Ambient Archives - World Asthma Foundation

October 12, 2015

Early life exposure to ambient air pollution and childhood asthma in China.

Early life exposure to ambient air pollution and childhood asthma in China.

Environ Res. 2015 Oct 7;143(Pt A):83-92

Authors: Deng Q, Lu C, Norbäck D, Bornehag CG, Zhang Y, Liu W, Yuan H, Sundell J

Abstract
BACKGROUND: Early life is suggested to be a critical time in determining subsequent asthma development, but the extent to which the effect of early-life exposure to ambient air pollution on childhood asthma is unclear.
OBJECTIVES: We investigated doctor-diagnosed asthma in preschool children due to exposure to ambient air pollution in utero and during the first year of life.
METHODS: In total 2490 children aged 3-6 years participated in a questionnaire study regarding doctor-diagnosed asthma between September 2011 and January 2012 in China. Children’s exposure to critical air pollutants, sulfur dioxide (SO2) as proxy of industrial air pollution, nitrogen dioxide (NO2) as proxy of traffic pollution, and particulate matter?10µm in diameter (PM10) as a mixture, was estimated from the concentrations measured at the ambient air quality monitoring stations by using an inverse distance weighted (IDW) method. Logistic regression analysis was employed to determine the relationship between early-life exposure and childhood asthma in terms of odds ratio (OR) and 95% confidence interval (CI).
RESULTS: Association between early-life exposure to air pollutants and childhood asthma was observed. SO2 and NO2 had significant associations with adjusted OR (95% CI) of 1.45 (1.02-2.07) and 1.74 (1.15-2.62) in utero and 1.62 (1.01-2.60) and 1.90 (1.20-3.00) during the first year for per 50µg/m(3) and 15µg/m(3) increase respectively. Exposure to the combined high level of SO2 and NO2 in China significantly elevated the asthmatic risk with adjusted OR (95% CI) of 1.76 (1.18-2.64) in utero and 1.85 (1.22-2.79) during the first year compared to the low level exposure. The associations were higher for males and the younger children aged 3-4 than females and the older children aged 5-6.
CONCLUSIONS: Early-life exposure to ambient air pollution is associated with childhood asthma during which the level and source of air pollution play important roles. The high level and nature of combined industrial and traffic air pollution in China may contribute to the recent rapid increase of childhood asthma.

PMID: 26453943 [PubMed – as supplied by publisher]

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July 21, 2015

Ambient air pollution, lung function, and airway responsiveness in asthmatic children.

Ambient air pollution, lung function, and airway responsiveness in asthmatic children.

J Allergy Clin Immunol. 2015 Jun 29;

Authors: Ierodiakonou D, Zanobetti A, Coull BA, Melly S, Postma DS, Boezen HM, Vonk JM, Williams PV, Shapiro GG, McKone EF, Hallstrand TS, Koenig JQ, Schildcrout JS, Lumley T, Fuhlbrigge AN, Koutrakis P, Schwartz J, Weiss ST, Gold DR, Childhood Asthma Management Program Research Group

Abstract
BACKGROUND: Although ambient air pollution has been linked to reduced lung function in healthy children, longitudinal analyses of pollution effects in asthmatic patients are lacking.
OBJECTIVE: We sought to investigate pollution effects in a longitudinal asthma study and effect modification by controller medications.
METHODS: We examined associations of lung function and methacholine responsiveness (PC20) with ozone, carbon monoxide (CO), nitrogen dioxide, and sulfur dioxide concentrations in 1003 asthmatic children participating in a 4-year clinical trial. We further investigated whether budesonide and nedocromil modified pollution effects. Daily pollutant concentrations were linked to ZIP/postal code of residence. Linear mixed models tested associations of within-subject pollutant concentrations with FEV1 and forced vital capacity (FVC) percent predicted, FEV1/FVC ratio, and PC20, adjusting for seasonality and confounders.
RESULTS: Same-day and 1-week average CO concentrations were negatively associated with postbronchodilator percent predicted FEV1 (change per interquartile range, -0.33 [95% CI, -0.49 to -0.16] and -0.41 [95% CI, -0.62 to -0.21], respectively) and FVC (-0.19 [95% CI, -0.25 to -0.07] and -0.25 [95% CI, -0.43 to -0.07], respectively). Longer-term 4-month CO averages were negatively associated with prebronchodilator percent predicted FEV1 and FVC (-0.36 [95% CI, -0.62 to -0.10] and -0.21 [95% CI, -0.42 to -0.01], respectively). Four-month averaged CO and ozone concentrations were negatively associated with FEV1/FVC ratio (P < .05). Increased 4-month average nitrogen dioxide concentrations were associated with reduced postbronchodilator FEV1 and FVC percent predicted. Long-term exposures to sulfur dioxide were associated with reduced PC20 (percent change per interquartile range, -6% [95% CI, -11% to -1.5%]). Treatment augmented the negative short-term CO effect on PC20.
CONCLUSIONS: Air pollution adversely influences lung function and PC20 in asthmatic children. Treatment with controller medications might not protect but rather worsens the effects of CO on PC20. This clinical trial design evaluates modification of pollution effects by treatment without confounding by indication.

