Reduced exposure to PM10 and attenuated age-related decline in lung function

Characteristics and outcomes of chronic obstructive pulmonary disease in never smokers in Denmark: a prospective population study

BACKGROUND

A substantial proportion of patients with chronic obstructive pulmonary disease (COPD) have never smoked. We tested the hypothesis that, in individuals with COPD, never smokers have different characteristics and less severe outcomes of the disease than smokers do.

METHODS

We included individuals from the Copenhagen General Population Study, a prospective population study. We identified individuals with COPD spirometrically; that is, as the ratio between forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) under the lower limit of normal (LLN), excluding individuals with self-reported asthma. We examined general characteristics, symptoms, disease severity, and levels of inflammatory biomarkers and α1-antitrypsin at baseline. We assessed risk of lung-related hospital admissions, cardiovascular comorbidities, and all-cause mortality during a median follow-up of 4 years (IQR 2.5-5.6).

FINDINGS

Between Nov 26, 2003, and July 29, 2010, 68,501 participants from the Copenhagen General Population Study had lung function measurements and complete information on smoking habits available. Of those, we identified 6623 with COPD and no asthma. Of these, 1476 (22%) were never smokers, 2696 (41%) former smokers, and 2451 (37%) current smokers. For comparison we included 24,529 never smokers without COPD. Never smokers with COPD had different clinical characteristics, fewer symptoms, milder disease, and lower levels of inflammatory biomarkers than did current and former smokers with COPD. During follow-up, HRs for hospital admission due to COPD were 8.6 (95% CI 5.3-14) in never smokers, 30 (22-41) in former smokers, and 43 (32-59) in current smokers compared with never smokers without COPD. HRs for hospital admission due to pneumonia were 1.9 (1.4-2.6) in never smokers, 2.8 (2.3-3.4) in former smokers, and 3.4 (2.9-4.2) in current smokers. For hospital admission due to lung cancer, HRs were 11 (5.7-23) in former smokers and 18 (9.2-35) in current smokers, whereas no cases were noted in never smokers. Furthermore, risk of cardiovascular comorbidities and all-cause mortality was increased in former and current smokers but not in never smokers with COPD.

INTERPRETATION

Compared with current and former smokers, never smokers with COPD had different characteristics and milder disease, limited to the lungs. However, morbidity due to lung-related hospital admissions was nonetheless substantial in never smokers with COPD.

FUNDING

Herlev Hospital, Copenhagen University Hospital, Copenhagen County Foundation, and University of Copenhagen.

Respiratory health effects of ambient air pollution: an update

There is new evidence for ambient air pollution (AAP) leading to an increased incidence of respiratory diseases in adults. Research has demonstrated that co-exposures have the potential to dramatically augment the effects of AAP and lower the threshold of effect of a given pollutant. Interactions between genes related to oxidative stress and AAP seem to significantly alter the effect of AAP on an individual and population basis. A better definition of vulnerable populations may bolster local or regional efforts to remediate AAP. Advances in genetic research tools have the potential to identify candidate genes that can guide further research.

Rationing health protection: a proposal to exempt nuisance dust from US Clean Air Act regulations

The US House of Representative has passed a bill called the "Farm Dust Regulation Prevention Act" (Dust Act) that would exempt most types of particulate matter (PM) in rural areas from the air quality controls of the US Clean Air Act. The Dust Act would markedly change the country's air quality standards. An examination of the proposed provisions shows that they would exempt non-combustion PM pollutants from mining, smelting, petroleum production, and power generation from existing air quality standards. Persons downwind from pollutants generated in rural areas could be exposed to concentrations of carcinogenic heavy metals, asbestos, and benzene known to adversely affect their health and ecological resources. Existing federal air quality standards based on science would be replaced by a flexible standard that rations health protection.

Epigenetically mediated pathogenic effects of phenanthrene on regulatory T cells

Phenanthrene (Phe), a polycyclic aromatic hydrocarbon (PAH), is a major constituent of urban air pollution. There have been conflicting results regarding the role of other AhR ligands 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD) and 6-formylindolo [3,2-b]carbazole (FICZ) in modifying regulatory T cell populations (Treg) or T helper (Th)17 differentiation, and the effects of Phe have been understudied. We hypothesized that different chemical entities of PAH induce Treg to become either Th2 or Th17 effector T cells through epigenetic modification of FOXP3. To determine specific effects on T cell populations by phenanthrene, primary human Treg were treated with Phe, TCDD, or FICZ and assessed for function, gene expression, and phenotype. Methylation of CpG sites within the FOXP3 locus reduced FOXP3 expression, leading to impaired Treg function and conversion of Treg into a CD4⁺CD25^lo Th2 phenotype in Phe-treated cells. Conversely, TCDD treatment led to epigenetic modification of IL-17A and conversion of Treg to Th17 T cells. These findings present a mechanism by which exposure to AhR-ligands mediates human T cell responses and begins to elucidate the relationship between environmental exposures, immune modulation, and initiation of human disease.

Health impact assessment of air pollution in megacity of Tehran, Iran

The aims of the present study were to provide quantitative data on the impact of air pollution on the health of people living in Tehran city, the most populated city of Iran. The approach proposed by the World Health Organization (WHO) was applied using the AirQ 2.2.3 software developed by the WHO European Centre for Environment and Health, Bilthoven Division. Concentrations of ozone, nitrogen dioxide, sulfur dioxide and particulate matter of aerodynamic diameter ≤ 10 μm (PM₁₀) were used to assess human exposure and health impacts in terms of attributable proportion of the health outcome, annual number of excess cases of mortality for all causes, and cardiovascular and respiratory diseases. The annual average of PM₁₀, SO₂, NO₂ and O₃ in Tehran were 90.58, 89.16, 85 and 68.82 μg/m³, respectively. Considering short-term effects, PM₁₀ had the highest health impact on the 8,700,000 inhabitants of Tehran city, causing an excess of total mortality of 2194 out of 47284 in a year. Sulfur dioxide, nitrogen dioxide and ozone caused about, respectively, 1458, 1050 and 819 excess cases of total mortality. Results indicate that the magnitude of the health impact estimated for the city of Tehran underscores the need for urgent action to reduce the health burden of air pollution.

The effects of age and carbon black on airway resistance in mice

CONTEXT

Ambient particulate matter (PM) is associated with acute exacerbations of airflow obstruction. Additionally, elderly individuals are more susceptible to increased functional morbidity following acute PM exposure.

OBJECTIVE

The purpose of this study is to determine the aging effects of PM exposure on the responsiveness of airway smooth muscle in mice. We hypothesized that airway reactivity induced by methacholine (Mch) will increase with age in PM exposed mice.

MATERIALS AND METHODS

Male C57BL/6 (B6) mice at 11, 39, 67, and 96 weeks of age were exposed to carbon black (CB) or room air (RA) for 3 h on 3 consecutive days. One day after the last exposure, mice were anesthetized and airways resistance (R(aw)) was measured by forced oscillation following half-log dose increases of aerosolized Mch.

RESULTS

Baseline R(aw) was significantly lower in 67 and 96 week mice compared to 11-week mice (p < 0.05). In RA exposed mice, an age-dependent decline in Mch-induced airway reactivity occurred in association with the highest Mch doses at ages 67 and 96 weeks (p < 0.05). A significantly (p < 0.05) greater Mch-induced R(aw) response occurred in 67-week mice exposed to CB compared with age-matched RA-exposed mice.

