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Biomedical subjects

F D Liddell

Publications and source records attributed to F D Liddell.

33 records · Page 2Linked to original sources
PubMed1980

Latent periods in lung cancer mortality in relation to asbestos dose and smoking.

Among 4463 deaths in a cohort of 10,939 men, born between 1891 and 1920, who had worked in the Quebec chrysotile mines and mills for at least a month, 244 were due to lung cancer. The interval from first asbestos exposure to death averaged 39.6 years; not unexpectedly, this interval was related to age at death and to age at first employment. However, the interval did not appear to be associated in any important way with other measures of exposure. All of the problems of interpretation pointed out by Enterline (1978) are acknowledged, and there is no guarantee of generalization to those exposed to asbestos in other circumstances. Nevertheless, among these 244 cases, there was no evidence to support the hypothesis that the latent period of asbestos-induced lung cancer depends on the dose.

Adult↗
PubMed1980

Validation of the UICC/Cincinnati classification of radiographs in terms of prediction of mortality of asbestos workers.

The mortality of 4559 Quebec chrysotile workers has been related to the findings from their last routine chest X-ray while still employed. In those 84 lung cancer cases who were X-rayed less than 10 years before their death, over two-thirds had 'less-than-normal' films; the abnormality was not specific, except for 'large opacities'. The three men who died from mesothelioma within about a year of X-ray were 'less-than-normal'. The findings of the completed project validated convincingly the 1967 UICC/Cincinnati classification.

Asbestos↗
PubMed1980

Chrysotile fibre concentration and lung cancer mortality: a preliminary report.

After checking on the accuracy of work histories and estimating prevailing fibre concentrations by relevant time and place, all 244 deaths from lung cancer (ICD 162-164) in the Quebec mortality cohort were compared with internal controls matched for date of birth, mining area and smoking habit. Further studies of other causes of death and of lung cancer with controls unmatched for smoking are in progress. In the meantime, we consider that a useful estimate of lung cancer risks is given by the equation: RR = 1 + 0.00038 (+/- 0.00013) fibres/ ml.yr.

Air Pollutants, Occupational↗
PubMed1978

Mortality after long exposure to cummingtonite-grunerite.

Ore containing cummingtonite-grunerite has been mined to extract gold since 1876 in Lead, South Dakota. Each of the 1,321 men who were recorded as having worked 21 years or more with the Homestake Mine was allocated to one of 5 dust-exposure categories on the basis of work history and available information on environmental conditions. All except 9 men were traced to the end of 1973, when 652 were still living; the cause of death was ascertained for 657 of the 660 men who had died. Deaths from cerebrovascular accidents and malignant disease were close to the numbers expected and from accidents and other causes were fewer than expected, but in each of the 3 diagnostic groups--pneumoconiosis (mainly silicosis), tuberculosis, and heart disease--there were more than 30 excess deaths. A clear dust-exposure relationship was found for pneumoconiosis and respiratory tuberculosis--with relative risks for the 2 groups with greatest exposure to dust as compared to the 2 with least exposure, of 19.9 and 16.0, respectively, but there was no convincing evidence of an increase in respiratory cancer.

Adolescent↗
PubMed1977

Radiological assessment of small pneumoconiotic opacities.

Problems in the assessment of small opacities, within the ILO U/C International Classification of Radiographs of the Pneumoconioses (International Labour Office, 1972), are discussed in the light of readings by three experts of a group of films in which both rounded and irregular small opacities frequently coexisted. There was considerable disagreement on whether opacities were rounded or irregular, but reasonable agreement on type (diameter or thickness). As expected, rounded opacities were more commonly recorded in upper zones of the lung, and irregular opacities in lower zones. However, determination of which zones were affected left much to be desired. Perhaps as a result, major problems arose over the assessment of combined profusion.

Diagnostic Errors↗
PubMed1972

Response to disodium cromoglycate in children with chronic asthma.

Twenty-three children with chronic severe perennial asthma received randomly-allocated disodium cromoglycate or placebo four times a day for 12 weeks, and the alternative regimen for the subsequent 12 weeks. More than half the patients improved while on DSCG according to clinical assessment. There was a significant increase in the mean FEV(0.75 second) during the drug period, largely owing to dramatic improvement in nine patients. No reduction in the mean decrease of FEV after exercise was demonstrated. Response, when it occurred, was evident within four weeks. The effect of the medication was consistent in individual patients throughout the 12-week period. No evidence of toxicity was discovered during the period of study.

Adolescent↗