A deficient study of smokeless tobacco use and cancer.
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Adult↗
Biomedical subjects
Philip Cole
Publications and source records attributed to Philip Cole.
Contemporary rhinomanometry.
By contrast with the smoked drum and other mechanical systems, modern electronic rhinomanometers provide superior sensitivity and frequency response. They enable accurate measurement of nasal airflow resistance to be made and are commercially available. In addition to a rhinomanometer, nasal airflow measurements require a face mask fitted with a flow measuring device (a pneumotach connected to an electronic differential pressure transducer) or, as an alternative to a face mask, a head-out body plethysmograph. Concurrently with nasal respiratory airflow, transnasal pressures between the nostril and pharynx are measured via nasal or oral tubing by a second differential pressure transducer. The transduced electronic analogue signals are digitized, and nasal airflow resistances are computed from the ratio between transnasal pressure and airflow. At a single sitting, a series of measurements with modern rhinomanometry can determine (1) the response to topical decongestant of the mucovascular contribution to nasal airflow resistance at the time of examination and (2) in the decongested nose, the presence, side, site, and severity of structural obstruction. Rhinomanometry is not "medically necessary" in assessment of all cases of nasal obstructive symptoms, but, in many situations, it can provide valuable objective information in compliance with the requirements of evidence-based medicine. This article includes a table listing situations in which rhinomanometry is particularly useful.
Airway Resistance↗
Epidemiologic studies of chrome and cancer mortality: a series of meta-analyses.
We used 49 epidemiologic studies based on 84 papers published since 1950 to develop an array of meta-analyses relating exposure to chrome-six compounds with 10 causes of death. Most exposures occurred in occupational settings. Studies were assessed for quality, and for control of smoking or economic status if they related to lung or stomach cancer. There was no excess mortality from all causes combined among chrome-exposed persons. A minimal excess of cancer (SMR=112), overall, was due primarily to an excess of lung cancer (SMR=141) but the SMR was 112 among the better-quality, smoking-controlled studies. The overall SMR for stomach cancer was 113 but it was 82 among the studies that were controlled for economic status. Findings were unremarkable for the six other cancers evaluated: prostate, kidney, and central nervous system cancer and leukemia, Hodgkin's disease and other lymphatohematopoietic cancer. This series of meta-analyses indicates that chrome-six is a weak cause of lung cancer and is not a cause of any of the other seven forms of cancer evaluated.
Central Nervous System Neoplasms↗
Seven year follow-up of smoking cessation with smokeless tobacco.
This study evaluated the tobacco use status of 63 subjects seven years after enrollment in a single-intervention smoking cessation study employing smokeless tobacco (SLT) as a nicotine substitute. Information about tobacco use and cessation attempts was obtained in interviews. The duration of follow-up and of smoke-free periods were derived from the date of the subject's enrollment and were expressed as person-years (p-y). Because the study focused on the use of SLT for smoking cessation, subjects who used SLT to quit were invited to return for verification (less than 10 parts per million of carbon monoxide in expired air). Follow-up was completed on 62 of 63 original subjects, classified according to tobacco use status at the end of the initial study. Of the 16 subjects who had quit smoking using SLT at one year, 12 were smoke-free at seven years. For all 16 subjects there was 106 p-y of follow-up, 97 (92%) of which were smoke-free. Of six subjects who had quit smoking at one year by a means other than SLT, four were smoke-free at seven years. This entire group had 42 p-y of follow-up, 34 (81%) of which were smoke-free. Of the 41 subjects who were smoking at one year, 12 had quit smoking by the seven-year mark, three of these subjects by using SLT. Total follow-up for this group was 284 p-y, of which 26 (9%) were smoke-free. Although the study is small, the long-term success rate of this pilot trial compares favorably with other cessation studies.
Follow-Up Studies↗
Smokeless tobacco and periodontal disease.
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Educational Status↗
Re: Mortality from lymphohematopoietic malignancies among workers in formaldehyde industries.
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Carcinogens↗
Formaldehyde and leukemia: an improbable causal relationship.
