The impact of smoking habits on lung cancer risk: 28 years' observation of 26,000 Norwegian men and women

While factory-made cigarettes dominate the market in most countries, the use of handrolled cigarettes accounts for a substantial proportion of the tobacco consumption in Norway. In the present study, we examined the impact of tobacco smoking on lung cancer in general, and the effect of handrolled cigarettes in particular. The data used was from a self-administered mailed questionnaire which included questions about smoking habits and which was completed by about 26,000 men and women in 1964–65. During the follow-up from 1966 to 1993, 333 lung cancers in men and 102 in women were registered. The analysis was performed by use of the Cox proportional hazards regression models. A clear dose-response relationship was found both for cigarette smoking, and for pipe smoking (in men). The dose-response relationship of cigarette smoking was seen in all the three histologic groups considered-squamous cell carcinoma, adenocarcinoma, and small cell carcinoma. The highest relative risks were noted in squamous cell and small cell carcinoma. A higher risk of lung cancer was found for cigarette-smoking women who started cigarette smoking before the age of 30 compared with similar groups of men. In a combined analysis of men and women, and elevated relative risk of 1.9 (95 percent confidence interval=1.2–3.3) was found for those smoking only handrolled cigarettes compared with those smoking factory-made filter cigarettes only.Authors are with the Cancer Registry of Norway, Oslo, Norway. Address correspondence to Mr Engeland, the Cancer Registry of Norway, Institute for Epidemiological Cancer Research, Montebello, N-0310 Oslo, Norway. This work was supported by grant no. 95080/001 from the Norwegian Cancer Society and Contract PH-64-499 from the US National Cancer Institute.     

Reproductive variables and risk of uterine cervical cancer in Norwegian registry data

The influence of reproductive variables on cervical cancer incidence, controlling for other sociodemographic factors, was estimated in Norwegian register and census data, using Poisson regression models. Among the 1.3 million women under observation, a total of 2,870 cases of cervical cancer were diagnosed. According to models restricted to parous women, parity level had no independent impact on cervical cancer incidence, but a clear effect of age at first birth was noted. It was most pronounced in the squamous cell carcinomas, where the incidence was reduced by 48 percent from age at first birth <21 years to age at first birth 27+years. Women without children had the same cervical cancer incidence as parous women with a first birth after age 24. The sociodemographic variables controlled for exerted a strong net effect on the cervical cancer incidence. Educational level was related inversely to the cancer risk. Moreover, an increased risk was seen for women who had given birth when they were still single (never married) and for those who were divorced/separated at the time of the last previous census. A fairly small excess risk was found to be associated with living in non-rural compared with rural areas.Dr Bjørge is with the Cancer Registry of Norway, Oslo, Norway. Dr Kravdal is with the Section for Demography, Department of Economics, University of Oslo, Oslo, Norway. Address correspondence to Dr Bjørge, the Cancer Registry of Norway, Institute for Epidemiological Cancer Research, Montebello, N-0310 Oslo, Norway. This work was supported by grant no. 95034/001 from the Norwegian Cancer Society.     

Incidence of breast cancer in Norwegian female radio and telegraph operators

Exposure to electromagnetic fields may cause breast cancer in women if it increases susceptibility to sex-hormone-related cancer by diminishing the pineal gland's production of melatonin. We have studied breast cancer incidence in female radio and telegraph operators with potential exposure to light at night, radio frequency (405 kHz-25 MHz), and, to some extent, extremely low frequency fields (50 Hz). We linked the Norwegian Telecom cohort of female radio and telegraph operators working at sea to the Cancer Registry of Norway to study incident cases of breast cancer. The cohort consisted of 2,619 women who were certified to work as radio and telegraph operators between 1920 and 1980. Cancer incidence was analyzed on the basis of the standardized incidence ratio (SIR), with the Norwegian female population as the comparison group. The incidence of all cancers was close to unity (SIR=1.2). An excess risk was seen for breast cancer (SIR=1.5). Analysis of a nested case-control study within the cohort showed an association between breast cancer in women aged 50 + years and shift work. In a model with adjustment for age, calendar year, and year of first birth, the rate ratio for breast cancer associated with being a radio and telegraph operator-in comparison with all Norwegian women born 1935 or later-analyzed with Poisson regression, was 1.5 after adjustment for fertility factors. These results support a possible association between work as a radio and telegraph operator and breast cancer. Future epidemiologic studies on breast cancer in women aged 50 and over, should address possible disturbances of chronobiological parameters by environmental factors.Mssrs Tynes, Andersen, and Haldorsen are with the Cancer Registry of Norway, Oslo, Norway. Authors are also affiliated with the Radiation Protection Authority, Østerås (Ms Hannevik, Mr Tynes), and the University of Oslo, Physics Department, Oslo, Norway (Dr Vistnes). Address correspondence to Mr Tynes, Norwegian Radiation Protection Authority, Pilestredet 46, N-0167 Oslo, Norway.     

