Impacts of infancy rapid weight gain on 5-year childhood overweight development vary by age and sex in China.
OBJECTIVE
To investigate the critical period for overweight development during early childhood by examining growth trajectory and related sex differences.


METHODS
Using piecewise linear mixed models and logistic regression, we examined the effect of growth trajectory at different periods on overweight at age 4-5 by sex among 13,6 971 regularly followed children (mean: 12.2 times) during 2000-2005 in south China.


RESULTS
The high-body mass index (BMI) group (>top tertile of BMI Z score at age of 4-5 years) had faster growth rates of BMI, BMI Z score, weight and height than the low-BMI group in the first 3 months of life. Boys were more likely to be overweight [odds ratio (OR) = 2.0, 95% confidence interval: 1.5-2.7] than girls; the male high-BMI group had higher growth rates during the first 3 months than girls with high-BMI, independently of environmental factors. Those fast grown (in the upper tertile of growth rates in BMI and BMI Z score) in periods 0-3 months had relatively higher OR of at risk of overweight at age of 4-5 years than those in other periods.


CONCLUSIONS
Overweight risk develops during the first 3 months of life. Boys have an earlier peak in growth than girls, which may help explain why overweight is more prevalent in boys in China.
Johns Hopkins Global Center for Childhood Obesity, Department of International Health, Human Nutrition Program, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA.
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J
Min
J
J
Li
Z
Z
Li
Y
Y
Wang
D000367:Age Factors; D015992:Body Mass Index; D001942:Breast Feeding; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D050177:Overweight / Q000453:epidemiology*; D012307:Risk Factors; D012737:Sex Factors; D015430:Weight Gain / Q000502:physiology*