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October 2012

Exposure to Traffic Air Pollution in Infancy Impairs Lung Function in Children

Exposure to ambient air pollution from traffic during infancy is associated with lung function deficits in children up to eight years of age, particularly among children sensitized to common allergens, according to a new study.

“Earlier studies have shown that children are highly susceptible to the adverse effects of air pollution and suggest that exposure early in life may be particularly harmful,” said researcher Göran Pershagen, MD, PhD, professor at the Karolinska Institutet Institute of Environmental Medicine in Stockholm, Sweden. “In our prospective birth cohort study in a large population of Swedish children, exposure to traffic-related air pollution during infancy was associated with decreases in lung function at age eight, with stronger effects indicated in boys, children with asthma and particularly in children sensitized to allergens.”

The findings were published online ahead of print publication in the American Thoracic Society’s American Journal of Respiratory and Critical Care Medicine.

The study included more than 1,900 children who were followed from birth through age eight with repeated questionnaires, spirometry and immunoglobulin E measurements. Outdoor concentrations of particulate matter from road traffic were estimated for residential, daycare and school addresses using dispersion modeling, a mathematical simulation of how air pollutants disperse in the atmosphere.

A 5th to 95th percentile difference in time-weighted exposure to outdoor concentrations of particulate matter from road traffic during the first year of life was associated with a reduced forced expiratory volume in one second (FEV1) of -59.3 mL (95% confidence interval (CI): -113.0 to -5.6) at age eight. This negative association was particularly pronounced in children who were sensitized to common inhalant and/or food allergens and also seemed stronger among boys and among children with asthma.

Exposure to traffic-related air pollution after the first year of life appeared to have less impact on subsequent lung function.

The study had a few limitations. Calculations of particulate matter concentrations were only performed for the year 2004 and were extrapolated to the other years of follow-up, and some miscalculation of individual exposure levels was likely.

“Our study shows that early exposure to traffic-related air pollution has long-term adverse effects on respiratory health in children, particularly among atopic children,” concluded Dr. Pershagen. “These results add to a large body of evidence demonstrating the detrimental effects of air pollution on human health.”

Contact for article: Göran Pershagen, MD, PhD, Professor, Karolinska Institutet, Institute of Environmental Medicine, Nobels väg 13 Box 210, SE- 171 77, Stockholm, Sweden
Email: Goran.Pershagen@ki.se
Phone: +46-8-524 87460

Statement from ATS Past President and TB Expert Dean Schraufnagel on WHO Report on TB

"The American Thoracic Society welcomes the news from  the World Health Organization (WHO)'s Global  Tuberculosis Report 2012 that progress is being made towards halting the  global tuberculosis (TB) pandemic and that implementation of a new rapid  diagnostic test, Xpert MTB/RIF, which was developed with U.S. government  support through the National Institutes of Health, is accelerating these  efforts.

"At the same time, we note that the WHO's report articulates  the challenges that remain in eliminating this disease. Although the incidence  of TB is slowly falling, the number of deaths from the disease remained the  same between 2010 and 2011. TB remains the second-leading infectious killer of  people around the globe. The continued spread of multi-drug resistant TB and  the funding gap for adequately addressing it are key challenges.

"The ATS reiterates  its call to the international community to fully fund the WHO's STOP TB  Strategy which, if implemented, will halt the global TB pandemic. Here, in the United States, the ATS is  concerned that proposed funding cuts to global health programs, including those  proposed under budget sequestration, threaten our progress against TB. We urge  Congress and the President to maintain U.S. leadership on global and domestic  TB control through appropriate funding for TB programs at the CDC, USAID and the  Global Fund to Fight AIDS, TB and Malaria.

"The ATS, originally founded as the American  Sanitorium Association in 1905, and its more than 15,000 worldwide members pledge  to continue our work to eliminate TB. In collaboration with the WHO and other  partners, we have produced international standards of care and are providing  technical assistance in implementing those standards and other TB control,  treatment and prevention strategies in over 30 countries. We know how to eliminate TB, so let's commit  to doing it.

Contact for article: Dean Schraufnagel, MD, Professor, Department of Medicine, University of Illinois Hospital and Health Sciences  System
Phone: 312-996-8039
Email: schrauf@uic.edu

High-Risk Carotid Artery Plaque Formation is Increased in Older COPD Patients

Older patients with chronic obstructive pulmonary disease (COPD) are at increased risk for carotid artery plaque formation and for the presence of vulnerable plaques with a lipid core, according to a new study from researchers in the Netherlands.

“We know that COPD is a risk factor for ischemic stroke, and that certain components of carotid artery plaques such as intraplaque hemorrhage and lipid core increase the risk of ischemic events, but plaque composition in patients with COPD has not been examined,” said researcher Bruno H.C. Stricker, MD, PhD, professor of pharmaco-epidemiology at the Erasmus Medical Center in Rotterdam, the Netherlands. “In our study, carotid artery wall thickening was increased twofold in older COPD patients compared with controls with normal lung function, and COPD was an independent predictor of the presence of plaques with a lipid core, which are more prone to rupture.”

The findings were published online ahead of print publication in the American Thoracic Society’s American Journal of Respiratory and Critical Care Medicine.

The cross-sectional study, part of the Rotterdam Study, an ongoing population-based cohort study examining the occurrence of and risk factors for chronic diseases in subjects aged 55 years and older, involved 253 COPD patients and 920 controls. COPD was confirmed by spirometry. Subjects with carotid wall thickening (intima-media thickness ≥ 2.5 mm) on ultrasonography underwent high-resolution magnetic resonance imaging (MRI) to characterize carotid plaques.

Subjects with COPD had a twofold increased risk (odds ratio 2.0, 95%CI 1.44-2.85, p<0.0001) of carotid wall thickening on ultrasonography compared to controls, and this risk increased significantly with the severity of airflow limitation. On MRI, vulnerable lipid core plaques were significantly more frequent in subjects with COPD compared with controls (odds ratio 2.1, 95%CI 1.25-3.69, p=0.0058).

“Clinicians should be aware that COPD patients are at increased risk for asymptomatic carotid atherosclerosis and that COPD might lead to vulnerable plaques by inducing or aggravating the presence of plaques with a lipid core,” said Dr. Stricker.

The study had a few limitations, including the study’s cross-sectional design, which doesn’t allow causal associations between COPD and carotid plaques to be inferred, and the lack of computed tomography confirmation of emphysema

“The results of our study provide new insights into the relationship between COPD and the increased risk for stroke seen in these patients,” concluded Dr. Stricker. “Understanding the underlying risk factors for stroke in COPD patients can help identify those at high risk and lead to the development of more personalized preventive treatment strategies targeting this devastating complication.”

Contact for article: Bruno H.C. Stricker; Department of Epidemiology; Erasmus University Medical Center; PO Box 2040; 3000 CA Rotterdam, the Netherlands
Phone: +31 (0)10 70 44294
Email: b.stricker@erasmusmc.nl