The study comprised 1474 women and 1527 men with a mean age of 52±10 years and 49±10 years, respectively. Mean ascending thoracic aortic dimensions was 23±2 mm in women and 26±3 mm in men. Mean abdominal aortic dimensions was 17±2 mm in women and 19±2 mm in men. All characteristics of the sample are summarized in . We identified significant correlations between all fat indices, including local and global measures of adipose tissue, with thoracic aortic dimensions (, ). On average, the correlation between adiposity measures and aortic diameter was stronger in the thoracic aorta than in the abdominal aorta.
Clinical Characteristics of Overall Sample
Age- and Sex-Adjusted Correlations Between Indices of Adiposity and Aortic Dimensions
Correlations between (A) AAT and BMI, (B) AAT and SAT, and (C) AAT and SAT. AAT indicates abdominal periaortic fat; BMI, body mass index; and SAT, subcutaneous adipose fat area.
Associations of Regional Adipose Tissue Volumes With Thoracic Aortic Dimensions
In age- and sex-adjusted models, TAT and VAT were associated with thoracic aortic dimensions (P<0.001) (). We found that for each standard deviation increment in thoracic periaortic fat, there was an associated increase of 0.67 mm (95% confidence interval [CI] 0.58 to 0.76 mm) in thoracic aortic dimensions. These associations persisted after adjustment for cardiometabolic risk factors and BMI. When VAT was added in the same model with TAT, TAT remained significantly associated with thoracic aortic dimensions (β coefficient 0.24, 95% CI 0.11 to 0.37; P<0.001 for TAT), whereas VAT did not (β coefficient 0.04, 95% CI −0.11 to 0.19; P=0.59). No significant interactions by age and sex were identified (all interaction P>0.05 by age and sex in fully adjusted models). For thoracic aortic dimensions, age, sex, cardiovascular risk factors, and BMI explained 56% of the variance. The addition of TAT to these covariates increased the R2 by 0.4%.
Association of Adipose Tissue Volumes With Thoracic Aortic Dimensions
Associations of Regional Adipose Tissue Volumes and Abdominal Aortic Dimensions
In age- and sex-adjusted models, TAT and VAT were associated with abdominal aortic dimensions (P<0.001 for all) (). These associations persisted after adjustment for cardiovascular risk factors. However, after adjustment for BMI, only TAT remained significantly associated with abdominal aortic dimensions (β coefficient 0.09, 95% CI 0.01 to 0.18; P=0.04). Furthermore, when VAT was added to the models with TAT, TAT remained associated with abdominal aortic dimensions (β coefficient 0.19, 95% CI 0.08 to 0.30; P<0.001), whereas VAT became negatively associated (β coefficient −0.18, 95% CI −0.31 to −0.06; P=0.004). These results were consistent in both men and women and in younger (<50 years) and older (≥50 years) individuals (interaction P>0.05 for both).
Association of Adipose Tissue Volumes With Abdominal Aortic Dimensions
As a secondary analysis, we also evaluated our measure of abdominal periaortic fat with abdominal aortic dimensions. The relations between AAT and abdominal aortic dimensions were largely the same as those reported for TAT and abdominal aortic dimensions (). In addition, we also examined AAT and VAT categories as defined by the median. Among both high and low VAT, mean abdominal dimensions were larger in the high AAT category (P<0.001 for all comparisons). For abdominal aortic dimensions, age, sex, risk factors, and BMI explained 46.8%; with the addition of periaortic fat, this was increased by 0.1%.
Circulating Resistin and Adiponectin in Associations Between Regional Fat Deposits and Aortic Dimensions
In secondary analyses, to determine whether circulating adipokines could explain the association between fat depots and aortic dimensions, we examined these associations in participants with adipokines available (n=965). In this sample, the associations between TAT and aortic dimensions were largely the same as for the entire sample. Adjustment for resistin and adiponectin levels did not materially change the reported associations ( and ).
Association of Adipose Tissue Volumes With Thoracic Aortic Dimensions in Subset of Individuals With Adipokines
Association of Adipose Tissue Volumes With Abdominal Aortic Dimensions in Subset of Individuals with Adipokines