Results of interaction analyses using age*MHT as an interaction term in our regression models are presented in Table 4 and Fig 2. Age significantly modified the association between MHT use and CMR parameters with smaller chambers observed with advancing tertiles of age: LV end-diastolic volume (47–60 years: β = 3.2%, 95% CI: -0.6% to 7.2%; 61–66 years: β = -2.9%, 95% CI: -5.8% to 0.2%; 67–77 years: β = -6.2%, 95% CI: -9.0% to -3.3%; p for interaction = 0.0005), LV end-systolic volume (47–60 years: β = 7.7%, 95% CI: 1.6% to 14.1%; 61–66 years: β = -3.1%, 95% CI: —7.6% to 1.6%; 67–77 years: β = -5.9%, 95% CI: -10.1% to -1.4%; p for interaction = 0.001), LV stroke volume (47–60 years: β = 0.3%, 95% CI: -3.8% to 4.5%; 61–66 years: β = -2.6%, 95% CI: -5.9% to 0.8%; 67–77 years: β = -6.4%, 95% CI: -9.4% to -3.2%; p for interaction = 0.033), and LA maximal volume (47–60 years: β = 0.1%, 95% CI: -6.6% to 7.3%; 61–66 years: β = -1.2%, 95% CI: -6.6% to 4.6%; 67–77 years: β = -10.1%, 95% CI: -15.0% to -5.0%; p for interaction = 0.006).