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Sex dimorphism in growth
T Gasser1, A Sheehy, L Molinari
1Universität Zürich, Abteilung Biostatistik, ISPM, Switzerland.
Annals of Human Biology
|April 18, 2000
Summary
Boys achieve greater adult height than girls primarily due to a later and more intense pubertal spurt (PS). This spurt significantly impacts leg length and contributes substantially to differences in sitting height and shoulder width.
Area of Science:
- Human growth and development
- Anthropometry
- Pediatric endocrinology
Background:
- Adult sex differences in height are established, averaging 13 cm.
- The precise contribution of different growth phases to this difference remains debated.
- Factors include the timing and intensity of the pubertal spurt (PS).
Purpose of the Study:
- To quantify the contribution of various growth phases to adult sex differences in height and body width.
- To differentiate the impact of later onset versus increased intensity of the pubertal spurt in boys.
- To analyze these contributions across different body segments.
Main Methods:
- Comparative analysis of growth variables including height, sitting height, leg height, arm length, bihumeral width, and biiliac width.
- Examination of growth patterns related to the pubertal spurt (PS) in boys versus girls.
- Assessment of morphological changes from infancy to adulthood.
Main Results:
- The later pubertal spurt in boys accounts for 64% of the adult sex difference in leg length.
- A more intense pubertal spurt in boys contributes nearly 50% to adult sex differences in bihumeral width and sitting height.
- Early childhood growth (1.5-6 years) largely corrects initial infant morphological deviations.
Conclusions:
- Both the timing and intensity of the pubertal spurt significantly influence adult sex differences in stature and body dimensions.
- Leg length is primarily affected by the delayed pubertal spurt in boys.
- Sitting height and shoulder width are significantly influenced by the intensity of the pubertal spurt in boys.