Objective: To investigate the effect of birth weight and early growth on body fat composition and insulin sensitivity.
Methods: The birth and growth data of 258 children of 6 to 7 years old in Guangzhou were collected from Jun.2009 to Feb. 2010. Physical and laboratory examination were preformed, which included body weight, body height and body fat composition index (body mass index (BMI), percentage of body fat (PBF), waist circumference to height ratio (WtHR), etc). Fasting blood glucose and insulin were measured. The homeostasis model assessment model for insulin resistance index (HOMA-IR) was calculated. According to birth weight, the children were divided into three groups from light to heavy: BW-I, BW-II, BW-III group. Then according to change in weight SDS between 0 and 36 months, the children were divided into three groups: changers up (CU), non-changers (NC), changers down (CD) group. The effect of birth weight and early growth on body fat composition and insulin sensitivity were analyzed.
Results: Change in weight SDS between 0 and 36 months was higher in BW-I group (1.06 ± 1.29) than in the BW-II group (-0.19 ± 0.94) and BW-III group (-0.10 ± 1.20) (all P values < 0.01). Birth weight of the CU group ((2.90 ± 0.47) kg) was lower than that of the NC group ((3.22 ± 0.34) kg) and the CD group ((3.57 ± 0.37) kg) (all P values < 0.01). The body fat composition index of BMI, PBF and WtHR were higher in the BW-III group ((16.35 ± 2.13) kg/m(2), (17.03 ± 5.88)%, (0.479 ± 0.033)) than in the BW-I group ((15.46 ± 2.06) kg/m(2), (14.06 ± 5.25)%, (0.459 ± 0.032)) and BW-II group ((15.47 ± 1.58) kg/m(2), (14.09 ± 5.01)%, (0.460 ± 0.025)) (P < 0.01), while there was no significant difference between the BW-I group and the BW-II group (P > 0.05). The body fat composition index of BMI, PBF and WtHR were higher in the CU group ((16.44 ± 2.20) kg/m(2), (16.51 ± 5.78)%, (0.473 ± 0.034)) than in the NC group ((15.62 ± 1.74) kg/m(2), (14.49 ± 5.30)%, (0.463 ± 0.030)) and the CD group ((15.26 ± 1.85) kg/m(2), (14.24 ± 5.54)%, (0.462 ± 0.031)) (all P values < 0.05). In the CU group, BMI, PBF and WtHR were higher in the BW-III-CU group ((18.76 ± 2.56) kg/m(2), (22.19 ± 8.28)%, (0.512 ± 0.029)) than in the BW-I-CU group ((16.04 ± 2.14) kg/m(2), (15.54 ± 5.28)%, (0.467 ± 0.034)) and BW-II-CU group ((16.70 ± 1.36) kg/m(2), (17.12 ± 4.44)%, (0.474 ± 0.017)) (all P values < 0.05), while there was no significant difference between the BW-I-CU group and the BW-II-CU group (P > 0.05). HOMA-IR was higher in the CU group (1.27 ± 0.44) than in the NC group (1.08 ± 0.31) and the CD group (1.00 ± 0.36) (all P values < 0.01). In the CU group, HOMA-IR was higher in the BW-III-CU group (1.69 ± 0.48) than in the BW-I-CU group (1.21 ± 0.41) and the BW-II-CU group (1.27 ± 0.44) (all P values < 0.01), while there was no significant difference between the BW-I-CU and BW-II-CU group (P > 0.05).
Conclusion: According to birth weight tertile, both lower birth weight individuals with more weight change-up growth postnatal early and higher birth weight individuals had greater body fat composition in childhood. They were high-risk people of insulin resistance.