Abstract 5158: Left Atrial Size is Independently Associated with Body Mass Index in Childhood
Introduction Left atrial (LA) enlargement is an independent risk factor for cardiovascular morbidity and mortality in adults. Body mass index (BMI) is associated with LA size in adults but this may be mediated (at least in part) by co-morbidities that accompany adult obesity and thus the relationship between LA size and BMI in children is of interest, to assess the effect of increased body mass per se. We studied the association between BMI z-score and LA size in healthy children and also assessed whether LA size differed significantly between healthy weight (HW), overweight (OW) and obese (OB) children.
Methods 991 children aged 5–15 years (9.3±2.8 years, 60% male), with normal cardiac structure and function were studied by echocardiography. LA diameter (indexed to height, to account for linear growth), LV posterior wall (LVPW) thickness, LV mass index (LVMI) and LV fractional shortening were measured by M-Mode. Regression analysis assessed the association between LA diameter and possible determinants, including BMI z-score. LA diameter was derived for the HW, OW and OB groups.
Results LA diameter was significantly associated with BMI z-score (r=0.239), age (r=0.282), body surface area (r=0.189), LVPW thickness (r=0.125) and LVMI (r=0.349) (p<0.001 for all). On multiple regression analysis, BMI z-score was significantly related to LA diameter after controlling for age, sex and LVMI or LVPW thickness. LA diameter increased across weight groups [19.8±2.9, 20.5±2.8 and 21.9±3.3 mm/m for HW, OW and OB, respectively (p<0.001)].
Conclusion In children, higher BMI z-score is an independent determinant of increased LA size after adjusting for age, height, sex and the effects of blood pressure on LV wall thickness and mass. LA size was significantly larger in the obese than in the overweight and in the overweight compared with the healthy weight children. These data suggest that obesity exerts an effect on LA size at an early age and thus potentially predisposes to later cardiovascular morbidity.