OBJECTIVETo study blood Leptin level of 154 (78 male, 76 female) Chinese obese/non-obese children aged 0 - 14 years during 1999 - 2001.

METHODSThe gender- and age-specific distribution pattern of Leptin and its relationship with anthropometric parameters (waist circumference, waist/hip ratio, lean body mass, fat mass, body fat percentage, BMI/Kaup index etc.) and blood insulin level were recorded.

RESULTS(1) The blood Leptin level in healthy non-obese kids ranged from 1.01 - 29.92 (ng/ml), the mean values and SD were 2.99 +/- 2.13 (ng/ml) [90% confidence interval was 1.36 - 14.21 (ng/ml) in boys and 1.74 - 21.17 (ng/ml) in girls]. There was no significant difference in the blood Leptin level between serum and plasma. (2) The blood Leptin level was higher in overweight/obese kids than that in non-obese kids (P < 0.001). (3) There was significant difference in the blood Leptin levels between boys and girls groups (P = 0.023), especially in non-obese group (P = 0.004). The multiple regression analysis showed that there was no correlation between gender and blood Leptin level when body fat factor was added (P = 0.138, 0.241, 0.990), but there was still a strong correlation between blood leptin level and BMI, FM and BF% (P < 0.001). (4) There was a correlation between blood Leptin level and age (P = 0.005), especially in overweight/obese group and in girls (P = 0.001). The blood Leptin level rose from early puberty, especially in girl group (P = 0.045). There was significant difference in blood Leptin level in different age groups (P < 0.001) (5) There were strong positive correlation between blood Leptin level and BMI, BM and FM%, a weak correlation with LBM, and no correlation with W/H ratio in boys and a positive relationship in girls. The Quatatic equation was better than the linear equation in description of the correlation mentioned above. (6) There was a correlation between blood Leptin from 0 to 7 yr and birth weight (P = 0.001), after 7 yr of age this correlation disappeared (P = 0.456). (7) A positive correlation was seen between blood Leptin level and blood insulin level (P < 0.001).

CONCLUSIONThe blood Leptin level of 0 - 14 years old children is consistent with the level of growth of adiposity tissue and the degree of adiposity rebound.