DISCUSSION AND CONCLUSION

Our results show a progressive decrease in the Mch-induced R(aw) response with age in mice. The effect of CB exposure resulted in greater airway reactivity in middle-aged mice, which highlights the effects of PM exposure on the lung as it relates to increased morbidity and mortality with older age.

Clearing the air: a review of the effects of particulate matter air pollution on human health

The World Health Organization estimates that particulate matter (PM) air pollution contributes to approximately 800,000 premature deaths each year, ranking it the 13th leading cause of mortality worldwide. However, many studies show that the relationship is deeper and far more complicated than originally thought. PM is a portion of air pollution that is made up of extremely small particles and liquid droplets containing acids, organic chemicals, metals, and soil or dust particles. PM is categorized by size and continues to be the fraction of air pollution that is most reliably associated with human disease. PM is thought to contribute to cardiovascular and cerebrovascular disease by the mechanisms of systemic inflammation, direct and indirect coagulation activation, and direct translocation into systemic circulation. The data demonstrating PM's effect on the cardiovascular system are strong. Populations subjected to long-term exposure to PM have a significantly higher cardiovascular incident and mortality rate. Short-term acute exposures subtly increase the rate of cardiovascular events within days of a pollution spike. The data are not as strong for PM's effects on cerebrovascular disease, though some data and similar mechanisms suggest a lesser result with smaller amplitude. Respiratory diseases are also exacerbated by exposure to PM. PM causes respiratory morbidity and mortality by creating oxidative stress and inflammation that leads to pulmonary anatomic and physiologic remodeling. The literature shows PM causes worsening respiratory symptoms, more frequent medication use, decreased lung function, recurrent health care utilization, and increased mortality. PM exposure has been shown to have a small but significant adverse effect on cardiovascular, respiratory, and to a lesser extent, cerebrovascular disease. These consistent results are shown by multiple studies with varying populations, protocols, and regions. The data demonstrate a dose-dependent relationship between PM and human disease, and that removal from a PM-rich environment decreases the prevalence of these diseases. While further study is needed to elucidate the effects of composition, chemistry, and the PM effect on susceptible populations, the preponderance of data shows that PM exposure causes a small but significant increase in human morbidity and mortality. Most sources agree on certain "common sense" recommendations, although there are lonely limited data to support them. Indoor PM exposure can be reduced by the usage of air conditioning and particulate filters, decreasing indoor combustion for heating and cooking, and smoking cessation. Susceptible populations, such as the elderly or asthmatics, may benefit from limiting their outdoor activity during peak traffic periods or poor air quality days. These simple changes may benefit individual patients in both short-term symptomatic control and long-term cardiovascular and respiratory complications.

Air pollution and asthma control in the Epidemiological study on the Genetics and Environment of Asthma

BACKGROUND

The associations between exposure to air pollution and asthma control are not well known. The objective of this study was to assess the association between long-term exposure to NO(2), O(3) and PM(10) and asthma control in the follow-up of the Epidemiological study on the Genetics and Environment of Asthma (EGEA2) (2003-2007).

METHODS

Modelled outdoor NO(2), O(3) and PM(10) estimates were linked to each residential address using the 4 km grid air pollutant surface developed by the French Institute of Environment in 2004. Asthma control was assessed in 481 subjects with current asthma using a multidimensional approach following the 2006-2009 Global Initiative for Asthma guidelines. Multinomial and ordinal logistic regressions were conducted adjusted for sex, age, body mass index, education, smoking and use of inhaled corticosteroids. The association between air pollution and the three domains of asthma control (symptoms, exacerbations and lung function) was assessed. ORs are reported per IQR.

RESULTS

Median concentrations (in micrograms per cubic metre) were 32 (IQR 25-38) for NO(2) (n=465), 46 (41-52) for O(3) and 21 (18-21) for PM(10) (n=481). In total, 44%, 29% and 27% had controlled, partly controlled and uncontrolled asthma, respectively. The ordinal ORs for O(3) and PM(10) with asthma control were 1.69 (95% CI 1.22 to 2.34) and 1.35 (95% CI 1.13 to 1.64), respectively. When including both pollutants in the same model, both associations persisted. Associations were not modified by sex, smoking status, use of inhaled corticosteroids, atopy, season of examination or body mass index. Both pollutants were associated with each of the three main domains of control.

CONCLUSIONS

The results suggest that long-term exposure to PM(10) and O(3) is associated with uncontrolled asthma in adults, defined by symptoms, exacerbations and lung function.

Air pollution and the respiratory system

Over the past 250 years-since the Industrial Revolution accelerated the process of pollutant emission, which, until then, had been limited to the domestic use of fuels (mineral and vegetal) and intermittent volcanic emissions-air pollution has been present in various scenarios. Today, approximately 50% of the people in the world live in cities and urban areas and are exposed to progressively higher levels of air pollutants. This is a non-systematic review on the different types and sources of air pollutants, as well as on the respiratory effects attributed to exposure to such contaminants. Aggravation of the symptoms of disease, together with increases in the demand for emergency treatment, the number of hospitalizations, and the number of deaths, can be attributed to particulate and gaseous pollutants, emitted by various sources. Chronic exposure to air pollutants not only causes decompensation of pre-existing diseases but also increases the number of new cases of asthma, COPD, and lung cancer, even in rural areas. Air pollutants now rival tobacco smoke as the leading risk factor for these diseases. We hope that we can impress upon pulmonologists and clinicians the relevance of investigating exposure to air pollutants and of recognizing this as a risk factor that should be taken into account in the adoption of best practices for the control of the acute decompensation of respiratory diseases and for maintenance treatment between exacerbations.

SERPINA1 PiZ and PiS heterozygotes and lung function decline in the SAPALDIA cohort

Background

Severe alpha1-antitrypsin (AAT) deficiency is a strong risk factor for COPD. But the impact of gene variants resulting in mild or intermediate AAT deficiency on the longitudinal course of respiratory health remains controversial. There is indication from experimental studies that pro-inflammatory agents like cigarette smoke can interact with these variants and thus increase the risk of adverse respiratory health effects. Therefore, we tested the effect of the presence of a protease inhibitor (Pi) S or Z allele (PiMS and PiMZ) on the change in lung function in different inflammation-exposed subgroups of a large, population-based cohort study.

Methodology and Principal Findings

The SAPALDIA population includes over 4600 subjects from whom SERPINA1 genotypes for S and Z alleles, spirometry and respiratory symptoms at baseline and after 11 years follow-up, as well as proxies for inflammatory conditions, such as detailed smoking history, obesity and high sensitivity C-reactive protein (hs-CRP), were available. All analyses were performed by applying multivariate regression models. There was no overall unfavourable effect of PiMS or PiMZ genotype on lung function change. We found indication that PiZ heterozygosity interacted with inflammatory stimuli leading to an accelerated decline in measures in use as indices for assessing mild airway obstruction. Obese individuals with genotype PiMM had an average annual decline in the forced mid expiratory flow (ΔFEF25-75%) of 58.4 ml whereas in obese individuals with PiMZ it amounted to 92.2 ml (p = 0.03). Corresponding numbers for persistent smokers differed even more strongly (66.8 ml (PiMM) vs. 108.2 ml (PiMZ), p = 0.005). Equivalent, but less strong associations were observed for the change in the FEV1/FVC ratio.

