BACKGROUND: This project directly and empirically measured the level of gastrointestinal (GI) illness related to the consumption of tapwater prepared from sewage-contaminated surface waters and meeting current water quality criteria. METHODS: A randomized intervention trial was carried out; 299 eligible households were supplied with domestic water filters (reverse-osmosis) that eliminate microbial and chemical contaminants from their water, and 307 households were left with their usual tapwater without a filter. The GI symptomatology was evaluated by means of a family health diary maintained prospectively by all study families over a 15-month period. RESULTS: The estimated annual incidence of GI illness was 0.76 among tapwater drinkers compared with 0.50 among filtered water drinkers (p less than 0.01). These findings were consistently observed in all population subgroups. CONCLUSION: It is estimated that 35% of the reported GI illnesses among the tapwater drinkers were water-related and preventable. Our results raise questions about the adequacy of current standards of drinking water quality to prevent water-borne endemic gastrointestinal illness.

A population-based case-control study of cancer and occupation was carried out in Montréal, Canada. Between 1979 and 1986, 449 pathologically confirmed cases of prostate cancer were interviewed, as well as 1,550 cancer controls and 533 population controls. Job histories were evaluated by a team of chemist/hygienists using a checklist of 294 workplace chemicals. After preliminary evaluation, 17 occupations, 11 industries, and 27 substances were selected for multivariate logistic regression analyses to estimate the odds ratio between each occupational circumstance and prostate cancer with control for potential confounders. There was moderate support for risk due to the following occupations: electrical power workers, water transport workers, aircraft fabricators, metal product fabricators, structural metal erectors, and railway transport workers. The following substances exhibited moderately strong associations: metallic dust, liquid fuel combustion products, lubricating oils and greases, and polyaromatic hydrocarbons from coal. While the population attributable risk, estimated at between 12% and 21% for these occupational exposures, may be an overestimate due to our method of analysis, even if the true attributable fraction were in the range of 5-10%, this represents an important public health issue.

This study is concerned with methods to measure population-based indicators of quality end-oflife care. Using a retrospective cohort approach, we assessed the feasibility, validity and reliability of using administrative databases to measure quality indicators of end-of-life care in two Canadian provinces. The study sample consisted of all females who died of breast cancer between 1 January 1998 and 31 December 2002, in Nova Scotia or Ontario, Canada. From an initial list of 19 quality indicators selected from the literature, seven were determined to be fully measurable in both provinces. An additional seven indicators in one province and three in the other province were partially measurable. Tests comparing administrative and chart data show a high level of

Epidemiologic research often involves the simultaneous assessment of associations between many risk factors and several disease outcomes. In such situations, often designed to generate hypotheses, multiple univariate hypothesis-testing is not an appropriate basis for inference. The number of true positive associations in a collection of many associations can be estimated by comparing the observed distribution of p values for the positive associations to a theoretical uniform distribution, or to the observed distribution of negative associations, or to an empiric randomization distribution. None of these approaches, however, will distinguish the true from the false positive associations. Various criteria for selecting a subset of associations to report are considered by the authors, including Bonferoni adjustment of p values, splitting the sample for searching and testing, Bayesian inference, and decision theory. The authors prefer an approach in which all associations in the data are reported, whether significant or not, followed by a ranking in order of priority for investigation using empirical Bayes techniques. Methods are illustrated by application to preliminary data from a study aimed at identifying hitherto unsuspected occupational carcinogens.

Insulin-dependent diabetes mellitus (IDDM) may be caused by a combination of genetic predisposition and environmental insults. However, there are few solid leads concerning human diabetogenic environmental agents. A case-control study was carried out to investigate the possible relationships between IDDM and various biological, chemical, and psychological factors. All 161 cases of IDDM among children aged 0-17 yr occurring in Montreal from 1983 to 1986 were included. The parent of each newly diagnosed diabetic subject was asked to provide the names of two of the child's friends or neighbors who would be age and sex matched to serve as controls. For those unable to do so, matched controls were selected from a hospital emergency room. Parents of cases and controls were interviewed concerning many factors. There was little or no difference between cases and controls with regard to parental smoking habits, exposure to pets, and consumption of meat products high in nitrosamines. In univariate analyses, there was some indication of elevated risk for children who had not been breast-fed, who attended day care or nursery before age 5 yr, who lived in a crowded household at age 3 yr, or who had a history of asthma or eczema, although in multivariate analyses the only variables that had any effect were crowding and day-care attendance. In univariate and multivariate analyses, there was high risk of IDDM among children who had experienced selected stressful life events during the 12 mo preceding onset of IDDM or who had exhibited symptoms of social or psychological dysfunction during that time.(ABSTRACT TRUNCATED AT 250 WORDS)