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Objectives: Since 2004, a surveillance system provides counts, almost in real time, of the number of deaths per day occurring on the Island of Montreal. The validity of this monitoring tool and its ability to detect spikes in daily deaths, such as can occur due to heat waves, have been evaluated., Method: Comparison of the number of deaths per day recorded in the monitoring system with the number of deaths per day recorded in the official record of deaths in Quebec for 134 days of 2004., Results: The monitoring system is accurate (for over 73% of days, the difference in the number of deaths between the two files falls within a range of +/-3 deaths given an average of 43 deaths per day). The system identifies more than 80% of all deaths and is efficient in identifying days with excess deaths that are 20% above the average., Discussion: This novel monitoring system, based on data used mainly for management of medical services, meets contemporary public health requirements in terms of early detection of unusual health events.

Background: Epidemiologic studies show that high temperatures are related to mortality, but little is known about the exposure-response function and the lagged effect of heat. We report the associations between daily maximum apparent temperature and daily deaths during the warm season in 15 European cities., Methods: The city-specific analyses were based on generalized estimating equations and the city-specific results were combined in a Bayesian random effects meta-analysis. We specified distributed lag models in studying the delayed effect of exposure. Time-varying coefficient models were used to check the assumption of a constant heat effect over the warm season., Results: The city-specific exposure-response functions have a V shape, with a change-point that varied among cities. The meta-analytic estimate of the threshold was 29.4 degrees C for Mediterranean cities and 23.3 degrees C for north-continental cities. The estimated overall change in all natural mortality associated with a 1 degrees C increase in maximum apparent temperature above the city-specific threshold was 3.12% (95% credibility interval = 0.60% to 5.72%) in the Mediterranean region and 1.84% (0.06% to 3.64%) in the north-continental region. Stronger associations were found between heat and mortality from respiratory diseases, and with mortality in the elderly., Conclusions: There is an important mortality effect of heat across Europe. The effect is evident from June through August; it is limited to the first week following temperature excess, with evidence of mortality displacement. There is some suggestion of a higher effect of early season exposures. Acclimatization and individual susceptibility need further investigation as possible explanations for the observed heterogeneity among cities.

Background: The absence of ongoing surveillance for childhood asthma in Montreal, Quebec, prompted the present investigation to assess the validity and practicality of administrative databases as a foundation for surveillance., Objective: To explore the consistency between cases of asthma identified through physician billings compared with hospital discharge summaries., Methods: Rates of service use for asthma in 1998 among Montreal children aged one, four and eight years were estimated. Correspondence between the two databases (physician billing claims versus medical billing claims) were explored during three different time periods: the first day of hospitalization, during the entire hospital stay, and during the hospital stay plus a one-day margin before admission and after discharge ('hospital stay +/- 1 day')., Results: During 1998, 7.6% of Montreal children consulted a physician for asthma at least once and 0.6% were hospitalized with a principal diagnosis of asthma. There were no contemporaneous physician billings for asthma 'in hospital' during hospital stay +/- 1 day for 22% of hospitalizations in which asthma was the primary diagnosis recorded at discharge. Conversely, among children with a physician billing for asthma 'in hospital', 66% were found to have a contemporaneous in-hospital record of a stay for 'asthma'., Conclusions: Both databases of hospital and medical billing claims are useful for estimating rates of hospitalization for asthma in children. The potential for diagnostic imprecision is of concern, especially if capturing the exact number of uses is more important than establishing patterns of use.

Excess mortality has been noted during high ambient temperature episodes. During such episodes, individuals are not likely to be uniformly exposed to temperatures within cities. Exposure of individuals to high temperatures is likely to fluctuate with the micro-urban variation of outdoor temperatures (heat island effect) and with factors linked to building properties. In this paper, a GIS-based regression mapping approach is proposed to model urban spatial patterns of indoor temperatures in time, for all residential buildings of an urban area. In July 2005, the hourly indoor temperature was measured with data loggers for 31 consecutive days, concurrently in 75 dwellings in Montreal. The general estimating equation model (GEE) developed to predict indoor temperatures integrates temporal variability of outdoor temperatures (and their 24 h moving average), with geo-referenced determinants available for the entire city, such as surface temperatures at each site (from a satellite image) and building characteristics (from the Montreal Property Assessment database). The proportion of the variability of the indoor temperatures explained increases from 20%, using only outdoor temperatures, to 54% with the full model. Using this model, high-resolution maps of indoor temperatures can be provided across an entire urban area. The model developed adds a temporal dimension to similar regression mapping approaches used to estimate exposure for population health studies, based on spatial predictors, and can thus be used to predict exposure to indoor temperatures under various outdoor temperature scenarios. It is thus concluded that such a model might be used as a means of mapping indoor temperatures either to inform urban planning and housing strategies to mitigate the effects of climate change, to orient public health interventions, or as a basis for assessing exposure as part of epidemiological studies.

