In 1951 the British Medical Association forwarded to all British doctors a questionnaire about their smoking habits, and 34440 men replied. With few exceptions, all men who replied in 1951 have been followed for 20 years. The certified causes of all 10 072 deaths and subsequent changes in smoking habits were recorded. The ratio of the death rate among cigarette smokers to that among lifelong non-smokers of comparable age was, for men under 70 years, about 2:1, while for men over 70 years it was about 1-5:1. These ratios suggest that between a half and a third of all cigarette smokers will die because of their smoking, if the excess death rates are actually caused by smoking. To investigate whether this is the case, the relation of many different causes of death to age and tobacco consumption were examined, as were the effects of giving up smoking. Smoking caused death chiefly by heart disease among middle-aged men (and, with a less extreme relative risk, among old men,) lung cancer, chronic obstructive lung disease, and various vascular diseases. The distinctive features of this study were the completeness of follow-up, the accuracy of death certification, and the fact that the study population as a whole reduced its cigarette consumption substantially during the period of observation. As a result lung cancer grew relatively less common as the study progressed, but other cancers did not, thus illustrating in an unusual way the causal nature of the association between smoking and lung cancer.

https://www.bmj.com/content/bmj/328/7455/1519.full.pdf

Mortality in relation to smoking: 50 years' observations on male British doctors

NOTE The report of the Committee without its annexes appears as Official Records of the General Assembly, Sixty-third Session, Supplement No. 46. The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. The country names used in this document are, in most cases, those that were in use at the time the data were collected or the text prepared. In other cases, however, the names have been updated, where this was possible and appropriate, to reflect political changes. Scientific Annexes Annex A. Medical radiation exposures Annex B. Exposures of the public and workers from various sources of radiation INTROdUCTION 1. In the course of the research and development for and the application of atomic energy and nuclear technologies, a number of radiation accidents have occurred. Some of these accidents have resulted in significant health effects and occasionally in fatal outcomes. The application of technologies that make use of radiation is increasingly widespread around the world. Millions of people have occupations related to the use of radiation, and hundreds of millions of individuals benefit from these uses. Facilities using intense radiation sources for energy production and for purposes such as radiotherapy, sterilization of products, preservation of foodstuffs and gamma radiography require special care in the design and operation of equipment to avoid radiation injury to workers or to the public. Experience has shown that such technology is generally used safely, but on occasion controls have been circumvented and serious radiation accidents have ensued. 2. Reviews of radiation exposures from accidents have been presented in previous UNSCEAR reports. The last report containing an exclusive chapter on exposures from accidents was the UNSCEAR 1993 Report [U6]. 3. This annex is aimed at providing a sound basis for conclusions regarding the number of significant radiation accidents that have occurred, the corresponding levels of radiation exposures and numbers of deaths and injuries, and the general trends for various practices. Its conclusions are to be seen in the context of the Committee's overall evaluations of the levels and effects of exposure to ionizing radiation. 4. The Committee's evaluations of public, occupational and medical diagnostic exposures are mostly concerned with chronic exposures of …

sources and effects of ionizing radiation

How much of the disease burden in a population could be eliminated if the effects of certain causal factors were eliminated from the population? To address this question, epidemiologists calculate the population attributable fraction. As noted in a recent editorial in the Journal, population attributable fraction estimates can help guide policymakers in planning public health interventions.' Despite numerous articles on population attributable fraction estimation, 2-7 errors in computation and interpretation persist. In addition, in certain settings, the value of a population attributable fraction estimate may be questionable. This commentary considers computational and conceptual issues relevant to population attributable fraction estimation that are infrequently discussed elsewhere, with illustrations from the breast cancer literature.

https://ajph.aphapublications.org/doi/pdfplus/10.2105/AJPH.88.1.15

Use and misuse of population attributable fractions.

Lung Cancer: Epidemiology, Etiology, and Prevention

Considerable indirect evidence, based on the natural history of colorectal cancer and the ability of tests to detect adenomas and invasive cancers, suggests that screening for colorectal cancer reduces mortality. Without screening, a 50-year-old person at average risk has approximately a 530-in-10,000 chance of developing invasive colorectal cancer in the rest of his or her life and approximately a 250-in-10,000 chance of dying from it. Analysis of indirect evidence with a mathematic model indicates that screening persons for 25 years, from the age of 50 to the age of 75 years should reduce the chance of developing or dying from colorectal cancer by 10% to 75%, depending on which screening tests are used and how often screening is done. Screening for colorectal cancer is optional. A possible recommendation is that annual fecal occult blood tests and 65-cm flexible sigmoidoscopy every 3 to 5 years be done for average-risk men and women who are between 50 and 75 years of age. In addition to having annual fecal occult blood tests, persons with first-degree relatives with colorectal cancer can be offered barium enemas instead of sigmoidoscopies every 3 to 5 years.

Screening for Colorectal Cancer

Mortality experience of insulation workers in the United States and Canada, 1943--1976.