Conclusions

We suggest that, in addition to the well established impact of the rare PiZZ genotype, one Z allele may be sufficient to accelerate lung function decline in population subgroups characterized by elevated levels of low grade inflammation.

Modification of the association between ambient air pollution and lung function by frailty status among older adults in the Cardiovascular Health Study

The susceptibility of older adults to the health effects of air pollution is well-recognized. Advanced age may act as a partial surrogate for conditions associated with aging. The authors investigated whether gerontologic frailty (a clinical health status metric) modified the association between ambient level of ozone or particulate matter with an aerodynamic diameter less than 10 µm and lung function in 3,382 older adults using 7 years of follow-up data (1990-1997) from the Cardiovascular Health Study and its Environmental Factors Ancillary Study. Monthly average pollution and annual frailty assessments were related to up to 3 repeated measurements of lung function using cumulative summaries of pollution and frailty histories that accounted for duration as well as concentration. Frailty history was found to modify long-term associations of pollutants with forced vital capacity. For example, the decrease in forced vital capacity associated with a 70-ppb/month greater cumulative sum of monthly average ozone exposure was 12.3 mL (95% confidence interval: 10.4, 14.2) for a woman who had spent the prior 7 years prefrail or frail as compared with 4.7 mL (95% confidence interval: 3.8, 5.6) for a similar woman who was robust during all 7 years (interaction P < 0.001).

Effect of residential proximity to major roadways on cystic fibrosis exacerbations

Ambient air pollution has been attributed with an increase in exacerbation frequencies among the cystic fibrosis (CF) population. This study correlates exacerbation frequency with proximity to roadways and two criteria air pollutants. Clinical data was extracted from the Cystic Fibrosis Foundation National Patient Registry and Electronic Medical Records at Children's Hospital Los Angeles (CHLA). Average annual air pollutant levels were obtained from selected US Environmental Protection Agency's monitoring stations. Geographic proximity to monitoring stations and roadways were analyzed using spatial mapping software. A total of 145 patients from the CHLA's CF center were characterized by a dichotomous exacerbation category. No significant association was determined between the frequency of exacerbations and exposure to fine particulate matter and ozone levels. Residential proximity to US-designated highways and freeways also did not achieve significance (p = 0.3777) but was noted to be correlated with major arterial roadways (p = 0.0420). Associations of environmental exposures may have important implications for future predictive models of CF clinical outcomes.

Different genes interact with particulate matter and tobacco smoke exposure in affecting lung function decline in the general population

BACKGROUND

Oxidative stress related genes modify the effects of ambient air pollution or tobacco smoking on lung function decline. The impact of interactions might be substantial, but previous studies mostly focused on main effects of single genes.

OBJECTIVES

We studied the interaction of both exposures with a broad set of oxidative-stress related candidate genes and pathways on lung function decline and contrasted interactions between exposures.

METHODS

For 12679 single nucleotide polymorphisms (SNPs), change in forced expiratory volume in one second (FEV(1)), FEV(1) over forced vital capacity (FEV(1)/FVC), and mean forced expiratory flow between 25 and 75% of the FVC (FEF(25-75)) was regressed on interval exposure to particulate matter <10 µm in diameter (PM10) or packyears smoked (a), additive SNP effects (b), and interaction terms between (a) and (b) in 669 adults with GWAS data. Interaction p-values for 152 genes and 14 pathways were calculated by the adaptive rank truncation product (ARTP) method, and compared between exposures. Interaction effect sizes were contrasted for the strongest SNPs of nominally significant genes (p(interaction)<0.05). Replication was attempted for SNPs with MAF>10% in 3320 SAPALDIA participants without GWAS.

RESULTS

On the SNP-level, rs2035268 in gene SNCA accelerated FEV(1)/FVC decline by 3.8% (p(interaction) = 2.5×10(-6)), and rs12190800 in PARK2 attenuated FEV1 decline by 95.1 ml p(interaction) = 9.7×10(-8)) over 11 years, while interacting with PM10. Genes and pathways nominally interacting with PM10 and packyears exposure differed substantially. Gene CRISP2 presented a significant interaction with PM10 (p(interaction) = 3.0×10(-4)) on FEV(1)/FVC decline. Pathway interactions were weak. Replications for the strongest SNPs in PARK2 and CRISP2 were not successful.

CONCLUSIONS

Consistent with a stratified response to increasing oxidative stress, different genes and pathways potentially mediate PM10 and tobacco smoke effects on lung function decline. Ignoring environmental exposures would miss these patterns, but achieving sufficient sample size and comparability across study samples is challenging.

Smoking cessation and environmental hygiene

Although there are nonmodifiable genetic risk factors for COPD, most known risk factors for development and progression of COPD can be corrected. Continued efforts to encourage smoking cessation and measures to reduce exposure to SHS, outdoor air pollution, biomass smoke, and occupational and related amateur exposures will have a significant impact on worldwide health.

Genome-wide association study of lung function decline in adults with and without asthma

BACKGROUND

Genome-wide association studies have identified determinants of chronic obstructive pulmonary disease, asthma, and lung function level; however, none have addressed decline in lung function.

OBJECTIVE

We conducted the first genome-wide association study on the age-related decrease in FEV(1) and its ratio to forced vital capacity (FVC) stratified a priori by asthma status.

METHODS

Discovery cohorts included adults of European ancestry (1,441 asthmatic and 2,677 nonasthmatic participants: the Epidemiological Study on the Genetics and Environment of Asthma, the Swiss Cohort Study on Air Pollution and Lung and Heart Disease in Adults, and the European Community Respiratory Health Survey). The associations of FEV(1) and FEV(1)/FVC ratio decrease with 2.5 million single nucleotide polymorphisms (SNPs) were estimated. Thirty loci were followed up by in silico replication (1,160 asthmatic and 10,858 nonasthmatic participants: Atherosclerosis Risk in Communities, the Framingham Heart Study, the British 1958 Birth Cohort, and the Dutch Asthma Study).

RESULTS

Main signals identified differed between asthmatic and nonasthmatic participants. None of the SNPs reached genome-wide significance. The association between the height-related gene DLEU7 and FEV(1) decrease suggested for nonasthmatic participants in the discovery phase was replicated (discovery, P = 4.8 × 10(-6); replication, P = .03), and additional sensitivity analyses point to a relation to growth. The top ranking signal, TUSC3, which is associated with FEV(1)/FVC ratio decrease in asthmatic participants (P = 5.3 × 10(-8)), did not replicate. SNPs previously associated with cross-sectional lung function were not prominently associated with decline.

CONCLUSIONS

Genetic heterogeneity of lung function might be extensive. Our results suggest that genetic determinants of longitudinal and cross-sectional lung function differ and vary by asthma status.

Metabolic syndrome biomarkers predict lung function impairment: a nested case-control study

RATIONALE

Cross-sectional studies demonstrate an association between metabolic syndrome and impaired lung function.

OBJECTIVES

To define if metabolic syndrome biomarkers are risk factors for loss of lung function after irritant exposure.

