Linkage between Particulate Matter Properties and Lung Function in Schoolchildren: A Panel Study in Southern China

Higher temperature and humidity exacerbate pollutant-associated lung dysfunction in the elderly

RATIONALE

Air pollution and extreme temperature and humidity are risk factors for lung dysfunction, but their interactions are not clearly understood.

OBJECTIVES

To assess the impact of exposure to air pollutants and meteorological factors on lung function, and the contribution of their interaction to the overall effect.

METHODS

The peak expiratory flow rates of 135 participants were repeatedly measured during up to four visits. Two weeks before each visit, the concentrations of gaseous pollutants and 19 fine particle components, and the temperature and relative humidity, were continuously monitored in the community where they lived. A Bayesian Kernel machine regression model was used to explore the non-linear exposure-response relationships of the peak expiratory flow rate with pollutant exposure and meteorological factors, and their interactions.

MEASUREMENTS AND MAIN RESULTS

Increased temperature and relative humidity could exacerbate pollutant-associated decline in the peak expiratory flow rate, although their associations with lung dysfunction disappeared after adjustment for pollutant exposure. For example, declines of peak expiratory flow rate associated with interquartile range increase of 3-day cadmium exposure were -0.03 and -0.07 units, when temperature was at 0.1 and 19.5 °C, respectively. Decreased temperature were associated with declines of peak expiratory flow rate after adjustment for pollutant exposure, and had interaction with pollutant exposure on lung dysfunction.

CONCLUSIONS

High temperature, low temperature, and high humidity were all high-risk factors for lung dysfunction, and their interactions with pollutant levels contributed greatly to the overall effects.

PM2.5-bound metals and blood metals are associated with pulmonary function and Th17/Treg imbalance: A panel study of asthmatic adults

Growing research has demonstrated that exposure to fine particulate matter (PM2.5) was associated with decreased pulmonary function and obvious inflammatory response. However, few pieces of research focus on the effects of PM2.5-bound metals on people with asthma. Here, we assessed whether PM2.5 and PM2.5-bound metals exposure could worsen pulmonary function in asthmatic patients and further elucidate the possible mechanisms. Thirty-four asthmatic patients were recruited to follow up for one year with eight visits in 2019-2020 in Taiyuan City, China. The index of pulmonary function was detected and blood and nasal epithelial lining fluid (ELF) samples were acquired for biomarkers measurement at each follow-up. Linear mixed-effect (LME) models were used to evaluate the relations between PM2.5, PM2.5-bound metals, and blood metals with lung function and biomarkers of Th17/Treg balance. The individual PM2.5 exposure concentration varied from 37 μg/m3 to 194 μg/m3 (mean: 59.63 μg/m3) in the present study. An interquartile range (IQR) increment of PM2.5 total mass was associated with a faster decline in maximal mid-expiratory flow (MMEF) and higher interleukin-23 (IL-23). PM2.5-bound metals [e.g. copper (Cu), nickel (Ni), manganese (Mn), titanium (Ti), and zinc (Zn)] were significantly associated with IL-23 (Cu: 5.1126%, 95% CI: 9.3708, 0.8544; Mn: 14.7212%, 95% CI: 27.926, 1.5164; Ni: 1.0269%, 95% CI: 2.0273, 0.0264; Ti: 16.7536%, 95% CI: 31.6203, 1.8869; Zn: 24.5806%, 95% CI: 46.609, 2.5522). Meanwhile, blood lead (Pb) and Cu were associated with significant declines of 0.382-3.895% in MMEF and maximum ventilatory volume (MVV). Blood Pb was associated with descending transforming growth factor β (TGF-β). In conclusion, exposure to PM2.5-bound metals and blood metals is a risk factor for decreased pulmonary function, especially in small airways. These alterations might be partially attributed to the imbalance of Th17/Treg.

