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Predicting heart growth during puberty: The Muscatine Study
K F Janz1, J D Dawson, L T Mahoney
1Department of Sport, Health, and Leisure Studies, University of Iowa, Iowa City 52242, USA. kathleen-janz@uiowa.edu
Pediatrics
|May 9, 2000
Summary
This study found that fat-free mass and aerobic fitness are key predictors of heart growth in children and adolescents. Maintaining these factors helps predict stable heart size throughout puberty.
Area of Science:
- Pediatric Cardiology
- Human Growth and Development
- Exercise Physiology
Background:
- Childhood heart growth correlates with somatic growth (weight, fat-free mass, height).
- Cardiac workload increases with age, leading to greater variability in heart size relative to body size.
- Limited understanding exists regarding functional attributes influencing cardiac workload and their impact on heart growth during childhood and adolescence.
Purpose of the Study:
- To investigate cross-sectional and longitudinal relationships between aerobic fitness, body size, blood pressure, and left ventricular mass (LVM) through puberty.
- To identify predictors of heart growth during puberty and the tracking of LVM from pre-puberty to late and post-puberty.
- To assist pediatricians in distinguishing normal LVM increases from those indicative of left ventricular hypertrophy.
Main Methods:
- A 5-year repeated-measures study of 125 healthy children (mean baseline age 10.5 years) in pre- or early puberty.
- Quarterly assessments of anthropometry (FFM, fatness, weight, height), resting BP, and LVM (echocardiography).
- Annual assessments of aerobic fitness, peak exercise BP, and sexual maturation; statistical analysis using Spearman correlations and gender-specific stepwise multivariate analysis.
Main Results:
- Boys exhibited greater height, FFM, aerobic fitness, and LVM compared to girls, with higher rates of change.
- Strong tracking of heart size was observed (r(s) =.65-.87), with individuals in extreme tertiles at baseline likely to remain so.
- In boys, baseline FFM predicted 54% of follow-up LVM; changes in aerobic fitness and FFM predicted 55% of LVM change.
- In girls, baseline aerobic fitness and fatness predicted 45% of follow-up LVM; changes in FFM predicted 58% of LVM change.
Conclusions:
- Fat-free mass and aerobic fitness are significant predictors of left ventricular mass in children and adolescents.
- Tracking of heart size is strong, suggesting early predictors influence long-term cardiac development.
- Findings aid in differentiating normal cardiac growth from potential left ventricular hypertrophy in pediatric populations.