Association between overweight and obesity in schoolchildren with rs9939609 polymorphism (FTO) and family history for obesity

Abstract

Objective: To determine the association between overweight/obesity in schoolchildren with FTO rs9939609 polymorphism (fatmass and obesity associated) and family history of obesity. Methods: Cross-sectional study comprising a sample of 406 children aged 7---17 years in a city in southern Brazil. Overweight/obesity in schoolchildren was assessed by body mass index (BMI), and family history of obesity was self-reported by parents. Polymorphism genotyping was performed by real time PCR (polymerase chain reaction). The association between the nutritional status of schoolchildren with the presence of family obesity, stratified by polymorphism genotypes (AA [at-risk for obesity], AT, and TT), was assessed by prevalence ratio values (PR) through Poisson regression. Results: Among schoolchildren with the AA genotype, 57.4% had overweight/obesity; the percentage was lower for the AT and TT genotypes (33.1% and 28.9%, respectively). Overweight/obesity in schoolchildren was associated with a family history of obesity, especially among children with the AA genotype. The prevalence was higher among those with an obese mother (PR: 1.28; p < 0.001), obese maternal or paternal grandmother (PR: 1.22; p = 0.047), and obese paternal grandfather (PR: 1.32; p < 0.001). Conclusions: There is an association between the AA genotype of rs9939609 polymorphism andBMI among schoolchildren. The association between overweight/obesity in schoolchildren witha family history of obesity was found mainly among students with the AA genotype.

Objetivo: Verificar se existe relac¸ão entre o sobrepeso/obesidade de escolares com o polimor-fismo rs9939609, do gene FTO (fat mass and obesity associated), e com o histórico familiar deobesidade.Métodos: Estudo transversal composto por uma amostra de 406 escolares, de sete a 17 anos, deum município do sul do Brasil. O sobrepeso/obesidade dos escolares foi avaliado(a) por meio doíndice de massa corporal (IMC) e o histórico familiar de obesidade por questões autorreferidaspelos pais. A genotipagem do polimorfismo foi feita por PCR (polymerase chain reaction) emtempo real. A associac¸ão entre o estado nutricional dos escolares com a presenc¸a de obesidadefamiliar, estratificada pelos genótipos do polimorfismo (AA --- risco para obesidade, AT e TT), foiavaliada pelos valores de razão de prevalência (RP), por meio da regressão de Poisson.Resultados: Entre os escolares com o genótipo AA, 57,4% apresentaram sobrepeso/obesidade;para os genótipos TT e AT, o percentual é inferior (33,1% e 28,9%, respectivamente). O sobre-peso/obesidade do escolar associou-se com o histórico familiar de obesidade, principalmenteentre os escolares portadores do genótipo AA, foi superior entre os que apresentam mãe obesa(RP: 1,28; p < 0,001), avó materna e paterna obesas (RP: 1,22; p = 0,047) e avô paterno obeso(RP: 1,32; p < 0,001).Conclusões: Há relac¸ão entre o genótipo AA, do polimorfismo rs9939609, com o IMC dos esco-lares avaliados. A relac¸ão entre sobrepeso/obesidade do escolar com o histórico familiar deobesidade foi encontrada, principalmente, entre os escolares com o genótipo AA.