Physical activity, cardiorespiratory fitness, and obesity among Chinese children.
OBJECTIVE
To investigate the relationships of cardiorespiratory fitness (CRF) and physical activity (PA) with the risk of overweight/obesity in Chinese schoolchildren.


METHODS
A total of 1795 children aged 8-13 years at baseline were followed-up for 18 months from 2006 to 2008 in Guangzhou, China. Children were categorized as "normal weight", "overweight", and "obese" using Chinese obesity cut-off points. Data on self-reported PA were obtained. CRF was determined by the 20-meter multistage fitness test, and the sex-specific median values were set as the cut-off points for the classification of high and low CRF.


RESULTS
Significantly higher CRF was found in children with normal weight (from 6.55 to 8.65 ml/kg/min) or physically active children (from 0.42 to 1.22 ml/kg/min) compared with the reference group. CRF was inversely associated with the kg/m(2) change in BMI during the follow-up period (β=-0.63 kg/m(2) and -0.64 kg/m(2) for boys and girls, respectively, both p<0.001). Significant association of baseline CRF with overweight/obesity was found in boys (odds ratio (OR) 8.71; 95% confidence interval (CI) 2.59-29.26, p<0.001), whereas the association was marginally insignificant in girls (OR 6.87; 95% CI 0.96-49.09, p=0.055).


CONCLUSIONS
The results showed a strong negative association between CRF levels and children's BMI and weight gain.
School of Public Health, Wuhan University, Wuhan, PR China.
Qi-qiang
QQ
He
Tze-wai
TW
Wong
Lin
L
Du
Zhuo-qin
ZQ
Jiang
Tak-sun Ignatius
TS
Yu
Hong
H
Qiu
Yang
Y
Gao
Wei-jia
WJ
Liu
Jia-gang
JG
Wu
D000293:Adolescent; D000367:Age Factors; D000886:Anthropometry; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000517:prevention & control; D002319:Cardiovascular System / Q000503:physiopathology*; D002648:Child; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D009765:Obesity / Q000175:diagnosis / Q000453:epidemiology*; D050177:Overweight / Q000175:diagnosis / Q000453:epidemiology; D010809:Physical Fitness / Q000502:physiology*; D011446:Prospective Studies; D018570:Risk Assessment; D012737:Sex Factors