Formaldehyde has been the subject of numerous toxicological and epidemiological investigations for almost 25 years. Though most toxicology studies have focused on the effects of the chemical on the nasal tract and respiratory system, epidemiology investigations have been more extensive evaluating the association between formaldehyde and cancers not only of the nasal cavities, nasopharynx, and lung, but also of the brain, prostate, pancreas, and hematopoietic system. Recently, three studies have been published which report on the possible association between exposure to formaldehyde and an increased incidence of leukemia, specifically myeloid leukemia. The article summarizes the results of these three studies, evaluates the evidence for causality based on recognized epidemiologic criteria, and provides an assessment that the association between formaldehyde and the increased incidence of leukemia reported in these studies is not plausible.
Carcinogens, Environmental↗
The burden of mortality from smoking: comparing Sweden with other countries in the European Union.
We describe the mortality currently attributable to smoking in the European Union (EU), and the change that would result if all EU countries had the smoking prevalence of Sweden. Almost 500,000 smoking-attributable deaths occur annually among men in the EU; about 200,000 would be avoided at Swedish smoking rates. In contrast, only 1100 deaths would be avoided if EU women smoked at Swedish rates. The low smoking-related mortality among Swedish men probably is due to their use of snus (Swedish smokeless tobacco).
Adolescent↗
Dioxin and cancer: a critical review.
2,3,7,8-tetrachlordibenzo-p-doxin (TCDD) would not have been designated as a Group 1 carcinogen by IARC had there not been a change in the criteria used for inclusion in this category. Furthermore, there is no precedent for indicating, as did IARC, that a single chemical acts as a pluripotential carcinogen by modestly increasing human risk for all cancer while not increasing the risk for any single cancer at least moderately. IARC moved TCDD to Group 1 based on mechanistic considerations focusing on the Ah receptor. However, while occupancy of the Ah receptor by TCDD may be necessary for its toxicity, it is not sufficient for toxicity or for potential carcinogenicity. Animal evidence relating TCDD exposure to cancer is much stronger than that for humans. However, the large inter-species variation in the relevant dose-response slopes severely limits generalizations from animals to humans. The epidemiologic studies of occupational exposures, pesticide applicators, and community exposures following industrial accidents, notably Seveso, have generated overall relative risks of all cancer of about 1.0. Only case-control studies of soft-tissue sarcoma and non-Hodgkin's lymphoma, all by the same investigator, reported elevated risk from TCDD exposure. However, these results have not been replicated. The representation that a chemical compound (TCDD) would be a late-stage carcinogen for all types of cancer has no precedent and lacks biological foundation. Virtually all late-stage or promoting carcinogens (e.g., hepatitis-C virus, asbestos, and estrogens) cause a very limited number of forms of cancer. The exposure-response meta-analysis of TCDD and cancer developed by the United States Environmental Protection Agency (USEPA) is seriously compromised by its failure to adequately fit the data. The studies used by the USEPA also likely underestimate TCDD body burdens and may be confounded by smoking and other occupational exposures. Furthermore, the use of a linear dose-response model by the USEPA is scientifically unjustified since the underlying model of TCDD as a human carcinogen is based primarily on its supposed receptor-mediated, non-genotoxic (or promotional) mode of action. There are few examples of an agent being suspected as a human carcinogen for decades and then eventually moving into the category of "known" human carcinogens. In contrast, there are hundreds of compounds that remain for decades on lists of "suspected" human carcinogens despite the lack of confirming evidence. The long-term accumulation of negative, weak, and inconsistent findings suggests that TCDD eventually will be recognized as not carcinogenic for humans.
Animals↗
Feasibility of aerosol vaccination in humans.
The feasibility of using aerosol vaccines to achieve mass and rapid immunization, especially in developing countries and disaster areas, is being assessed on the basis of current available information. The aerosol mode of vaccine introduction, which best follows the natural route of many infections, may first lead to development of immunity at the portal of entry, and may also induce a more generalized defense. The recommended optimal way of introducing an aerosol vaccine is nasal breathing, which is more suitable for geriatric and pediatric populations, permits use of greater antigen volumes, and allows easier monitoring of results. Technical requirements for ideal aerosol vaccines and delivery systems, possible adverse effects, and cost-effectiveness are other issues addressed. Several thousand human subjects have been aerosol-vaccinated over a period of many years in Russia with live-attenuated strains against many diseases. Extensive field trials in South America with aerosolized live-attenuated measles vaccine have also been successful, and excellent results have been reported with pilot projects employing inactivated or live-attenuated aerosol influenza A vaccine. We conclude that aerosol immunization seems a promising method of vaccination. Although some basic information is still lacking, this method has already been used successfully in large populations and has therefore passed the phase of initial feasibility evaluation.
