Northrup described how “it is reassuring ... that public health agencies have rejected the demand for a mass lay educational program against the alleged dangers of smoking. Not one of the leading insurance companies, who consider health hazards in terms of monetary risk, has raised the life insurance rates for heavy smokers.” To this day it has proved virtually impossible to induce lung cancer in animals by the inhalation method.30
© Lorraine Kay
(1)Smoking: Health warnings, although woefully inadequate,
were delayed for years because of contradictory animal research.
Another case is asbestos-induced lung cancer.31 The first reports of an association between asbestos and lung cancer came from America, England and Germany during the 1930s following examination of people who had died with the lung disease asbestosis. By 1938 there were six reported cases and five years later the German government declared asbestos- induced lung cancer an occupational disease. But in some countries, notably the United States, the carcinogenic action of asbestos was doubted until the 1960s because it proved impossible to induce the disease in animals. By 1955, six separate animal studies had been carried out but only one appeared to show that asbestos might cause cancer and even this was discredited by scientists. Researchers were also concerned that the early autopsy findings might not be representative of all asbestos workers. The issue should have been resolved in 1949 when more cancer cases were found among workers seeking compensation for asbestosis than for silicosis, and again in 1955 when Doll reported the incidence of lung cancer in asbestos workers was ten times that in the general population. But the debate continued. Only in 1967 were experimenters finally able to induce cancer in animals by dosing them with asbestos.
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