Of the 374 study subjects, 222 (59%) were men, and mean age was 58±8 (range 36–79) years. shows the baseline and follow-up demographics of the study population. Prevalence of diabetes, hypertension, and cigarette smoking increased at follow-up (). Serum TC, LDL and TG levels were lower at follow-up compared to baseline (p<0.0001 for all). Serum HDL level was similar between baseline and follow-up (p=0.4). CCS increased significantly from baseline [median 0 (0–399)] to follow-up [median 19.5 (0–1051)] (p<0.0001).
Relationship of EFV to biophysical parameters
Baseline EFV was moderately correlated to baseline weight (r=0.51, p<0.0001), BMI (r=0.41, p<0.0001) and waist circumference (r=0.50, p<0.0001) measurements (). At follow up EFV increased compared to baseline (93±40 vs. 84±38, p<0.0001). This was accompanied by an increase in waist circumference (95.3±14.2 vs. 93.0±13.7, p<0.0001) but not weight (81.7±19.1 vs. 81.4±18.3, p=0.4) or BMI (28.0±5.5 vs. 27.8±5.4, p=0.1) ().
Relationship between baseline EFV and baseline weight (a), BMI (b) and waist circumference (c). Relationship between percentage EFV change and percentage weight (d), BMI (e) and waist circumference change (f). EFV, epicardial fat volume.
Relationship between EFV change and biophysical parameter changes
EFV change was weakly correlated to weight change (r=0.37, p<0.0001), BMI change (r=0.39, p<0.0001) and waist circumference change (r=0.21, p=0.002) (). Using multivariable linear regression analysis, weight change (%) (β= 1.2, 95% CI 0.9–1.5, p<0.001), BMI change (%) (β=1.2, 95% CI 0.9–1.5, p<0.001), and hypertension (β=4.7, 95% CI 0.5–9.0, p=0.03) were significantly associated with EFV increase (%) (). Male sex (β=−6.4, 95% CI −10.9–−1.8, p=0.006) was significantly associated with EFV decrease. Multivariable logistic regression analysis showed that hypertension (OR=1.6, 95% CI 1.0–2.6, p=0.03), weight change (%) (OR=1.1, 95% CI 1.1–1.2, p<0.001) and BMI change (%) (OR=1.1, 95% CI 1.1–1.2, p<0.001) predicted significant change (10% increase) in EFV ().
Of the 374 study subjects, 71 subjects showed a >5% weight gain, 54 subjects >5% weight loss, and 249 subjects had a weight change of less than 5%. EFV change in these three groups is shown in . EFV change was lowest (−2.3±21.1%) in the subjects with weight loss, and increased progressively with weight change (p<0.001, ).
Scatter plot comparing the percentage EFV change among subjects with >5% weight loss, maintained weight and >5% weight gain.
Subjects with weight loss also showed lower frequencies of EFV gain (20%, compared to 54% in subjects with no significant weight change and 70% in subjects with weight gain, p<0.001) and higher frequencies of EFV loss (35%, compared to 10% in subjects with no significant weight change and 4% in subjects with weight gain, p<0.0001).
We also assessed change in EFV according to change in CCS upon follow-up scan. The mean %EFV change was significantly higher in high progressors compared to low progressors (14.4±22.5 vs. 7.3±20.7, p=0.04) but the mean %EFV change was similar in converters and non-converters (15.3±23.4 vs. 13.1±20.7, p=0.46). shows the correlation of baseline EFV with blood serum biomarkers; EFV correlated with CRP, TG, and glucose and showed inverse correlation with adiponectin and HDL. However, after adjusting waist circumference, BMI, age and gender, the remaining significant associations were only with HDL (coefficient −0.05, standardized coefficient −0.12, p=0.03) and TG (coefficient 0.72, standardized coefficient 0.33, p<0.001).
Spearman rank correlation of baseline EFV with serum biomarkers