key: cord-0264632-evmajhlt authors: Feng, S.; Miao, J.; Wang, M.; Jiang, N.; Dou, S.; Yang, L.; Ma, Y.; Yu, P.; Ye, T.; Wu, Y.; Wen, B.; Lu, P.; Li, S.; Guo, Y. title: Long-term Improvement of Air Quality Associated with Lung Function Benefits in Chinese Young Adults: A Quasi-experiment Cohort Study date: 2022-01-12 journal: nan DOI: 10.1101/2022.01.12.22269121 sha: 467ada8d86ea9a3c7793006bb0ef310e191f6648 doc_id: 264632 cord_uid: evmajhlt Background: Long-term exposure to air pollution is associated with lung function impairment. However, whether long-term improvements in air quality could improve lung function is unclear.Methods: We conducted a prospective quasi-experiment cohort study with 1731 college students in Shandong, China from September 2019 to September 2020, covering COVID-19 lockdown period. Data on PM2.5, PM10, NO2 and SO2 concentrations were obtained from China Environmental Monitoring Station. The concentration of O3 was obtained from Tracking Air Pollution in China. Lung function indicators included forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1) and forced expiratory flow at 50% of FVC (FEF50%). Linear mixed-effects model was used to examine the associations between the change of air pollutants concentrations and the change of lung functions. We also conducted stratified analysis by sex.Results: Compared with 2019, the mean FVC, FEV1 and FEF50% were elevated by 414.4ml, 321.5ml, and 28.4ml respectively in 2020. Every 5g/m3 decrease in annual average PM2.5 concentrations was associated with 36.0ml [95% confidence interval (CI):6.0, 66.0ml], 46.1ml (95% CI:16.7, 75.5ml), and 124.2ml/s (95% CI:69.5, 178.9ml/s) increment in the FVC, FEV1, and FEF50%, respectively. Similar associations were found for PM10. There was no significant effect difference between male and female.Conclusions: Long-term improvement of air quality can improve lung function among young adults. Stricter policies on improving air quality are needed to protect human health.Funding: Taishan Scholar Program Therefore, we extracted data from the Chinese Undergraduates Cohort to evaluate the 77 association between air quality improvement and changes of lung function among young adults. 78 For better assessing the differences of the effects between sex, stratified analysis was also 79 conducted. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint 102 Fig. 1 Flow chart of cohort study participants. 103 104 Lung function test 105 Participants in this study did two-round lung function tests. The first lung function test was Statistical methods 142 We used linear mixed-effects models for longitudinal data analysis to examine associations 143 between annual average air pollution exposure and lung function (Brown, 2021 is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. ; https://doi.org/10.1101/2022.01.12.22269121 doi: medRxiv preprint natural cubic spline term for them. To facilitate the comparison of estimates between pollutants, 155 effect estimates of the milliliters change in lung function were presented as per 5µg/m 3 156 increment in air pollutant concentrations. We repeated analyses using data stratified by sex 157 (male and female) to explore potential effect modifications by them. To adjust the potential 158 confounding effects of co-pollutants, we ran two pollutant models. Since PM2.5 and PM10 are 159 highly correlated, these two are not included in the same model. We conducted the following sensitivity analyses: the air pollution exposure duration of 10 and 162 11 months before lung function measurement were used to assess the robustness of our results. All analyses were conducted in R software, with the "nlme" package (version 4.0.3). The 164 threshold of statistical significance was p value of < 0.05 for 2-sided test. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. ; https://doi.org/10.1101/2022.01.12.22269121 doi: medRxiv preprint participate in the study. Compared with the nonparticipants, there were more women among the 177 participants (by 8.2%, Appendix 1- Table 2 ). The geographical distribution of the participants' 178 home addresses is shown in 10. Appendix 1-figure 1. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. ; https://doi.org/10.1101/2022.01.12.22269121 doi: medRxiv preprint 225 Appendix 1- Table 3 shows the stratified analysis results. We did not observe significant effect 226 modification by sex on associations with FVC, FEV1, or FEF50%. