[Associations between airflow obstruction and total and cause-specific mortality in adults in China]

Objective: To examine the prospective associations between airflow obstruction and total and cause-specific mortality. Methods: The study was based on China Kadoorie Biobank, in which 199 099 men and 287 895 women aged 30-79 years at baseline survey were included after excluding those with heart disease, stroke and cancer. The Global Initiative on Obstructive Lung Disease (GOLD) guideline was used to classify airflow obstruction. Cox regression models were used to estimate adjusted HR and 95%CI. Results: During 3 494 079 person-years of follow-up between 2004 and 2013 (median 7.2 years), a total of 21 649 people died. Absolute mortality rates were 5.5, 9.9, 13.1, 32.4 and 63.3 deaths per 1 000 person-years for participants who had normal airflow, GOLD-1 to GOLD-4 airflow obstruction, respectively. After adjusting potential confounders, compared with participants with normal lung function, the HRs for death were 0.98 (95%CI: 0.88-1.09), 1.03 (95%CI: 0.97-1.09), 1.62 (95% CI: 1.53-1.73) and 2.83 (95% CI: 2.59-3.10) for those whose airflow obstruction were classified as GOLD-1 to GOLD-4, respectively. The airflow obstruction was also associated with increased risk for deaths due to ischemic heart disease, cerebrovascular disease and chronic obstructive pulmonary disease. Conclusion: Airflow obstruction is associated with total and certain cause-specific mortality, the higher the airflow obstruction degree is, the higher the death risk is.