Mediating Effect of Tobacco Dependence on the Association Between Maternal Smoking During Pregnancy and Chronic Obstructive Pulmonary Disease: Case-Control Study.
Li J., Xu J., Yang L., Xu Y., Zhang X., Bai C., Kang J., Ran P., Shen H., Wen F., Huang K., Yao W., Sun T., Shan G., Yang T., Lin Y., Zhu J., Wang R., Shi Z., Zhao J., Ye X., Song Y., Wang Q., Hou G., Zhou Y., Li W., Ding L., Wang H., Chen Y., Guo Y., Xiao F., Lu Y., Peng X., Zhang B., Wang Z., Zhang H., Bu X., Zhang X., An L., Zhang S., Cao Z., Zhan Q., Yang Y., Liang L., Cao B., Dai H., Chung KF., Chen Z., He J., Wu S., Xiao D., Wang C., China Pulmonary Health Study Group None.
BACKGROUND: Maternal smoking during pregnancy (MSDP) is a known risk factor for offspring developing chronic obstructive pulmonary disease (COPD), but the underlying mechanism remains unclear. OBJECTIVE: This study aimed to explore whether the increased COPD risk associated with MSDP could be attributed to tobacco dependence (TD). METHODS: This case-control study used data from the nationwide cross-sectional China Pulmonary Health study, with controls matched for age, sex, and smoking status. TD was defined as smoking within 30 minutes of waking, and the severity of TD was assessed using the Fagerstrom Test for Nicotine Dependence. COPD was diagnosed when the ratio of forced expiratory volume in 1 second to forced vital capacity was <0.7 in a postbronchodilator pulmonary function test according to the 2017 Global Initiative for Chronic Obstructive Lung Disease criteria. Logistic regression was used to examine the correlation between MSDP and COPD, adjusting for age, sex, BMI, educational attainment, place of residence, ethnic background, occupation, childhood passive smoking, residential fine particulate matter, history of childhood pneumonia or bronchitis, average annual household income, and medical history (coronary heart disease, hypertension, and diabetes). Mediation analysis examined TD as a potential mediator in the link between MSDP and COPD risk. The significance of the indirect effect was assessed through 1000 iterations of the "bootstrap" method. RESULTS: The study included 5943 participants (2991 with COPD and 2952 controls). Mothers of the COPD group had higher pregnancy smoking rates (COPD: n=305, 10.20%; controls: n=211, 7.10%; P