Short-term effects of the chemical components of fine particulate matter on pulmonary function: A repeated panel study among adolescents

The effects of the chemical components of fine particulate matter (PM2.5) have been drawing attention. However, information regarding the impact of low PM2.5 concentrations is limited. Hence, we aimed to investigate the short-term effects of the chemical components of PM2.5 on pulmonary function and their seasonal differences in healthy adolescents living on an isolated island without major artificial sources of air pollution. A panel study was repeatedly conducted twice a year for one month every spring and fall from October 2014 to November 2016 on an isolated island in the Seto Inland Sea, which has no major artificial sources of air pollution. Daily measurements of peak expiratory flow (PEF) and forced expiratory volume in 1 s (FEV1) were performed in 47 healthy college students, and the concentrations of 35 chemical components of PM2.5 were analyzed every 24 h. Using a mixed-effects model, the relationship between pulmonary function values and concentrations of PM2.5 components was analyzed. Significant associations were observed between several PM2.5 components and decreased pulmonary function. Among the ionic components, sulfate was strongly related to decreases in PEF and FEV1 (-4.20 L/min [95 % confidence interval (CI): -6.40 to -2.00] and - 0.04 L [95 % CI: -0.05 to -0.02] per interquartile range increase, respectively). Among the elemental components, potassium induced the greatest reduction in PEF and FEV1. Therefore, PEF and FEV1 were significantly reduced as the concentrations of several PM2.5 components increased during fall, with minimal changes observed during spring. Several chemical components of PM2.5 were significantly associated with decreased pulmonary function among healthy adolescents. The concentrations of PM2.5 chemical components differed by season, suggesting the occurrence of distinct effects on the respiratory system depending on the type of component.

Short-term exposure to ozone and ECG abnormalities in China: A nationwide longitudinal study

Ambient ozone (O3) pollution has been associated with an increased risk of cardiovascular diseases. However, few studies have addressed the effect of O3 exposure on electrocardiogram (ECG) abnormalities, a subclinical indicator of early damage to the cardiovascular system. This study aimed to examine the association between short-term exposure to O3 and ECG abnormalities. We included 102,027 visits of 47,290 participants over 40 years old who had a normal ECG at baseline and then visited again at least once from the China National Stroke Screening Survey (CNSSS). Short-term ozone exposure concentrations were measured as averages of maximum daily 8-h O3 concentrations over the two weeks prior to ECG measurements. The generalized estimation equations models were used to evaluate the association between O3 exposure and ECG abnormalities. For every 10 µg/m3 increment in short-term O3 concentration, the odds ratio of any ECG abnormality was 1.055 (95% confidence interval [CI] 1.045-1.064). For ECG-diagnosed cardiac arrhythmia, the odds ratio was 1.062 (95% CI 1.052-1.072). A nonlinear analysis showed a sublinear relationship between O3 exposure and risk for ECG abnormalities. The association between O3 exposure and ECG abnormalities varied by subpopulation. Our study provided new epidemiological evidence on the association between short-term O3 exposure and ECG abnormalities. There is an urgent need to control ambient O3 pollution to prevent cardiovascular events.

Exposure to ambient particulate matter and hyperuricemia: An eight-year prospective cohort study on male traffic officers in China

BACKGROUND AND OBJECTIVES

Studies on the effects of airborne particulates of diameter ≤ 1 µm (PM₁), airborne particulates of diameter ≤ 2.5 µm (PM_2.5) and airborne particulates of diameter ranges from 1 to 2.5 µm (PM_1-2.5) on incidence of hyperuricemia are limited. We aimed to investigate the associations between PM₁, PM_2.5, and PM_1-2.5 and hyperuricemia among male traffic officers.

METHODS

We conducted a prospective cohort study of 1460 traffic officers without hyperuricemia in Guangzhou, China from 2009 to 2016. Exposures of PM₁ and PM_2.5 were estimated with a spatiotemporal model. PM_1-2.5 concentrations were calculated by subtracting PM₁ from PM_2.5 concentrations. Cox's proportional hazards regressions models were used to examine the association between PM₁, PM_2.5, and PM_1-2.5 and hyperuricemia, adjusted for potential confounders. Associations between PM₁, PM_2.5, and PM_1-2.5 and serum uric acid (SUA) levels were evaluated with multiple linear regression models.

