Gene Interactions Have Effects on Caries of Aadolescents in China

Objectives: The aim of this study was to identify genetic factors that contribute to caries susceptibility in adolescents of southern china, either direct or interaction effects.
Methods: A cross-sectional study was conducted among 1055 adolescents in Foshan, southern China. Demographic data and oral health habits were obtained through a questionnaire and caries experience were collected by clinical examinations according to International Caries Detection and Assessment System (ICDAS). The acidogenicity of plaque microbiology was examined by Cariostat kit. 23 single nucleotide polymorphisms (SNP) in 14 genes were carried out by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry using genomic DNA extracted from saliva samples. Chi-square analysis and regression analysis were used for the evaluation of direct and interactions of genes under the hypothesis of an additive model and using the minor allele as the reference.
Results: Female adolescents had a higher level of caries than male adolescents (P=0.011). Adolescents from one-child family had a lower level of caries (P=0.030). Plaque Index scored 2-3 increased caries susceptibility appropriately 2.2 times (OR=2.212; 95%CI 1.437-3.405). Cariostat scored 2-3 increased the risk of caries almost 5 times (OR=5.012 95% CI 3.326-7.552). The genotype allele G in AMBN(rs13115627) were protective factors for caries (OR=0.728; 95% CI 0.579-0.916). 11 pairwise SNPs were significantly associated with caries, lighting on the interaction between rs1800972×rs923911 (P<0.01; OR=1.966 95%CI 1.178-3.283) after tested by univariate regression analysis adjusted for gender, one-child family, Plaque Index and cariostat score. None of the interaction reached the Bonferroni correction for multiple testing (P<0.0002).
Conclusions: Our study suggested variation in AMBN (rs13115627) have independent protective effects on dental caries, and 11 interactions of SNPs have effects on caries susceptibility of adolescents in southern China.