Crisis of COPD in China: the future is now

Burden of COPD in China and the global from 1990 to 2019: a systematic analysis for the Global Burden of Disease Study 2019

OBJECTIVE

To investigate the current disease burden of chronic obstructive pulmonary disease (COPD) in China and globally using the Global Burden of Disease (GBD) data in 2019, as well as to analyse the changes in its risk factors, providing a scientific basis for the formulation of a comprehensive prevention and control strategy for COPD in China.

STUDY DESIGN

An observational study based on the GBDs.

METHODS

Based on the GBD 2019 database, we obtained data on incidence, prevalence, mortality, disability-adjusted life years (DALYs) and corresponding age-standardised rates of COPD in China and the global, and analysed and described the changing trends of COPD burden in China and the global from 1990 to 2019.

RESULTS

In 2019, the total number of COPD deaths in China was 1.04 (95% uncertainty intervals (95% UI): 0.89-1.27) million cases, the number of patients with COPD was 45.16 (95% UI: 41.13-49.62) million cases, and the number of new cases was 4.0 (95% UI: 3.6-4.4) million cases. DALYs were 74.4 (95% UI: 68.2-80.2) million years. Compared with 1990, the number of new incident cases and the overall prevalence of COPD in China in 2019 increased by 66.20% and 66.76%, respectively, which is lower than the overall global level.

CONCLUSION

From 1990 to 2019, the age-standardized prevalence rate (ASPR), the age-standardized incidence rate (ASIR) and the age-standardized death rate (ASDR) in China and the global all showed a downward trend, and the rate of decline in China was much higher than the overall level of the world, indicating that China has made specific achievements in the prevention and treatment of COPD, but overall the disease burden of COPD is still hefty, and the number of affected individuals is still increasing.

Cathelicidin induces epithelial-mesenchymal transition to promote airway remodeling in smoking-related chronic obstructive pulmonary disease

Background

Epithelial-mesenchymal transition (EMT) is an important characteristic in the remodeling of airways that occurs in chronic obstructive pulmonary disease (COPD). Cigarette smoke is a potential driving factor of this EMT in COPD. However, the mechanisms by which cigarette smoke induce EMT remain uncertain. Cathelicidin has been implicated as a causal factor of airway inflammation and mucus hypersecretion in smoking-related COPD. This study aimed to investigate whether cathelicidin induces EMT to promote airway remodeling in this disease.

Methods

Human lung tissue was collected from smokers with COPD and smokers without COPD. The EMT markers E-cadherin and vimentin were examined by immunohistochemistry. Mouse models of COPD were established by taking mice with airway cathelin-related antimicrobial peptide (CRAMP), the murine homologue of cathelicidin, either upregulated or downregulated by intranasal introduction of lentiviral vectors and then exposing them to cigarette smoke. E-cadherin and vimentin expression in the airways of the model mice was examined using immunofluorescence. Tumor necrosis factor alpha (TNF-α) converting enzyme (TACE), transforming growth factor alpha (TGF-α), and epidermal growth factor receptor (EGFR) expression was analyzed by Western blot. Additionally, NCI-H292 human airway epithelial cells, both with and without cathelicidin downregulation, were stimulated with cigarette smoke extract (CSE) and LL-37 synthetic peptide, a bioactive fragment of cathelicidin. This was done to confirm that the TACE/TGF-α/EGFR signaling pathway is activated in humans exposed to cigarette smoke.

Results

Significant EMT was found in the small airways of smokers both with and without COPD, as well as in the airways of COPD model mice. Downregulation of CRAMP in COPD mice, however, ameliorated airway EMT induced by cigarette smoke. Conversely, upregulation of CRAMP enhanced airway EMT in vivo; TACE, TGF-α, and EGFR were found to be involved in this process. In vitro, EMT induced by CSE and LL-37 was inhibited by blocking TACE, TGF-α, and EGFR expression.

Conclusions

Cathelicidin promotes airway EMT by activating the TACE/TGF-α/EGFR signaling pathway. This mediates smoking-induced airway remodeling in the pathogenesis of COPD.

Difference in Long-Term Trends in COPD Mortality between China and the U.S., 1992⁻2017: An Age⁻Period⁻Cohort Analysis

Complications due to chronic obstructive pulmonary disease (COPD) is a leading cause of death in China and the United States (U.S.). This study aimed to investigate the long-term trends in COPD mortality in China and the U.S. using data from the Global Burden of Disease Study 2017 (GBD 2017) and explore the age, period, and cohort effects independently by sex under the age-period-cohort (APC) framework. Taking the age group 40-44 years old, the period 1992-1996, and the birth cohort 1913-1917 as reference groups, we found that the age relative risks (RRs) of COPD mortality increased exponentially in both China and the U.S., the period RRs increased in the U.S. but decreased in China; and the cohort RRs showed an overall downward trend in both China and the U.S. with the year of birth. From 1992 to 2017, the increased RRs of COPD mortality in the U.S. was mainly attributable to the increased prevalence of smoking before 1965, while the decreased RRs of COPD mortality in China was mainly attributable to reduced air pollution as well as improvements in medical technology and more accessible health services. Reducing tobacco consumption may be the most effective and feasible way to prevent COPD in China. However, we also need to pay more attention to COPD in nonsmokers in the future.