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Biomedical subjects

A C Edwards

Publications and source records attributed to A C Edwards.

42 records · Page 3Linked to original sources
PubMedDate not supplied

A case-control study to investigate the association between indices of dust exposure and the development of radiologic pneumoconiosis.

A case-control study on employees at an iron ore surface mining plant was undertaken to determine which indices of occupational dust exposure related most closely to radiologic categories for pneumoconiosis. Forty cases, with radiographs compatible with the ILO Categories (1980) for simple pneumoconiosis, were matched for age, smoking habit, and date of entry into the workforce with 80 control subjects whose radiographs were read as normal. The six indices of dust exposure were cumulative and "peak" respirable dust, quartz, and iron oxide. Both iron oxide indices were not significant at the 5% level for either ILO Category 1 or Categories 2,3. The association between dust composition and ILO radiologic category for simple pneumoconiosis was consistent, with respirable quartz being the best differentiating index between the case and control groups.

Dust↗
PubMedDate not supplied

Effect of mixing soil aggregates on the phosphorus concentration in surface waters.

At any time, the phosphorus (P) concentration in surface waters is determined by a complex interaction of inputs of soluble P and sorption-desorption reactions of P with sediments. This study investigated what factors control P in solution when various soil aggregates were mixed, seen as being analogous to selective soil erosion events, transport, and mixing within river systems. Fifteen soils with widely differing properties were each separated into three aggregate size fractions (2-52 microm, 53-150 microm, and 151-2,000 microm). Resin P, water-soluble phosphorus (WSP), and the phosphorus buffer capacity (PBC = resin P/WSP) were measured for each aggregate size fraction and WSP was also measured for 11 mixes of the aggregate fractions. The smallest aggregates tended to be enriched with resin P relative to the larger aggregates and the whole soils, while the opposite was true for WSP. As the PBC was a function of resin P and WSP, the PBC was greatest in the 2- to 52-microm aggregate size fraction in most cases. When two aggregate size fractions were mixed, the measured WSP was always lower than the predicted WSP (i.e., the average of the WSP in the two individual aggregates), indicating that WSP released by one aggregate fraction could be resorbed by another aggregate fraction. This resorption of P may result in lower than expected solution P concentration in some surface waters. The strength with which an eroded aggregate can release or resorb P to or from solution is in part determined by that aggregate's PBC.

Adsorption↗
PubMedDate not supplied

Newfoundland Panel on Health and Medical Care--adult health survey.

An adult health survey was undertaken on the island portion of the Province of Newfoundland as part of the Newfoundland Panel on Health and Medical Care. This study aims to develop models of medical care utilization over a seven-year period, before and after a major restructuring of the provincial health care system. A health survey on a large sample (11,789 individuals) permits both descriptive and explanatory analysis at the regional level. The results of the survey are presented first in a descriptive format, as they were included in reports for policy makers and managers, using administrative aggregations. To study regional differences, descriptive and multivariate analyses were done on an aggregation by an urban dimension, which divides the island into three areas. As expected, there were major differences across regions, and complex interactions on selected variables. The usefulness of health surveys for planning and evaluation of health reform is discussed.

Adult↗
PubMedDate not supplied

The association between self-assessed health status and individual health practices.

We report the association between single health practices and self-assessed health status. Data were collected by telephone survey applied to all adults in a sample of households in metropolitan St. John's; questionnaires were completed for 3,300 subjects. Five health practices--smoking, exercise, sleep, weight and drinking--as defined by previous studies were compared with self-assessed health status--good or poor--using logistic regression; linear and quadratic functions were fitted, plots were prepared and the direction and strength of the associations studied using odds and odds ratios. For sleep, smoking, weight and exercise, our results confirm the definitions used in previous studies. Current non-drinkers in our sample do not report good health as frequently as moderate drinkers. Breakfast--which was analyzed by conventional cross-tabulation--showed no association with health status.

Adult↗