Background: The project "Assessment and prevention of acute health effects of weather conditions in Europe" (PHEWE) had the aim of assessing the association between weather conditions and acute health effects, during both warm and cold seasons in 16 European cities with widely differing climatic conditions and to provide information for public health policies., Methods: The PHEWE project was a three-year pan-European collaboration between epidemiologists, meteorologists and experts in public health. Meteorological, air pollution and mortality data from 16 cities and hospital admission data from 12 cities were available from 1990 to 2000. The short-term effect on mortality/morbidity was evaluated through city-specific and pooled time series analysis. The interaction between weather and air pollutants was evaluated and health impact assessments were performed to quantify the effect on the different populations. A heat/health watch warning system to predict oppressive weather conditions and alert the population was developed in a subgroup of cities and information on existing prevention policies and of adaptive strategies was gathered., Results: Main results were presented in a symposium at the conference of the International Society of Environmental Epidemiology in Paris on September 6th 2006 and will be published as scientific articles. The present article introduces the project and includes a description of the database and the framework of the applied methodology., Conclusion: The PHEWE project offers the opportunity to investigate the relationship between temperature and mortality in 16 European cities, representing a wide range of climatic, socio-demographic and cultural characteristics; the use of a standardized methodology allows for direct comparison between cities.

Background: Mortality during sustained periods of hot weather is generally regarded as being in excess of what would be predicted from smooth temperature-mortality gradients estimated using standard time-series regression models. However, the evidence for an effect of continuous days of exceptional heat ("heat wave effect") is indirect. In addition, because some interventions may be triggered only during forecasted heat waves, it would be helpful to know what fraction of all heat-related deaths falls during these specific periods and what fraction occurs throughout the remainder of the summer., Methods: Extended time-series data sets of daily mortality counts in 3 major European cities (London, 28 years of data; Budapest, 31 years; Milan, 18 years) were examined in relation to hot weather using a generalized estimating equations approach. We modeled temperature and specific heat wave terms using a variety of specifications., Results: With a linear effect of same-day temperature above an identified threshold, an additional "heat wave" effect of 5.5% was observed in London (95% confidence interval = 2.2 to 8.9), 9.3% in Budapest (5.8 to 13.0), and 15.2% in Milan (5.7 to 22.5). Heat wave effects were reduced slightly when we relaxed the linear assumption and these effects were reduced substantially when temperature was modeled as an average value of lags 0 to 2 days. In London, fewer than half of all heat-related deaths could be attributed to identified heat wave periods. In Milan and Budapest, the fraction was less than one fifth., Conclusions: Heat wave effects were apparent in simple time-series models but were reduced in multilag nonlinear models and small when compared with the overall summertime mortality burden of heat. Reduction of the overall heat burden requires preventive measures in addition to those that target warnings and responses uniquely to heat waves.

Biological hazards associated with the collection of solid and compostable waste have not been well characterized in North America. This is an issue because workers who handle such materials may be exposed to bioaerosols (airborne bacteria and fungi) and dusts resulting in infections or allergic diseases. We conducted a personal sampling campaign for culturable bacteria and fungi in the breathing zones of waste collectors in a variety of typical work settings (scenarios) in the province of Quebec, Canada. Total culturable bacterial and fungal counts were analyzed and compared to ambient environmental levels (background) to determine the degree of incremental exposure among workers. In several scenarios, worker exposure counts were significantly (p < or = 0.05) higher than ambient levels measured upwind, with the highest personal exposures to bacteria observed for urban compostable waste collectors (median = 50,300 Colony Forming Units/m(3) of air (CFU/m(3))). On the other hand, fungal counts collected on an every-other-week cycle were highest among a group of rural compostable waste collectors (median = 101,700 CFU/m(3)). Similar exposures to culturable bacteria and fungi have been reported in European workers who showed such adverse health effects as nausea, diarrhea, upper respiratory tract irritation, and allergy. Therefore, it may be necessary to modify certain work practices in order to minimize exposure. Recommendations include automation of waste and compost collection, use of personal protective equipment including goggles, gloves, and disposable masks, and meticulous personal hygiene.

