Reply to Künzli and Tager Regarding Causality in PM2.5Cohort Studies

pollution epidemiology: a valid design as compared to ecologic studies. Environ Health Perspect 105:1078-1083 (1997). 3. Brenner H, Savitz D, Joeckel K, Greenland S. Effects of nondifferential exposure misclassification in ecologic studies. Am J Epidemiol 135(1):85-95 (1992). 4. Greenland S. Divergent biases in ecologic and individual-level studies. Stat Med 11:1209-1223 (1992). 5. Wacholder S. When measurement errors correlate with truth: surprising effects of nondifferential misclassification. Epidemiology 6(2):157-161 (1995). 6. Navidi W, Thomas D, Stram D, Peters J. Design and analysis of multilevel analytic studies with applications to a study of air pollution. Environ Health Perspect 102(suppl 8):25-32 (1994). 7. Abbey D, Moore J, Petersen F, Beeson L. Estimating cumulative ambient concentrations of air pollutants: description and precision of methods used for an epidemiologic study. Arch Environ Health 46(5):281-287 (1991). 8. Dockery D, Pope A, Xu X, Spengler J, Wae J, Fay M, Ferris BJ, Speizer F. An association between air pollution and mortality in six U.S. cities. N EngI J Med 329(24):1753-1759 (1993). 9. KOnzli N, Lurman F, Segal M, Ngo L, Balmes J, Tager I. Association between lifetime ambient ozone exposure and pulmonary function in college freshman-results of a pilot study. Env Research 72(1):8-23 (1997). 10. Ashley F, Kannel W, Sorlie P, Masson R. Pulmonary function: relation to aging, cigarette habit, and mortality; the Framingham Study. Ann Internal Med 82:739-745 (1975). 11. Neas LM, Schwartz J. Pulmonary function levels as predictors of mortality in a national sample of US adults. Am J Epidemiol 147(11):1011-1018 (1998). 12. Ackermann-Liebrich U, Leuenberger P, Schwartz J, Schindler C, Monn C, Bolognini G, Bongard J, Brindli 0, Domenighetti G, Elsasser S, et al. Lung function and long-term exposure to air pollutants in Switzerland. Am J Respir Crit Care Med 155(1):122-129 (1997). 13. Neas L, Hoek G, Dockery D. Air pollution and the incidence of adult pulmonary function deficits in six US cities [abstract]. Epidemiology 9(4):S160 (1998). 14. Rothman KJ. Modern Epidemiology. Boston/ Toronto:Little, Brown and Company, 1986.