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. ; https://doi.org/10.1101/2022.01.12.22269121 doi: medRxiv preprint The results of sensitivity analyses were presented in Appendix 1- Table 4 Our quasi-experiment cohort study found that reductions in PM2.5 and PM10 concentrations 234 were significantly associated with the increment in FVC, FEV1 and FEF50% among young 235 adults, after controlling for the physiological increase in lung function caused by age in the 236 model. Among all the outcome variables, the small airway index FEF50% was more sensitive 237 to a variety of pollutants, and the estimated change was the largest. After adjusting for gaseous 238 pollutants, the PM impact was estimated to be stronger. We did not observe significant effect 239 modification by sex on associations between air pollution and lung function. Air pollution has always been a global concern. In high-income countries, studies have explored 242 the benefits of air pollution improvement on lung function. In California, researchers used 243 longitudinal data on 2,120 participants from three cohorts (1993-2001; 1997-2004; 2007-2011) 244 aged 11 to 15 to study the effects of policy-driven air pollution interventions on children's lung 245 development, the study showed that if the PM2.5 concentration had been reduced by 30% from 246 the levels observed in the 1993 cohort, the growth of FVC and FEV1 would be increase by 4.5% 247 and 2.5% compared with observed growth, respectively. Similar results were also observed for is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. We conducted a stratification analysis by sex. In our study, we did not observe significant effect is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. ; https://doi.org/10.1101/2022.01.12.22269121 doi: medRxiv preprint modification effects. People were rarely exposed to a single air pollutant. Recent studies have proposed that air The study had several strengths. First, prospective cohort study design allowed us to explore 312 the causal relationship between long-term air pollution exposure and lung function. Secondly, 313 the natural decline of the air pollutants concentrations offered us a good opportunity to conduct 314 a quasi-experiment cohort to clarify the health benefits of air quality improvements. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. ; https://doi.org/10.1101/2022.01.12.22269121 doi: medRxiv preprint Our study had some limitations. First, due to the availability of data, except O3, we used data 317 from city-level monitoring stations as personal exposure concentrations. Second, although we 318 adjusted the impact of potential confounding factors, there are still some unmeasured 319 confounding factors that we cannot rule out. Third, a potential source of bias in all cohort studies 320 is the loss to follow-up. In our study, there is a certain difference in sex distribution between 321 non-participants and participants, but the stratified analysis of sex found that there was no 322 significant effect modification by sex on associations between air pollution and lung function. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. ; https://doi.org/10.1101/2022.01.12.22269121 doi: medRxiv preprint Data will be shared under the auspices of the Principal Investigators. Investigators and potential 339 collaborators interested in the datasets will be asked to submit a brief concept note and analysis 340 plan. Requests will be vetted by PHD. Yuming Guo and Peng lu and appropriate datasets will 341 be provided through a password protected secure FTPS link. No personal identifying 342 information will be made available to any investigator. General de-identified datasets will be 343 prepared that can accommodate the majority of requests. These will be prepared, with 344 documentation, as the data is cleaned for analysis in order to reduce time and resources required 345 to respond to individual requests. Recipients of study data will be asked to sign a data sharing 346 agreement that specifies what the data may be used for (specific analyses), criteria for 347 acknowledging the source of the data, and the conditions for publication. It will also stipulate 348 that the recipient may not share the data with other investigators. Requests for data use must be 349 made directly to the PI and not through third parties. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. ; https://doi.org/10.1101/2022.01.12.22269121 doi: medRxiv preprint is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. ; https://doi.org/10.1101/2022.01.12.22269121 doi: medRxiv preprint is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. ; https://doi.org/10.1101/2022.01.12.22269121 doi: medRxiv preprint is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. ; https://doi.org/10.1101/2022.01.12.22269121 doi: medRxiv preprint Appendix 1 Table 2 . Baseline characteristics of the present study participants and participants who did not participate in this study. 3. Appendix 1- Table 3 is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. ; is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. ; https://doi.org/10.1101/2022.01.12.22269121 doi: medRxiv preprint Appendix 1- is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. ; https://doi.org/10.1101/2022.01.12.22269121 doi: medRxiv preprint is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint The copyright holder for this this version posted January 12, 2022. ; https://doi.org/10.1101/2022.01.12.22269121 doi: medRxiv preprint Lung function in early adulthood and Appendix 1-figure 1. Geographical distribution of the study population Note: The gray area on the left represents Shandong Province; The yellow dots on the right represent participants' home addresses.