Adolescent smoking and trends in lung cancer incidence among young adults in Norway 1954–1998

OBJECTIVE: To describe the national trends in lung cancer incidence among young adults and the relationship to adolescent smoking. METHODS: Between 1954 and 1998, a total of 1108 non-carcinoid lung cancers were reported to the Cancer Registry of Norway in individuals aged 20-44 years. Temporal variations were studied in age and sex specific rates, in age-adjusted rates, and by means of age-period-cohort modelling. The association between cancer incidence and smoking prevalence was evaluated. RESULTS: The lung cancer incidence rate among women aged 40-44 in Norway continued to increase into the most recent time interval (1994-1998) whereas the rate among men aged 40-44 was essentially constant after 1970. Consequently, lung cancer incidence rates converged among male and female young adults. Lung cancer incidence rates at age 40-44 were highly correlated with smoking prevalence at age 15-19 in males ( r = 0.88) and females ( r = 0.82) within the same birth cohort. CONCLUSIONS: The lung cancer incidence rate in young Norwegian women now equals that of men. The risk at age 40-44 was closely associated with teenage smoking, indicating that duration and age of onset are important.     

Norwegian case-control study testing the hypothesis that seafood increases the risk of thyroid cancer

The hypothesis that consumption of seafood increases the risk of thyroid cancer has been tested by means of a matched case-control study. Linking the file of the National Health Screening Service (NHSS) containing dietary information about 60,000 Norwegians with the 1955–89 thyroid-cancer file of the Cancer Registry, by means of the 11-digit person-number, resulted in 92 cases—each of whom was matched with five controls with regard to age, gender, and place of residence. Forty-eight cases had answered questions on diet before diagnosis; 44 did so after diagnosis. Exposure data on seafood and seafood-related vitamins were recovered from the NHSS files for all 552 subjects. Odds ratios (OR) were computed by means of conditional logistic regression analysis. Univariate analysis of the 48 sets in which the case had answered the dietary questionnaire prior to the thyroid cancer diagnosis, as well as of all 92 sets, indicate that regular users of cod-liver oil, fish liver, or fish sandwich-spread run a higher risk of thyroid cancer than irregular and nonusers, and people eating more fish dinners per week also run a higher risk of thyroid cancer. Stepwise regression analysis corroborates the study hypothesis by showing that these two seafood variables increase the risk of thyroid cancer significantly. On the other hand, the results of a simultaneous regression analysis of these two seafood variables and a dietary vitamin-D index-variable tend to reduce the tenability of the above-mentioned conclusion since none of the OR estimates (all greater than one) reached significance in this part of the statistical analysis.Dr Glattre and Mr Haldorsen are with the Cancer Registry of Norway, Oslo, Norway. Dr Berg is with The Norwegian Radium Hospital, Oslo, Norway, and the Norwegian Cancer Society. Ms Stensvold is with the National Health Screening Service, Oslo, Norway. Ms Solvoll is with the Section for Dietary Research, University of Oslo, Norway. Correspondence should be addressed to Dr Glattre, Cancer Registry of Norway, Montebello, 0310 Oslo, Norway.     