Administration, Inhalation↗
Alcohol-containing mouthwash and oropharyngeal cancer: a review of the epidemiology.
BACKGROUND: There has been concern that the use of alcohol-containing mouthwash may increase the risk of developing oropharyngeal cancer, or OPC. The authors examine the epidemiologic literature relating to this issue. TYPES OF STUDIES REVIEWED: The authors identified all nine English-language epidemiologic studies of OPC that made reference to mouthwash. The findings and major strengths and limitations of each study are described. In addition, the authors reanalyzed data from one of the studies. RESULTS: The results of six of the studies reviewed are negative and provide no support for the hypothesis that use of alcohol-containing mouthwash increases the risk of OPC. One of the three studies with positive results was a case series and included a follow-up case-control study, the results of which were negative. The authors reanalyzed the study with the most positive results. This analysis found that the study results were just as positive for nonmucosal cancers developing in the mouth as they were for the usual type of OPC. The authors concluded that this study's positive finding resulted from recall bias. CLINICAL IMPLICATIONS: It is unlikely that the use of mouthwashes that contain alcohol increases the risk of developing OPC.
Alcohol Drinking↗
Impact of the American anti-smoking campaign on lung cancer mortality.
Customary statistics on smoking practices are limited because they do not correlate well with the frequency of smoking-related diseases. Our study developed outcome measures based on lung cancer mortality and used them to assess the anti-smoking campaign. Changes in mortality from lung cancer were used to assess significant smoking among 5-year birth cohorts of white men born from 1901 to 1942. We used each cohort's lung cancer mortality rate at ages 40-44 to indicate its earlier smoking. A lung cancer mortality ratio was developed to describe each cohort's continued smoking from ages 40-44 to 55-59. These ratios were then compared with the durations of the cohorts' exposure to the anti-smoking campaign that began in 1965. Lung cancer mortality in white men ages 40-44 peaked in 1970 and declined continuously thereafter, indicating that the anti-smoking campaign promptly reduced significant smoking among younger men. However, the lung cancer mortality ratio indicates that only half of smokers in the specified birth cohorts were able to quit by ages 55-59, despite receiving ever more intense anti-smoking messages. The anti-smoking campaign produced moderate benefits among younger white male smokers but fewer benefits among older smokers because of the existence of a large number of inveterate smokers.
Adult↗
Smokeless tobacco use and cancer of the upper respiratory tract.
The most recent epidemiologic review of the cancer risks associated with smokeless tobacco use appeared in 1986, when 10 studies were available. This review describes 21 published studies, 20 of which are of the case-control type. We characterize each study according to the specific anatomic sites and according to the type of smokeless tobacco products for which it provides relative risks of cancer. The use of moist snuff and chewing tobacco imposes minimal risks for cancers of the oral cavity and other upper respiratory sites, with relative risks ranging from 0.6 to 1.7. The use of dry snuff imposes higher risks, ranging from 4 to 13, and the risks from smokeless tobacco, unspecified as to type, are intermediate, from 1.5 to 2.8. The strengths and limitations of the studies and implications for future research are discussed.
Case-Control Studies↗
The four components of the nasal valve.
The nasal valve consists of four distinct airflow-resistive components. (i) The vestibule terminates in an airflow-resistive aperture between the septum and the caudal end of the upper lateral cartilage. Its cross-sectional area is stabilized by the cartilaginous structures and by inspiratory isometric contractions of alar dilator muscles. Its walls are devoid of erectile tissues that might otherwise affect its cross-sectional area and airflow resistance. By contrast, (ii) the bony entrance to the cavum is occupied by erectile tissues of both (iii) lateral (turbinate) and (iv) septal nasal walls that modulate the cross-sectional area of the airway and airflow resistance. The body of the cavum offers little resistance to airflow. Valve constrictions induce "orifice flow" of inspiratory air as it enters the body of the cavum, disrupting laminar characteristics and thereby enhancing exchanges with the nasal mucosa of heat, water, and contaminants. Acoustic rhinometric and rhinomanometric measurements show the sites, dimensions, and resistances of the valve constrictions and indicate that it is seldom necessary to extend septal and/or turbinate surgery far beyond the piriform aperture in the treatment of nasal obstruction.
Airway Obstruction↗