Abstract:

Objective  To explore the relationship and interaction between smoking, anemia and susceptibility to chronic obstructive pulmonary disease(COPD), and to provide evidence for screening high-risk population and prevention and treatment of COPD.

Methods  Eighty-nine patients with COPD(COPD group) and 89 healthy people(control group) were selected. Age, body mass index(BMI), comorbid diseases, educational level, marital status, smoking status, smoking index(SI), anemia status, hemoglobin(Hb) level, forced expiratory volume in one second as a percentage of forced vital capacity(FEV1/FVC), and forced expiratory volume in one second as percentage of predicted value(FEV1% pred) were compared between two groups. Pearson correlation analysis was used to analyze the correlation between SI, Hb and FEV1/FVC, FEV1% pred, and the Logistic regression equation was used to analyze the related influencing factors of COPD. The relative excess risk ratio(RERI), attribution ratio(AP) and interaction index(S) were used to analyze the interaction between smoking, anemia and the susceptibility to COPD.

Results  Pearson correlation analysis showed that SI was negatively correlated with FEV1/FVC and FEV1% pred(P＜0.05), while Hb was positively correlated with FEV1/FVC and FEV1% pred(P＜0.05). Smoking, anemia, FEV1/FVC, and FEV1% pred were related to the susceptibility to COPD(P＜0.05).  After smoking factor stratification, the distribution of anemia among the smokers′ groups was significantly different (P＜0.05). Smoking and anemia were related to the susceptibility to COPD, with OR values of 3.384 and 1.141, respectively. There was a positive additive interaction between smoking and anemia. When the two factors coexisted, the risk of COPD was 6.600 times that of non-smokers and non-anemia patients. The interaction analysis showed S=2.218, RERI=3.075, and AP=46.59%. The prevalence of COPD caused by the interaction of smoking and anemia was 3.075 times higher than that caused by other unpredictable factors. In addition, 46.59% of the risk of COPD in patients with coexistence of smoking and anemia was caused by the interaction of the two.

Conclusion  Smoking, anemia and COPD are closely related. Smoking, anemia, and lung function are the influencing factors of susceptibility to COPD. Smoking and anemia have an interactive effect on susceptibility to COPD.

Key words: pulmonary disease, chronic obstructive, smoking, anemia