Birth weight, infant growth, and childhood body mass index: Hong Kong's children of 1997 birth cohort.
OBJECTIVE
To investigate the association between birth weight, infant growth rate, and childhood adiposity as a proxy for adult metabolic or cardiovascular risk in a Chinese population with a history of recent and rapid economic development.


METHODS
Prospective study in a population-representative birth cohort.


METHODS
Hong Kong Chinese population.


METHODS
Six thousand seventy-five term births (77.5% successful follow-up). Main Exposures Birth weight and growth rate (change in the weight z score) at ages 0 to 3 and 3 to 12 months. Main Outcome Measure Body mass index (BMI) (calculated as the weight in kilograms divided by the height in meters squared) z score at about age 7 years.


RESULTS
Each unit increase in the weight z score at ages 0 to 3 and 3 to 12 months increased the BMI z score by 0.52 and 0.33, respectively. Children in the highest birth weight and growth rate tertiles had the highest BMI z scores. In the lowest birth weight tertile, increases in the weight z score at ages 0 to 3 months had a larger effect on the BMI z score in boys (mean difference, 0.88; 95% confidence interval 0.69-1.07) than in girls (mean difference, 0.52; 95% confidence interval, 0.33-0.71); these differences by birth weight, growth rate at ages 0 to 3 months, and sex were significant (P = .007).


CONCLUSIONS
Faster prenatal and postnatal growth were associated with higher childhood BMI in a population with a recent history of rapid economic growth and relatively low birth weight, suggesting that maximal growth may not be optimal for metabolic risk. However, there may be a developmental trade-off between metabolic risk and other outcomes.
Hui
L L
LL
Department of Community Medicine and School of Public Health, The University of Hong Kong, 5/F William M. W. Mong Block, 21 Sassoon Rd, Pokfulam, Hong Kong, China.
Schooling
C Mary
CM
Leung
Shirley Sze Lee
SS
Mak
Kwok Hang
KH
Ho
Lai Ming
LM
Lam
Tai Hing
TH
Leung
Gabriel M
GM
D001724:Birth Weight; D015992:Body Mass Index; D002648:Child; D002657:Child Development; D015331:Cohort Studies; D005260:Female; D005865:Gestational Age; D006723:Hong Kong; D006801:Humans; D007223:Infant; D008297:Male; D009765:Obesity / Q000453:epidemiology; D016017:Odds Ratio; D011446:Prospective Studies; D012016:Reference Values