METHODS

A nested case-control study of Fire Department of New York personnel with normal pre-September 11th FEV(1) and who presented for subspecialty pulmonary evaluation before March 10, 2008. We correlated metabolic syndrome biomarkers obtained within 6 months of World Trade Center dust exposure with subsequent FEV(1). FEV(1) at subspecialty pulmonary evaluation within 6.5 years defined disease status; cases had FEV(1) less than lower limit of normal, whereas control subjects had FEV(1) greater than or equal to lower limit of normal.

MEASUREMENTS AND MAIN RESULTS

Clinical data and serum sampled at the first monitoring examination within 6 months of September 11, 2001, assessed body mass index, heart rate, serum glucose, triglycerides and high-density lipoprotein (HDL), leptin, pancreatic polypeptide, and amylin. Cases and control subjects had significant differences in HDL less than 40 mg/dl with triglycerides greater than or equal to 150 mg/dl, heart rate greater than or equal to 66 bpm, and leptin greater than or equal to 10,300 pg/ml. Each increased the odds of abnormal FEV(1) at pulmonary evaluation by more than twofold, whereas amylin greater than or equal to 116 pg/ml decreased the odds by 84%, in a multibiomarker model adjusting for age, race, body mass index, and World Trade Center arrival time. This model had a sensitivity of 41%, a specificity of 86%, and a receiver operating characteristic area under the curve of 0.77.

CONCLUSIONS

Abnormal triglycerides and HDL and elevated heart rate and leptin are independent risk factors of greater susceptibility to lung function impairment after September 11, 2001, whereas elevated amylin is protective. Metabolic biomarkers are predictors of lung disease, and may be useful for assessing risk of impaired lung function in response to particulate inhalation.

A mixture of anatase and rutile TiO₂ nanoparticles induces histamine secretion in mast cells

Background

Histamine released from mast cells, through complex interactions involving the binding of IgE to FcεRI receptors and the subsequent intracellular Ca²⁺ signaling, can mediate many allergic/inflammatory responses. The possibility of titanium dioxide nanoparticles (TiO₂ NPs), a nanomaterial pervasively used in nanotechnology and pharmaceutical industries, to directly induce histamine secretion without prior allergen sensitization has remained uncertain.

Results

TiO₂ NP exposure increased both histamine secretion and cytosolic Ca²⁺ concentration ([Ca²⁺]_C) in a dose dependent manner in rat RBL-2H3 mast cells. The increase in intracellular Ca²⁺ levels resulted primarily from an extracellular Ca²⁺ influx via membrane L-type Ca²⁺ channels. Unspecific Ca²⁺ entry via TiO₂ NP-instigated membrane disruption was demonstrated with the intracellular leakage of a fluorescent calcein dye. Oxidative stress induced by TiO₂ NPs also contributed to cytosolic Ca²⁺ signaling. The PLC-IP₃-IP₃ receptor pathways and endoplasmic reticulum (ER) were responsible for the sustained elevation of [Ca²⁺]_C and histamine secretion.

Conclusion

Our data suggests that systemic circulation of NPs may prompt histamine release at different locales causing abnormal inflammatory diseases. This study provides a novel mechanistic link between environmental TiO₂ NP exposure and allergen-independent histamine release that can exacerbate manifestations of multiple allergic responses.

Risk factors for COPD spirometrically defined from the lower limit of normal in the BOLD project

Chronic obstructive pulmonary disease (COPD) is predicted to become the third most common cause of death and disability worldwide by 2020. The prevalence of COPD defined by the lower limit of normal was estimated using high-quality spirometry in surveys of 14 populations aged ≥ 40 yrs. The strength and consistency of associations were assessed using random effects meta-analysis. Pack-years of smoking were associated with risk of COPD at each site. After adjusting for this effect, we still observed significant associations of COPD risk with age (OR 1.52 for a 10 yr age difference, 95% CI 1.35-1.71), body mass index in obese compared with normal weight (OR 0.50, 95% CI 0.37-0.67), level of education completed (OR 0.76, 95% CI 0.67-0.87), hospitalisation with a respiratory problem before age 10 yrs (OR 2.35, 95% CI 1.42-3.91), passive cigarette smoke exposure (OR 1.24, 95% CI 1.05-1.47), tuberculosis (OR 1.78, 95%CI 1.17-2.72) and a family history of COPD (OR 1.50, 95% CI 1.19-1.90). Although smoking is the most important risk factor for COPD, other risk factors are also important. More research is required to elucidate relevant risk factors in low- and middle-income countries where the greatest impact of COPD will occur.

A genome-wide meta-analysis of genetic variants associated with allergic rhinitis and grass sensitization and their interaction with birth order

BACKGROUND

Hay fever or seasonal allergic rhinitis (AR) is a chronic disorder associated with IgE sensitization to grass. The underlying genetic variants have not been studied comprehensively. There is overwhelming evidence that those who have older siblings have less AR, although the mechanism for this remains unclear.

OBJECTIVE

We sought to identify common genetic variant associations with prevalent AR and grass sensitization using existing genome-wide association study (GWAS) data and to determine whether genetic variants modify the protective effect of older siblings.

METHOD

Approximately 2.2 million genotyped or imputed single nucleotide polymorphisms were investigated in 4 large European adult cohorts for AR (3,933 self-reported cases vs 8,965 control subjects) and grass sensitization (2,315 cases vs 10,032 control subjects).

RESULTS

Three loci reached genome-wide significance for either phenotype. The HLA variant rs7775228, which cis-regulates HLA-DRB4, was strongly associated with grass sensitization and weakly with AR (P(grass) = 1.6 × 10(-9); P(AR) = 8.0 × 10(-3)). Variants in a locus near chromosome 11 open reading frame 30 (C11orf30) and leucine-rich repeat containing 32 (LRRC32), which was previously associated with atopic dermatitis and eczema, were also strongly associated with both phenotypes (rs2155219; P(grass) = 9.4 × 10(-9); P(AR) = 3.8 × 10(-8)). The third genome-wide significant variant was rs17513503 (P(grass) = 1.2 × 10(-8); PAR = 7.4 × 10(-7)) which was located near transmembrane protein 232 (TMEM232) and solute carrier family 25, member 46 (SLC25A46). Twelve further loci with suggestive associations were also identified. Using a candidate gene approach, where we considered variants within 164 genes previously thought to be important, we found variants in 3 further genes that may be of interest: thymic stromal lymphopoietin (TSLP), Toll-like receptor 6 (TLR6) and nucleotide-binding oligomerization domain containing 1 (NOD1/CARD4). We found no evidence for variants that modified the effect of birth order on either phenotype.

CONCLUSIONS

This relatively large meta-analysis of GWASs identified few loci associated with AR and grass sensitization. No birth order interaction was identified in the current analyses.

