Measuring passive smoking: Methods, problems, and perspectives

The definition of passive smoking used by T. Hirayama [Brit. Med. J. 282, 183-185 (1981)] and other authors has at least three major shortcomings: it is only applicable to a highly selective sub-population; varying lifestyle patterns cannot be taken into account; and exposure outside the home is neglected. To overcome these shortcomings, a preliminary qualitative and classificatory definition of passive smoking that includes the total population as well as any smoke exposure, regardless of its location, was developed. This definition does not include the quantity of exposure or changes over time. Based on a representative survey, 17.8% of the population over 35 years are potential passive smokers according to this definition. The questionnaire developed by E.L. Wynder and associates (American Health Foundation, New York) presents difficulties in scoring the results for different lifestyles. Therefore a quantitative concept was developed for estimating exposure over any period of time as a generalized assessment instrument. The concept of maximum exposed M-time for an individual (TMI) as well as for a group (TMG) is introduced. The results are presented graphically by a cumulative standardized exposed M-time diagram. Results obtained so far lean toward plausibility and stability of the data and the concept. The interview form has still to be validated.     

Perceived vulnerability in adolescents to the health consequences of cigarette smoking

Adolescent feelings of vulnerability, an aspect of the Health Belief Model and Elkind's concept of adolescent egocentrism, were examined in two groups of white, middle-class 6th to 12th graders. Feelings of vulnerability were examined with respect to developmental course, antecedents, and relationship to the specific risk-taking behavior of cigarette smoking. Feelings of vulnerability to the negative consequences of smoking were found to decrease rapidly from sixth to eighth grade and to increase slowly thereafter. Experience with illness and accidents was correlated with the general vulnerability measure. However, experience with illness due to smoking was not related to smoking vulnerability. This may have been because few adolescents were found to have had personal experiences with the health consequences of smoking. Feelings of vulnerability with respect to the negative consequences of cigarette smoking were correlated with adolescent smoking behavior. General feelings of vulnerability were unrelated to cigarette smoking.     

Preventing the onset of cigarette smoking through life skills training

The effectiveness of a 10-session social psychological approach to the prevention of cigarette smoking was tested on 8th, 9th, and 10th graders (N = 281) in suburban New York. The program was designed to address both the social and psychological factors promoting the onset of smoking by attempting to: (a) increase students' ability to cope with direct pressures to smoke, (b) decrease their susceptibility to indirect pro-smoking social influences, and (c) improve their ability to cope with anxiety. The program was conducted by allied health professionals and utilized group discussion, modeling, and behavior rehearsal. Results indicate significant differences between the experimental and control groups in terms of the proportion of new “experimental smokers” (P < 0.01). Furthermore, there were significantly greater pretest—post-test changes for the experimental group on several of the knowledge and psychological measures, suggesting that the decrease in the onset of smoking behavior among the experimental subjects did occur for the hypothesized reasons.     

Effects of physician counseling on the smoking behavior of asbestos-exposed workers

Physician antismoking advice has been shown to increase smoking cessation, particularly among patients who have medical problems or perceive themselves to be at risk. The present study tested three hypotheses: (a) providing 3 to 5 min of behavioral counseling regarding a cessation strategy would be more effective than simply warning the smoker to quit smoking; (b) smokers with abnormal pulmonary function would be more likely to comply with medical advice than would smokers with normal pulmonary function; and (c) that smokers with abnormal pulmonary function who receive behavioral counseling would be the group most likely to achieve prolonged abstinence. Asbestos-exposed smoking men undergoing screening in a mandated program for naval shipyard workers were categorized as having normal or abnormal pulmonary status on the basis of chest X ray and pulmonary function tests (PFT). They were then randomly assigned within PFT categories to receive either a simple warning or 3 to 5 min of behavioral cessation counseling from the physician who gave them the results of their pulmonary tests. Subjects' smoking status was evaluated at 3- and 11-month intervals following the physician intervention. Smokers who received behavioral counseling were more likely to quit and remain abstinent over the 11-month period (8.4% abstinent) than were smokers given a minimal warning (3.6% abstinent). Prolonged abstinence rates among abnormal PFT subjects (3.7%) did not differ from those of normals (5.9%). The group with normal PFT who received behavioral counseling achieved the highest level of abstinence (9.5%). Maintaining adequate physician compliance with the counseling protocol proved difficult; implications of this for future efforts are discussed.     

