This is a multi-center, randomized, controlled intervention clinical trial. A total of 1000 current smokers with rapid decline in lung function will be recruited and equally divided into two groups, comprehensive smoking cessation intervention group (early health warning intervention combined with brief smoking cessation intervention) and brief smoking cessation intervention group. It is aimed to evaluate whether early health warning intervention will increase the rate of smoking cessation.

This is a multi-center, randomized, controlled intervention clinical trial. A total of 1,000 current smokers ( ≥ 10 pack-years) with rapid decline in lung function will be recruited from Predictive Value of Inflammatory Biomarkers and FEV1 for COPD (PIFCOPD) study (clinical trails. gov ID NCT03532893) after 1 year of follow-up. Subjects will be qually divided into two groups, comprehensive smoking cessation intervention group (early health warning intervention combined with brief smoking cessation intervention) and brief smoking cessation intervention group. Health warning intervention is to tell the subjects that smoking leads to the rapid decline of their lung function, and they are at the high risk of developing COPD. The Department of Respiratory and Critical Care of Peking University First Hospital is responsible for this research. Other 9 units participating in the study, include the The Second Hospital of Hebei Medical University, Henan Provincial People's Hospital, The Second Hospital of Jilin University, The First Affiliated Hospital of Xi'an Jiaotong University, Shandong Provincial Hospital Affiliated to Shandong University, Shan xi Dayi Hospital（Shanxi Academy of Medical Sciences）, Tianjin Medical University General Hospital, The Affiliated Hospital of Inner Mongolia University. Some questionnaire about tobacco dependence, depression, anxiety, the willingness to quit smoking and withdrawal symptoms will be collected. Exhaled CO will be measured. Subjects will recived 6 times of smoking cessation intervention in 6 month and followed in another 6 month. The primary outcome is the rate of quitting smoking. The study protocol has been approved by the Peking University First Hospital Institutional Review Board (IRB) (2019-255). Any protocol modifications will be submitted for the IRB review and approval.

Inclusion Criteria:

1. aged at 40-75 years old;
2. FEV1/FVC>70% after inhaled bronchodilator
3. current smoker (≥ 10 pack-years)
4. rate of FEV1 decline >30ml/y
5. lived in a community for more than 1 years and has no plans to move out in the next 4 years

Exclusion Criteria:

1. history of asthma, COPD, lung cancer, active pulmonary tuberculosis, bronchiectasis, diffuse lung disease (interstitial pneumonia, pulmonary sarcoidosis, occupational lung disease, sarcoidosis et al) and pleural disease;
2. history of lobectomy and / or lung transplantation;
3. predicted life expectancy less than 3 years;
4. history of severe psychiatric illnesses, mental disorders, neurological disorders, malignant tumors, chronic liver disease, heart failure, autoimmune diseases, chronic kidney disease;
5. Alcoholism, drug abuse or abuse of toxic solvents;
6. Cannot finish long term follow-up or poor compliance;
7. Do not provide consent