Do Biochemical Markers and Apa I Polymorphism in IGF-II Gene Play a Role in the Association of Birth Weight and Later BMI?

BACKGROUND The aim of the study was to explore the mechanisms underlying the association of birth weight with later body mass index (BMI) from the biochemical markers related to metabolism and the Apa I polymorphism in IGF-II gene. METHODS A total of 300 children were selected randomly from the Macrosomia Birth Cohort in Wuxi, China. The height and weight were measured and blood samples were collected. Plasma concentrations of 8 biochemical markers were detected. Apa I polymorphism was analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS Biochemical markers were detected for 296 subjects and 271 subjects were genotyped for the Apa I polymorphism. No association was found between birth weight and 8 biochemical markers. In boys, the BMIs of AA, AG and GG genotypes were 16.10 ± 2.24 kg/m(2), 17.40 ± 3.20 kg/m(2), 17.65 ± 2.66 kg/m(2). And there was statistical difference among the three genotypes. But in girls, there was no statistical difference. The birth weights of AA, AG and GG genotypes were 3751.13 ± 492.43 g, 3734.00 ± 456.88 g, 3782.00 ± 461.78 g. And there was no statistical difference among the three genotypes. CONCLUSION Biochemical markers are not associated with birth weight. Apa I polymorphism may be related to childhood BMI, but it may be not associated with birth weight. Therefore, biochemical markers and Apa I polymorphism might not play a role in the association of birth weight and BMI.