Incidence of cancer among male waiters and cooks: two Norwegian cohorts

Previous occupational survey studies have identified waiter and cook as possible high risk occupations for cancer. However, few cohort studies have been performed among persons in the restaurant business, and we therefore have analyzed cancer incidence in two cohorts of Norwegian waiters and cooks. The cohorts consisted of skilled male workers, 1,463 waiters and 2,582 cooks, who received their craft certificate between 1958 and 1983. The cohorts were followed from 1959 through 1991. The standardized incidence ratio (SIR) for all causes of cancer was 1.4 (95 percent confidence interval [CI]=1.2–1.7] for waiters, and 1.1 (CI=0.9–1.4) for cooks. Cancers of the tongue, mouth, pharynx, larynx, esophagus, and liver were grouped together as alcohol-associated cancers. SIR for these cancers combined was 5.1 (CI=3.4–-7.4) for waiters and 4.2 (CI=2.2–7.2) for cooks. For lung cancer, SIR was 2.0 (CI=1.3–2.9) for waiters and 0.7 (CI=0.2–1.7) for cooks. For alcohol-associated cancers, the analysis carried out according to number of years since first employment showed a larger number of cases than expected for both occupations in all time-periods. The excess of lung cancer cases among waiters appeared after 30 years or more of employment. The study shows that waiters and cooks are at high risk of cancers associated with alcohol consumption, and that waiters, in addition, show high rates for lung cancer. The hypothesis of an occupational lung-cancer risk in cooks was not supported by this study.Dr Kjerheim and Mr Andersen are with The Cancer Registry of Norway. Address crrespondence to Dr Kjerheim, The Cancer Registry of Norway, Institute for Epidemiological Cancer Research, Montebello, 0310 Oslo, Norway. This project was supported by grants from the Confederation of Norwegian Business and Industry.     

Cigarette smoking and liver cancer among US veterans

The relationship of tobacco use with risk of primary liver cancer was investigated using data from a 26-year mortality follow-up of nearly 250,000 US veterans, mostly from World War I. Significantly increased risks for liver cancer (289 deaths) were associated with most forms of tobacco use, including pipe and cigar smoking. Elevated relative tisks (RRs) were seen for current cigarette smokers (RR=2.4; 95 percent confidence interval [CI] 1.6–3.5) and former cigarette smokers (RR=1.9, 1.2–2.9). A strong dose-response relationship (P<0.001) was found for cigarette smoking, with smokers of 40 or more cigarettes per day having almost a fourfold risk (RR=3.8, 1.9–8.0). Risks were also found to increase significantly with years of cigarette use and with earlier age at the start of cigarette smoking. These results are consistent with those of other cohort and case-control studies, suggesting that cigarette smoking may be related to the risk of liver cancer.All authors are in the Epidemiology and Biostatistics Program, Division of Cancer Etiology, National Cancer Institute. Address correspondence to Dr Hsing at Executive Plaza North, Room 415, Bethesda, MD 20892, USA.     

Lifestyle changes during adolescence and risk of breast cancer: an ecologic study of the effect of World War II in Norway

There are biologic reasons to believe that the period between thelarche and the first full-term pregnancy is a particularly sensitive period in a woman's life regarding the development of breast cancer. In this ecologic study, data provided by the Norwegian Cancer Registry were analyzed to compare risk of breast cancer among women who experienced this sensitive period before, during, or after World War II. An ordinary age-cohort model and a model where the cohort was described by exposure by calendar period and sensitivity to this exposure at different ages, were fitted to the data. The incidence of breast cancer was lower than expected among women who experienced puberty during the war. The estimated configuration of the exposure variable showed an increase in exposure up to the start of WWII to twice the levelin 1916, dropped by 13 percent during the war, and increased again after the war. The levelin 1975 was approximately 2.7 times higher than the level in 1916. The results indicate that one or more lifestyle factors that changed among adolescent women during the war, influenced their risk of breast cancer. Dietary intake of energy, fat, meat, milk, fish, fresh vegetables, and potatoes, in addition to physical activity level and height, are important factors to consider in relation to breast cancer risk.Tretli and Gaard are with the Cancer Registry of Norway. Address correspondence to Dr Tretli, The Cancer Registry of Norway, Institute for Epidemiological Cancer Research, Montebello, 0310 Oslo, Norway.     

