Insulin-like growth factor-I and growth in height, leg length, and trunk length between ages 5 and 10 years.
OBJECTIVE
IGF-I, a major regulator of childhood growth, is also associated with the risk of several cancers in adult life. Adult height and particularly leg length are also associated with cancer risk. Prepubertal growth is more in leg than trunk length, and it has been suggested that leg length might be a biomarker of childhood IGF-I. However, there is little information on the association between childhood IGF-I and subsequent leg and trunk growth. In this study, we investigated the association of IGF-I measured at 5 and 7-8 yr with growth in height and the components of height (leg and trunk length) from 5 yr to 9-10 yr.


METHODS
A total of 675 children participated in the Avon Longitudinal Study of Parents and Children.


RESULTS
IGF-I was strongly positively associated with growth in height in both sexes. Among boys, IGF-I was strongly associated with subsequent growth in both leg and trunk length, but there was no evidence that IGF-I was more strongly associated with one component of growth than the other. Among girls, IGF-I was strongly positively associated with growth in trunk but not leg length, although there was only weak evidence that these two associations differed in strength (P = 0.058).


CONCLUSIONS
These results support the contention that the associations between height and cancer may be mediated by variation in childhood IGF-I. However, they provide no evidence to support the hypothesis that leg length is a better biomarker of childhood IGF-I levels than trunk length.
Rogers
Imogen
I
Unit of Paediatric and Perinatal Epidemiology, Department of Community-Based Medicine, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, United Kingdom. imogen.rogers@bristol.ac.uk
Metcalfe
Chris
C
Gunnell
David
D
Emmett
Pauline
P
Dunger
David
D
Holly
Jeff
J