EPO rs1617640 A>C is a protective factor for chronic obstructive pulmonary disease: a case control study

Abstract

Abstract Background The occurrence and development of chronic obstructive pulmonary disease (COPD) are regulated by environmental and genetic factors. In the absence of oxygen, Erythropoietin (EPO) satisfies the body's need for oxygen by promoting the production of red blood cells. Hypoxia was proven to be a common physiological condition within COPD progression and associated with many complications. Some studies have found that EPO is involved in the development of COPD. But the mechanism has not been fully proven. Methods We conducted a case-control study enrolled 1095 COPD patients and 1144 healthy controls in Guangdong Province to evaluate the association between EPO polymorphism (rs1617640 A > C, rs507392 A > G, rs564449 G > T) and COPD susceptibility. And recruited 872 participants from southern Gansu Province to verify the effect of EPO polymorphisms on lung function. Results We found that EPO rs1617640 C allele significantly reduced COPD susceptibility in southern Chinese (AC vs. AA: adjusted OR = 0.805, 95%CI = 0.669–0.969; AC + CC vs. AA: adjusted OR = 0.822, 95%CI = 0.689–0.980). However, there was not any association between rs507392A > G and rs564449G > T polymorphisms and COPD susceptibility (P > 0.05). We further observed that the rs1617640 C allele was significantly associated with higher FEV1 and FVC in Guangzhou and Gansu populations (both P < 0.05). In brief, the level of FEV1 and FVC increased with the increase of the C allele number. We modeled relative risk for men and women, in which the population-attributable risks were 0.449 (0.258–0.641) and 0.262 (0.128–0.396) respectively. Smoking status, coal as fuels, education level, and rs1617640 A > C were finally retained for males, while smoking status, biomass as fuels, and1617640 A > C were retained for females. In the end, using the method developed by Gail and Bruzzi, we fitted a 10-year absolute risk model for southern Chinese with different individual relative risks, which was presented as a table. Conclusions In conclusion, this study found that EPO rs1617640A > C polymorphism is associated with COPD susceptibility in southern Chinese, and the C allele was associated with better lung function. In addition, it could also be considered as a genetic marker associated with environmental factors to predict the absolute 10-year risk of COPD in southern Chinese.