Cigar and pipe smoking and lung cancer risk: a multicenter study from Europe

BACKGROUND: Because limited information is available on the quantitative association between consumption of tobacco products other than cigarettes and lung cancer risk, we undertook a case-control study of this relationship. METHODS: We investigated lung cancer risk among smokers of cigars and/or cigarillos only and of pipes only and compared these risks with the risk of smokers of cigarettes only in a case-control study conducted in seven European areas. Our study population consisted of 5621 male case patients with lung cancer and 7255 male control subjects. Each subject or his proxy was interviewed with respect to the subject's smoking history and other risk factors for lung cancer. RESULTS: The odds ratio (OR) for smoking cigars and cigarillos only was 9.0 (95% confidence interval [CI] = 5.8-14.1), based on 43 exposed case patients and 77 exposed control subjects, and the OR for smoking a pipe only was 7.9 (95% CI = 5.3-11.8), representing 61 case patients and 129 control subjects. The OR for smoking cigarettes only was 14.9 (95% CI = 12.3-18.1), based on 4204 case patients and 3930 control subjects. A dose-response relationship was present for duration of use and cumulative consumption both for cigars and cigarillos and for pipe tobacco. An effect was also suggested for inhalation of cigar and cigarillo smoke. The dose-response relationships between lung cancer risk and either duration of smoking or average and cumulative consumption were similar for cigar and cigarillo smoking, pipe smoking, and cigarette smoking. CONCLUSION: Our results suggest that smoking of European cigars, cigarillos, and pipe tobacco might exert a carcinogenic effect on the lung comparable to that of cigarettes.     

Cigarette smoking and risk of prostate cancer in middle-aged men.

Cigarette smoking may increase the risk of prostate cancer by affecting circulating hormone levels or through exposure to carcinogens. Although there are plausible mechanisms that could explain an association between smoking and prostate cancer, previous studies are inconsistent. The goal of this population-based case-control study was to assess this association in middle-aged men. Cases (n = 753) were men ages 40-64 years diagnosed with prostate cancer from 1993 to 1996 identified using the Seattle-Puget Sound Cancer Registry. Age-matched controls without prostate cancer from the same region (n = 703) were identified using random digit dialing. Participants completed detailed in-person interviews. Logistic regression was used to compute adjusted odds ratios (ORs) and 95% confidence intervals (CIs) to assess the prostate cancer-cigarette smoking relationship. Current smokers had an increased risk (OR = 1.4, 95% CI 1.0-2.0) relative to nonsmokers. A dose-response relationship was noted between number of pack-years smoked and prostate cancer risk (trend P = 0.03). The OR = 1.6 (95% CI 1.1-2.2) for men with >40 pack-years of smoking, with a stronger association observed in men with more aggressive disease (OR = 2.0, 95% CI 1.3-3.1). Smoking cessation resulted in a decline in risk (trend P = 0.02). Smoking is associated with a moderately increased relative risk of prostate cancer. Furthermore, a dose-response relationship exists between number of pack-years smoked and cancer risk. Given that smoking cessation seems to reduce these risks, results from this study have public health ramifications and suggest that prostate cancer should be added to the list of tumors for which cigarette smoking is a risk factor.     

Lung cancer and cigarette smoking in women: a multicenter case-control study in Europe