Cadmium levels in the blood of inhabitants in nonpolluted areas in Japan with special references to aging and smoking

Blood samples, 2259 in winter and 523 in other seasons of the year, were collected nationwide in Japan from inhabitants (primarily farmers) in areas with no known man-made pollution, and analyzed for cadmium. The levels were distributed log normally, and were lower among young adults and increased gradually to reach a plateau at the 40–59 age group, where the values in females (about 3.6 ng/ml as a geometric mean) were significantly higher than in males (3.0–3.4 ng/ml). The sex difference was positive (P < 0.01) even when 77 pairs of levels were compared between husbands and their wives, both being nonsmokers in the age range of 40–59 years. Smoking habits gave an additional increase in the blood cadmium level. The increase was dose dependent up to 20–29 cigarettes/day and leveled off with further consumption. Effects of passive smoking could not be confirmed. Seasonal variation in blood cadmium level appeared negligible. Variation in the level by geographic location in the country was of doubtful significance. The estimated ratio of cadmium doses by two routes, i.e., via the gastrointestinal tract and via the lungs, was in agreement with the ratio of the blood cadmium level among nonsmokers and the additional increase in the level due to smoking.     

Obesity in relation to smoking: A population study of women in Göteborg,Sweden

A population sample of 1,462 middle-aged women (participation rate 90.1%) was studied in 1968–1969, 1,302 of whom (participation rate 80.3%) were reexamined in 1974–1975. Cigarette smoking was more frequent among younger women. Current smokers were leaner than nonsmokers. A U-shaped relationship was found between obesity index and cigarette consumption. This relationship was not explained by differences in energy intake, physical activity, or social class. Cessation of smoking was correlated with weight gain, and commencement of smoking with weight loss. Of those who quit 13% gained weight ?10.0 kg and 22% gained between 5.0 and 9.9 kg compared with 4 and 14%, respectively, among those who did not change smoking habits. The average weight change was +3.5 and ?0.7 kg among those who quit smoking and started smoking, respectively, compared with +1.4 kg among those who did not change smoking habits. A greater weight gain with the amount smoked was found both in those who stopped smoking and in those who continued smoking. Increased physical activity and reduced energy intake need consideration at cessation of smoking, especially among heavy smokers. The quantitative aspects of the relationship between smoking and obesity, and between cessation of smoking and weight gain, are considered to be of special interest for health personnel engaged in antismoking campaigns.     

Women's smoking trends and awareness of health risk

National data on smoking cessation rates indicate that female smokers may have more difficulty than male smokers in quitting smoking. To test the hypothesis that awareness of risk of smoking and personal vulnerability may be not as strong in female as in male smokers, we conducted a series of telephone interviews dealing with smokers' awareness and knowledge of the recent Surgeon General's Report on Smoking and Health, and their perception of and attitudes toward personal risk. The results indicated no marked sex difference in awareness of the Surgeon General's Report, but showed that significantly more female than male smokers worried about what they heard and read about the risk of smoking. A larger percentage of female smokers attributed a greater health risk from smoking to men than to women, thus suggesting that women's feelings of personal vulnerability may be weaker than men's.     

Cigarette smoking and tobacco usage behavior in children and adolescents: Bogalusa heart study

As part of a comprehensive program to assess cardiovascular disease risk factor variables in an entire biracial pediatric population, a study of cigarette smoking was included in the Bogalusa Heart Study. The purpose of the study was to obtain reliable and valid data on attitudes, beliefs, and cigarette-smoking behavior. The questionnaire demonstrates good internal consistency, test-retest reliability, and external validation with plasma thiocyanate. For all sex and race groups the percentage of smokers increases with age. White boys begin smoking exposure and adopt cigarette smoking earlier (32% of 14- to 15-year-olds) while white girls increase and surpass the boys by ages 16 to 17 (41%). Black boys and girls lag behind white children in early experience and adoption of smoking behavior. The largest percentage of experimental nonadopters (those who said they tried cigarettes to see what they were like but do not smoke now) occurs among the 12- to 13-year-olds for each race-sex group except black girls.     

The contribution of ionizing radiation to cancer mortality in the United States

Although ionizing radiation has been well known as a carcinogen for more than 70 years, only a small part of the total cancer mortality burden in the United States can be attributed to radiation effects—less than 3%. Little can be done about much of the exposure to radiation that exists—about half of the total results from natural background radiation. More than 40% derives from medical and dental practice—mostly as diagnostic X-rays. Something less than 5% comes from nuclear weapons fallout from atmospheric tests and well under 1% from the use of nuclear energy for generating electric power. Substantial reduction of the total radiation burden on the population can be achieved only by reduction of X-rays used in medicine and dentistry. This will, however, involve careful consideration of the balance between radiation benefits and risks, as well as requiring that such X-ray exposures be reduced to the minimum required to achieve the necessary medical purpose.     