Human health risk in relation to air quality in two municipalities in an industrialized area of Northern Italy

Air quality is one of the major environmental issues related to human health, and people and authorities are increasingly aware and concerned about it, asking to be involved in decisions whose fallout can have consequences on their health. The objectives of the present study were to provide quantitative data on the impact of air pollution on the health of people living in two small municipalities in a highly industrialized, densely populated area of Northern Italy. We applied the approach proposed by the World Health Organization (WHO) using the AirQ 2.2.3 software developed by the WHO European Centre for Environment and Health, Bilthoven Division. Daily concentrations of ozone, nitrogen dioxide, and particulate matter of aerodynamic diameter≤10 μm (PM10) and ≤2.5 μm (PM2.5) were used to assess human exposure and health effects in terms of attributable proportion of the health outcome, annual number of excess cases of mortality for all causes, and cardiovascular and respiratory diseases. Long-term effects were estimated for PM2.5 as years of life lost. Considering short-term effects, PM2.5 had the highest health impact on the 24,000 inhabitants of the two small towns, causing an excess of total mortality of 8 out of 177 in a year. Ozone and nitrogen dioxide each caused about three excess cases of total mortality. Results on long-term effects showed, respectively, 433, 180, and 72 years of life lost for mortality for all causes, cardiopulmonary diseases and lung cancer, in a year. These results are consistent with other reports of the impact of air quality on human health and the AirQ software seems an effective and easy tool, helpful in decision-making.

Diesel exhaust particulates exacerbate asthma-like inflammation by increasing CXC chemokines

Particulate matter heavily pollutes the urban atmosphere, and several studies show a link between increased ambient particulate air pollution and exacerbation of pre-existing pulmonary diseases, including asthma. We investigated how diesel exhaust particulates (DEPs) aggravate asthma-like pulmonary inflammation in a mouse model of asthma induced by a house dust extract (HDE) containing cockroach allergens and endotoxin. BALB/c mice were exposed to three pulmonary challenges via hypopharyngeal administration of an HDE collected from the home of an asthmatic child. One hour before each pulmonary challenge, mice were exposed to DEP or PBS. Pulmonary inflammation was assessed by histological features, oxidative stress, respiratory physiological features, inflammatory cell recruitment, and local CXC chemokine production. To prove the role of CXC chemokines in the augmented inflammation, CXC chemokine-specific antibodies were delivered to the lungs before DEP exposure. DEP exacerbated HDE-induced airway inflammation, with increased airway mucus production, oxidative stress, inflammatory cell infiltration, bronchoalveolar lavage concentrations of CXC chemokines, and airway hyperreactivity. Neutralization of airway keratinocyte-derived chemokine and macrophage inflammatory protein-2 significantly improves the respiratory function in addition to decreasing the infiltration of neutrophils and eosinophils. Blocking the chemokines also decreased airway mucus production. These results demonstrate that DEP exacerbates airway inflammation induced by allergen through increased pulmonary expression of the CXC chemokines (keratinocyte-derived chemokine and macrophage inflammatory protein-2).

Air pollution, lung function, and physical symptoms in communities near concentrated Swine feeding operations

BACKGROUND

Concentrated animal feeding operations emit air pollutants that may affect health. We examined associations of reported hog odor and of monitored air pollutants with physical symptoms and lung function in people living within 1.5 miles of hog operations.

METHODS

Between September 2003 and September 2005, we measured hydrogen sulfide (H2S), endotoxin, and particulate matter (PM10, PM2.5, and PM2.5-10) for approximately 2-week periods in each of 16 eastern North Carolina communities. During the same time periods, 101 adults sat outside their homes twice a day for 10 minutes, reported hog odor and physical symptoms, and measured their lung function. Conditional fixed-effects logistic and linear regression models were used to derive estimates of associations.

RESULTS

The log odds (±1 standard error) of acute eye irritation following 10 minutes outdoors increased by 0.53 (±0.06) for every unit increase in odor, by 0.15 (±0.06) per 1 ppb of H2S, and by 0.36 (±0.11) per 10 μg/m of PM10. Odor and H2S were also associated with irritation and respiratory symptoms in the previous 12 hours. The log odds of difficulty breathing increased by 0.50 (±0.15) per unit of odor. A 10 μg/m increase in mean 12-hour PM2.5 was associated with increased log odds of wheezing (0.84 ± 0.29) and declines in forced expiratory volume in 1 second (-0.04 ± 0.02 L). A 10 EU/mg increase in endotoxin was associated with increased log odds of sore throat (0.10 ± 0.05), chest tightness (0.09 ± 0.04), and nausea (0.10 ± 0.05).

CONCLUSIONS

Pollutants measured near hog operations are related to acute physical symptoms in a longitudinal study using analyses that preclude confounding by time-invariant characteristics of individuals.

Particulate matter air pollution causes oxidant-mediated increase in gut permeability in mice

BACKGROUND

Exposure to particulate matter (PM) air pollution may be an important environmental factor leading to exacerbations of inflammatory illnesses in the GI tract. PM can gain access to the gastrointestinal (GI) tract via swallowing of air or secretions from the upper airways or mucociliary clearance of inhaled particles.

METHODS

We measured PM-induced cell death and mitochondrial ROS generation in Caco-2 cells stably expressing oxidant sensitive GFP localized to mitochondria in the absence or presence of an antioxidant. C57BL/6 mice were exposed to a very high dose of urban PM from Washington, DC (200 μg/mouse) or saline via gastric gavage and small bowel and colonic tissue were harvested for histologic evaluation, and RNA isolation up to 48 hours. Permeability to 4 kD dextran was measured at 48 hours.

RESULTS

PM induced mitochondrial ROS generation and cell death in Caco-2 cells. PM also caused oxidant-dependent NF-κB activation, disruption of tight junctions and increased permeability of Caco-2 monolayers. Mice exposed to PM had increased intestinal permeability compared with PBS treated mice. In the small bowel, colocalization of the tight junction protein, ZO-1 was lower in the PM treated animals. In the small bowel and colon, PM exposed mice had higher levels of IL-6 mRNA and reduced levels of ZO-1 mRNA. Increased apoptosis was observed in the colon of PM exposed mice.

CONCLUSIONS

Exposure to high doses of urban PM causes oxidant dependent GI epithelial cell death, disruption of tight junction proteins, inflammation and increased permeability in the gut in vitro and in vivo. These PM-induced changes may contribute to exacerbations of inflammatory disorders of the gut.

Air pollution and airway disease

Epidemiological and toxicological research continues to support a link between urban air pollution and an increased incidence and/or severity of airway disease. Detrimental effects of ozone (O(3)), nitrogen dioxide (NO(2)) and particulate matter (PM), as well as traffic-related pollution as a whole, on respiratory symptoms and function are well documented. Not only do we have strong epidemiological evidence of a relationship between air pollution and exacerbation of asthma and respiratory morbidity and mortality in patients with chronic obstructive pulmonary disease (COPD), but recent studies, particularly in urban areas, have suggested a role for pollutants in the development of both asthma and COPD. Similarly, while prevalence and severity of atopic conditions appear to be more common in urban compared with rural communities, evidence is emerging that traffic-related pollutants may contribute to the development of allergy. Furthermore, numerous epidemiological and experimental studies suggest an association between exposure to NO(2) , O(3) , PM and combustion products of biomass fuels and an increased susceptibility to and morbidity from respiratory infection. Given the considerable contribution that traffic emissions make to urban air pollution researchers have sought to characterize the relative toxicity of traffic-related PM pollutants. Recent advances in mechanisms implicated in the association of air pollutants and airway disease include epigenetic alteration of genes by combustion-related pollutants and how polymorphisms in genes involved in antioxidant pathways and airway inflammation can modify responses to air pollution exposures. Other interesting epidemiological observations related to increased host susceptibility include a possible link between chronic PM exposure during childhood and vulnerability to COPD in adulthood, and that infants subjected to higher prenatal levels of air pollution may be at greater risk of developing respiratory conditions. While the characterization of pollutant components and sources promise to guide pollution control strategies, the identification of susceptible subpopulations will be necessary if targeted therapy/prevention of pollution-induced respiratory diseases is to be developed.