The association between cigarette smoking and lung cancer risk in women was investigated within the framework of a case-control study in 9 centres from 6 European countries. Cases were 1,556 women up to 75 years of age with histologically confirmed primary lung cancer; 2, 450 controls with age distribution similar to cases were selected. The predominant cell type was adenocarcinoma (33.5%), with similar proportions for squamous-cell type (26.4%) and small-cell carcinoma (22.3%). Overall, smoking cigarettes at any time was associated with a 5-fold increase in lung cancer risk (odds ratio 5.21, 95% confidence interval 4.49-6.04); corresponding figures for current smoking habits were 8.94, 7.54-10.6. The association showed a dose-response relationship with duration of the habit and daily and cumulative lifetime smoking. A significant excess risk of 70% was associated with every 10 pack-years smoked. After 10 years of smoking cessation, the relative risk decreased to 20% compared to current smokers. The following characteristics were associated with a higher relative risk: inhalation of smoke, smoking non-filter cigarettes, smoking dark-type cigarettes and starting at young age. The association was observed for all major histological types, being the strongest for small-cell type carcinoma, followed by squamous-cell type and the lowest for adenocarcinoma. The proportion of lung-cancer cases in the population attributable to cigarette smoking ranged from 14% to 85%. We concluded that women share most features of the association between cigarette smoking and lung cancer observed in men.     

Cancer in waiters

The risk of cancer was studied in 2,413 males registered as waiters at the 1960 census in Norway. A personal identification number was used in linking this cohort of waiters with the Norwegian Cancer Registry. The follow-up period was 1961-1984. An excess risk of cancer was observed for the following primary sites: upper respiratory and digestive tracts combined 42 observed against 11.3 expected, liver (14 versus 2.87), rectum (28 versus 13.89), and lung (67 versus 43.66). The highest risk for all these types of cancer was seen among those who were waiters at both censuses in 1960 and 1970. In the case of cancer of the stomach the observed number of cases was significantly lower than expected (14 versus 25.68). It is known that smoking habits and alcohol consumption are substantial aetiological factors for the types of cancer in which an excess risk has been demonstrated here.     

Cigarette smoking and lung cancer in women: results of the French ICARE case-control study

Background

The incidence of female lung cancer in developed countries has been increasing since 1950. In order to have recent and reliable data on the association between cigarette smoking and the risk of lung cancer in women, we analysed cases from a French population-based case-control study.

Methods

The ICARE study is a multicenter case-control study on respiratory cancers (lung and UADT cancers), set up in 10 départements that include a general cancer registry. We included 648 women lung cancer cases up to 76 years of age, with a histologically confirmed primary lung cancer. The 775 controls were randomly selected from the general population and frequency-matched with cases by age and département.

Results

Overall, smoking cigarettes at some time was associated with a 8-fold increase in lung cancer risk (OR = 8.2, 95% CI 6.0-11.4). A dose-response relationship was observed as a function of duration, intensity and pack-years. Using restricted splines cubic models, we have shown that intensity dose-response departed significantly from linearity while the risk increased linearly with duration and decreased linearly with time since cessation. The following characteristics were associated with a higher relative risk: smoke inhalation, smoking non-filter cigarettes, smoking dark tobacco cigarettes and starting at a young age. In addition, duration, intensity and time since cessation was significantly related with histological type. This was not the case for characteristics such as the use of a filter or not, the inhalation pattern, or the type of tobacco smoked. The proportion of lung cancer cases attributable to cigarette smoking was 55% (95% CI: [47-63%]).

Conclusions

Our results confirm that cigarette smoking is by far the most important cause of the current epidemic of lung cancer among French women and that the most important smoking-related variables for varying the risk of lung cancer are the duration, the intensity and the time since cessation.     

Cigarette smoking and leukemia: results from the Lutheran Brotherhood Cohort Study

In a 20-year follow-up (1966–86) of 17,633 White males who described tobacco use in a mailed questionnaire sent in 1966, there were 74 deaths from leukemia (including 30 myeloid, 30 lymphatic, and 14 other and unspecified leukemia). Among men who ever smoked cigarettes, increased risks were observed for lymphatic (relative risk [RR]=2.7), and other and unspecified leukemia (RR=1.5); risks rose with increasing number of cigarettes smoked, although the dose-response relationship was statistically significant only for total leukemia. Mortality from myeloid leukemia was not elevated, except among those smoking over a pack of cigarettes per day. Results from this cohort support a relationship between cigarette smoking and leukemia. Further studies are needed to elucidate subtype associations with cigarette smoking.Drs Linet, McLaughlin, Hsing, Wacholder, and Blot are with the Epidemiology and Biostatistics Program, National Cancer Institute. Dr Co-Chien is at Westat, Inc., Rockville, Maryland, USA, Dr Schuman is at the University of Minnesota, Minneapolis, Minnesota, USA. Dr Bjelke is with the Center for Epidemiologic Research, University of Bergen, Norway. Address correspondence to Dr Linet, Epidemiology and Biostatistics Program, National Cancer Institute, Executive Plaza North Room 415B, Bethesda, MD 20892, USA.     

