[Mortality trend of chronic respiratory diseases in China, 1990-2019].

Objective: To analyze mortality and its trend of chronic respiratory diseases (CRD) in China from 1990 to 2019. Methods: Based on the provincial results of China from the 2019 Global Burden of Disease (GBD) study, the average annual percent change (AAPC) of standardized mortality rates of different CRDs were analyzed by using Joinpoint 4.8.0.1, and the age-standardized mortality rate of CRD was calculated by using the GBD 2019 world standard population. Based on the comparative risk assessment theory of GBD, the attributable deaths due to 12 CRD risk factors were estimated, including smoking, indoor air pollution, occupational gas exposure, particulates and smog exposure, environmental particulate pollution, low temperature, passive smoking, ozone pollution, occupational exposure to silica, occupational asthma, high body mass index, high temperature and occupational exposure to asbestos. Results: From 1990 to 2019, the number of deaths and standardized mortality of chronic obstructive pulmonary disease (COPD) showed a downward trend (P<0.001). The number of COPD deaths decreased from 1 244 000 (912 000 - 1 395 000) in 1990 to 1 037 000 (889 000 - 1 266 000) in 2019. AAPC=-0.9% (95%CI: -1.5% - -0.3%), P<0.001; The standardized mortality rate decreased from 217.9/100 000 (163.3/100 000 - 242.0/100 000) in 1990 to 65.2/100 000 (55.5/100 000 - 80.1/100 000) in 2019. AAPC= -4.2% (95%CI:-5.2% - -3.2%), P<0.001. The number of deaths from asthma decreased from 40 000 (30 000 - 58 000) in 1990 to 25 000 (20 000 - 31 000) in 2019. AAPC=-2.0% (95%CI: -2.6% - -1.4%), P<0.001; The standardized mortality rate of asthma decreased from 6.4/100 000 (4.7/100 000 - 9.5/100 000) in 1990 to 1.5/100 000 (1.2/100 000 - 1.9/100 000) in 2019. AAPC=-5.1% (95%CI: -5.8% - -4.4%), P<0.001. The number of pneumoconiosis deaths decreased from 11 000 (8 000 - 14 000) in 1990 to 10 000 (8 000 - 14 000) in 2019, AAPC=-0.2%(95%CI:-0.4% - 0.1%), P=0.200; The standardized mortality rate of pneumoconiosis decreased from 1.4/100 000 (1.0/100 000 - 1.7/100 000) in 1990 to 0.5/100 000 (0.4/100 000 - 0.7/100 000) in 2019. AAPC=-3.1% (95%CI: -3.4% - -2.8%), P<0.001. The number of deaths from pulmonary interstitial diseases and pulmonary sarcoidosis increased from 3 000 (3 000 - 6 000) in 1990 to 8 000 (6 000 - 10 000) in 2019, AAPC=3.5% (95%CI: 2.7% - 4.2%), P<0.001; The corresponding standardized mortality rate changed little from 1990 to 2019, and AAPC was not statistically significant.The age-standardized mortality rates of different CRDs were higher in men than those in women. In 1990 and 2019, the mortality rates of COPD, asthma, pneumoconiosis and interstitial pulmonary disease and pulmonary sarcoidosis increased with age. In 2019, the population attributable fractions (PAFs) for smoking, environmental particulate pollution, occupational gas exposure, particulate and smog exposure, low temperature exposure and passive smoking were 71.1% (68.0% - 74.3%), 24.7% (20.1% - 30.0%), 19.3% (13.0% - 25.4%), 15.7% (13.6% - 18.3%) and 8.8% (4.5% - 13.1%) respectively in men, and the PAFs for environmental particulate pollution, smoking, low temperature exposure, occupational gas exposure, particulate and smog exposure, and passive smoking were 24.1% (19.6% - 29.3%), 21.9% (18.7% - 25.2%), 16.4% (14.0% - 19.2%), 15.6% (10.2% - 21.1%) and 14.7% (7.9% - 21.3%) respectively in women. Conclusions: During 1990-2019, the overall death level of CRD decreased significantly in China, but it is still at high level in the world. Active prevention and control measures should be taken to reduce the death level caused by CRD.

[Regional and demographic differences on passive smoking among non-smokers aged 30-79 years in 10 regions of China].

Objective: To describe the regional and demographic differences on passive non-smokers from 10 regions involved in the China Kadoorie Biobank (CKB) study. Methods: Detailed information regarding passive smoking behaviors related to 317 486 non-smokers who were 30-79 years old from the 10 study regions were gathered and analyzed. Results: Following the standardization of the 2010 China national population, the prevalence rate of passive smoking was 56.7%, and the prevalence rate of living with smokers was 66.5% among the Chinese adults. Both of the aforementioned rates were higher in rural than in urban areas. Meanwhile, the regional distribution of weekly passive smoking frequency and cumulative duration of passive smoking per week and cumulative duration of passive smoking per day were significantly different. The cumulative passive smoking duration per week increased along with the weekly frequency in people living in urban areas. Among women, the weekly passive smoking frequency was the highest, and the cumulative durations per week and per day appeared the lowest in Hunan, opposite to the situation in Henan. The prevalence of passive smoking among participants living with smokers was 2.27 times (95%CI: 2.24-2.29) of those who were not and the association appeared stronger in women (OR=2.61, 95%CI: 2.58-2.64) but not in men (OR=1.01, 95%CI: 0.95-1.06). Almost all the indicators seemed higher in women than those in men, except for the cumulative duration per day. Furthermore, these indicators appeared higher among those who were at younger age or with less education. The prevalence rates of passive smoking and living with smokers were lower but the cumulative duration per day was higher among those with lower household income. And the two rates were higher in married women and lower in married men, as compared to their counterparts. Conclusion: Regional and demographic differences in passive smoking were noticed among study population of CKB in the 10 regions.

Predicting transient particle transport in enclosed environments with the combined computational fluid dynamics and Markov chain method.

To quickly obtain information about airborne infectious disease transmission in enclosed environments is critical in reducing the infection risk to the occupants. This study developed a combined computational fluid dynamics (CFD) and Markov chain method for quickly predicting transient particle transport in enclosed environments. The method first calculated a transition probability matrix using CFD simulations. Next, the Markov chain technique was applied to calculate the transient particle concentration distributions. This investigation used three cases, particle transport in an isothermal clean room, an office with an underfloor air distribution system, and the first-class cabin of an MD-82 airliner, to validate the combined CFD and Markov chain method. The general trends of the particle concentrations vs. time predicted by the Markov chain method agreed with the CFD simulations for these cases. The proposed Markov chain method can provide faster-than-real-time information about particle transport in enclosed environments. Furthermore, for a fixed airflow field, when the source location is changed, the Markov chain method can be used to avoid recalculation of the particle transport equation and thus reduce computing costs.