Investigating air pollution and atherosclerosis in humans: concepts and outlook

Although ambient particulate matter contributes to atherosclerosis in animal models, its role in atherogenesis in humans needs to be established. This article discusses concepts, study design, and choice of health outcomes to efficiently investigate the atherogenic role of ambient air pollution, with an emphasis on early preclinical biomarkers of atherosclerosis that are unaffected by short-term exposure to air pollution (eg, carotid intima-media thickness [CIMT] and functional performance of the vessel). Air pollution studies using these end points are summarized. The CIMT is currently the most frequently used outcome in this field (6 studies). The continuous nature of CIMT, the lack of short-term variation, its relationship to atherosclerotic changes in the artery wall, its predictive value for coronary heart disease, and the noninvasiveness of the assessment make it a useful candidate for cross-sectional and longitudinal studies investigating the role of air pollution in atherogenesis.

Particulate allergens potentiate allergic asthma in mice through sustained IgE-mediated mast cell activation

Allergic asthma is characterized by airway hyperresponsiveness, inflammation, and a cellular infiltrate dominated by eosinophils. Numerous epidemiological studies have related the exacerbation of allergic asthma with an increase in ambient inhalable particulate matter from air pollutants. This is because inhalable particles efficiently deliver airborne allergens deep into the airways, where they can aggravate allergic asthma symptoms. However, the cellular mechanisms by which inhalable particulate allergens (pAgs) potentiate asthmatic symptoms remain unknown, in part because most in vivo and in vitro studies exploring the pathogenesis of allergic asthma use soluble allergens (sAgs). Using a mouse model of allergic asthma, we found that, compared with their sAg counterparts, pAgs triggered markedly heightened airway hyperresponsiveness and pulmonary eosinophilia in allergen-sensitized mice. Mast cells (MCs) were implicated in this divergent response, as the differences in airway inflammatory responses provoked by the physical nature of the allergens were attenuated in MC-deficient mice. The pAgs were found to mediate MC-dependent responses by enhancing retention of pAg/IgE/FcεRI complexes within lipid raft–enriched, CD63(+) endocytic compartments, which prolonged IgE/FcεRI-initiated signaling and resulted in heightened cytokine responses. These results reveal how the physical attributes of allergens can co-opt MC endocytic circuitry and signaling responses to aggravate pathological responses of allergic asthma in mice.

High-altitude treatment: a therapeutic option for patients with severe, refractory asthma?

High-altitude treatment has been applied for more than a century in the treatment of pulmonary diseases including asthma. Many uncontrolled and controlled studies have shown its beneficial effects in children and adolescents with house dust mite allergic asthma. A recent study also showed an improvement in markers of airway inflammation in adult patients with severe intrinsic asthma, suggesting that factors other than HDM avoidance may contribute to the beneficial influence of the high-altitude climate therapy on asthma. The dry mountain climate not only has decreased levels of mite allergens but also decreased levels of pollens, fungal spores and air pollution, as well as high exposure to UV light with immunomodulatory and anti-inflammatory effects. Treatments targeting environmental control have never been investigated systematically in severe asthma, which is surprising, as environmental factors have been recognized as important contributors to asthma severity for many years and more evidence has been accumulating ever since. Preliminary evidence shows the beneficial effects of high-altitude treatment in patients with severe refractory asthma on symptoms, lung function and oral corticosteroid requirement, irrespective of atopic status. In this narrative review, we will discuss why high-altitude treatment might be a promising therapeutic option for patients who suffer from this disabling disease.

Preventing asthma exacerbations: what are the targets?

Exacerbations of asthma are the main cause of asthma morbidity. They induce acute respiratory failure, and sometimes death. Two immunological signals acting in synergy are necessary for inducing asthma exacerbations. The first, triggered by allergens and/or unknown agents leads to the chronic Th2 inflammation characteristic of asthma. The second, caused by either viral infection, allergens, pollutants or a combination of these, results in an acute Th1 and Th2 inflammation precipitating symptoms. In both, innate and adaptive immunities are involved, providing a series of potential targets for therapy. Molecules associated to the first, chronic inflammation constitute targets for preventing therapies, when these related to the second, acute signal provide the rationale for curative treatments. Toll like receptors and bronchial epithelial cell-derived cytokines, engaged upstream of inflammation constitute interesting candidates for future treatments. The great heterogeneity of asthma has to be taken into account when considering targets for therapy to identify clusters of responders and nonresponders, and an integrative system biology approach will be necessary to go further.

Plasma cortisol concentrations and lifestyle in a population of outdoor workers

The aim of this study was to assess whether exposure to urban pollution in outdoor workers, may alter plasma cortisol concentrations also in relation to the effect of smoking and drinking habits. The research was carried out on 498 outdoor police workers, divided into three groups; Group A: traffic policemen (TP), Group B: drivers (D), Group C: Other duties (OD). To evaluate separately the effect of using alcohol and smoking, each group was divided into three subgroups: (1) non-smokers and non-drinkers, (2) smokers and non-drinkers, (3) non-smokers and drinkers. Our results show cortisol mean values were significantly higher in the TP group compared to the D and OD groups without significant differences between the last two groups. The results suggest that exposure to pollutants associated with urban psychosocial stress may play a more important role on plasma cortisol levels than smoking and alcohol.

From good intentions to proven interventions: effectiveness of actions to reduce the health impacts of air pollution

BACKGROUND

Associations between air pollution and a multitude of health effects are now well established. Given ubiquitous exposure to some level of air pollution, the attributable health burden can be high, particularly for susceptible populations.

OBJECTIVES

An international multidisciplinary workshop was convened to discuss evidence of the effectiveness of actions to reduce health impacts of air pollution at both the community and individual level. The overall aim was to summarize current knowledge regarding air pollution exposure and health impacts leading to public health recommendations.

DISCUSSION

During the workshop, experts reviewed the biological mechanisms of action of air pollution in the initiation and progression of disease, as well as the state of the science regarding community and individual-level interventions. The workshop highlighted strategies to reduce individual baseline risk of conditions associated with increased susceptibility to the effects of air pollution and the need to better understand the role of exposure duration in disease progression, reversal, and adaptation.

CONCLUSION

We have identified two promising and largely unexplored strategies to address and mitigate air pollution-related health impacts: reducing individual baseline risk of cardiovascular disease and incorporating air pollution-related health impacts into land-use decisions.

Susceptibility of the aging lung to environmental injury

With an ever-increasing number of elderly individuals in the world, a better understanding of the issues associated with aging and the environment is needed. The respiratory system is one of the primary interfaces between the body and the external environment. An expanding number of studies suggest that the aging pulmonary system (>65 years) is at increased risk for adverse health effects from environmental insult, such as by air pollutants, infection, and climate change. However, the mechanism(s) for increased susceptibility in this subpopulation are not well understood. In this review, we provide a limited but comprehensive overview of how the lung ages, examples of environmental exposures associated with injury to the aging lung, and potential mechanisms underlying the increased vulnerability of the aging lung to injury from environmental factors.