Tobacco, alcohol use, and risks of laryngeal and lung cancer by subsite and histologic type in Turkey

Effects of tobacco smoking and alcohol use on risks of cancers of thelarynx and lung have been evaluated extensively in industrialized countries.Few studies on the effect of these risk factors have been reported fromdeveloping countries. We conducted a case-control study to evaluate risks oflaryngeal and lung cancers in men by subsite and cell type in relation tosmoking and alcohol drinking in Turkey, a country where smoking and alcoholconsumption patterns are different from those in industrialized countries. Weidentified 832 laryngeal and 1,210 lung cancer cases and 829 controls withinformation on smoking and alcohol use (amount and duration) and histologiccell type from an oncology treatment center of a Social Security Agencyhospital in Istanbul, Turkey, admitted between 1979 and 1984. Both laryngealand lung cancer showed significant associations with smoking and alcoholdrinking, but no monotonic dose-response was obtained for alcohol drinking.Among smokers, the highest risks were observed in the supraglottis region ofthe larynx (odds ratio [OR] = 4.1) after adjustment for age and alcohol use.Among alcohol drinkers, the highest risks were observed in the glottis regionof the larynx (OR = 1.7) after adjustment for age and smoking. In theanalysis by the cell type of lung cancer among ever-smokers, small cell typeshowed the highest risk (OR = 5.4), while it showed no association withalcohol drinking. Cumulative cigarette use (pack-years) and number ofcigarettes per day showed stronger associations than years smoked for bothcancer sites. The relative risks of joint exposure to smoking and alcoholwere 12.2 for laryngeal cancer and 14.1 for lung cancer among heavy smokersand heavy alcohol drinkers. This study provides epidemiologic evidence fromTurkey that smoking and alcohol use are associated with risks of cancers ofthe larynx and lung.     

Associations between cigarette smoking and the risk of four leading cancers in Miyagi Prefecture, Japan: a multi-site case-control study

Although cigarette smoking is a well-known risk factor of lung cancer, associations of cigarette smoking with the risk of other sites have not been fully elucidated in Japan. To simultaneously evaluate the associations of cigarette smoking with the risks of cancers of the stomach, lung, colon, and rectum, which have been the leading cancer sites in recent years in Miyagi Prefecture, Japan, we conducted a hospital-based case-control study. Study subjects consisted of 614 stomach, 515 lung, 324 colon, and 164 rectal cancer cases and 2444 hospital controls admitted to a single hospital in Miyagi Prefecture from 1997 to 2001. Information on smoking habit and other lifestyle factors was collected using a self-administered questionnaire. Distributions of referral base among cases and controls were also investigated. For each site, odds ratios (ORs) and 95% confidence intervals (95% CIs) for smoking habit were estimated with adjustment for age, year of survey, history of alcohol drinking, family history of index cancer, and occupational history, respectively, using an unconditional logistic regression model. Cigarette smoking (ever vs. never) was associated with an increased risk of stomach (OR = 1.62; 95% CI 1.20-2.19) and lung (OR = 3.82; 95% CI 2.49-5.86) cancer among males and lung cancer among females (OR = 2.02; 95% CI 1.28-3.18). For female stomach cancer, the association with cigarette smoking was uncertain (OR = 0.65, P = 0.1533). For rectal cancer, a significant increased risk was observed in both-sex-combined analysis. There was no association between cigarette smoking and the risk of colon cancer. Detailed analysis showed that the association of cigarette smoking with cancer risk might be modified by the patient referral pattern, i.e., screened or not screened. The present results indicate that the association of cigarette smoking with cancer risk may differ among sites and sexes. In terms of the population attributable risk, a large proportion of leading cancers in males appears to be related to cigarette smoking.     