RESULTS

Hazard ratios (HRs) and 95% confidence intervals (CIs) of hyperuricemia associated with 10 μg/m³ increment in PM₁, PM_2.5, and PM_1-2.5 were 1.67 (95% CI:1.30-2.36), 1.49 (95% CI: 1.27-1.75), and 2.18 (95% CI: 1.58-3.02), respectively. The SUA concentrations increased by 12.23 μmol/L (95% CI: 5.91-18.56), 6.93 μmol/L (95% CI: 3.02-10.84), and 8.72 μmol/L (95% CI: 0.76-16.68) per 10 μg/m³ increase in PM₁, PM_2.5, and PM_1-2.5, respectively. Stratified analyses indicated the positive associations of PM_2.5 and PM_1-2.5 with SUA levels were stronger in non-smokers, and PM₁, PM_2.5, and PM_1-2.5 with SUA levels were stronger in non-drinkers.

CONCLUSION

Long-term PM₁, PM_2.5, and PM_1-2.5 exposures may increase the risk of hyperuricemia and elevate SUA levels among male traffic officers, especially in non-smokers and non-drinkers.

Association of high PM2.5 levels with short-term and medium-term lung function recovery in patients with pulmonary lobectomy

The association between exposure to ambient fine particulate matter with an aerodynamic diameter of ≤ 2.5 μm (PM_2.5) and short- and medium-term lung function recovery (LFR) in patients undergoing lobectomy remains uncertain. This study investigated the associations between PM_2.5 concentrations and LFR in adult patients (n = 526) who underwent video-assisted thoracoscopic (VATS) lobectomy in Guangzhou, China between January 2018 and June 2021. All patients underwent at least two spirometry tests. Environmental PM_2.5 concentrations in the same period were collected from the nearest monitoring station. A multiple linear regression (MLR) model was employed to investigate the associations between changes in PM_2.5 concentrations and LFR in patients who underwent lobectomy after adjusting for potential confounders. We assessed short- and medium-term LFR in patients who underwent lobectomy. The three- and 6-month average PM_2.5 concentrations in each patient's residential area were divided into regional mild pollution (PM_2.5 <25 μg/m³), moderate pollution (25 μg/m³ ≤ PM_2.5 <35 μg/m³), and severe pollution (35 μg/m³ ≤ PM_2.5) periods. The MLR model confirmed that PM_2.5 was an independent risk factor affecting short-term forced lung capacity (FVC), forced expiratory volume in 1 s (FEV1), and maximum expiratory flow at 50% vital capacity (MEF₅₀) recovery (adjusted P = 0.041, 0.014, 0.016, respectively). The MLR model confirmed that PM_2.5 was an independent risk factor affecting medium-term MEF₅₀ recovery (adjusted P = 0.046). Compared with the moderate and severe pollution periods, the short- and medium-term LFR (FVC, FEV1, MEF₅₀) of patients in the mild pollution period were faster and better (P < 0.001, P < 0.001, P < 0.001, P = 0.048, P = 0.010, P = 0.013, respectively). Thus, exposure to high PM_2.5 levels was associated with significantly reduced speed and degree of short- and medium-term LFR in patients who underwent lobectomy.

The relationship between particulate matter and lung function of children: A systematic review and meta-analysis