Jet exhaust particles alter human dendritic cell maturation

OBJECTIVE AND DESIGN

Among combustion-derived air pollutants, little is known about jet kerosene characteristics and effects.

MATERIALS AND METHODS

Particles yielded by experimental kerosene combustion in a jet engine were characterized with electron microscopy and X-ray energy dispersive spectroscopy. Immature human monocyte-derived dendritic cells were exposed for 18 h to 10, 25 or 100 μg/mL jet exhaust particles and/or Escherichia coli-derived endotoxin. Antigen-presenting and costimulation molecules (HLA DR, CD40, CD80, CD86, CD11c), tumor necrosis factor-α and interleukin-10 production were measured.

RESULTS

The primary particles of jet exhaust are spherical (9.9 nm), carbonaceous and exert an adjuvant effect on human monocyte-derived dendritic cell maturation in vitro. Concomitant particle and endotoxin stimulation induced a high cytokine production with low antigen-presenting molecules; particle contact prior to endotoxin contact led to an opposite phenotype. Finally, low cytokine production and high costimulation molecules were present when particle adjunction followed endotoxin contact.

CONCLUSIONS

Jet exhaust particles act as adjuvants to endotoxin-induced dendritic cell maturation, suggesting possible implications for human health and a role for the time pattern of infectious and pollutant interplay.

An official American Thoracic Society public policy statement: Novel risk factors and the global burden of chronic obstructive pulmonary disease

RATIONALE

Although cigarette smoking is the most important cause of chronic obstructive pulmonary disease (COPD), a substantial proportion of COPD cases cannot be explained by smoking alone.

OBJECTIVES

To evaluate the risk factors for COPD besides personal cigarette smoking.

METHODS

We constituted an ad hoc subcommittee of the American Thoracic Society Environmental and Occupational Health Assembly. An international group of members was invited, based on their scientific expertise in a specific risk factor for COPD. For each risk factor area, the committee reviewed the literature, summarized the evidence, and developed conclusions about the likelihood of it causing COPD. All conclusions were based on unanimous consensus.

MEASUREMENTS AND MAIN RESULTS

The population-attributable fraction for smoking as a cause of COPD ranged from 9.7 to 97.9%, but was less than 80% in most studies, indicating a substantial burden of disease attributable to nonsmoking risk factors. On the basis of our review, we concluded that specific genetic syndromes and occupational exposures were causally related to the development of COPD. Traffic and other outdoor pollution, secondhand smoke, biomass smoke, and dietary factors are associated with COPD, but sufficient criteria for causation were not met. Chronic asthma and tuberculosis are associated with irreversible loss of lung function, but there remains uncertainty about whether there are important phenotypic differences compared with COPD as it is typically encountered in clinical settings.

CONCLUSIONS

In public health terms, a substantive burden of COPD is attributable to risk factors other than smoking. To prevent COPD-related disability and mortality, efforts must focus on prevention and cessation of exposure to smoking and these other, less well-recognized risk factors.

Age-related changes in cardiac and respiratory adaptation to acute ozone and carbon black exposures: interstrain variation in mice

CONTEXT

Epidemiological studies show positive associations between increased ambient air pollutant levels and adverse cardiopulmonary effects. These studies suggest that the elderly and those with certain genetic polymorphisms are susceptible to adverse air pollution-associated health events.

HYPOTHESIS/OBJECTIVE

We hypothesize that physiological responses to air pollutants vary with age and are genetically influenced.

MATERIALS AND METHODS

To test this hypothesis, we exposed mice from three inbred strains (C57BL/6J, B6; C3H/HeJ, HeJ; C3H/HeOuJ, OuJ) to ozone (O(3)) and carbon black (CB) at two ages, (5 months, 12 months), for 3 consecutive days, to either filtered air (FA), CB particles, or O(3) and CB sequentially (O(3)CB) (CB, 550 µg/m(3); O(3), 600 ppb). Heart rate (HR), HR variability (HRV), breathing, and core temperature (Tco) responses were analyzed.

RESULTS

We observed time-dependent physiological changes in response to O(3)CB exposure in each strain, relative to FA exposure for both age groups. Each mouse strain showed distinct adaptation profiles to repeated acute exposures to O(3). In younger mice, several time-dependent effects (decreased HR and increased HRV) were prominent in HeJ and OuJ mice but not B6 mice. We also observed variability in adaptation in older mice. However, responses in older mice were generally attenuated when compared to the younger mice. In addition, cardiac-respiratory interactions were affected with CB and O(3)CB exposures albeit with patterns differing by age or exposure.

DISCUSSION/CONCLUSION

Our results suggest that age considerably attenuates physiological responses to O(3) and O(3)CB exposures. Age-related physiological changes such as increased oxidative stress in mouse tissue may be involved in this attenuation.

Chronic obstructive pulmonary disease and long-term exposure to traffic-related air pollution: a cohort study

RATIONALE

Short-term exposure to air pollution has been associated with exacerbation of chronic obstructive pulmonary disease (COPD), whereas the role of long-term exposures on the development of COPD is not yet fully understood.

OBJECTIVES

We assessed the effect of exposure to traffic-related air pollution over 35 years on the incidence of COPD in a prospective cohort study.

METHODS

We followed 57,053 participants in the Danish Diet, Cancer, and Health cohort in the Hospital Discharge Register for their first hospital admission for COPD between 1993 and 2006. We estimated the annual mean levels of nitrogen dioxide (NO₂) and nitrogen oxides (NO(x)) at all residential addresses of the cohort participants since 1971 to an event or 2006 and used indicators of traffic near the residential address at recruitment. We assessed the association between exposure to air pollution and COPD incidence by Cox regression analyses for the full cohort, and for participants with and without comorbid conditions, including asthma, diabetes, or cardiovascular disease.

MEASUREMENTS AND MAIN RESULTS

A first hospital admission for COPD was recorded for 1,786 (3.4%) of 52,799 eligible subjects between recruitment (1993-1997) and 2006. COPD incidence was associated with the 35-year mean NO₂ level (hazard ratio, 1.08; 95% confidence interval, 1.02-1.14, per interquartile range of 5.8 μg/m³), with stronger associations in subjects with diabetes (1.29; 1.05-1.50) and asthma (1.19; 1.03-1.38).

CONCLUSIONS

Long-term exposure to traffic-related air pollution may contribute to the development of COPD with possibly enhanced susceptibility in people with diabetes and asthma.

Respiratory Parameters in Traffic Policemen Exposed to Urban Pollution

Studies in scientific literature have proved that urban pollution affects the respiratory system. The aim of our study is to assess the effects that different time of exposure to urban pollution can cause on respiratory function in municipal traffic policemen. The research was carried out on a sample of 120 traffic police officers of both sexes divided into two groups, group A with work service between 1 and 10 years and group B with more than 10 years of service. All subjects included in the study were tested for respiratory functions by a spirometer test. Statistical analysis showed a significant difference between group A and group B (p<0.005) in some Spirometric parameters, such as Forced Expiratory Volume in one second (FEV1) and Forced Vital Capacity (FVC). The study suggests that longer occupational exposure to urban pollutants increases the risk of modifications of respiratory function.

