FACTORS AFFECTING LEFT-VENTRICULAR MASS IN CHILDHOOD - THE MUSCATINE STUDY

Objective. To examine the contribution of age, body size, and blood pr essure to left ventricular mass (LVM) in childhood and develop a popul ation-based reference of normative LVM data. Methods. Age, sex, height , weight, and auscultatory systolic and diastolic blood pressures were measured and an echocardiogram was performed to estimate LVM in 904 n ormal children, aged 6 to 16 years, in Muscatine, IA. Pearson product- moment correlation coefficients were determined to describe the degree of linear association between LVM and age, body size, and blood press ure. Age-sex-, weight-sex-, and height-sex-specific Z scores were dete rmined for LVM, age, weight, height, and blood pressure. Sex-specific LVM prediction equations were derived using weighted-least-squares reg ression analysis. Results. A strong positive linear association of LVM with age, weight, height, Quetelet index, and systolic and diastolic blood pressure was demonstrated. Z scores for eight different LVM quin tile patterns revealed that age, height, weight, and blood pressure ea ch exert an independent influence on LVM in children. Sex-specific pre dicted M-mode LVM and upper limits of the 90% prediction intervals bas ed on age and height are presented. Conclusion. Since age, height, wei ght, and blood pressure may each exert an independent influence on LVM in children, each factor must be considered when interpreting LVM in childhood. While age, sex, and height are unalterable, both weight and blood pressure can be modified. Thus the pathologic contribution of e xcess weight and blood pressure ought not be masked by statistical adj ustments in reference values for LVM. Sex-specific values of LVM and t he 90% and 95% prediction intervals of LVM that do not factor out the effects of obesity or blood pressure are presented. These provide the upper-limit reference values of LVM for the evaluation of children in whom increased LVM is suspected.