There have been many studies on the relationship between fine particulate matter (PM_2.5) and lung function. However, the impact of short-term or long-term PM_2.5 exposures on lung function in children is still inconsistent globally, and the reasons for the inconsistency of the research results are not clear. Therefore, we searched the PubMed, Embase and Web of Science databases up to May 2022, and a total of 653 studies about PM_2.5 exposures on children's lung function were identified. Random effects meta-analysis was used to estimate the combined effects of the 25 articles included. PM_2.5 concentrations in short-term exposure studies mainly come from individual and site monitoring. And for every 10 μg/m³ increase, forced vital capacity (FVC), forced expiratory volume in the first second (FEV₁) and peak expiratory flow (PEF) decreased by 21.39 ml (95% CI: 13.87, 28.92), 25.66 ml (95% CI: 14.85, 36.47) and 1.76 L/min (95% CI: 1.04, 2.49), respectively. The effect of PM_2.5 on lung function has a lag effect. For every 10 μg/m³ increase in the 1-day moving average PM_2.5 concentration, FEV₁, FVC and PEF decreased by 14.81 ml, 15.40 ml and 1.18 L/min, respectively. PM_2.5 concentrations in long-term exposure studies mainly obtained via ground monitoring stations. And for every 10 μg/m³ increase, FEV₁, FVC and PEF decreased by 61.00 ml (95% CI: 25.80, 96.21), 54.47 ml (95% CI: 7.29, 101.64) and 10.02 L/min (95% CI: 7.07, 12.98), respectively. The sex, body mass index (BMI), relative humidity (RH), temperature (Temp) and the average PM_2.5 exposure level modify the relationship between short-term PM_2.5 exposure and lung function. Our study provides further scientific evidence for the deleterious effects of PM_2.5 exposures on children's lung function, suggesting that exposure to PM_2.5 is detrimental to children's respiratory health. Appropriate protective measures should be taken to reduce the adverse impact of air pollution on children's health.

Co-exposure to priority-controlled metals mixture and blood pressure in Chinese children from two panel studies

Metals may affect adversely cardiovascular system, but epidemiological evidence on the associations of priority-controlled metals including antimony (Sb), arsenic (As), cadmium, lead, and thallium with children's blood pressure (BP) was scarce and inconsistent. We conducted two panel studies with 3 surveys across 3 seasons among 144 and 142 children aged 4-12 years in Guangzhou and Weinan, respectively. During each seasonal survey, urine samples were collected for 4 consecutive days and BP was measured on the 4th day. We obtained 786 BP values and urinary metals measurements at least once within 4 days, while 773, 596, 612, and 754 urinary metals measurements were effective on the health examination day (Lag 0), and the 1^st, 2^nd, and 3^rd day preceding BP measurement (Lag 1, lag 2 and lag 3), respectively. We used linear mixed-effect models, generalized estimating equations and multiple informant models to assess the associations of individual metal at each lag day and accumulated lag day (4 days averaged, lag 0-3) with BP and hypertension, and Bayesian Kernel Machine Regression to evaluate the relations of metals mixture at lag 0-3 and BP outcomes. We found Sb was positively and consistently related to systolic BP (SBP), mean arterial pressure (MAP), and odds of having hypertension within 4 days, which were the strongest at lag 0 and declined over time. And such relationships at lag 0-3 showed in a dose-response manner. Meanwhile, Sb was the only contributor to the relations of mixture with SBP, MAP, and odds of having hypertension. Also, synergistic interaction between Sb and As was significant. In addition, modification effect of passive smoking status on the association of Sb and SBP was more evident in passive smokers. Accordingly, urinary Sb was consistently and dose-responsively associated with increased BP and hypertension, of which Sb was the major contributor among children.

Urinary phthalate metabolites mixture, serum cytokines and renal function in children: A panel study

Epidemiological evidence regarded the relations of phthalates with children's renal function and its underlying mechanism were largely unknown. We conducted a panel study using 287 paired urine-blood samples by repeated measurements of 103 children (4-13 years) across 3 seasons to explore effects of urinary phthalate metabolites on estimated glomerular filtration rate (eGFR) and the potential role of multiple cytokines. We found that mono-ethyl phthalate (MEP), monobutyl phthalate (MBP), mono-benzyl phthalate (MBzP) and mono-n-octyl phthalate (MOP) were significantly associated with eGFR reduction. Compared with the lowest quartile, MBP, MBzP and MEP in the third and fourth quartiles exhibited a graded decrease in eGFR. Meanwhile, weighted quantile sum regression analyses showed an inverse association of metabolites mixture with eGFR, to which MEP, MBzP, MOP were the major contributors. MEP also remained robust in multiple-phthalate model. Age and weight status might modify such relationships with significant interactions. Furthermore, eGFR related phthalate metabolites were associated with increased multiple cytokines, and CCL27, CXCL1 might be potential mediators between MEP and eGFR with mild mediated proportions. Accordingly, urinary phthalate metabolites were related to eGFR reduction in dose-response manner and multiple cytokines elevation, of which CCL27 and CXCL1 might partly mediate phthalate-associated decreased renal function among children.