The influence of passive smoking on pulmonary function—A study of 1,351 office workers

Until now it has been difficult to ascertain how much passive inhalation of tobacco smoke affects bronchopulmonary function. To answer this question, an investigation involving 1,351 white collar workers was carried out. Information about active and passive tobacco smoke exposure was obtained by a standardized questionnaire. This made it possible to subdivide the overall group into five subgroups: Never smokers, passive smokers, ex-smokers, current smokers, and other smokers. Forced expiratory vital capacity (FVC) and maximal expiratory flow-volume (MEFV) curves were used for lung function analysis. From these curves FVC, forced mid-expiratory flow (FEF 25/75), forced end-expiratory flow (FEF 75/85), and maximal mid-expiratory flow (MEF 25/75) were determined and standardized for sex, age, height, and body weight. Passive smokers evaluated by this method showed essentially no decrease in parameters describing ventilatory function. It is concluded from the dose-and time-effect relationships obtained in active smokers between the lung function parameters and the duration of tobacco smoke exposure on the one hand and the daily consumption of cigarettes on the other that passive smoking in small doses may have no essential effect on pulmonary function.     

Maternal hepatic and embryonic effects of 1,2,4-trichlorobenzene in the rat

The possible maternal hepatic and reproductive effects of 1,2,4-trichlorobenzene (TCB) were assessed in rats given 0, 36, 120, 360, and 1200 mg/kg/day of TCB on Days 9-13 of gestation. The animals were sacrificed on Day 14 of pregnancy. Maternal deaths (2/9 rats, 6/6 rats) were recorded in the 360 and 1200 mg/kg/day treatment groups and body weight gain was significantly decreased in the 360 mg/kg/day TCB group. Maternal liver weight, liver/body weight ratio, and hepatic microsomal protein content were unaffected by TCB treatment. Although Day 14 NADPH-cytochrome c reductase activity was affected only at 360 mg/kg/day TCB, the maternal hepatic microsomal cytochrome P-450 content was significantly increased by administration of both 120 and 360 mg/kg/day of TCB. Hepatic microsomal aminopyrine N-demethylase, ethoxyresorufin O-deethylase, and UDP-glucuronyl transferase activity towards p-nitrophenol were also increased at 120 and 360 mg/kg TCB. Glutathione S-transferase activity to 1-chloro-2,4-dinitrobenzene and 1,2 dichloro-4-nitrobenzene were both increased by pretreatment with TCB. Although pretreatment with 360 mg/kg/day TCB did not increase resorptions, embryolethality, or teratogenicity, embryonic development was significantly retarded by all four growth criteria used (head length, crown-rump length, somite number, and protein content).     

The relationship of alcohol consumption to atherosclerotic heart disease

A review of the literature indicated that moderate alcohol consumers appear to have a lower rate of heart disease and a lower mortality than nondrinkers or heavy drinkers. A geographic analysis of 20 countries in 1972 suggested that moderate alcohol consumption appeared to be negatively related to rates of heart disease mortality. A temporal analysis within the United States indicated that changes in alcohol consumption, particularly beer, were highly negatively related to changes in heart disease mortality for 1950 to 1975. The review, in addition to the geographic and temporal analyses, suggests a U-shaped relationship between alcohol consumption and heart disease. Possible reasons for the negative relationship between moderate alcohol consumption and heart disease were discussed, including relationships to high-density lipoprotein cholesterol, changes in food patterns, and stress.     

The less harmful cigarette

Risk assessment shows that the adverse effects of cigarette smoking on human health are clearly related to the total consumption of cigarettes. Such dose-response is evident from data on the incidence of lung and larynx cancer and is also supported by results from bioassays with Syrian golden hamsters and mice. The concept of a less harmful cigarette, therefore, involves primarily a reduction of the quantities of tar and nicotine in cigarette smoke. The identification of tumorigenic and toxic tobacco smoke constituents and the study of their formation during smoking has guided the development of products with 40–60% reduction of sales-weighted tar and nicotine levels in most western countries. These changes have been effected mainly through development of efficient filter tips, through selection of specific tobacco types, and modifications in tobacco blends, including the technology of reconstituted tobacco preparation. This presentation discusses details of the development of cigarettes with reduced levels of tar, nicotine, and carbon monoxide. It is emphasized that the risk for diseases associated with tobacco usage can be eliminated only by abstention from smoking, but that a risk reduction through product modification has been achieved and may be further improved.     

