Cyclooxygenase 2 1195G>A polymorphism is associated with chronic obstructive pulmonary disease in Japanese and Chinese patients

Background Cyclooxygenase-2 (COX-2) is overexpressed during airway inflammation in chronic obstructive pulmonary disease (COPD) patients. Single nucleotide polymorphisms (SNPs) in the COX-2 promoter might contribute to differential COX-2 expression and subsequent interindividual variability in susceptibility to COPD. We investigated the association between COX-2 (-765G>C, -1195G>A) polymorphisms and COPD susceptibility in Japanese and Chinese patients. Methods COX-2 genotypes were determined by polymerase chain reaction, restriction fragment length polymorphism in 230 COPD patients (103 Japanese and 127 Chinese) and 273 healthy controls (129 Japanese and 144 Chinese). Results The frequency of -1195AA homozygote was significantly higher than the controls in Chinese COPD (adjusted OR=2.43, 95% CI 1.14-4.19), Japanese COPD (adjusted OR=2.25, 95% CI 1.06-4.76) and combined COPD groups (adjusted OR=2.26, 95% CI 1.34-3.99). There was no difference in COX-2-765G>C polymorphism between COPD and control groups in either Japanese or Chinese, while more Chinese individuals carried the -765C allele than Japanese in both groups (15.3% vs. 2.9% in COPD, 18.8% vs. 5.5% in control). Chinese individuals with the haplotype -765G:-1195A were at higher risk for COPD (adjusted OR=1.93, 95% CI 1.05-3.55). Conclusions The COX-2-1195AA genotype is associated with increased risk for COPD in both Japanese and Chinese individuals. Although COX-2-765G>C polymorphism was not associated with COPD in either ethnic group, the -765C allele frequency was higher in Chinese than Japanese and haplotype -765G-1195A may confer susceptibility to COPD in Chinese.