Born Against
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longbough, simply citing the EPA study does not necessarily call into question any conclusions of a study; it certainly doesn't call into question the study that maximumus cited.
The WHO memo you are referring to was a response to a disinformation campaign by the tobacco industry, which touted the cited study as "proof" that SHS as completely harmless. I think you'll agree that that interpretation of the study is off base.
Anybody interested in the conclusions of the best, largest studies on this subject can check out these papers I cite below. They are a good starting point. And their conclusions are completely independent of the EPA paper, in case that matters. Note that these are very conservative studies, that include even small exposure to SHS in their risk assessment. The important result is the dose trend response, which is very highly significant. The greater your exposure, the greater your risk of lung cancer.
Brennan, P., P. A. Buffler, et al. (2004). "Secondhand smoke exposure in adulthood and risk of lung cancer among never smokers: A pooled analysis of two large studies." International Journal of Cancer 109(1): 125-131.
The interpretation of the evidence linking exposure to secondhand smoke with lung cancer is constrained by the imprecision of risk estimates. The objective of the study was to obtain precise and valid estimates of the risk of lung cancer in never smokers following exposure to secondhand smoke, including adjustment for potential confounders and exposure misclassification. Pooled analysis of data from 2 previously reported large case-control studies was used. Subjects included 1,263 never smoking lung cancer patients and 2,740 population and hospital controls recruited during 1985-1994 from 5 metropolitan areas in the United States, 11 areas in Germany, Italy, Sweden, United Kingdom, France, Spain and Portugal. Odds ratios (ORs) of lung cancer were calculated for ever exposure and duration of exposure to secondhand smoke from spouse, workplace and social sources. The OR for ever exposure to spousal smoking was 1.18 (95% CI = 1.01-1.37) and for long-term exposure was 1.23 (95% CI = 1.01-1.51). After exclusion of proxy interviews, the OR for ever exposure from the workplace was 1.16 (95% CI = 0.99-1.36) and for long-term exposure was 1.27 (95% CI = 1.03-1.57). Similar results were obtained for exposure from social settings and for exposure from combined sources. A dose-response relationship was present with increasing duration of exposure to secondhand smoke for all 3 sources, with an OR of 1.32 (95% CI = 1.10-1.79) for the long-term exposure from all sources. There was no evidence of confounding by employment in high-risk occupations, education or low vegetable intake. Sensitivity analysis for the effects of misclassification (both positive and negative) indicated that the observed risks are likely to underestimate the true risk. Clear dose-response relationships consistent with a causal association were observed between exposure to secondhand smoke from spousal, workplace and social sources and the development of lung cancer among never smokers. (C) 2003 Wiley-Liss, Inc.
Fontham, E. T. H., P. Correa, et al. (1994). "Environmental Tobacco-Smoke and Lung-Cancer in Nonsmoking Women - a Multicenter Study." Jama-Journal of the American Medical Association 271(22): 1752-1759.
Objective.-To determine the relative risk (RR) of lung cancer in lifetime never smokers associated with environmental tobacco smoke (ETS) exposure. Design.-Multicenter population-based case-control study. Setting.-Five metropolitan areas in the United States: Atlanta, Ga, Houston, Tex, Los Angeles, Calif, New Orleans, La, and the San Francisco Bay Area, Calif. Patients or Other Participants or Other Participants.-Female lifetime never smokers: 653 cases with histologically confirmed lung cancer and 1253 controls selected by random digit dialing and random sampling from the Health Care Financing Administration files for women aged 65 years and older. Main Outcome Measure.-The RR of lung cancer, estimated by adjusted odds ratio (OR) with 95% confidence interval (Cl), associated with ETS exposure. Results.-Tobacco use by spouse(s) was associated with a 30% excess risk of lung cancer: all types of primary lung carcinoma (adjusted OR=1.29; P<.05), pulmonary adenocarcinoma (adjusted OR=1.28; P<.05), and other primary carcinomas of the lung (adjusted OR=1.37; P=.18). An increasing RR of lung cancer was observed with increasing pack-years of spousal ETS exposure (trend P=.03), such that an 80% excess risk of lung cancer was observed for subjects with 80 or more pack-years of exposure from a spouse (adjusted OR=1.79; 95% Cl=0.99 to 3.25). The excess risk of lung cancer among women ever exposed to ETS during adult life in the household was 24%; in the workplace, 39%; and in social settings, 50%. When these sources were considered jointly, an increasing risk of lung cancer with increasing duration of exposure was observed (trend P=.001). At the highest level of exposure, there was a 75% increased risk. No significant association was found between exposure during childhood to household ETS exposure from mother, father, or other household members; however, women who were exposed during childhood had higher RRs associated with adult-life ETS exposures than women with no childhood exposure. At the highest level of adult smoke-years of exposure, the ORs for women with and without childhood exposures were 3.25 (95% Cl, 2.42 to 7.46) and 1.77 (95% Cl, 0.98 to 3.19), respectively. Conclusion.-Exposure to ETS during adult life increases risk of lung cancer in lifetime nonsmokers.
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