A Study of Twelve Southern California Communities with Differing Levels and Types of Air Pollution

Abstract

To study the possible chronic respiratory effects of air pollutants, we designed and initiated a 10-yr prospective study of Southern California public schoolchildren living in 12 communities with different levels and profiles of air pollution. The design of the study, exposure assessment methods, and survey methods and results related to respiratory symptoms and conditions are described in the accompanying paper. Pulmonary function tests were completed on 3,293 subjects. We evaluated cross-sectionally the effects of air pollution exposures based on data collected in 1986-1990 by existing monitoring stations and data collected by our study team in 1994. Expected relationships were seen between demographic, physical, and other environmental factors and pulmonary function values. When the data were stratified by sex, an association was seen between pollution levels and lower pulmonary function in female subjects, with the associations being stronger for the 1994 exposure data than the 1986-1990 data. After adjustment, PM10, PM2.5, and NO2 were each significantly associated with lower FVC, FEV1, and maximal midexpiratory flow (MMEF); acid vapor with lower FVC, FEV1, peak expiratory flow rate (PEFR), and MMEF; and O3 with lower PEFR and MMEF. Effects were generally larger in those girls spending more time outdoors. Stepwise regression of adjusted pulmonary function values for girls in the 12 communities showed that NO2 was most strongly associated with lower FVC (r = -0.74, p < 0.01), PM2.5 with FEV1 (r = -0.72, p < 0.01), O3 with PEFR (r = -0.75, p < 0.005), and PM2.5 with MMEF (r = -0.80, p < 0.005). There was a statistically significant association between ozone exposure and decreased FVC and FEV1 in girls with asthma. For boys, significant associations were seen between peak O3 exposures and lower FVC and FEV1, but only in those spending more time outdoors. These findings underline the importance of follow-up of this cohort.

Long-term ambient air pollution levels in four Chinese cities: inter-city and intra-city concentration gradients for epidemiological studies

“…In each study, exposure -effects relationships can be derived for the pollution range encountered in the study and thus, a wide pollution range is favorable. The eight districts of this study exhibited a wide range for each concerned pollutant, as shown clearly in Figure 5 where the ranges from major previous US /Europe studies are also shown for comparison purposes (Ware et al, 1986;Dockery et al, 1989Dockery et al, , 1996Spengler et al, 1996;Braun -Fahrlander et al, 1997;Peters et al, 1999b;Pikhart et al, 2000 ). The comparison indicates that the data on pollution levels collected in this study substantially extended the upper end of the pollution ranges of major published studies.…”

“…Annual means or multiyear means of air pollutants are often used in epidemiologic studies of long -term air pollution effects (Ware et al, 1986;Dockery et al, 1989;Peters et al, 1999a ). In each study, exposure -effects relationships can be derived for the pollution range encountered in the study and thus, a wide pollution range is favorable.…”

The association between contextual socioeconomic factors and prevalent asthma in a cohort of Southern California school children

“…Model 2 added parental education, which was included in subsequent models so that these results would be adjusted for individual SEP. Model 3 added medical insurance to account for possible diagnostic bias resulting from differential access to care. Model 4 adjusted for a total of 21 covariates that follow the adjustment used by Peters et al in their original CHS study (Peters, Avol, Navidi et al, 1999). Model 5 added census block group population density.…”

“…Associations of asthma with housing characteristics, obesity, air pollution, family history and exercise have been previously described (Gauderman, Avol, Lurmann, Kuenzli, Gilliland, Peters et al, 2005;Gilliland, Berhane, Islam, McConnell, Gauderman, Gilliland et al, 2003;Kunzli, McConnell, Bates, Bastain, Hricko, Lurmann et al, 2003;London, James Gauderman, Avol, Rappaport, & Peters, 2001;McConnell, Berhane, Gilliland, Islam, Gauderman, London et al, 2002a;McConnell, Berhane, Gilliland et al, 2002b;McConnell, Berhane, Yao, Jerrett, Lurmann, Gilliland et al, 2006). A detailed description of the selection of communities, subject recruitment, and survey methods to assess demographic, household, activity, and baseline medical characteristics has also been reported (Peters, Avol, Navidi, London, Gauderman, Lurmann et al, 1999). The current analysis is the first examination of the contextual effects of SEP on asthma in the CHS.…”

“…Socioeconomic position and other demographic, medical and home environmental exposures have been examined in the CHS with respect to childhood asthma (Gauderman, Avol, Lurmann et al, 2005;Gilliland, Berhane, Islam et al, 2003;Peters, Avol, Navidi et al, 1999). Variables of interest here include age of the child (centered on 10 years of age), race/ethnicity, gender, height, age-and sex-adjusted body mass index below the 10 th percentile or in the 90 th percentile, cohort group (defined by year and subject's grade at enrollment: 1993 in 4 th , 7 th or 10 th grade or 1996 in 4 th grade), current vitamin use, hay fever symptoms in the last 12 months, current medical insurance coverage and parental history of asthma.…”