Inhaled Carbon and Lung Function in Children
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《新英格兰医药杂志》
To the Editor: Kulkarni and colleagues (July 6 issue)1 found that the level of carbon in airway macrophages in children was strongly associated with expiratory flow rates, although in the 64 healthy children with sufficient numbers of airway macrophages for analysis, all these values were within generally acceptable normal limits. Why should this be? We suggest that this finding indicates that an accumulation of particles was a strong indicator of exposure to urban particulate air pollution and that exposure, in turn, is associated with chronic respiratory subclinical bronchiolitis. If so, we suggest that current exposures to urban pollution have to be taken very seriously.
David V. Bates, C.M.
James C. Hogg, O.C.
University of British Columbia
Vancouver, BC V6T 1G6, Canada
dvbates@shaw.ca
References
Kulkarni N, Pierse N, Rushton L, Grigg J. Carbon in airway macrophages and lung function in children. N Engl J Med 2006;355:21-30.
To the Editor: The editorial by Gauderman (July 6 issue)1 accompanying the report by Kulkarni et al. emphasizes the continuing risk to child health from air pollution in the United States, despite widespread compliance with air-quality standards. This is consistent with recent downward revisions of the guidelines for particulate matter from the World Health Organization.2 Such risks, however, should be viewed in the context of the far higher levels of exposure of children (and adults, particularly women) to particulate matter in developing countries, arising from the household use of solid fuels (wood, dung, crop wastes, and coal). This type of pollution results in substantial carbon loading of alveolar macrophages3 and a risk of childhood pneumonia and chronic obstructive pulmonary disease in adults.4,5
About 75% of global exposure to particulate matter is attributed to indoor exposures in developing countries, two thirds of which occur in rural areas, mainly from household fuel combustion.6 To this exposure is added, in urban environments of poor countries, pollution from traffic, industry, and uncontrolled burning of waste. Urgent action is needed to better understand and find ways to reduce household and other exposures in children in developing countries. Levels of particulate matter in developing countries far exceed those in developed countries, which we also seek to reduce further.
Nigel G. Bruce, M.B., B.S.
Mukesh K. Dherani, M.B., B.S.
University of Liverpool
Liverpool L69 3GB, United Kingdom
ngb@liv.ac.uk
Kirk R. Smith, Ph.D.
University of California, Berkeley
Berkeley, CA 94720-7360
References
Gauderman WJ. Air pollution and children -- an unhealthy mix. N Engl J Med 2006;355:78-79.
World Health Organization. WHO air quality guidelines: global update 2005. (Accessed September 19, 2006, at http://www.euro.who.int/Document/E87950.pdf.)
Kulkarni NS, Prudon B, Panditi SL, Abebe Y, Grigg J. Carbon loading of alveolar macrophages in adults and children exposed to biomass smoke particles. Sci Total Environ 2005;345:23-30.
Bruce NG, Rehfuess E, Mehta S, Hutton G, Smith KR. Indoor air pollution. In: Jamison DT, Breman JG, Measham AR, et al., eds. Disease control priorities in developing countries. 2nd ed. New York: Oxford University Press/World Bank, 2006:793-815.
Smith KR, Mehta S, Maeusezahl-Feuz M. Indoor air pollution from household use of solid fuels. In: Ezzati M, Lopez AD, Rodgers A, Murray CJL, eds. Comparative quantification of health risks: global and regional burden of disease attributable to selected major risk factors. Vol. 2. Geneva: World Health Organization, 2004:1435-94
Smith KR. Fuel combustion, air pollution exposure, and health: the situation in developing countries. Annu Rev Energy Environ 1993;18:529-66.
To the Editor: Air pollution does have an adverse effect on the lungs of children, and interventions to improve air quality can decrease lung diseases. In Ahmadabad, Gujarat, India, public transportation consisted of diesel-powered buses and three-wheeled automobiles powered by kerosene-adulterated gasoline. Hospital admissions for asthma and bronchiolitis steadily increased over a 5-year period until the government decided to order the conversion of all buses and automobiles to run only on compressed natural gas. A year later, admissions for asthma and bronchiolitis (diagnosed clinically) had declined, as had the number of new cases of asthma at the asthma clinic.
Jayendra R. Gohil, M.D.
B.J. Medical College
Ahmadabad 381006, India
jayukids@yahoo.com
The author replies: In response to Bates and Hogg, it is very likely that the amount of carbon in airway macrophages of healthy persons reflects the exposure of other airway cells to inhaled particles. Persistent subepithelial fibrosis and remodeling caused by the direct effect of particles on bronchiolar cells would explain why, in our study, bronchodilator therapy had no effect on the inverse association between the carbon content of airway macrophages and lung function in healthy children.
Bruce et al. rightly point out that on a global scale, particulate matter from the burning of biomass fuel is a major environmental health threat to children. Recently, my colleagues and I reported that particles from biomass smoke rapidly deplete antioxidants in the epithelial lining fluid of the lung.1 The analysis of induced sputum, which contains cells and antioxidants from the lower airways, may therefore be a useful addition to studies of the mechanism of the effects on health of biomass smoke in the developing world.
Citywide initiatives similar to the one reported by Gohil have been invaluable for identifying particles as the major toxic component of air pollution.2 Measuring the effect of air-pollution initiatives on human health requires ongoing collaboration among local council officials, nongovernmental organizations, and air-pollution scientists.
Jonathan Grigg, M.D.
Institute of Cell and Molecular Science
London E1 2AT, United Kingdom
j.grigg@qmul.ac.uk
References
Mudway IS, Duggan ST, Venkataraman C, Habib G, Kelly FJ, Grigg J. Combustion of the biomass fuel dung cake results in the generation of highly redox active fine particulates. Part Fibre Toxicol 2005;2:6-6.