Role of nitrosation in the mutagenic activity of coal dust: A postulation for gastric carcinogenesis in coal miners

The mutagenicity of coal dust solvent extracts with and without nitrosation was studied using the Salmonella/microsome assay system. Coal dust solvent extracts were either non-mutagenic or very weakly mutagenic with S9 activation. High mutagenic activities, however, were found when extracts of bituminous, subbituminous, and lignite coal dusts were reacted with nitrite under an acidic condition. Formation of mutagens from coal dust extracts by nitrosation was highest at pH 3.2 and decreased with increasing pH in the reaction mixture. Mutagenic activity appeared to be independent of metabolic activation. The mutagens formed from nitrosation of coal dust extracts induced frameshift mutations. The results reported here may have possible implications for the explanation of an elevated incidence of gastric cancer in coal miners.     

Absence of initiating activity by quercetin in the rat liver

Initiating activity of quercetin was tested in rats which were treated with partial hepatectomy and given a liver cancer promoter, phenobarbital. A few intestinal neoplasms were seen but without significant difference in incidence from those in the quercetin-untreated group. Moreover, neither neoplastic nor preneoplastic liver changes were detected in quercetin-treated groups. With hepatocyte primary culture/DNA repair test, quercetin did not produce genotoxicity. The results show that quercetin has no initiating or genotoxic activities in the rat liver.     

Evidence for an intimate geochemical factor in the etiology of esophageal cancer

Epidemiological data for esophageal cancer in the Butterworth District, Transkei, was used to calculate incidence contours which confirmed large variations within short distances (less than 5 km). High- and low-risk zones were demarcated, and a close relationship with underlying geology observed. The low-incidence zones in the study regions were underlain by dolerite intrusions, whereas higher-risk regions were on sedimentary strata. Analysis of rocks indicated that those from the higher-risk regions contain less copper, cobalt, and manganese. Soil samples were analyzed for boron, cobalt, copper, manganese, molybdenum, nickel, sodium, lead, vanadium, and zinc; the results also indicated a strong geochemical association with the disease. The concentrations of copper (P = 0.001), nickel (P = 0.001), and boron were markedly lower in the high-risk zones. Manganese, zinc, and molybdenum levels in soils also tended to be substantially lower in the high-risk zone.     

Recovery of ingested asbestos fibers from the gastrointestinal lymph in rats

Using the transmission electron microscope, asbestos fibers have been assessed in lymph fluid collected from the thoracic lymph duct in five groups of rats previously exposed to asbestos fibers (by ingestion). Ten rats were gavaged a single dose weighing approximately 20 mg. Five were given pure UICC chrysotile A while another group of five had pure UICC crocidolite. All the rats of the chrysotile group were positive animals with recovery rate values ranging from 6.9 × 10^?7 to 3 × 10^?5 (90% of the fibers being recovered during the first 16 hr following the gavage). The crocidolite group had only three positive animals and lower recovery rate values of 5.7 × 10^?8 to 5.6 × 10^?7. A third group was fed a synthetic diet containing 1%, by weight, chrysotile with a majority of short fibers (90% below 4 μm). Of the 15 rats comprising this group, 13 were positive with maximum daily recovery rates ranging from 2.1 × 10^?7 to 2.1 × 10^?6. A group of eight rats fed the same kind of diet but containing a higher proportion of long fibers, showed only four positive animals, however, they had higher daily recovery rates ranging from 1.9 × 10^?5 to 2.1 × 10^?4. No fibers were encountered in the samples of the two control rats. This study demonstrates the passage of chrysotile and crocidolite fibers across the gastrointestinal wall, with the passage rate being higher for long fibers than short ones.     

Assessment of potential exposure to antineoplastic agents in the health care setting

In response to reports of measurable air levels of antineoplastic agents in hospitals and preliminary evidence of exposure to personnel handling these agents, a survey was designed and conducted to document the current handling practices of injectable antineoplastic drugs by hospital and health care workers at two major teaching hospitals and three affiliated community hospitals. The survey included assessment of drug preparation, administration, and disposal. A sample of nurses, pharmacists, physicians, and other staff who routinely come in contact with these drugs was interviewed for validation of the observed results. Typical working conditions encountered and the potential numbers of people at risk and their job titles are presented here. Drug preparation facilities and methods were not uniform even within a single institution, including local preparation in the pharmacy under controlled or uncontrolled conditions, as well as individual drug preparation and administration on the hospital floors. Handling practices for drug preparation were not consistent from practitioner to practitioner. In some cases, where laboratory coats and disposable gloves were provided, it was not a routine practice to wear them. Based on such analysis of risk factors, recommendations for improved practices are given.