Decline in air pollution and change in prevalence in respiratory symptoms and chronic obstructive pulmonary disease in elderly women

Background

While adverse effects of exposure to air pollutants on respiratory health are well studied, little is known about the effect of a reduction in air pollutants on chronic respiratory symptoms and diseases. We investigated whether different declines in air pollution levels in industrialised and rural areas in Germany were associated with changes in respiratory health over a period of about 20 years.

Methods

We used data from the SALIA cohort study in Germany (Study on the influence of Air pollution on Lung function, Inflammation and Aging) to assess the association between the prevalence of chronic obstructive pulmonary disease (COPD) and chronic respiratory symptoms and the decline in air pollution exposure. In 1985-1994, 4874 women aged 55-years took part in the baseline investigation. Of these, 2116 participated in a questionnaire follow-up in 2006 and in a subgroup of 402 women lung function was tested in 2008-2009. Generalized estimating equation (GEE) models were used to estimate the effect of a reduction in air pollution on respiratory symptoms and diseases.

Results

Ambient air concentrations of particulate matter with aerodynamic size < 10 μm (PM₁₀) declined in average by 20 μg/m³. Prevalence of chronic cough with phlegm production and mild COPD at baseline investigation compared to follow-up was 9.5% vs. 13.3% and 8.6% vs. 18.2%, respectively. A steeper decline of PM₁₀ was observed in the industrialized areas in comparison to the rural area, this was associated with a weaker increase in prevalence of respiratory symptoms and COPD. Among women who never smoked, the prevalence of chronic cough with phlegm and mild COPD was estimated at 21.4% and 39.5%, respectively, if no air pollution reduction was assumed, and at 13.3% and 17.5%, respectively, if air pollution reduction was assumed.

Conclusion

We concluded that parallel to the decline of ambient air pollution over the last 20 years in the Ruhr area the age-related increase in chronic respiratory diseases and symptoms appears to attenuate in the population of elderly women.

Effects of ambient air pollution on lung function growth in Chinese schoolchildren

OBJECTIVE

To evaluate the adverse effect of exposure to air pollution on lung function growth in school-aged children.

METHODS

A cohort of 1983 children from three districts in Guangzhou, China was followed-up for 6 months. The children performed pulmonary function tests twice, and their parents reported the child's respiratory symptoms by self-administered questionnaires in both surveys.

RESULTS

The annual mean concentrations of air pollutants for the past 5 years for particulate matter less than 10 microns in diameter (PM(10)), nitrogen (NO(2)), and sulfur dioxide (SO(2)) were respectively: 96.1 microg/m(3), 76.0 microg/m(3), and 65.7 microg/m(3) in the highly-polluted district (HPD), 80.3 microg/m(3), 67.6 mug/m(3), and 54.5 microg/m(3) in the moderately-polluted district (MPD), and 80.0 microg/m(3), 48.1 microg/m(3), and 52.2 microg/m(3) in the least-polluted district (LPD). After adjustment for potential confounders, significant deficits were found in the annual growth rates of forced expiratory flows at 25% (FEF(25)), and between 25% and 75% (FEF(25-75)) in boys and FEF(25) in girls (In boys, for FEF(25), -0.136 l/s, p = 0.008 in MPD and -0.153 l/s, p = 0.004 in HPD, respectively; for FEF(25-75), -0.176 l/s, p = 0.013 in MPD and -0.167 l/s, p = 0.021 in HPD, respectively. In girls, for FEF(25), -0.123 l/s, p = 0.043 in HPD), using LPD as the reference. Deficits in the annual growth rate of forced expiratory volume in 1 s (FEV(1)) were also negatively associated with air pollution in boys (-0.063 L, p = 0.032 in HPD).

CONCLUSIONS

The study adds more evidence that exposure to air pollution has adverse effects on lung function growth in schoolchildren.

Polycyclic aromatic hydrocarbon metabolite levels and pediatric allergy and asthma in an inner-city cohort

Exposure to polycyclic aromatic hydrocarbons (PAH) has been associated with allergic sensitization and asthma. We hypothesized that increased urinary PAH metabolites are associated with allergy or asthma among children age 5 yrs in an inner-city birth cohort. As part of an ongoing prospective birth cohort under the auspices of the Columbia Center for Children's Environmental Health (CCCEH), urine was collected from 5-yr-old children (n = 222) of Dominican American and African American mothers in Northern Manhattan and South Bronx of New York City. Twenty-four PAH metabolites were measured in these specimens, and their levels (unadjusted and specific gravity corrected) were evaluated with IgE levels and asthma outcomes. Ten metabolites were detected in urine from all children. Concentrations ranged higher than those in representative samples of US children ages 6-11 in the National Health and Nutrition Examination Survey (NHANES). Among CCCEH children, compared with African Americans, the Dominican children had higher 2-hydroxynaphthalene but lower 9-hydroxyfluorene and 4-hydroxyphenanthrene concentrations. Increased 3-hydroxyfluorene and 3-hydroxyphenanthrene levels were associated with higher anti-mouse IgE levels (p < 0.05). These plus 2-hydroxynaphthalene, 2-hydroxyflourene and 1-hydroxyphenanthrene concentrations were associated with higher anti-mouse IgE levels on multivariate analyzes. Increased 2-hydroxyphenanthrene, 3-hydroxyphenanthrene and 4-hydroxyphenanthrene levels were associated with higher anti-cat IgE levels (p < 0.05) in univariate, but not multivariate, analyzes. Levels of PAH metabolites were not associated with respiratory symptoms. Measures of PAH metabolites suggest considerable exposure in an urban pediatric population, and possible associations with allergic sensitization to mouse.

Environmental air pollution has decremental effects on pulmonary function test parameters up to one week after exposure

BACKGROUND

Recent exposure to air pollution has a decremental effect on pulmonary function. This short-term effect has only been studied for up to a few days postexposure. Our objective was to analyze the effect of air pollution on spirometric parameters in varying lag times of up to 1 week from the time of exposure.

METHODS

Healthy subjects, never smokers, who were participants in the Tel Aviv Sourasky Medical Center Inflammation Survey held between 2002 and 2007, were included if residing within an 11-km range to the nearest air pollution monitoring station. Linear regression models were applied to each lung function variable [first second of exhalation (FEV(1)), forced vital capacity (FVC), FEV(1)/FVC] against air pollutant variables (particulate matter under 10 microns in diameter, sulfur dioxide, nitrogen dioxide, carbon monoxide, and ozone) for increasing lag periods of up to 7 days, and they were adjusted for possible confounders that affect air pollution and spirometric measurements.

RESULTS

The study population comprised 2380 individuals. We found a statistically significant negative correlation between air pollutants, mainly SO(2), and between FEV(1) and FVC. This effect was significant from days 3 to 6, with a maximal effect noted for the fifth day and for the 7-day average before pulmonary function measurement. No significant change was found for FEV(1)/FVC ratio.

CONCLUSIONS

Air pollution has a decremental effect on lung function parameters for up to 6 days after exposure in healthy adults. SO(2) emerged as the most significant air pollutant affecting short-term lung function parameters.