Sex‐Difference of Associations Between Cigarette Smoking and Myocardial Fibrosis: The Multi‐Ethnic Study of Atherosclerosis

Background Extracellular volume (ECV) and native T1 time (nT1) are markers of interstitial‐myocardial‐fibrosis by cardiac magnetic resonance and are associated with cardiovascular events, heart failure, and death. However, the association between smoking and interstitial‐myocardial‐fibrosis at the population level has not been explored. This cross‐sectional analysis of the MESA (Multi‐Ethnic Study of Atherosclerosis) cohort investigated the relationship between smoking and interstitial‐myocardial‐fibrosis by cardiac magnetic resonance, as well as the sex differences of this association. Methods A total of 2118 participants (53% women) had data on smoking between 2000 and 2012 and ECV (%) and nT1 (ms) at exam 5 (2010–2012). We constructed participant‐specific trajectories of average cigarettes per day (ACPD) based on linear interpolation to estimate ACPD between exams 1 through 5 (ACPD 1‐5 ). We explored the associations of smoking status at exam 5, ACPD at exam 5, ACPD 1‐5 , and temporal change in smoking status, with ECV and nT1 using multivariable analysis. Results Current smoking status was associated with increased markers of interstitial‐myocardial‐fibrosis in women but not in men, ECV% (ꞵ=2% P ≤0.001 versus 0.5%; P =0.2) and nT1 (ꞵ=28 ms; P ≤0.001 versus 3 ms; P =0.5) in women versus men, respectively. A higher ACPD 1‐5 was associated with increased ECV% (ꞵ=0.1%; P