Myocardial native T1 mapping in the German National Cohort (NAKO): associations with age, sex, and cardiometabolic risk factors

BACKGROUND AND AIMS: In cardiovascular magnetic resonance (CMR), myocardial native T1 mapping enables quantitative, non-invasive tissue characterization and is sensitive to subclinical changes in myocardial structure and composition. We investigated how age, sex, and cardiometabolic risk factors are associated with myocardial T1 in a population-based analysis within the German National Cohort (NAKO). METHODS: This cross-sectional study included 29,573 prospectively enrolled participants who underwent CMR-based midventricular T1 mapping at 3.0 T, alongside clinical phenotyping. After artificial intelligence-assisted myocardial segmentation, a subset of 9,162 outliers was subjected to manual quality control according to clinical evaluation standards. Associations with cardiometabolic risk factors, identified through self-reported medical history, clinical chemistry, and blood pressure measurements, were evaluated using adjusted linear regression models. RESULTS: Women had higher T1 values than men, with sex differences progressively declining with age. T1 was significantly elevated in individuals with diabetes (β=3.91 ms; p<0.001), kidney disease (β=3.44 ms; p<0.001), and current smoking (β=6.67 ms; p<0.001). Conversely, hyperlipidaemia was significantly associated with lower T1 (β=−4.41 ms; p<0.001). Associations with hypertension showed a sex-specific pattern: T1 was lower in women but increased with hypertension severity in men. CONCLUSIONS: Myocardial native T1 varies by sex and age and shows associations with major cardiometabolic risk factors. Notably, lower T1 times in participants with hyperlipidaemia may indicate a direct effect of blood lipids on the heart. Our findings support the utility of T1 mapping as a sensitive marker of early myocardial changes and highlight the sex-specific interplay between cardiometabolic health and myocardial tissue composition.