Cyclooxygenase‐2 Gene⁻⁷⁶⁵single nucleotide polymorphism as a protective factor against periodontitis in Taiwanese

AIM: Prostaglandin E(2) (PGE(2)) is considered to be an important mediator of tissue destruction in periodontitis. The cyclooxygenase (COX) catalyses the production of PGs. COX-2, which is induced in an inflammatory response, is responsible for PGs synthesis at sites of inflammation. A single nucleotide polymorphism of COX-2(-765) has been shown to alter the expression of the COX-2 gene. The purpose of the present study was to evaluate the association of the COX-2(-765) polymorphism and susceptibility to periodontitis in Taiwanese. MATERIAL AND METHODS: Eighty-five cases of aggressive periodontitis (AgP), 343 cases of chronic periodontitis (CP) and 153 cases of healthy controls (HC) were recruited for the study. Genotypes of COX-2(-765) were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The distribution of genotypes among groups was compared by logistic regression analyses. The risk for periodontitis associated with genotypes was calculated as the odds ratio (OR). RESULTS: The prevalence of the GC and CC genotypes was significantly lower in AgP (5%) and in CP (29%) compared with the HC (42%). The ORs for carriage of the -765C allele (GC+CC versus GG) in AgP and CP were 0.068 (95% CI=0.020-0.173, p<0.0001) and 0.571 (95% CI=0.385-0.849, p=0.006), respectively. After adjustment for age, gender and smoking status, the OR was 0.071 (95% CI=0.017-0.219) and 0.552 (95% CI=0.367-0.829) for AgP and CP, respectively. CONCLUSIONS: The results of the study suggest that the -765G to C polymorphism of the COX-2 gene is associated with a decreased risk for periodontitis in Taiwanese, especially in AgP. However, the biological meaning needs further investigation.