Biomedical subjects
Publications and source records attributed to C Buck.
The season of birth distribution of 1,039 sibs of Canadian schizophrenic patients was compared with that of births in the Canadian general population over the same time period. The excess of winter births observed among the schizophrenics was not found among their sibs.
Explore the source record for details and available documents.
Evidence was found against the hypothesis that heterozygous carriers of a schizophrenic gene have a reproductive advantage through enhanced fertility. In consequence an investigation was made of the possibility that an advantage is gained through diminished early mortality among the off-spring of carriers. The results were equivocal. While an observed deficit of infant deaths was attributable to under-reporting, the possibility of a true advantage could not be ruled out, because of the statistical unreliability of the findings in a sample of the size available. A plea is made for a collaborative effort to settle the issue.
Sixty patients who visited their general practitioner were matched with 60 patients registered with the same doctor, who were of the same sex and in the same ten-year age group, and who had not visited the doctor for at least one year, but had recently experienced symptoms similar to those presented by the attending patients.Comparison of the 60 pairs revealed the following differences, all substantial although not all statistically significant. The patients who visited the doctor perceived themselves as less healthy, fewer had attempted self-treatment, more reported serious personal problems, and fewer reported obstacles to visiting the doctor.Differences between the pairs were negligible for total number of current ailments, effectiveness of self-treatment, if used, optimism about the healing powers of doctors, and fear of troubling their doctor with trivia.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
This paper discusses the application of Popper's philosophy to epidemiological research, examining in particular the problems of replication without risk of refutation, of mistaking statistical sophistication for deductive inference, and of dealing with causality at a general level. An example is given of a Popperian approach to the test of a causal hypothesis concerning cancer of the cervix.
A multicenter prospective study has been designed to determine whether participation in an exercise program which produces a significant training effect will affect the recurrence rate in men who have survived an initial myocardial infarction. The control group consists of subjects who participate in a program involving low intensity activities designed to avoid a significant training effect. The subjects will be followed for a period of 4 years and a reduction of 50 per cent in the risk of recurrence will be considered clinically significant. The criteria for entry, the method of allocation, the structure of the exercise program and method of assessing cardiorespiratory fitness are described.
This investigation has provided evidence against the hypothesis that heterozygous carriers of schizophrenic gene have a reproductive advantage through enhanced fertility. An advantage arising from lower mortality between birth and the end of the reproductive period was not investigated, but should be examined before we search for other explanations of the apparently stable polymorphism of schizophrenia.
Increased perinatal mortality among smokers' babies has been observed in many but not in all studies, with a statistically significant difference in some. This paper explores the hypothesis that maternal smoking may interact with other risk factors, so that a dose-related increase in perinatal mortality may be enhance or masked depending upon the presence or absence of these factors. Data are from the Ontario Perinatal Mortality Study of all single b irths in 10 teaching hospitals in Ontario in 1960-1961 a total of 51,490 births, including 701 fetal deaths and 655 early neonatal deaths. Perinatal mortality increased significantly with smoking, and was also affected by such factors as maternal age, parity, hospital status, previous pregnancy history, hemoglobin level, and others. Smoking frequencies also varied by many of these characteristics. Perinatal mortality was therefore analyzed by the amount smoked during pregnancy within subgroups of these antecedent risk factors. When smoking and other risk factors were cross-tabulated among 52 data subgroups, only the light smokers (less than 1 pack per day) under age 20 had lower perinatal mortality rates than their nonsmoking counterparts. In almost all subgroups the mortality increase with smoking was dose-related, but not in a simple, linear way. The increased risk of perinatal mortality associated with light smoking among young, low-parity, non-anemic mothers was less than 10 percent. At the other extreme, mothers of high parity, public hospital status, with previous low birthweight births, or with hemoglobin less than 11 gm had increased perinatal mortality risks of 70-100 percent when they were heavy smokers. The failure of some studies to find a significant increase in perinatal mortality with maternal smoking may be due to selection of study populations from the end of the spectrum where light smoking is associated with only a slight increase in perinatal risk. Other studies may select higher risk populations, where the influence of smoking on mortality is stronger. Depending on the magnitude of the difference, the amount smoked, and the size of the study, results might or might not be statistically significant.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.