A trade-off between early growth rate and fluctuating asymmetry in Brazilian boys.
BACKGROUND
Right-left discrepancies in normally symmetrical traits are assumed to result from inability of the individual to buffer environmental and genetic stresses. Fluctuating asymmetry (FA) may therefore signal the quality of an individual to potential mates, or to parents during early life. FA could signal the heritable ability to buffer stress-the 'good genes' hypothesis. Alternatively, FA could signal the degree of within-lifetime exposure to stress, in particular during specific sensitive periods of development--the 'good development' hypothesis.


OBJECTIVE
We tested the hypotheses that FA at 9 years of age is positively related to (a) fetal growth rate, (b) early infant growth rate, and (c) total post-natal growth rate.


METHODS
FA, weight and height were measured in a sample of 172 boys aged 9 years from Pelotas, Brazil, who had previous measurements of weight and height at birth and 6 months.


RESULTS
Fetal growth was not related to FA, however FA was positively related to total weight gain after birth (p < 0.05). This association could be broadly attributed to weight gain in the first 6 months of post-natal life (p = 0.075). Those currently obese had significantly greater FA than those non-obese (p < 0.05).


CONCLUSIONS
Our results support the 'good development' hypothesis, and suggest that growth rate during an early post-natal critical window, previously linked to numerous health outcomes, also has long-term effects on FA.
Wells
Jonathan C K
JC
MRC Childhood Nutrition Research Centre, Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK. J.Wells@ich.ucl.ac.uk
Hallal
Pedro C
PC
Manning
John T
JT
Victora
Cesar G
CG
D000886:Anthropometry; D001724:Birth Weight / Q000502:physiology; D001938:Brazil; D002648:Child; D015331:Cohort Studies; D047109:Fetal Development; D006128:Growth; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009765:Obesity / Q000503:physiopathology; D015430:Weight Gain / Q000502:physiology