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

BackgroundIn 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). MethodsThis cross-sectional study included 29,573 prospectively enrolled participants who underwent midventricular T1 mapping using 3.0 T 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. ResultsAfter quality control, 27,794 participants (44.6% women; 20-75 years) were included. Mean T1 was higher in women (1,231 {+/-} 33 ms) than in men (1,209 {+/-} 34 ms), with sex differences progressively declining with age. 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. ConclusionsMyocardial 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. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=139 SRC="FIGDIR/small/25331651v2_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@1d5b45borg.highwire.dtl.DTLVardef@133ef6aorg.highwire.dtl.DTLVardef@ab1ff2org.highwire.dtl.DTLVardef@be568b_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO Associations of Age, Sex, and Cardiometabolic Risk Factors with Myocardial Native T1 in the NAKO Study Bottom left panel: unstandardized coefficients and 95% confidence intervals from multiple linear regressions, stratified by sex. Bottom right panel: linear regression (solid line), median (dotted line), and interquartile range (shaded area) in 2-year age bins, stratified by sex. The last bin is defined as [≥] 70 years. MOLLI: modified look-locker inversion recovery; LDL-c: LDL-cholesterol, AI: artificial intelligence; SD: standard deviation; HR: heart rate; CVD: cardiovascular disease; TD: thyroid disease; IQR: interquartile range C_FIG