Outdoor air pollution and uncontrolled asthma in the San Joaquin Valley, California.
BACKGROUND
The San Joaquin Valley (SJV) in California ranks among the worst in the USA in terms of air quality, and its residents report some of the highest rates of asthma symptoms and asthma-related emergency department (ED) visits and hospitalisations in California. Using California Health Interview Survey data, the authors examined associations between air pollution and asthma morbidity in this region.


METHODS
Eligible subjects were SJV residents (2001 California Health Interview Survey) who reported physician-diagnosed asthma (n=1502, 14.6%). The authors considered two outcomes indicative of uncontrolled asthma: (1) daily or weekly asthma symptoms and (2) asthma-related ED visits or hospitalisation in the past year. Based on residential zip code, subjects were assigned annual average concentrations of ozone, PM(10) and PM(2.5) for the 1-year period prior to the interview date from their closest government air monitoring station within an 8 km (5 miles) radius.


RESULTS
Adjusting for age, gender, race/ethnicity, poverty level and insurance status, the authors observed increased odds of experiencing daily or weekly asthma symptoms for ozone, PM(10) and PM(2.5) (OR(ozone) 1.23, 95% CI 0.94 to 1.60 per 10 ppb; OR(PM10) 1.29, 95% CI 1.05 to 1.57 per 10 microg/m(3); and OR(PM2.5) 1.82; 95% CI 1.11 to 2.98 per 10 microg/m(3)). The authors also observed increased odds of asthma-related ED visits or hospitalisations for ozone (OR 1.49, 95% CI 1.05 to 2.11 per 10 ppb) and a 29% increase in odds for PM(10) (OR 1.29, 95% CI 0.99 to 1.69 per 10 microg/m(3)).


CONCLUSIONS
Overall, these findings suggest that individuals with asthma living in areas of the SJV with high ozone and particulate pollution levels are more likely to have frequent asthma symptoms and asthma-related ED visits and hospitalisations.
Meng
Ying-Ying
YY
UCLA Center for Health Policy Research, Los Angeles, California, USA. yymeng@ucla.edu
Rull
Rudolph P
RP
Wilhelm
Michelle
M
Lombardi
Christina
C
Balmes
John
J
Ritz
Beate
B
D000393:Air Pollutants / Q000009:adverse effects* / Q000032:analysis; D000397:Air Pollution / Q000009:adverse effects; D001249:Asthma / Q000453:epidemiology*; D002140:California / Q000453:epidemiology; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D010126:Ozone / Q000009:adverse effects* / Q000032:analysis; D052638:Particulate Matter / Q000009:adverse effects* / Q000032:analysis
D000393:Air Pollutants; D052638:Particulate Matter; D010126:Ozone