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Biomedical subjects

E Hnizdo

Publications and source records attributed to E Hnizdo.

42 records · Page 3Linked to original sources
PubMed1986

Relationship between silicosis and rheumatoid arthritis.

The relationship between rheumatoid arthritis and silicosis was studied by means of a case-control study in South African gold miners. One hundred and fifty seven miners with rheumatoid arthritis classified as "definite" (91) or "probable" (66) were individually matched by year of birth with miners who had no evidence of rheumatoid arthritis. Unmatched analysis of the case-control status for "probable" and "definite" cases yielded an odds ratio of 2.84 (p = 0.0001). Separate analyses yielded an odds ratio of 3.79 (p = 0.0006) for "definite" cases, a non-significant odds ratio for "probable" cases, and an odds ratio of 5.00 (p = 0.0003) for the presence of rheumatoid factor. These results could not be explained on the basis of cumulative dust exposure or intensity of exposure. The rate of progression of silicosis in both the "definite" and the "probable" groups was greater than for the control patients with silicosis, as was the probability of silicosis presenting at the start with larger nodules (type r).

Arthritis, Rheumatoid↗
PubMed1985

Relative observer accuracy for dichotomized variables.

We suggest that the relative accuracy of several observers of a disease manifestation can be assessed by comparing the strength of association between their observations and a known cause of that disease. In principle, the observer whose findings are most strongly associated with the causal variable has the least error. In practice many observations appear binary ("normal" or "abnormal") when the underlying distribution of the variable they measure is continuous. For this case of a dichotomized variable, several observers may find different prevalences of abnormality in the same sample either because their accuracy differs or because they use different thresholds above which they regard abnormality as present. A comparison of how strongly their observations are associated with a causal variable using statistical methods for binary observations may lead to incorrect conclusions about the relative accuracy of the observers. We suggest and evaluate a method, based on the biserial correlation coefficient, for comparing the relative accuracy of several observers who may differ in the thresholds they use.

Asbestosis↗
PubMedDate not supplied

Factors influencing the reading of small irregular opacities in a radiological survey of asbestos miners in South Africa.

A cross-sectional radiological survey of 2,245 men who were employed in South African asbestos mines was conducted in 1976. Since 1976, the lungs of 172 of these men who died have been examined to establish the presence of asbestosis or other pneumoconiosis. The x-ray readings (ILO/UC 1971) were compared with the pathological findings. A high prevalence of false positive readings, particularly for two of the three readers, was found. False negative readings were also very prevalent. Detailed information about asbestos and other mining exposure, smoking habit, age, height, and weight were examined to determine what influence they may have had in inducing false positive findings. Other dust exposure and smoking appeared to be possible factors, whereas age and obesity were probably not. It is suggested that the term "small irregular opacities" requires more precise definition.

Adolescent↗