Long-term exposure of physical inactivity and MRI-derived left ventricular myocardial Function: Results from a population-based cohort

Objective The association of physical inactivity with subclinical alteration of cardiac structure and function is not well established. In the present study, we investigated this association with left-ventricular (LV) function assessed by advanced MRI strain analysis in a population-based cohort free of known cardiovascular disease (CVD). Materials and Methods We used data of an MRI sub-study of the community-based KORA (Cooperative Health Research in the Region of Augsburg) cohort with 360 participants (156 women; aged 39 to 73 years). Physical activity was assessed at three examination cycles (Exam 1 [baseline], at Exam 2 [7-years follow-up] and at Exam 3 [14-years follow-up]) of the KORA S4 cohort. The MRI-derived myocardial 2D feature-tracking strain examination was conducted at Exam 3 and included longitudinal, radial and circumferential global strain parameters. Associations between physical inactivity and strain values were investigated in cross-sectional and longitudinal analyses. Results Current physical inactivity (Exam 3) was associated with reduced longitudinal (β = -1.09%; 95%CI −2.02; −0.15. p = 0.023), radial (β = -2.64%; 95%CI −4.79; −0.49. p = 0.016), and circumferential strain (β = -0.90%; 95%CI −1.60; −0.20. p = 0.012). Similarly, past physical inactivity reported at baseline (Exam 1) was associated with reduced strain parameters. The more often physical inactivity was reported across the three examinations (two or three times) the more reduced were radial (β = -2.09%; 95%CI −3.71; −0.47. p = 0.012) and circumferential strain (β = -0.69%; 95%CI −1.22; −0.16. p = 0.011). These associations were stronger in men than in women. Conclusion In a population-based cohort without overt CVD, repeated self-reported leisure-time physical inactivity was consistently associated with lower MRI-derived LV strain parameters at Exam 3. These results indicate that sustained inactivity may be linked to subtle impairments in myocardial deformation detectable before clinical disease onset.