Rs12355840 Polymorphism in Pre-miR-202 Is Associated With Dental Caries Risk in Chinese Children: A Case-Control Study

Objectives Genetic polymorphisms emerge as risk factors for dental caries. The study investigated the possible link between rs12355840 polymorphism in pre-miR-202 and susceptibility to dental caries in Han Chinese children, and measured miR-202 levels in patients with different genotypes. Materials A total of 460 Chinese Han preschool children aged 3‑5 years were enrolled in this case‑control study, including 230 children with dental caries (dmft ≥ 1) and 230 caries‑free controls (dmft = 0, without early enamel demineralization). The rs12355840 polymorphism was genotyped using a TaqMan genotyping assay. Relative miR-202 levels in the saliva samples were gathered through qRT-PCR assay. The genetic risk associations were quantified via odds ratios (OR) and 95% confidence intervals (95% CI), followed by logistic regression analysis to further explore independent association effects. Results A higher proportion of children with dental caries carried the C allele. Under both the heterozygous (TC vs TT) and the dominant (TC/CC vs TT) models, the genotype frequency of rs12355840 showed a statistically significant difference between the 2 groups, with the OR of 1.665 (95% CI: 1.082-2.561, P = .020) and 1.714 (95% CI: 1.116-2.632, P = .013), respectively. Carriers of the TC genotype exhibited severe dmft and dmfs scores. Stratified analyses detected significant associations in subgroup of 5-year-old children and those with low dental visit frequency, while formal interaction tests only indicated borderline age‑related heterogeneity ( P ‑interaction = .050), with no evidence for effect modification by other factors. A logistic regression analysis proved the independent association of rs12355840 with dental caries risk (OR = 1.607, 95% CI: 1.026-2.517, P = .038). Reduced miR-202-5p levels were also observed in children with TC/CC genotype. Conclusion Rs12355840 polymorphism is independently associated with higher dental caries risk in Chinese preschool children and linked to disease severity. Its mechanism may relate to downregulated miR-202-5p expression.