Long-Term Ambient Ozone Concentrations and Incidence of Emphysema in Nonsmoking California Adults: Results from the Ahsmog Study

S (ACE) AEP Vol. 20, No. 9 September 2010: 691–724 706 emphysema with OR 1.07(95% CI: 1.01–1.22) and 1.24 (95% CI: 1.05–1.47) respectively. Sensitivity analysis was conducted to further evaluate association between PM10 and incidence of emphysema by gender. This showed that the association between PM10 and incidence of emphysema was limited to females with an OR of 1.37 (95% CI: 1.11– 1.69) for each increase of 10 mg/m3 in PM10 as well as a significant association with exceedance frequencies of PM10 (40 days/year in excess of 40, 60, 80 and 100 mg/ m3) (Table 6). These point estimates did not change significantly as SO2, NO2 and O3 was added to the models one at a time. For males no association was observed betweenmean concentration of PM10, O3, and SO2 and incidence of emphysema. In conclusion, a significant positive association was observed between ambient PM10 and incidence of emphysema in females after adjusting for relevant confounders, including packyears of smoking. This association remained after adjusting for O3 in two-pollutant models. Also, a significant positive association was found between incidence of emphysema and each increment of 40 days/year that PM10 exceeded several cutoff points. The PM10 regression estimates increased as the cutoffs increased. For males, no significant associations were found. Our findings are in line with other studies that indicate a gender difference in effect of ambient air pollution on cardio-pulmonary disease. Further research with larger study size is needed to better understand the gender difference in the relationship between incidence of emphysema and PM10. P43 LONG-TERM AMBIENT OZONE CONCENTRATIONS AND INCIDENCE OF EMPHYSEMA IN NONSMOKING CALIFORNIA ADULTS: RESULTS FROM THE AHSMOG STUDY S Metghalchi, L Beeson, S Knutsen, Loma Linda University, Loma Linda, CA The aim of this study was to evaluate the relationship of long-term concentrations of ozone (O3) and risk of emphysema in nonsmoking California adults. A cohort study of 6,338 nonsmoking, non-Hispanic, white Californian adults, ages 27–95, was followed from 1977 to 2000 for recently diagnosed emphysema. Monthly ambient air pollution data were interpolated to zip code centroids according to home and work location histories and averaged over time. We observed significant associations between incidence of emphysema and 10 ppb increase in mean concentration of ozone in females with OR of 1.87 (95% CI: 1.11–3.15). In addition, we observed a significant associations between incidence of emphysema and 10-h average annual increment of ozone 100 and 120 (ppb) in females with OR of 1.15 (95% CI: 1.02–1.28), and OR of 1.17 (95% CI: 1.01– 1.37). These risk estimates remained virtually unchanged in two-pollutant analysis with PM10. In summary, we found that subjects living in areas that regularly experience high ozone levels, have increasing risk of developing emphysema even after adjusting for smoking and other potential confounding variables. The risk increased in a dose-response fashion with those experiencing levels above 150 ppb having the highest risk. Further research is needed to better understand the relationship between incidence of emphysema and ozone exposure and also to better separate the independent effects of PM10, O3, SO2, and NO2. P44 EFFECTS OF TRIHALOMETHANES ON BIRTH OUTCOMES S Kumar, S Forand, New York State Department of Health, Troy, NY PURPOSE: Disinfection by-products (DBPs), including trihalomethanes (THMs), result from the reaction between chlorine and natural organic matter in drinking water. The possible reproductive effects of DBPs exposure during pregnancy are receiving considerable interest because of the wide-spread occurrence of DBPs in drinking water. To understand the effect of total trihalomethane (TTHM) exposure on birthweight and gestation period, we studied the association of four THMs that are routinely monitored in drinking water with low birthweight and prematurity. METHODS: All singleton live births from 1998 through 2003 in New York were linked with public water supply system boundary based on mother’s residential address on birth certificate. THMmeasurements of water supply system were assigned geographically and temporally to each birth record. Individual level maternal information including mother’s race, ethnicity, education, employment status, age, adequacy of prenatal care along with infant’s gender was used to adjust for confounding. We used several regression model including linear, logistic, GLM and quantile based regression model. Of all the tested models, we selected quantile based regression model because of its features that includes the use of input data for model training, validation and testing. RESULTS: A small but inconsistent association was detected between term low birthweight births and TTHM exposure, suggesting some increase in risk for low birth weight is associated with maternal exposure to water containing THMs. CONCLUSION: Though there is a possibility of potential misclassification due to maternal mobility, water use, and daily change in the level of THMs, our findings are consistent with other published work.