Long-term exposure to outdoor air pollution and the prevalence of asthma: meta-analysis of multi-community prevalence studies
- 590 Downloads
The effect of outdoor air pollution on variations in asthma prevalence is unclear. We have conducted a meta-analysis of multi-community studies to evaluate and quantify the evidence for an association between community levels of pollution and asthma prevalence. We identified peer-reviewed articles reporting associations between community levels of air pollution and the prevalence of wheeze symptom or asthma diagnosis which were based on five or more communities. Associations were investigated by meta-analysis and by analysis of the direction and statistical significance of estimates. We identified 21 studies of more than five communities (range 6 to 62). The proportion of studies reporting at least one significantly positive association was 43% but, of the total of 178 pollution-outcome estimates, only 11% were statistically significantly positive. Thirteen studies reported associations with pollution analysed as a quantitative variable, and these results were meta-analysed. For period prevalence (mainly wheeze symptom), the results were null: Random effects estimates (95% confidence intervals) for the odds ratios of nitrogen dioxide, particulate matter with aerodynamic diameter <10 μm, ozone and sulphur dioxide were 1.00 (0.95, 1.06), 1.00 (0.94, 1.07), 1.01 (0.96, 1.07) and 1.03 (0.97, 1.09), respectively. For lifetime prevalence (mainly asthma diagnosis), the random effects estimates were similar: 1.00 (0.99, 1.01), 0.99 (0.96, 1.02), 1.06 (0.98, 1.14) and 1.00 (0.96, 1.05), respectively. We found no evidence of an association between community levels of outdoor air pollution and asthma prevalence.
KeywordsAir pollution Asthma prevalence Epidemiology Meta-analysis Review
We gratefully acknowledge the support of Mary Field-Smith in the preparation of the paper for publication and the encouragement of the Health Protection Agency Air Quality Unit (Head: Professor Robert Maynard) in developing this study.
The study was funded by the Policy Research Unit of the UK Department of Health. The views expressed in this paper are those of the authors alone and do not necessarily reflect those of the Department of Health.
The authors declare that they have no competing interests.
- Anderson HR, Ruggles R, Pandey KD, Kapetanakis V, Brunekreef B, Lai CKW, Strachan DP, Weiland SK (2010) Ambient particulate pollution and the world-wide prevalence of asthma, rhinoconjunctivitis and eczema in children: phase one of the International Study of Asthma and Allergies in Childhood (ISAAC). Occup Environ Med 67:293–300CrossRefGoogle Scholar
- Braun-Fahrlander C, Vuille JC, Sennhauser FH, Neu U, Kunzle T, Grize L, Gassner M, Minder C, Schindler C, Varonier HS, Wuthrich B (1997) Respiratory health and long-term exposure to air pollutants in Swiss schoolchildren. SCARPOL Team. Swiss study on childhood allergy and respiratory symptoms with respect to air pollution, climate and pollen. Am J Respir Crit Care Med 155:1042–1049Google Scholar
- de Marco R, Poli A, Ferrari M, Accordini S, Giammanco G, Bugiani M, Villani S, Ponzio M, Bono R, Carrozzi L, Cavallini R, Cazzoletti L, Dallari R, Ginesu F, Lauriola P, Mandrioli P, Perfetti L, Pignato S, Pirina P, Struzzo P (2002) The impact of climate and traffic-related NO2 on the prevalence of asthma and allergic rhinitis in Italy. Clin Exp Allergy 32:1405–1412CrossRefGoogle Scholar
- Department of Health Committee on the Medical Effects of Air Pollutants (1995) Asthma and outdoor air pollution. HMSO, LondonGoogle Scholar
- Dockery DW, Speizer FE, Stram DO, Ware JH, Spengler JD, Ferris BG Jr (1989) Effects of inhalable particles on respiratory health of children. Am Rev Respir Dis 139:587–594Google Scholar
- Florey CD, Swan AV, Van der Lende R, Holland WW, Berlin A, Di Ferrante E (1983) Report on the EC epidemiological survey on the relationship between air pollution and respiratory health in primary schoolchildren. Commission of the European Communities, BrusselsGoogle Scholar
- Health Effects Institute (2010) HEI special report 17: Traffic-related air pollution: a critical review of the literature on emissions, exposure, and health effects. Health Effects Institute, BostonGoogle Scholar
- Janssen NA, Brunekreef B, Van VP, Aarts F, Meliefste K, Harssema H, Fischer P (2003) The relationship between air pollution from heavy traffic and allergic sensitization, bronchial hyperresponsiveness, and respiratory symptoms in Dutch schoolchildren. Environ Health Perspect 111:1512–1518CrossRefGoogle Scholar
- Liebhart J, Malolepszy J, Wojtyniak B, Pisiewicz K, Plusa T, Gladysz U (2007) Prevalence and risk factors for asthma in Poland: results from the PMSEAD study. J Investig Allergol Clin Immunol 17:367–374Google Scholar
- Peters JM, Avol E, Navidi W, London SJ, Gauderman WJ, Lurmann F, Linn WS, Margolis H, Rappaport E, Gong H, Thomas DC (1999) A study of twelve Southern California communities with differing levels and types of air pollution. I. Prevalence of respiratory morbidity. Am J Respir Crit Care Med 159:760–767Google Scholar
- Stata Corporation (2007) STATA/SE 10.1 statistics/data analysis. Stata Corporation, College StationGoogle Scholar
- WHO European Centre for Environment and Health (2005) Effects of air pollution on children's health and development—a review of the evidence. WHO Regional Office for Europe, BonnGoogle Scholar
- World Health Organisation (1980) Study on chronic respiratory diseases in children in relation to air pollution. WHO, GenevaGoogle Scholar
- World Health Organisation (2006) Air quality guidelines: global update 2005, particulate matter, ozone, nitrogen dioxide and sulphur dioxide. WHO Regional Office for Europe, CopenhagenGoogle Scholar
- Zemp E (1999) Long-term ambient air pollution and respiratory symptoms in adults (SAPALDIA Study). Am J Respir Crit Care Med 159:1257–1266Google Scholar