Myocardial Native T1 Mapping in the German National Cohort (NAKO): Associations with Age, Sex, and Cardiometabolic...

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. However, data on the association between cardiometabolic risk and myocardial alterations are still limited. We therefore investigated how age, sex, and cardiometabolic risk factors are associated with myocardial T₁ as a potential imaging marker of myocardial target-organ involvement in a population-based analysis within the German National Cohort (NAKO).

This cross-sectional study included 29,573 prospectively enrolled participants who underwent midventricular T₁ mapping using 3.0T CMR along with deep clinical phenotyping. After artificial intelligence-assisted myocardial segmentation, a subset of 9,162 outlier cases was subjected to manual quality control according to clinical evaluation standards. Cardiometabolic risk factors were identified through self-reported, physician-diagnosed medical history, clinical chemistry, and blood pressure measurements. Associations with myocardial T₁ were evaluated using multiple linear regression models adjusted for age, sex, heart rate, imaging site, and comorbidities.

After quality control, 27,794 participants (12,401 [44.6%] women; 20-75 years) were included. Mean T₁ was overall higher in women (1,231 ± 33 ms) than in men (1,209 ± 34 ms), with differences progressively declining with age. The sex difference was confirmed in a healthy subcohort (n = 3,910), whilst age interaction was less pronounced. In adjusted analyses, T₁ was significantly higher in individuals with diabetes, kidney disease, and current smoking. Conversely, hyperlipidaemia was significantly associated with lower T₁. Associations with hypertension showed strongly sex-specific patterns: women had lower T₁ values, while T₁ increased with hypertension severity in men.

Myocardial native T₁ varies by sex and age and shows distinct sex-specific associations with major cardiometabolic risk factors, supporting its role as a sensitive imaging marker of subtle myocardial alterations. Unexpectedly lower T₁ times in participants with hyperlipidaemia suggest a potential direct effect of blood lipids on the heart, which warrants further investigation.