A case-control study of stomach cancer and its relation to diet,cigarettes, and alcohol consumption in Saitama Prefecture,Japan

A case-control study of stomach cancer in relation to dietary, smoking, and drinking habits was undertaken in Saitama Prefectur, Japan. The study was based on 294 cases of newly diagnosed adenocarcinoma of the stomach at a single institution, 294 general population controls (matched by sex, age, and administrative division), and 202 hospital controls. Dietary habits were investigated based on the intake of 12 separate foods and 12 food groups in a food frequency questionnaire, together with individual food preferences. The consumption of raw vegetables was inversely related to the risk of stomach cancer, with a dose-response relation observed consistently in the comparisons with both sets of controls. Current cigarette smokers (1–29/day) had an increased risk (relative risk = 1.8,95 percent confidence interval = 1.1–3.0) compared with nonsmokers in the general population controls, but no dose-response effect with heavier cigarette smoking. Alcohol use did not affect the risk of stomach cancer. In the multiple logistic regression, the comsumption of raw vegetables showed a protective effect on stomach cancer while cigarette smoking had no significant association, in both sets of controls.Drs Hoshiyama and Sasaba are in the Department of Epidemiology, Saitama Cancer Center Research Institute, Japan. Address correspondence to Dr Hoshiyama, Komuro 818, Ina, Saitama 362, Japan.     

Smoking and breast cancer risk in Denmark

The effect of smoking on breast cancer risk was evaluated in a population-based case-control study, including 1,480 women diagnosed with breast cancer in Denmark between 1983–84. They were identified from the files of the nationwide clinical trial of the Danish Breast Cancer Cooperative Group and the Danish Cancer Registry. The control group was an age-stratified sample of 1,332 women from the general population. Data on risk factors were collected by self-administered questionnaires. The risk of breast cancer among current smokers and ex-smokers was similar to that in non-smokers, both risk estimates being close to unity. No dose-response relation was observed for any measure of smoking (age at start, duration, number of cigarettes per day, or cigarette-years of exposure) in all subjects, and when pre- and post-menopausal women were examined separately. These findings suggest that smoking is not associated with the risk of breast cancer.This work was undertaken during tenures of fellowships awarded to Dr. M. Ewertz by the Danish Cancer Society and the International Agency for Research on Cancer. The study was funded by the Danish Cancer Society, the Danish Medical Research Council, and Astrid Thaysens Legat.Dr Ewertz is with the Danish Cancer Registry, Institute of Cancer Epidemiology, Danish Cancer Society, Rosenvaengets Hovedvej 35, Box 839 DK-2100 Copenhagen Ø, Denmark.     

Evaluation of Certain Risk Factors for Lung Cancer in Cracow (Poland): A Case-Control Study

The relationship of lung cancer risk to cigarette smoking, occupational exposure, air pollution at permanent residence and usual frequency of consumption of fruits and vegetables was analysed in a case-control study in Cracow, Poland. The cases were 176 male lung cancer patients diagnosed in 1992-1994 with histological confirmation of the diagnosis, obtained from the population-based Cracow Cancer Registry, and 341 controls randomly selected from the general population. Classification of exposure to outside air pollution was based on measured level of total suspended particular matter and sulphur dioxide by particular districts of town (from 1973 to 1980). Except calculation of odds ratios for male lung cancer associated with exposures among all study subjects, the association between lung cancer risk and frequency of consumption of fruit and vegetables was examined among drinkers of vodka above average. Risk of lung cancer was increased significantly with increasing number of pack-years of smoking (OR = 18.7 for more than 40 pack-years). The significant inverse association of frequent usual consumption of boiled vegetables was present both among all subjects and among vodka drinkers (OR = 4.6 and 12.5, respectively, for a rare consumption). The risk of male lung cancer was negatively associated with the level of air pollution but positively with the percentage of occupationally exposed. Our study provides no evidence of a significant harmful effect of air pollution and found a strong inverse association between frequent fruit and vegetables consumption and lung cancer risk.