Background: Persons exposed to residential traffic have increased rates of respiratory morbidity and mortality. As poverty is an important determinant of ill health, some have argued that these associations may relate to the lower socioeconomic status of those living along major roads., Aims: The objective was to evaluate the association between traffic intensity at home and hospital admissions for respiratory disease among Montreal residents of 60 years and older., Methods: Case hospitalisations were those with respiratory diagnoses and control hospitalisations were those where the primary discharge diagnosis was non-respiratory. Morning peak traffic estimates from the EMME/2 Montreal traffic model (MOTREM98) were used as an indicator of exposure to road traffic outside the homes of those hospitalised. The crude association between traffic intensity and hospitalisation for respiratory disease was adjusted by an area based estimate of the appraised value of patients' residences, expressed as a dollar average over a small segment of road (lodging value). This indicator of socioeconomic status, as calculated from the Montreal property assessment database, is available at a finer geographical scale than the neighbourhood socioeconomic indicators accessible from the Canadian census., Results: Increased odds of being hospitalised for a respiratory compared with a control diagnosis were associated with higher levels of estimated road traffic nearby patients' homes, even after adjustment for lodging value (crude OR 1.35, CI95% 1.22 to 1.49; adjusted OR 1.18, CI95% 1.06 to 1.31 for >3160 vehicles passing during the three hour morning traffic peak compared with secondary roads off network)., Conclusion: The results suggest that road traffic intensity itself, may affect the respiratory health of elderly residents of a large Canadian city, an association that is not solely a reflection of socioeconomic status.

Unlabelled: Methylmercury is a neurotoxicant that bio-accumulates in the aquatic food chain and is present in all fish. Little is known about the effects of long-term low-dose exposure to methylmercury in adults. The aim of this study was to determine whether a dose-response relationship exists between long-term methylmercury exposure and neurological abnormalities in aboriginal Quebec Cree adults for whom fish is a dietary staple. We re-analysed data from a 1977 cross-sectional study conducted by Kofman and collaborators on a group of Quebec Cree individuals claiming ill health from local fish consumption. In the original 1977 study, 306 adult participants aged 18-82 years were assessed for methylmercury exposure. Tremor and other neurologic outcomes were assessed with a clinical examination. The investigators did not find clinical evidence of methylmercury intoxication based on an analysis of covariance. We used ordinal regression to obtain odds ratios for the relationship between total hair mercury levels and neurologic abnormalities. Hair mercury concentrations ranged from 0.5 to 46 ppm (parts per million). A 6 ppm increase in hair mercury was associated with increasing levels of tremor (OR, 2.22; 95% CI, 1.15-4.26) in adults under 40 years of age. There was no association with nine other outcomes considered, nor with tremor among older persons. Odds ratios were not influenced by gender, smoking, alcohol use, or co-morbidity., Conclusion: : Dose-dependent effects of methylmercury on tremor may occur below the commonly accepted 50 ppm threshold, particularly in young adults. These effects may be detectable by clinical examination. However, the results should be interpreted with caution given that alcohol use was probably under-reported and that multiple outcomes were studied.

Background: The Health and Social Survey of Quebec Children and Youth, conducted on representative samples of children nine, 13 and 16 years of age, provided data on the prevalence and determinants of asthma and allergic rhinitis in Quebec., Objectives: To determine the prevalence of asthma and allergic rhinitis among children in the province of Quebec and to identify the determinants of these pathologies., Methods: Three groups of more than 1100 children aged nine, 13 and 16 years were recruited. Respiratory symptoms were documented using the International Study of Asthma and Allergies in Childhood questionnaire. Questions enquiring about family income, smoking, degree of urbanization of the child's school's location and various variables related to indoor air were also included. The comparisons of proportions were done using the chi2 test., Results: The prevalence rates for reported history of asthma varied from 14% to 15% depending on the age group. The prevalence of wheezing in the past year was 7% to 8%. Asthma was the primary cause of the limitation of activities due to a health problem in nine- and 13-year-old Quebecers, and the second most common cause in 16-year-old Quebecers. The prevalence of rhinitis, rhinoconjunctivitis and reported history of hay fever increased with age, reaching 28.0%, 15.9% and 21.1%, respectively, in the 16-year-old group. The prevalence of asthma and wheezing was associated with family history and allergies, and inversely related to family income., Conclusions: The prevalence of childhood asthma is high in the province of Quebec. It is a major cause of the limitation of activities due to a health problem for young Quebecers. A family history of asthma and an atopic predisposition are important determinants in the development of asthma in Quebec.

