Background: Left atrial (LA) enlargement has been linked to obesity and insulin resistance in adults.
Objective: The purpose of this study was to determine the association in children between LA area and: (i) different components of the metabolic syndrome including obesity (OB), measures of body mass index (BMI) and waist circumference (WC), homeostasis model assessment-insulin resistance (HOMA-IR, proinsulin), and blood pressure (BP); and (ii) left ventricular mass (LVM) and diastolic function, measured using echo Doppler.
Methods and results: Eighty-four (44 females) subjects, [40 OB (BMI>95%), 28 overweight (BMI>85%)], 16 non-OB (BMI<85%)] aged 9+/-2.24 yrs were matched for sex and age. BMI, WC, BP, Tanner stage, and Mode M, 2-dimensional and Doppler transmitral echocardiography were assessed. A standard oral glucose tolerance test (OGTT) was done, measuring glucose, insulin, and proinsulin concentrations. Hypertension was only present in OB subjects (25%). Significant univariate association (p<0.001) was found between LA area and height (r=0.52), age (r=0.45), Tanner stage (r=0.45), BMI (r=0.66), WC (r=0.70), systolic BP (r=0.52), diastolic BP (r=0.53), proinsulin (r=0.36), and HOMA-IR (r=0.36). In the multivariate regression analysis, independent variables were entered in a stepwise fashion: initially, gender (p=0.006) and Tanner stage (p=0.011) were still significant independent correlates of LA area after adjusting for age, gender, and Tanner stage. Subsequently, incorporation of WC showed that WC (p=0.018) was a significant independent correlate of LA area. A larger model constructed to test the significance of adjustment factors, including WC, BP, LVM, and HOMA-IR showed that WC (p<0.001) was the only significant independent variable.
Conclusion: LA enlargement is present in childhood and is related to abdominal OB and insulin resistance, suggesting that children with central OB are at increased risk for cardiovascular disease.