Clancy L, Goodman P, Sinclair H, Dockery DW. Effect of air-pollution control on death rates in Dublin, Ireland: an intervention study. Lancet 2002;360:1210-1214.
David V. Bates, C.M.
James C. Hogg, O.C.
University of British Columbia
Vancouver, BC V6T 1G6, Canada
dvbates@shaw.ca
References
Kulkarni N, Pierse N, Rushton L, Grigg J. Carbon in airway macrophages and lung function in children. N Engl J Med 2006;355:21-30.
To the Editor: The editorial by Gauderman (July 6 issue)1 accompanying the report by Kulkarni et al. emphasizes the continuing risk to child health from air pollution in the United States, despite widespread compliance with air-quality standards. This is consistent with recent downward revisions of the guidelines for particulate matter from the World Health Organization.2 Such risks, however, should be viewed in the context of the far higher levels of exposure of children (and adults, particularly women) to particulate matter in developing countries, arising from the household use of solid fuels (wood, dung, crop wastes, and coal). This type of pollution results in substantial carbon loading of alveolar macrophages3 and a risk of childhood pneumonia and chronic obstructive pulmonary disease in adults.4,5
About 75% of global exposure to particulate matter is attributed to indoor exposures in developing countries, two thirds of which occur in rural areas, mainly from household fuel combustion.6 To this exposure is added, in urban environments of poor countries, pollution from traffic, industry, and uncontrolled burning of waste. Urgent action is needed to better understand and find ways to reduce household and other exposures in children in developing countries. Levels of particulate matter in developing countries far exceed those in developed countries, which we also seek to reduce further.
Nigel G. Bruce, M.B., B.S.
Mukesh K. Dherani, M.B., B.S.
University of Liverpool
Liverpool L69 3GB, United Kingdom
ngb@liv.ac.uk
Kirk R. Smith, Ph.D.
University of California, Berkeley
Berkeley, CA 94720-7360
References
Gauderman WJ. Air pollution and children -- an unhealthy mix. N Engl J Med 2006;355:78-79.
World Health Organization. WHO air quality guidelines: global update 2005. (Accessed September 19, 2006, at http://www.euro.who.int/Document/E87950.pdf.)
Kulkarni NS, Prudon B, Panditi SL, Abebe Y, Grigg J. Carbon loading of alveolar macrophages in adults and children exposed to biomass smoke particles. Sci Total Environ 2005;345:23-30.
Bruce NG, Rehfuess E, Mehta S, Hutton G, Smith KR. Indoor air pollution. In: Jamison DT, Breman JG, Measham AR, et al., eds. Disease control priorities in developing countries. 2nd ed. New York: Oxford University Press/World Bank, 2006:793-815.
Smith KR, Mehta S, Maeusezahl-Feuz M. Indoor air pollution from household use of solid fuels. In: Ezzati M, Lopez AD, Rodgers A, Murray CJL, eds. Comparative quantification of health risks: global and regional burden of disease attributable to selected major risk factors. Vol. 2. Geneva: World Health Organization, 2004:1435-94
Smith KR. Fuel combustion, air pollution exposure, and health: the situation in developing countries. Annu Rev Energy Environ 1993;18:529-66.
To the Editor: Air pollution does have an adverse effect on the lungs of children, and interventions to improve air quality can decrease lung diseases. In Ahmadabad, Gujarat, India, public transportation consisted of diesel-powered buses and three-wheeled automobiles powered by kerosene-adulterated gasoline. Hospital admissions for asthma and bronchiolitis steadily increased over a 5-year period until the government decided to order the conversion of all buses and automobiles to run only on compressed natural gas. A year later, admissions for asthma and bronchiolitis (diagnosed clinically) had declined, as had the number of new cases of asthma at the asthma clinic.
Jayendra R. Gohil, M.D.
B.J. Medical College
Ahmadabad 381006, India
jayukids@yahoo.com
The author replies: In response to Bates and Hogg, it is very likely that the amount of carbon in airway macrophages of healthy persons reflects the exposure of other airway cells to inhaled particles. Persistent subepithelial fibrosis and remodeling caused by the direct effect of particles on bronchiolar cells would explain why, in our study, bronchodilator therapy had no effect on the inverse association between the carbon content of airway macrophages and lung function in healthy children.
Bruce et al. rightly point out that on a global scale, particulate matter from the burning of biomass fuel is a major environmental health threat to children. Recently, my colleagues and I reported that particles from biomass smoke rapidly deplete antioxidants in the epithelial lining fluid of the lung.1 The analysis of induced sputum, which contains cells and antioxidants from the lower airways, may therefore be a useful addition to studies of the mechanism of the effects on health of biomass smoke in the developing world.
Citywide initiatives similar to the one reported by Gohil have been invaluable for identifying particles as the major toxic component of air pollution.2 Measuring the effect of air-pollution initiatives on human health requires ongoing collaboration among local council officials, nongovernmental organizations, and air-pollution scientists.
Jonathan Grigg, M.D.
Institute of Cell and Molecular Science
London E1 2AT, United Kingdom
j.grigg@qmul.ac.uk
References
Mudway IS, Duggan ST, Venkataraman C, Habib G, Kelly FJ, Grigg J. Combustion of the biomass fuel dung cake results in the generation of highly redox active fine particulates. Part Fibre Toxicol 2005;2:6-6.
Clancy L, Goodman P, Sinclair H, Dockery DW. Effect of air-pollution control on death rates in Dublin, Ireland: an intervention study. Lancet 2002;360:1210-1214.