SexDifferences intheDeterminants of LeftVentricular Mass inChildhood

Background. Left ventricular (LV)hypertrophy isa predictor ofcardiovascular eventsinadults andhas beenobserved inchildren andadolescents withhypertension. Wewanted toestablish thedeterminants of LV mass innormotensive preadolescent children. Ourobjectives were 1)toproduce a simplified and generalizable modeloftheclinical variables thatdetermine normalcardiac growth during childhood and 2)tounderstand better whymaleshavean increased LVmass relative tofemales, even as children. Methods andResults. In a group of243eleven-year-old children, we analyzed anthropometric, hemodynamic, andechocardiographic datatodefine whichvariables werepredictors ofechocardiograph- ically determined LVmass.Stepwise regression was usedtopredict LVmass overall, bysex,andbybody size(body mass index). Overall, LV mass was directly related toweight, malesex,andsystolic and diastolic bloodpressureandinversely related toresting heartrateandskin-fold thicknesses. Systolic blood pressurewas adeterminant inboysbutnotingirls. Heartrate was aweakinverse correlate inboth sexes.Whenthedata wereanalyzed bybodymass index quartile, weight was thesole predictor ofLVmass inthelargest children. Conclusions. We conclude thatinnormotensive preadolescent children, 1)weight, butnotponderosity, isa strong predictor ofLV mass;2)bodyfatisnegatively associated withLV mass;3)boyshavean increased LVmass relative togirls; and4)boysandgirls havesimilar anthropometric determinants and may havedifferent hemodynamic determinants. Ourdatasuggest thatbodysize, andinparticular lean bodymass,explains muchofthevariability incardiac growthseen inchildren. Theinfluence of hemodynamic variables seemstobemore limited. Ourfindings areofgeneral interest because, although hypertensive heartdisease iswelldescribed, theearly developmental stages are notwellunderstood. (Circulation 1992;85:1661-1665)