Association of OPG, TNF-α, and IL-1B gene variants with periodontitis in a South African population

Abstract

This study aimed to investigate candidate single-nucleotide polymorphisms linked to periodontitis susceptibility in a Western Cape cohort, providing insights into population-specific host genetic factors. Materials and Methods This observational case-control study recruited a total of 150 South African participants. Saliva samples were genotyped using the Open Array Quant Studio 12K Flex qPCR System. Genotype and allele frequencies were assessed for Hardy–Weinberg equilibrium and tested for associations with clinical variables and disease status using Chi-square tests and logistic regression adjusted for age, gender, and smoking. Results A total of 24 SNPs were analysed. Several genotypes showed suggestive associations with periodontitis risk prior to multiple testing correction. The OPG + 1181 CG, RANKL RL2 AG, and IL-17A + 197 GG genotypes were linked to higher plaque score. The TNF-α -238 GG genotype was associated with lower bleeding score and reduced disease risk (OR = 0.157, 95% CI: 0.039-0.638, P = .010), while IL-1B -511 GG genotype corresponded with a reduced disease risk (adjusted OR = 0.216, 95% CI: 0.054-0.867, P = .031). Conversely, OPG + 1181 CC was related to increased disease risk under multiple models (adjusted OR = 20.42, 95% CI: 1.95-213.9, P = .012). These associations lost significance after correction for multiple testing. Ethnicity-based subgroup analysis revealed differences in genotype distribution, while smoking status showed no effect. Conclusion Genetic variants may influence periodontitis susceptibility, underscoring the importance of population-specific risk profiling and the need for replication in larger cohorts to support targeted diagnostics in resource-limited settings.