Objectives and interpretations.
Explore the source record for details and available documents.
Decision Trees↗
Biomedical subjects
G M Paddle
Publications and source records attributed to G M Paddle.
Mortality of employees in plants manufacturing 4,4'-bipyridyl.
A historical-prospective cohort study was conducted of 729 male employees of plants manufacturing 4,4'-bipyridyl. The cohort was studied because employment in some of the plants had been linked to malignant and nonmalignant skin lesions attributed to exposure to tarry by-products. The overall mortality experience of the cohort did not show any statistically significant findings. More-detailed analysis of subdivision of the cohort gave results that justified further inquiry into lung cancer incidence. A nested case-referent study did not indicate that any occupational factor other than employment in a bipyridyl plant was related to the incidence of lung cancer. The epidemiologic, toxicologic, and industrial hygiene information was assessed, and it was concluded that there was no evidence of a plausible occupational hazard of lung cancer to the bipyridyl workers, but that a follow-up of the cohort after an interval of five years should be undertaken.
Cohort Studies↗
Better quality studies through review of protocols.
The importance of a protocol is well recognized by scientists whose work is governed by good laboratory practices. Epidemiologists have used protocols for many years but have not always reaped the full benefits. Until relatively recently, there has been little consensus among epidemiologists about what constitutes a good protocol and, consequently, expectations of the pre-study review process may not be fulfilled. This paper examines some of the benefits to be derived from a good protocol and the importance of prestudy review. Our experience suggests that peer review cannot substitute for a competent principal investigator supported by a strong study management team. If such a study management team exists, the most important contribution of the external peer reviewer should be to ensure the impartiality of the study.
Clinical Protocols↗
Does formaldehyde cause nasopharyngeal cancer in man?
Formaldehyde is a widely used industrial chemical, which also has uses in consumer products, and hence large numbers of people are exposed to it. It is also an endogenous metabolite with measurable levels in body fluids and tissues. The reports of its carcinogenicity to rats have raised concern about its potential to cause a carcinogenic response in exposed populations. This letter reviews the information on the carcinogenicity of formaldehyde, particularly to the upper respiratory tract, in animals and man.
Adenoma↗
Chromosomal analyses in vinyl chloride-exposed workers.
Chromosomal morphology from cultured peripheral lymphocytes was studied in 81 men; 57 of the men were employed on plants manufacturing vinyl chloride or polyvinylchloride, 19 were on-site controls and 5 were off-site controls. There was a significant increase in chromosomal abnormalities in the exposed workers when compared with the controls. The greatest statistically significant increase in total B and total C cells occurred in autoclave operators, with smaller increases in other job categories. The increase in chromosomal aberrations was correlated with the length of exposure and with a history during the year prior to sampling (1973--1974) of exposure to excursion levels of vinyl chloride. Information on smoking habits was obtained 18 months after blood sampling and a positive correlation between these and total C cell abnormalities was found. There was no positive correlation with various other parameters (bilirubin, platelets, gamma-glutamyltranspeptidase, alkaline phosphatase, alanine transaminase and aspartate transaminase). It was not possible to estimate which of the three parameters (smoking history, length of employment or exposure to excursion levels) was the most important.
Chromosomes↗