2.Main results

In 2014，75，107 individuals aged 40 years or older were investigated in the COPD surveillance，including 37，312（49.7%）males and 37，795（50.3%）females.The sample size for different age group（40-49，50-59，60-69，and 70+）was 23，508（31.3%），24，526（32.7%），19，882（26.5%）and 7，191（9.5%）respectively.There were 35，702 urban residents（47.5%）and 39，405 rural residents（52.5%）.The proportion of rural residents was slightly higher than that of urban.The number of participants from eastern，middle and western regions were 26，487（35.3%），22，195（29.5%）and 26，425（35.2%），respectively.

In 2014，the prevalence of COPD in residents aged 40 years or order in China was 13.6%.The prevalence of COPD among males（19.0%）was significantly higher than females（8.1%）.The prevalence of COPD for the 40-49，50-59，60-69，70+ age groups were 6.5%（9.0% for males and 4.0% for females），12.7%（17.8% for males，7.5% for females），21.2%（30.4% for males and 11.7%for females），29.9%（42.3% for males and 18.5% for females），respectively，indicating that the prevalence increased with age.The prevalence of COPD in rural areas（14.9%）was higher than that in urban areas（12.2%）.The prevalence of COPD in the eastern，middle and western regions were 13.7%，10.9% and 16.9%，respectively，of which the western rural areas（18.2%）were the highest，followed by the eastern rural areas（15.3%）and the western urban areas（15.0%）.The rate in eastern urban areas（12.4%），middle rural areas（11.7%）and middle urban areas（9.8%）declined in turn.

In 2014，among the patients with COPD aged 40 years or older，56.4% of patients were GOLD stage Ⅰ（mild），36.3% were GOLD stage Ⅱ（moderate），6.5% were GOLD stage Ⅲ（severe），and 0.9% were GOLD stage Ⅳ（extremely severe）.The proportion of moderate and higher airflow limitation among the females（44.4%）was higher than that among the males（43.3%）.The proportion of moderate and higher airflow limitation in the older age group was higher than that in the younger age group.The proportion of GOLD stage in urban and rural areas was similar.The proportion of moderate or higher in the middle region was the highest（49.5%），followed by the eastern region（43.8%）and the western region（39.4%）.

In 2014，the smoking rate of residents aged 40 years or order in China was 40.0%，and that of men（74.1%）was significantly higher than that of women（5.4%）.The smoking rates of the 40-49，50-59，60-69 and 70+ age groups were 38.1%，42.2%，43.2%，and 37.0%，respectively.The smoking rate of rural residents（41.2%）was slightly higher than that of urban residents（38.8%）.The smoking rate was highest in the western region（40.9%），followed by the middle region（39.8%）and the eastern region（39.6%）.

The current smoking rate of residents aged 40 years or order in China was 31.0%，and that of men（57.6%）was significantly higher than that of women（4.0%）.The current smoking rate of residents aged 40-49，50-59，60-69，and 70+ age groups was 32.6%，33.4%，30.2%，and 22.8%，respectively.The rate was higher in rural areas（32.4%）than urban areas（29.5%）.The current smoking rates in the eastern（30.5%），middle（31.0%）and western regions（32.0%）increased sequentially but the difference was slight.

In 2014，46.3% residents aged 40 years or order exposed to occupational dust and/or hazardous chemical gases.The rate of occupational exposure in men（51.4%）was higher than women（41.0%）.The rate of occupational exposure at 40-49 age group among males was highest（54.0%），and the rate at 50-59 age group among females was highest（43.6%）.The rate in rural areas（51.7%）was significantly higher than urban areas（40.3%），and the rate in western regions（59.0%）were significantly higher than the middle regions（42.7%）and the eastern regions（41.2%）.

Among people exposed to occupational dust and/or chemical gases，26.7% individual used occupational protection.The occupational protection rate among men（26.9%）was basically the same as women（26.5%）.The occupational protection rate was highest at the 40-49 year old population（32.8%）.The rate in urban areas（30.6%）was higher than rural areas（24.0%）.The rate was lowest in the western region which was only 22.9%.The rate in the middle region and the eastern region were 27.0% and 29.9%.

In 2014，48.8% residents aged 40 years or order used polluting fuels for household cooking（including biomass and coal/kerosene fuels）.There were 38.5% residents using biomass for household cooking，which was the mainly composition of polluting fuels.The rate of household cooking using polluting fuel was highest at the 60-69 age group（56.3%）.The rate of polluting fuel used in rural household cooking（66.4%）was significantly higher than that in urban（29.7%），and that in the middle region（59.5%）and the western region（56.5%）were similar，which was significantly higher than those in the eastern region（35.8%）.

The rate of using polluting fuel（including biomass and coal fuel）for household heating among residents aged 40 years or older was 36.3%.There were 26.7% residents using coal fuel for household heating，which was the mainly composition of the polluting fuel.The rate of using polluting fuels for households heating in rural areas（48.3%）was significantly higher than that in urban areas（23.3%）.The rate of using polluting fuels for households heating in the middle region was the highest（43.6%），followed by the western region（34.6%），and the eastern region（31.7%）.There was no obvious difference between the western region and eastern region.

Only 0.9% of patients with COPD aged 40 years or older were aware of their diagnosis of COPD.A higher proportion of male patients（1.0%）were aware of the COPD than female patients（0.6%）.The awareness of COPD was highest in the 60-69 year old population（1.1%），and patients in urban areas（1.2%）were more aware of their COPD than those in rural areas（0.7%）.The differences between the eastern，middle and western regions were small，which was 0.8%，0.7% and 1.1%respectively.

Overall，9.2% of residents aged 40 years or older knew the term of COPD，and men（9.3%）were basically the same as women（9.1%）.The awareness rate of the term of COPD was highest at the 60-69 age group（10.4%），and it was lowest at 70+ age group（8.1%）.The rate was higher in urban areas（11.1%）than in rural areas（7.5%），and it was highest in the eastern region（11.2%），followed by the western region（10.1%）and the middle region（5.9%）.

The pulmonary function test rate of patients with COPD aged 40 years or older was 5.9%，and the rate of males（6.1%）were slightly higher than that of females（5.3%）.The total of 7.2% of patients aged 70 years and older had been examined by the pulmonary function tests before，which was highest among different age groups.The pulmonary function test rate in urban areas（8.2%）was significantly higher than that in rural areas（4.2%）.The rate in the eastern，middle，and western regions were 6.6%，5.3%，and 5.6%，respectively.

The pulmonary function test rate of residents aged 40 years or older in China was 4.5%，and the rate of males（5.6%）was higher than females（3.3%）.The rate of pulmonary function test was highest in the population aged 60-69 years old（4.8%）.The rate in urban areas（5.8%）was higher than rural areas（3.2%）.It was highest in the eastern region（5.3%），followed by the western region（4.2%）and the middle region（3.5%）.