Keiko Shinozaki1, Masayuki Okuda1, Naoko Okayama2, Ichiro Kunitsugu3. 1. Department of Environmental Safety, Graduate School of Science and Engineering, Yamaguchi University, Ube, Yamaguchi, Japan. 2. Yamaguchi University Hospital, Ube, Yamaguchi, Japan. 3. Department of Public Health, Graduate School of Medicine, Yamaguchi University, Ube, Yamaguchi, Japan.
Abstract
BACKGROUND: Evidence of the effects of fat mass and obesity-associated (FTO) variation and long-term effects of physical activity (PA) on adiposity in adolescents is largely scarce. This study therefore investigated whether PA modulates the effects of the FTO on body mass index (BMI) changes in Japanese adolescents between the ages of 13 and 18 years. METHODS: Data on 343 subjects (156 boys; 187 girls) who were enrolled in 2006 and 2007 at schools in Shunan City, Japan, were collected. Genotyping (rs1558902) was conducted, and anthropometry and blood test results were recorded for subjects in the eighth grade. A second survey involving self-reporting of anthropometry was conducted when the subjects were in the 12th grade. PA was estimated using the International Physical Activity Questionnaire. BMI and the standard deviation score for BMI (BMI-SDS) were calculated. BMI changes and BMI-SDS changes were compared between FTO genotypes using a multivariate model. RESULTS: The effect of the interaction between PA and the FTO genotype on BMI changes was significant in boys but not in girls. In boys, PA had a significant negative influence on BMI-SDS changes in those with the AA genotype and a significant positive influence on BMI and BMI-SDS changes in those with the TT genotype. CONCLUSION: The influence of PA on BMI change and BMI-SDS change varies on the basis of genotype. PA modified the effect of FTO on BMI change in Japanese boys.
BACKGROUND: Evidence of the effects of fat mass and obesity-associated (FTO) variation and long-term effects of physical activity (PA) on adiposity in adolescents is largely scarce. This study therefore investigated whether PA modulates the effects of the FTO on body mass index (BMI) changes in Japanese adolescents between the ages of 13 and 18 years. METHODS: Data on 343 subjects (156 boys; 187 girls) who were enrolled in 2006 and 2007 at schools in Shunan City, Japan, were collected. Genotyping (rs1558902) was conducted, and anthropometry and blood test results were recorded for subjects in the eighth grade. A second survey involving self-reporting of anthropometry was conducted when the subjects were in the 12th grade. PA was estimated using the International Physical Activity Questionnaire. BMI and the standard deviation score for BMI (BMI-SDS) were calculated. BMI changes and BMI-SDS changes were compared between FTO genotypes using a multivariate model. RESULTS: The effect of the interaction between PA and the FTO genotype on BMI changes was significant in boys but not in girls. In boys, PA had a significant negative influence on BMI-SDS changes in those with the AA genotype and a significant positive influence on BMI and BMI-SDS changes in those with the TT genotype. CONCLUSION: The influence of PA on BMI change and BMI-SDS change varies on the basis of genotype. PA modified the effect of FTO on BMI change in Japanese boys.