Associations between long-term ozone exposure and small airways function in Chinese young adults: a longitudinal cohort study.

BACKGROUND: Increasing evidence is appearing that ozone has adverse effects on health. However, the association between long-term ozone exposure and lung function is still inconclusive. OBJECTIVES: To investigate the associations between long-term exposure to ozone and lung function in Chinese young adults. METHODS: We conducted a prospective cohort study among 1594 college students with a mean age of 19.2 years at baseline in Shandong, China from September 2020 to September 2021. Lung function indicators were measured in September 2020 and September 2021, including forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), forced expiratory flow at the 25th, 50th, and 75th percentile of the FVC (FEF25, FEF50, and FEF75) and mean flow rate between 25% and 75% of the FVC (FEF25-75) were measured. Daily 10 km×10 km ozone concentrations come from a well-validated data-fusion approach. The time-weighted average concentrations in 12 months before the lung function test were defined as the long-term ozone exposure. The associations between long-term ozone exposure and lung function indicators in Chinese young adults were investigated using a linear mixed effects model, followed by stratified analyses regarding sex, BMI and history of respiratory diseases. RESULTS: Each interquartile range (IQR) (8.9 µg/m3) increase in long-term ozone exposure were associated with a -204.3 (95% confidence interval (CI): -361.6, -47.0) ml/s, -146.3 (95% CI: -264.1, -28.4) ml/s, and - 132.8 (95% CI: -239.2, -26.4) ml/s change in FEF25, FEF50, and FEF25-75, respectively. Stronger adverse associations were found in female participants or those with BMI ≥ 24 kg/m2 and history of respiratory diseases. CONCLUSION: Long-term exposure to ambient ozone is associated with impaired small airway indicators in Chinese young adults. Females, participants with BMI ≥ 24 kg/m2 and a history of respiratory disease have stronger associations.

Association between mercury exposure and lung function in young adults: A prospective cohort study in Shandong, China.

BACKGROUND: Mercury has been associated with many adverse health outcomes. However, limited studies have explored the association between blood mercury concentrations and lung function. OBJECTIVE: To examine the association between blood mercury concentrations and lung function among young adults. METHODS: We conducted a prospective cohort study among 1800 college students based on the Chinese Undergraduates Cohort in Shandong, China during August 2019 and September 2020. Lung function indicators including forced vital capacity (FVC, ml), forced expiratory volume in 1 s (FEV1, ml) and peak expiratory flow (PEF, ml) were collected with a spirometers (Chestgraph Jr. HI-101, Chest M.I., Tokyo, Japan). The blood mercury concentration was measured using inductively coupled plasma mass spectrometry. We divided participants into low (≤25 percentiles), intermediate (25-75 percentiles), and high (≥75 percentile) subgroups according to blood mercury concentrations. The multiple linear regression model was used to examine the associations between blood mercury concentrations and lung function changes. Stratification analyses by sex and fish consumption frequency were also conducted. RESULTS: The results showed that each 2-fold increase in blood mercury concentrations was significantly associated with -70.75 ml [95 % confidence interval (CI): -122.35, -19.15] change in FVC, -72.68 ml (95%CI: -120.36, -25.00) in FEV1, and -158.06 ml (95%CI: -283.77, -32.35) in PEF. The effect was more pronounced among participants with high blood mercury and male participants. Participants who consumed fish more than once a week more likely to be affected by mercury. CONCLUSION: Our study indicated that blood mercury was significantly associated with decreased lung function in young adults. It is necessary to implement corresponding measures to reduce the effect of mercury on the respiratory system, especially for men and people who consumed fish more than once a week.

Life-time summer heat exposure and lung function in young adults: A retrospective cohort study in Shandong China.

BACKGROUND: The health impact of short-term heat exposure is well documented. However, limited studies explored the association between life-time summer heat exposure and lung function. OBJECTIVE: To examine the association between life-time summer heat exposure and lung function among young adults. METHODS: We conducted a retrospective cohort study among 1928 college students in Shandong, China from September 4, 2020 to November 15, 2020. Life-time summer heat exposure for participants were estimated based on the nearest station meteorological data after the participant's birth date and divided by their learning phases. Lung function indicators included forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). A multiple linear regression model was conducted to examine the associations between summer heat exposure and lung function. Stratificationanalysis by cooling facilities and respiratory diseases history were also conducted. RESULTS: The study subjects had a slight majority of women (58.8%), age 19.2 ± 0.6 years. Each 1 °C increase in life-time summer mean temperature was associated with 1.07% [95% confidence interval (CI): -1.95-0.18%] decrease in FVC and 0.88% (95 %CI: -1.71, -0.05%) decrease in FEV1. Participants with respiratory diseases and non-cooling facility users were more susceptible to summer heat exposure. The usage of fan and air condition could effectively reduce the deleterious heat effects on lung function. CONCLUSION: Life-time summer heat exposure is significantly associated with the reduction of lung function in young adults. Cooling facilities are necessary for pre-school children to reduce heat effects. Fan and air-condition are effective cooling facilities, especially for people with respiratory diseases.

Long-term improvement of air quality associated with lung function benefits in Chinese young adults: A quasi-experiment cohort study.

INTRODUCTION: 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. OBJECTIVES: To examine whether the reduction of long-term air pollution was associated with lung function improvement among Chinese young adults. 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 air pollution concentrations were obtained from China Environmental Monitoring Station. Lung function indicators included forced vital capacity (FVC), forced expiratory volume in 1st second (FEV1) and forced expiratory flow at 50 % of FVC (FEF50%). We used linear mixed-effects model to examine the associations between the change of air pollutants concentrations and the change of lung function, and additional adjustments for indoor air pollution (IAP) source. We also conducted stratified analysis by sex. RESULTS: Compared with 2019, the mean FVC, FEV1 and FEF50% were elevated by 414.4 ml, 321.5 ml, and 28.4 ml/s respectively in 2020. Every 5 µg/m3 decrease in annual average PM2.5 concentrations was associated with 36.0 ml [95 % confidence interval (CI):6.0, 66.0 ml], 46.1 ml (95 % CI:16.7, 75.5 ml), and 124.2 ml/s (95 % CI:69.5, 178.9 ml/s) increment in the FVC, FEV1, and FEF50%, respectively. Similar associations were found for PM10. The estimated impact was almost unchanged after adjusting for IAP source. There was no significant effect difference between males and females. CONCLUSION: 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.