factors. We assessed whether changes in leisure time PA were associated with longitudinal changes in cardiac structure in a community-based population. Methods We included 2779 Multi-Ethnic Study of Atherosclerosis participants, free of baseline CVD, who had available data on PA and cardiac magnetic resonance imaging at examinations 1 (2000-2002) and 5 (2010-2012). Physical activity was measured by a Typical Week PA Survey and converted to MET-minutes per week of moderate+vigorous activity. We used linear mixed effect models to estimate the associations of baseline and change in PA with baseline and change in cardiac structure, adjusting for CVD risk factors and body size. Results At baseline, the mean age was 59 yr, 53% were women, and 58% of nonwhite race/ethnicity. During average 10-yr follow-up, and after accounting for baseline PA levels, the highest quintiles of PA increase were significantly associated with increases in LV mass (2.3 g; 95% confidence interval [CI], 0.4-4.2), LV end-diastolic volume (4.7 mL; 95% CI, 2.4-7.0), and stroke volume (3.3 mL; 95% CI, 1.6-5.1), but lower M:V ratio (-2.9; 95% CI, -5.0 to -0.8) compared with the lowest quintiles. Increasing exercise PA was associated with increases in LV diameter and reductions in M:V ratio, whereas occupational PA was associated with increases in m:v ratio. Increasing PA over 10 yr was also associated with greater risk of eccentric dilated LV hypertrophy at examination 5. Conclusions After accounting for baseline PA, greater positive changes in leisure-time PA levels were associated with a more eccentric-type of LV remodeling pattern over 10 yr. The clinical implications of such findings remain to be determined.