Background: The development of obesity has a large genetic component, and the gene encoding the transcription factor 2 beta (TFAP2B) has been identified as one of the responsible factors. We investigated the effect of TFAP2B intron 2 variable number tandem repeat (VNTR) genotype on obesity, insulin resistance and dietary intake from 15 to 33 years of age.
Methods: The sample included both birth cohorts (originally n = 1176) of the longitudinal Estonian Children Personality Behaviour and Health Study. The association between TFAP2B genotype, and anthropometric measurements, glucose metabolism and dietary intake at ages 15, 18 and 25 years was assessed using the linear mixed-effects regression models. Differences in anthropometric measurements, biochemical measures, blood pressure and dietary intake between TFAP2B genotypes at different age, including data of the older cohort at age 33, were assessed by one-way ANOVA.
Results: Male homozygotes for the TFAP2B 5-repeat allele had significantly higher body weight, body mass index, sum of 5 skinfolds, proportion of body fat, waist circumference, hip circumference, waist-to-hip ratio, waist-to-height ratio, fasting insulin and HOMA index. In female subjects, homozygotes for the TFAP2B 5-repeat allele had significantly larger increase in the rate of change per year in body weight, body mass index and hip circumference between years 15 and 25. By age 33, the findings were similar. A decrease in daily energy intake from adolescence to young adulthood was observed. In males, heterozygotes had significantly smaller decrease in the rate of change per year in daily energy intake.
Conclusions: The association of TFAP2B with the development of obesity and insulin resistance is present throughout adolescence to young adulthood in males. In females the effect of TFAP2B on obesity appears later, in young adulthood. The TFAP2B effect is rather related to differences in metabolism than energy intake.