The authors examine the relationship between exposure to asbestos dust cigarette smoking and mortality. The data covering 17800 asbestos workers in the United States and Canada were compiled from the records of the International Association of Heat and Frost Insulators and Asbestos Workers (ANNOTATION)

Asbestos exposure, cigarette smoking and death rates*

Very high survival rates have been observed in four through 11 years of follow-up in 4,240 women with a histologically confirmed diagnosis of breast cancer in the Breast Cancer Detection Demonstration Project (BCDDP). The relative five, eight, and 10-year survival rates were 88, 83, and 79 percent, respectively.



Allowances were made for lead-time bias among cancers detected through screening, and the validity of the findings was supported by internal analyses, which showed that length-time bias was of little, if any, importance, and that any possible “overdiagnosis” of cancer cases was also of small relevance. In view of current interest in the value of screening women before age 50, intensive analyses were made comparing the BCDDP data for women in their 40s with women in their 50s. In terms of kinds of breast cancers found, modality of finding them, and survival rates once they have been found, the parallel results for the two groups show that screening was vitually as effective in the younger as in the older women.



Some authorities are of the opinion that the benefits of mammography after age 50 are well documented, but at younger ages the evidence is still inconclusive. The findings in this study show there is no doubt of the very successful results of screening for breast cancer with mammography in younger as well as older women.



In comparing relative five-year and eight-year survival rates for women with invasive breast cancers detected through screening in the BCDDP, with those for cases diagnosed in the National Cancer Institute's Surveillance, Epidemiology and End Results (NCISEER) program from 1977 to 1982, it is seen that for individual subcategories by tumor size and nodal class, the survival rates are about the same. However, for overall invasive cancers, the five-year and eight-year survival rates were 87 and 81 percent, respectively, for the BCDDP, compared with 74 and 65 percent for SEER. Thus the substantial gains in survival followed the large shift toward a high proportion of cancers being diagnosed and treated in more favorable stages through the screening accomplishments.



With respect to the relative case fatality rates, the complements of the relative survival rates, the eight-year rate of 19 percent for the BCDDP versus that of 35 percent for SEER connotes 46 percent fewer women dying in the BCDDP group.

Survival experience in the breast cancer detection demonstration project

Mesothelioma death rates in asbestos workers appear to be proportional to the 3rd or 4th power of time from first exposure under a wide range of conditions of exposure for both pleural and peritoneal tumours, though the peritoneal:pleural ratio depends on fibre dimension and type. Age at first exposure has little or no influence, however, which supports the "multi-stage" model of carcinogenesis under which the increase in most cancer incidence rates with age is due to a constant incidence of genetic or epigenetic accidents, rather than to progressive generalized changes in regulatory or immune function. These relationships provide a simple basis for risk assessment, and support the suggestion that mesotheliomas may constitute a high proportion of cancer deaths resulting from early exposure to asbestos.

Mesothelioma mortality in asbestos workers: implications for models of carcinogenesis and risk assessment.

The usual measures of the magnitude of the cancer problem are annual incidence and mortality data We present another measure of the magnitude of the cancer problem We computed the probabilities at birth and at various ages of developing or dying of the disease within 10 years, 20 years, or total lifetime and show the trends that have occurred in these data since 1975 These probabilities were computed for males and females and among whites and blacks for 1975 and 1980, and projected to 1985 The data indicate a continuing, albeit modest, increase in the probabilities of eventually developing cancer in each of the four sex-race groups, both excluding and including carcinoma in situ White males now show the highest probability at birth of eventually developing cancer, and black females, the lowest, with the figures for the other two groups being intermediate Larger increases were seen for males between 1980 and 1985 (more than three percent) than for females (two percent or less) A child born in the US in 1985 has more than one in three chances of eventually developing invasive cancer (exclusive of epidermoid skin cancer) By site, for males the largest probabilities and the largest increases in the probabilities are for eventually developing lung and prostate cancer For women, the largest eventual probabilities are for breast cancer, almost one in 10 for white females and one in 14 for black females The largest increases are seen for lung cancer and cancer of the colon-rectum The probability of eventually dying of cancer is increasing among the four sex-race groups and is now greater for males of both races than for their female counterparts For males born in 1985, the chances of eventual death from cancer are almost one in four, and for females, almost one in five With the long-term, downward trends in terms of other causes of death--most specifically, decreases in mortality from cardiovascular diseases--the effect on the population at large is greater longevity This situation, in turn, leaves more people longer time to be exposed to cancer risks Thus, while the probabilities of developing or dying of cancer are seen to increase, the increases should be viewed in light of the increasing numbers of people available for such an occurrence(ABSTRACT TRUNCATED AT 400 WORDS)

Herbert Seidman

Papers

Mortality experience of insulation workers in the United States and Canada, 1943--1976.

Asbestos exposure, cigarette smoking and death rates*

Survival experience in the breast cancer detection demonstration project

Mesothelioma mortality in asbestos workers: implications for models of carcinogenesis and risk assessment.

Probabilities of eventually developing or dying of cancer--United States 1985