Lung cancer and environmental tobacco smoke: Occupational risk to nonsmokers

The principal epidemiologic evidence that environmental tobacco smoke (ETS) increases the risk of lung cancer in (lifelong) nonsmokers is from studies of nonsmoking women married to smokers. This article estimates exposure-re sponse curves for 14 studies (1,249+ cases, 7 countries) with data on lung cancer categorized by the number of cigarettes/day smoked by the husband. T he pooled results from the five U.S. studies alone are extrapolated to ETS levels in the workplace using measures of serum cotinine and nicotine sampl es from personal monitors as markers, of exposure to ETS. it is predicted t hat the increase in lung cancer risk for nonsmoking women from average ETS exposure at work (among those exposed at work) is on the order of 25% (95% confidence interval (CI) = 8, 41) relative to background risk (i.e., with n o ETS exposure from any source). This compares to an estimate of 39% (95% C I = 5, 65) for nonsmoking women whose husbands smoke at the adult male smok er's average of 25 cigarettes/day. At the 95th percentiles of exposure, the estimate from spousal smoking is 85% (95% CI = 32, 156), compared to 91% ( 95% CI = 34, 167) from workplace ETS exposure. Subject to the validity of t he assumptions required in this approach, the outcome supports the conclusi on that there is a significant excess risk from occupational exposure to ET S, The excess risk from ETS at work is typically lower than that from spous al smoking, but may be higher at the 95th percentiles of exposure.