Association of abnormal-glucose tolerance during pregnancy with exposure to PM2.5 components and sources

Maternal exposure to PM_2.5 has been associated with abnormal glucose tolerance during pregnancy, but little is known about which constituents and sources are most relevant to glycemic effects. We conducted a retrospective cohort study of 1148 pregnant women to investigate associations of PM_2.5 chemical components with gestational diabetes mellitus (GDM) and impaired glucose tolerance (IGT) and to identify the most harmful sources in Heshan, China from January 2015 to July 2016. We measured PM_2.5 using filter-based method and analyzed them for 28 constituents, including carbonaceous species, water-soluble ions and metal elements. Contributions of PM_2.5 sources were assessed by positive matrix factorization (PMF). Logistic regression model was used to estimate composition-specific and source-specific effects on GDM/IGT. Random forest algorithm was applied to evaluate the relative importance of components to GDM and IGT. PM_2.5 total mass and several chemical constituents were associated with GDM and IGT across the early to mid-gestation periods, as were the PM_2.5 sources fossil fuel/oil combustion, road dust, metal smelting, construction dust, electronic waster, vehicular emissions and industrial emissions. The trimester-specific associations differed among pollutants and sources. The third and highest quartile of elemental carbon, ammonium (NH₄⁺), iron (Fe) and manganese (Mn) across gestation were consistently associated with higher odds of GDM/IGT. Maternal exposures to zinc (Zn), titanium (Ti) and vehicular emissions during the first trimester, and vanadium (V), nickel (Ni), road dust and fossil fuel/oil combustion during the second trimester were more important for GDM/IGT. This study provides important new evidence that maternal exposure to PM_2.5 components and sources is significantly related to elevated risk for abnormal glucose tolerance during pregnancy.

Respiratory function declines in children with asthma associated with chemical species of fine particulate matter (PM2.5) in Nagasaki, Japan

BACKGROUND

The differential effects of PM_2.5 fractions on children's lung function remain inconclusive. This study aimed to examine whether lung function in asthmatic children was associated with increased PM_2.5 fractions in urban areas in Nagasaki prefecture, Japan, where the air pollution level is relatively low but influenced by transboundary air pollution.

METHODS

We conducted a multiyear panel study of 73 asthmatic children (boys, 60.3%; mean age, 8.2 years) spanning spring 2014-2016 in two cities. We collected self-measured peak expiratory flow (PEF) twice a day and daily time-series data for PM_2.5 total mass and its chemical species. We fitted a linear mixed effects model to examine short-term associations between PEF and PM_2.5, adjusting for individual and time-varying confounders. A generalized linear mixed effects model was also used to estimate the association for worsening asthma defined by severe PEF decline. Back-trajectory and cluster analyses were used to investigate the long-range transboundary PM_2.5 in the study areas.

RESULTS

We found that morning PEFs were adversely associated with higher levels of sulfate (- 1.61 L/min; 95% CI: - 3.07, - 0.15) in Nagasaki city and organic carbon (OC) (- 1.02 L/min; 95% CI: - 1.94, - 0.09) in Isahaya city, per interquartile range (IQR) increase at lag1. In addition, we observed consistent findings for worsening asthma, with higher odds of severe PEF decline in the morning for sulfate (odds ratio (OR) = 2.31; 95% CI: 1.12, 4.77) and ammonium (OR = 1.73; 95% CI: 1.06, 2.84) in Nagasaki city and OC (OR = 1.51; 95% CI: 1.06, 2.15) in Isahaya city, per IQR increase at lag1. The significant chemical species were higher on days that could be largely attributed to the path of Northeast China origin (for sulfate and ammonium) or both the same path and local sources (for OC) than by other clusters.

CONCLUSIONS

This study provides evidence of the differential effects of PM_2.5 fractions on lung function among asthmatic children in urban areas, where the Japanese national standards of air quality have been nearly met. Continuous efforts to promote mitigation actions and public awareness of hazardous transboundary air pollution are needed to protect susceptible children with asthma.