Risk assessment methodologies for passive smoking-induced lung cancer

Our plain-English summary of Risk assessment methodologies for passive smoking-induced lung cancer, by J.L. Repace, A.H. Lowrey (Risk Analysis, 1990).

The study

• Authors: J.L. Repace, A.H. Lowrey
• Journal: Risk Analysis
• Published: 1990;10(1):27-37
• Type of article: Review
• Cited by: 32 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 004971).

Abstract

Risk assessment methodologies have been successfully applied to control societal risk from outdoor air pollutants. They are now being applied to indoor air pollutants such as environmental tobacco smoke (ETS) and radon. Nonsmokers' exposures to ETS have been assessed based on dosimetry of nicotine, its metabolite, continine, and on exposure to the particulate phase of ETS. Lung cancer responses have been based on both the epidemiology of active and of passive smoking. Nine risk assessments of nonsmokers' lung cancer risk from exposure to ETS have been performed. Some have estimated risks for lifelong nonsmokers only; others have included ex-smokers; still others have estimated total deaths from all causes. To facilitate interstudy comparison, in some cases lung cancers had to be interpolated from a total, or the authors' original estimate had to be adjusted to include ex-smokers. Further, all estimates were adjusted to 1988. Excluding one study whose estimate differs from the mean of the others by two orders of magnitude, the remaining risk assessments are in remarkable agreement. The mean estimate is approximately 5000 +/- 2400 nonsmokers' lung cancer deaths (LCDSs) per year. This is a 25% greater risk to nonsmokers than is indoor radon, and is about 57 times greater than the combined estimated cancer risk from all the hazardous outdoor air pollutants currently regulated by the Environmental Protection Agency: airborne radionuclides, asbestos, arsenic, benzene, coke oven emissions, and vinyl chloride.

In plain English

This article was a review, not a new study of people. The authors reviewed methods used to estimate how many lung cancer deaths among U.S. nonsmokers (never-smokers and ex-smokers) are caused by breathing other people's tobacco smoke, called environmental tobacco smoke (ETS). They compared nine published risk assessments by U.S., Canadian and U.K. researchers. For comparison they adjusted all estimates to 1988 and, where needed, to include ex-smokers. The estimates ranged from 58 to 8124 lung cancer deaths per year. The mean of all nine was 4500. Leaving out one study that differed sharply from the rest (Arundel et al.), the mean was 5000, plus or minus 2400, per year. The authors set this beside an estimate of about 4000 lung cancer deaths per year in nonsmokers from indoor radon. They also cited an estimate that nonoccupational asbestos-related mortality causes less than 15 cancer deaths per year. The authors concluded that ETS may cause about 5000 lung cancer deaths per year. They noted that the estimates rest on relatively few studies that are not national probability samples.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Review and comparison of published risk assessments (risk assessment methodology review)
• Who was studied: Nine published risk assessments of lung cancer in nonsmokers from ETS, performed by U.S., Canadian and U.K. researchers; estimates were applied to U.S. nonsmokers (never-smokers plus ex-smokers) and adjusted to 1988
• Exposure: Environmental tobacco smoke (exhaled mainstream smoke plus sidestream smoke from cigarettes, pipes and cigars), assessed through nicotine/cotinine dosimetry, modeled exposure to respirable suspended particulate matter (RSP) from ETS, and epidemiology. Asbestos appears only as a comparison pollutant.
• Main results:
  • Across the nine risk assessments, after adjustment to 1988 (and to include ex-smokers where needed), estimates ranged from 58 to 8124 nonsmokers' lung cancer deaths per year
  • The mean of all nine estimates was 4500 (plus or minus 2800) lung cancer deaths per year
  • Excluding Arundel et al., the mean of the remaining eight studies was 5000 plus or minus 2400 lung cancer deaths per year among U.S. nonsmokers
  • For comparison, the authors estimated about 4000 lung cancer deaths per year in nonsmokers from indoor radon
  • Nonoccupational asbestos-related mortality was cited as estimated at less than 15 cancer deaths per year; Table II lists asbestos at 15 cancer deaths per year among outdoor pollutants
  • Outdoor air pollutants regulated by EPA as hazardous air pollutants were cited as totaling less than 87 cancer deaths per year before control
  • The three studies that explicitly estimated the workplace contribution suggested the workplace contributes at least half of the risk
  • The authors' own phenomenological model gave an average risk of lung cancer from ETS exposure at home of 26% (relative risk 1.26)
• The authors' conclusion: The authors concluded that, based on their analysis of the risk assessment literature, ETS exposure may cause an estimated 5000 lung cancer deaths per year, about one fourth of nonsmokers' lung cancer deaths. They also stated this risk is about one hundred times the total from carcinogenic outdoor air pollutants regulated by EPA.
• Limitations the authors state:
  • The estimates are based on relatively few studies that do not represent national probability samples
  • The greatest source of uncertainty is that neither cotinine nor RSP measurements come from a national probability sample
  • In two cases, lung cancer deaths had to be interpolated from the original authors' estimates of total mortality
  • The cotinine half-life adjustment relies on a small sample of smokers and nonsmokers

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer.

Medical terms in this study, explained in our Lexicon: Lung Cancer, Epidemiology.

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