Association Analysis Of MC4R Gene Polymorphisms With Obesity Among Primary And Middle School Students In Guangzhou

Objectives1.To analyze the association between environmental factors and obesity among primary and middle school students in Guangzhou.2.To explore the association between MC4R gene polymorphisms and obesity among primary and middle school students in Guangzhou.3.To evaluate the effect of MC4R gene-environment interaction on obesity among primary and middle school students in Guangzhou.MethodsThis research adopted the method of frequency-matched case-control study,and the MC4R gene polymorphisms were selected by the literature review and bioinformatics methods,and the Taqman fluorescence quantitative PCR technique was adopted to detect the genotypes.The Multivariable logistic regression model was used to analyze the association between MC4R gene polymorphisms and obesity among primary and middle school students in Guangzhou,and Genetic risk score was applied to further discuss the effects of genetic polymorphisms on obesity among primary and middle school students.For the logistic regression model,the multiplicative interaction term and the bootstrapping self-help re-sampling method were used to mine the multiplicative and additive interactions of gene-environment.Logistic regression model was used to analyze and evaluate the correlation between gene polymorphisms and appetite.Results1.A total of 877 obese students and 950 normal body weight students according to BMI were included in this study.The multivariate logistic regression analysis showed that the statistically significant correlation between appetite,mealtime,screen time in weekday and obesity among primary and middle school students（P<0.05）.The good appetite（OR=2.01,95%CI=1.66-2.43）and long screen time in weekday（OR=1.29,95%CI=1.01-1.65）may be the risk factors for obesity in primary and middle school students.However,the moderate/long mealtime reduced the risk of obesity among students（OR=0.68,95%CI=0.50-0.92）.2.The polymorphisms of MC4R gene rs12970134 and rs17782313were statistically significantly associated with the risk of obesity in primary and middle school students（P<0.05）.The multivariate logistic regression model showed that compared with GG genotype,the risk of obesity among students with rs12970134 GA+AA genotype increased（OR=1.27,95%CI=1.03-1.56）.For each additional rs12970134 A allele carried in the additive model,the risk of obesity increased（OR=1.24,95%CI=1.04-1.48）.Compared with TT genotype,the risk of obesity among students with rs17782313 TC genotype increased（OR=1.41,95%CI=1.14-1.75）,and the risk of obesity among students with rs17782313TC+CC genotype also increased（OR=1.39,95%CI=1.14-1.71）.For each additional rs17782313 C allele carried in the additive model,the risk of obesity increased（OR=1.29,95%CI=1.08-1.54）.In this study,no statistical association was found between rs8087522 and the risk of obesity in primary and middle school students（P>0.05）.The results of the haplotypes constructed by rs17782313 and rs12970134 showed that CA（OR=1.25,95%CI=1.04-1.51）,TA+CG（OR=1.61,95%CI=1.12-2.31）haplotype were associated with the increased risk of obesity among primary and middle school students.The genetic risk scores of rs17782313 and rs12970134 were constructed,and the results showed that students with more than one risk allele had an increased risk of obesity compared with those without risk allele（OR=1.38,95%CI=1.13-1.69）.There was no significant association between rs12970134,rs17782313 polymorphisms and appetite（P>0.05）.3.There was no statistically significant gene-environment interaction between rs12970134,rs17782313 in the dominant model and appetite,meal time and screen time in weekday(P_mult>0.05,P_add>0.05).There was no statistically significant gene-environment interaction between genetic risk score and appetite and meal time.There was a multiplicative interaction between genetic risk score and screen time in weekday(P_mult<0.05),but there was no statistically significant additive interaction.Conclusions1.Appetite,mealtime and screen time in weekday may be influencing factors of obesity risk among primary and middle school students in Guangzhou.2.MC4R rs12970134 and rs17782313 polymorphisms are influencing factors of obesity risk among primary and middle school students in Guangzhou..3.There is a statistically significant multiplicative interaction between the genetic risk score constructed by rs12970134 and rs17782313 and screen time in weekday.