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Biomedical subjects

E C Hammond

Publications and source records attributed to E C Hammond.

At least 19 recordsLinked to original sources
PubMed1985

Matched groups analysis method.

The matched group analysis method in prospective studies is a variation of matched pairs analysis with the advantage of sampling error avoided in the choosing of pairs of subjects. An example is shown in which comparisons are given of mortality in triads of cases classified by the tar and nicotine level of the cigarettes they smoked and matched on 10 variables. The method can also be used in retrospective and autopsy studies.

Adult↗
PubMed1983

Possible contribution from epidemiological studies.

The problem of chemically contaminated water supplies are in general terms followed by a description of three examples of water supply problems in China. A large-scale prospective epidemiological study, now in the early planning stages, to be carried out in China is also described.

China↗
PubMed1982

Mortality of brain tumors among asbestos insulation workers in the United States and Canada.

Death resulting from brain tumors among workers in the petrochemical industry have called attention to the possibility that these neoplasms may be the result of occupational exposure to carcinogens. We have examined the experience of a cohort of 17,800 insulation workers known to be at significant increased risk of cancer at a number of sites (lung, mesothelioma, gastrointestinal, oral cavity, pharyngeal, larynx, renal) to ascertain whether their asbestos exposure also increased their risk of brain tumors. From 1967 to 1979, there were 24 deaths from primary brain tumors in this cohort, somewhat more than were anticipated (18.0 such deaths were expected based on U.S. general population data, and 20.5 if smoking was taken into account). The excess was not "statistically significant" at the 5% level although this does not rule out the possibility of an etiological association. It was of interest that the observed excess was concentrated (about twice expected) among insulators in the younger ages (those under 50) and during the early period after onset of work (15-24 years), in contrast with age distribution and latency in other asbestos-associated neoplasms. This may have relevance to theoretical concerns about questions of initiation and promotion in the etiology of cancer, particularly with regard to brain tumors.

Adult↗
PubMed1980

Latency of asbestos disease among insulation workers in the United States and Canada.

Two thousand two hundred seventy-one deaths were recorded among 17,800 asbestos insulation workers observed from January 1, 1967-December 31, 1976. There was little increase in cancer deaths or of asbestosis in less than 15-19 years from onset of employment. In general, though, the period of clinical latency was 2-4 decades or more and there were important differences among the several asbestos-associated diseases. Lung cancer peaked at about 30-35 years from onset and asbestosis at 40-45 years. Each tended to decline in incidence afterwards. Pleural and peritoneal mesothelioma reached their highest incidence later than lung cancer, but the incidence did not decline. In studies of effects of asbestos exposure, it appears advantageous to observe for at least 35-40 years or more from onset of exposure and to analyze the experience in duration-from-onset categories. If this is not possible, only the very limited early effects will be identified and the full import of the exposure may not be appreciated.

Adolescent↗
PubMed1980

Presence of asbestos bodies in organs other than the lung.

This study was designed to test the hypothesis that subjects with many asbestos bodies in their lungs at autopsy would also have asbestos bodies in various other organs. The subjects included 19 cases with diagnosis of asbestosis at death (two of these had mesothelioma, five had lung cancer) and 18 with pleural plaques but not asbestosis. Occupational histories were obtained from relatives. In subjects occupationally exposed to asbestos, large numbers of asbestos bodies were found in the lungs, and in most of these, asbestos bodies were found in many of the other organs examined. In the 18 cases with only pleural plaques found at autopsy, considerably fewer asbestos bodies were found in the lungs. The number of other organs with one or more asbestos bodies ranged from 32 percent to 62 percent of the sites examined. The findings seem to confirm the hypothesis of the study.

Aged↗
PubMed1979

Changes in bronchial epithelium in relation to cigarette smoking, 1955-1960 vs. 1970-1977.

To test the hypothesis that the reduction in tar and nicotine content of cigarette smoke that began in the 1950s should be reflected by the histologic changes in the bronchial epithelium of cigarette smokers, 20, 424 sections taken at autopsy from the bronchial tubes of 445 men (non-lung-cancer deaths) were examined microscopically in random order. There were 211 men who died in 1955-1960, of whom 154 smoked regularly, and 234 men who died in 1970-1977, of whom 181 were regular smokers. Changes studied included basal-cell hyperplasia, loss of cilia and occurrence of cells with atypical nuclei. In both periods studied these histologic changes occurred far less frequently in nonsmokers than in cigarette smokers and increased in frequency with amount of smoking, adjusted for age. Sections with advanced histologic changes in those dying in 1955-1960 occurred in 0 per cent of nonsmokers, in 2.6 per cent of those smoking one to 19 cigarettes a day, in 13.2 per cent of those smoking 20 to 39 and in 22.5 per cent of those smoking 40+ cigarettes a day. In those who died in 1970-1977 the percentages were 0, 0.1, 0.8, and 2.2, respectively.

Adult↗
PubMed1979

Short and long sleep and sleeping pills. Is increased mortality associated?

Prospective epidemiologic data of the American Cancer Society disclosed that reported usual sleep durations among groups who complained of insomnia and sleeping pill use "often" overlapped with those of groups who had no complaints. Reports of insomnia were not consistently associated with increased mortality when several factors were controlled; however, men who reported usually sleeping less than four hours were 2.80 times as likely to have died within six years as men who reported 7.0 to 7.9 hours of sleep. The ratio for women was 1.48. Men and women who reported sleeping ten hours or more had about 1.8 times the mortality of those who reported 7.0 to 7.9 hours of sleep. Those who reported using sleeping pills "often" had 1.5 times the mortality of those who "never" used sleeping pills. These results do not prove that mortality could be reduced by altering sleep durations or by reducing hypnotic prescribing. Rather, studies are needed to determine the causes of these mortality risk factors.

Adult↗
PubMed1979

Adenomatous lesions of the large bowel: an autopsy survey.

A comprehensive autopsy survey of the large bowel showed that adenomas were very common lesions occurring in about one-half of the 518 cases studied. The great majority were small adenomatous polyps (tubular adenomas), 86.7% measuring less than 10 mm in diameter. Adenomas with a more complex tubulovillous pattern were larger with a mean diameter of 19.0 mm. There was no apparent incresae in mean size of adenomas with age. Nineteen clinically unsuspected cancers were discovered. Fourteen (8 in situ and 6 invasive) cancers had areas of residual benign adenoma. Five invasive cancers had no residual benign component. No in situ carcinomas or small (less than 10 mm) invasive cancers not containing residual adenoma were found. The results suggest that, although adenomas of the large bowel are very common, the vast majority are simple adenomatous polyps which do not undergo progressive growth and malignant change. Conversely, it appears that cancers may arise from benign adenomas which have the characteristics of large size and a more complex villous architecture.

Adenoma↗