Proximity to Air Pollution Sources Increases Childhood Asthma Attacks

American Journal of Epidemiology 2007 165(8):927-935
Air Pollution Sources and Childhood Asthma Attacks in Cataño, Puerto Rico

Nilsa I. Loyo-Berríos1, Rafael Irizarry2, Joseph G. Hennessey3,4, Xuguang Grant Tao5,6,7 and Genevieve Matanoski6,7

1 Office of Surveillance and Biometrics, Center for Devices and Radiological Health, Food and Drug Administration, US Department of Health and Human Services, Rockville, MD
2 Department of Biostatistics, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD
3 Center for Imaging Science, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD
4 Department of Psychiatry, School of Medicine, Johns Hopkins University, Baltimore, MD
5 Division of Environmental and Occupational Health, School of Medicine, Johns Hopkins University, Baltimore, MD
6 Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD
7 District of Columbia Cancer Registry, District of Columbia Health Department, Washington, DC

Correspondence to Dr. Nilsa I. Loyo-Berríos, Center for Devices and Radiological Health, Food and Drug Administration, US Department of Health and Human Services, 1350 Piccard Drive, HFZ-541, Rockville, MD 20850 (nilsa.loyo-berrrios@fda.hhs.gov).

Asthma prevalence in the Cataño Air Basin of Puerto Rico is 27% for children aged 13–14 years and 45% for children aged 5–6 years. There is concern that these rates are related to air pollution. The authors conducted a nested case-control study to evaluate whether proximity to air pollution point sources was associated with increased risk of asthma attacks. For 1997–2001, 1,382 asthma-related medical visits (International Classification of Diseases, Ninth Revision, codes 493 and 493.9) in children under 17 were identified through health insurance claims. Controls were children with no asthma attacks who were randomly selected from enrollees in two health insurance companies by incidence density sampling (1:5) and matched to cases on gender, age, insurance company, and event date. The distance from a point source to the subject's residence area represented a surrogate exposure measurement. Odds ratios for a 1-km decrease in distance were obtained by conditional logistic regression. Risk of asthma attack was associated with residing near a grain mill (odds ratio (OR) = 1.35), petroleum refinery (OR = 1.44), asphalt plant (OR = 1.23), or power plant (OR = 1.28) (all p's <>Residence near major air emissions sources (>100 tons/year) increased asthma attack risk by 108% (p <>
>>>>>>>>>>>>>>>>>>
BrooklynDodger(s) comment: This study provides some evidence that increased "air pollution" - nature unspecified - increases the risk of childhood asthma. The Dodger(s) concede(s) this is not a totally settled question and that continuing work in this area is needed.
The Dodger(s) are impressed at the methods - mapping addresses of cases and controls against locations of air pollution sources, which are likely in some kind of geographical data base. This provides a semi-quantitative exposure measure derived at the computer terminal, not pounding the pavement taking measurements. An idea others can use. Quibbling, air emissions don't spread uniformly as the inverse square of distance, they move in a plume. As long as all the heavy statistical and mapping guns were trained on this project, it could have been enhanced by applying a wind fan and plume mapping software to exposure assessment. It might also be feasible to map PM2.5 in the street using real time monitoring equipment, in relation to these sources. That might be looking for the lost keys under a lampost because that's where the light is, but PM2.5 or black carbon is the strongest known candidates for causes. Ozone variation at the ground level in relation to these sources is unlikely.
The sociology of this project interests. There's no institution in Puerto Rico listed on this project. The project was done at the "Mayor of New York for One More Term (so far)" School of Public Health in Baltimore. The first author - likely the doctoral student, likely in epidemiology given the last author - is now affiliated in the DC area outside of environmental health.