PMID: 26187234 [PubMed – as supplied by publisher]

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September 1, 2014

Ambient Air Pollution Exposure and Incident Adult Asthma in a Nationwide Cohort of US Women.

Ambient Air Pollution Exposure and Incident Adult Asthma in a Nationwide Cohort of US Women.

Am J Respir Crit Care Med. 2014 Aug 29;

Authors: Young MT, Sandler DP, DeRoo LA, Vedal S, Kaufman JD, London SJ

Abstract
Rationale: Limited prior data suggests an association between traffic-related air pollution and incident asthma in adults. No published studies assess the effect of long-term exposures to particulate matter less than 2.5 µm in diameter (PM2.5) on adult incident asthma. Objectives: To estimate the association between ambient air pollution exposures (PM2.5 and nitrogen dioxide, NO2) and development of asthma and incident respiratory symptoms. Methods: The Sister Study is a US cohort study of risk factors for breast cancer and other health outcomes (n=50,884) in sisters of women with breast cancer (enrollment: 2003-2009). Annual average (2006) ambient PM2.5 and NO2 concentrations were estimated at participants’ addresses using a national land-use/kriging model incorporating roadway information. Outcomes at follow-up (2008-2012) included incident self-reported wheeze, chronic cough, and doctor-diagnosed asthma in women without baseline symptoms. Measures and Main Results: Adjusted analyses included 254 incident cases of asthma, 1,023 of wheeze, and 1,559 of chronic cough. For an interquartile range (IQR) difference (3.6 µg/m3) in estimated PM2.5 exposure, the adjusted odds-ratio (aOR) was 1.20 (95% CI=0.99-1.46, P=0.063) for incident asthma and 1.14 (95% CI=1.04-1.26, P=0.008) for incident wheeze. For NO2, there was evidence for an association with incident wheeze (aOR=1.08, 95% CI=1.00-1.17, P=0.048 per IQR of 5.8 ppb). Neither pollutant was significantly associated with incident cough (PM2.5: aOR=0.95, 95% CI=0.88-1.03, P=0.194, NO2: aOR=1.00, 95% CI=0.93-1.07, P=0.939). Conclusions: Results suggest that PM2.5 exposure increases the risk of developing asthma and PM2.5 and NO2 increase the risk of developing wheeze, the cardinal symptom of asthma, in adult women.

PMID: 25172226 [PubMed – as supplied by publisher]

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April 28, 2014

A Statistical Modeling Framework for Projecting Future Ambient Ozone and its Health Impact due to Climate Change.

A Statistical Modeling Framework for Projecting Future Ambient Ozone and its Health Impact due to Climate Change.

Atmos Environ (1994). 2014 Jun 1;89:290-297

Authors: Chang HH, Hao H, Sarnat SE

Abstract
The adverse health effects of ambient ozone are well established. Given the high sensitivity of ambient ozone concentrations to meteorological conditions, the impacts of future climate change on ozone concentrations and its associated health effects are of concern. We describe a statistical modeling framework for projecting future ozone levels and its health impacts under a changing climate. This is motivated by the continual effort to evaluate projection uncertainties to inform public health risk assessment. The proposed approach was applied to the 20-county Atlanta metropolitan area using regional climate model (RCM) simulations from the North American Regional Climate Change Assessment Program. Future ozone levels and ozone-related excesses in asthma emergency department (ED) visits were examined for the period 2041-2070. The computationally efficient approach allowed us to consider 8 sets of climate model outputs based on different combinations of 4 RCMs and 4 general circulation models. Compared to the historical period of 1999-2004, we found consistent projections across climate models of an average 11.5% higher ozone levels (range: 4.8%, 16.2%), and an average 8.3% (range: -7% to 24%) higher number of ozone exceedance days. Assuming no change in the at-risk population, this corresponds to excess ozone-related ED visits ranging from 267 to 466 visits per year. Health impact projection uncertainty was driven predominantly by uncertainty in the health effect association and climate model variability. Calibrating climate simulations with historical observations reduced differences in projections across climate models.

PMID: 24764746 [PubMed – as supplied by publisher]

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