The authors designed an email-based discussion forum with the objective of promoting and supporting peer discussion on the health effects of outdoor air pollution, linked to a recently published review article. Clinical cases served as stimulus material and participants were provided with an online toolbox of resources. Message postings from 27 participants were most frequent (92) during the first of four weeks and lowest (17) during the second, suggesting that some participants were overwhelmed by the initial volume. Evaluation of short-term impact completed by 16 participants indicated that the course was successful in improving some participants' knowledge. Evaluation three months after course completion by 20 participants revealed an impact on clinical practice. As an alternative to email, requiring participants to visit a web page to view and submit postings may avoid problems related to volume of messages. Controlled delivery of small portions of information tied to specific self-directed tasks is also recommended.

This study performed a preliminary investigation of the incidence and determinants of environmental-temperature injury among residents of Montreal Island, Quebec, Canada. Incidence rates, mortality rates and determinants of environmental-temperature injury were estimated for Montreal Island's 1,802,309 urban and suburban residents. Sources of information included coroner's reports, death certificates, hospital discharge summaries, and hospital chart reviews. The estimated incidence rate for environmental-temperature injury requiring hospitalization on Montreal Island was 3.1 per 100,000 person-years. The estimated mortality rate for all environmental-temperature injuries on Montreal Island was 0.3 per 100,000 person-years. The majority of hospitalizations and deaths were due to cold injury. Male gender, alcohol intoxication, psychiatric illness, older age, and homelessness were suggestive of important risk factors in cold injury. All deaths due to heat injury occurred in elderly females. Montreal Island's ambulance transport service, with its unique database, was identified as a novel surveillance design for environmental-temperature injury. Knowing more about the incidence and determinants of environmental-temperature injury may suggest priorities for interventions to decrease morbidity and mortality.

The benefits of sportfish consumption and omega-3 fatty acid (omega3-FA) intake for cardiovascular risk factors were evaluated in a sample of 112 male fishers from the St. Lawrence River in the Montreal area during the 1996 winter and fall fishing seasons. A questionnaire on fishing practices and fish consumption was administered, and fasting blood samples were collected for lipid and phospholipid determination. Linear regression analyses, which considered the confounding effect of major risk factors, did not show any significant association between measured omega3-FAs or reported fish intake and blood lipids or blood pressure. This study is limited by its low statistical power due to the small sample size and the possibility that the fish eaten by the participants were low in omega3-FAs or that the participants diets contained foods high in cholesterol-raising fat.

Analyses of xenobiotics in human tissues are used to screen individuals whose habits or environments put them at high risk of overexposure, for the surveillance of exposure patterns over time and between places, and as part of research to identify the sources and pathways of exposure in a population. Both study goals and technical considerations should guide the choice of which xenobiotics to sample and in which tissues. Understanding the absorption and distribution of the specific compound to be measured is essential to the choice of when to sample and how to interpret results. Laboratory quality is of major concern. A particular issue in the statistical treatment of results are those near to the laboratory's detection limit. Theoretical concepts are discussed in the context of studies of xenobiotic exposure among eaters of Great Lakes and St. Lawrence River sport fish.

Little information is available concerning the level of consumption and degree of contaminant exposure for North American women of childbearing age who eat sport fish. The authors reanalyzed a 1995-1996 study of Montreal-area (Canada) sport fishers. The authors focused on women sport fishers of childbearing age and male sport fishers who had spouses of childbearing age. The primary research involved an on-site questionnaire about fish consumption, with follow-up assessment of sport fishers estimated to have either the highest or lowest levels of fish-based contaminant exposure. Among the 1,654 interviewees were 100 women less than 45 yr of age who had eaten sport fish for an average of 11 yr; 45% ate fish less than once a month. From the follow-up subsample of high- and low-level consumers, the authors identified 17 women less than 45 yr of age and 25 males whose spouses who were less than 45 yr of age and who consumed similar quantities of sport fish. Among this group of 42, the high-exposure women differed from the low-exposure women with respect to their yearly consumption of freshwater fish, blood mercury levels (median = 6.4 vs. 1.4 microgram/l), and plasma polychlorinated biphenyl congener 99 (median = 10.5 vs. 5.9 microgram/kg plasma lipids). Few Montreal-area women of childbearing age consume local sport fish frequently or for extended periods. However, among the small proportion that consumes sport fish frequently or for extended periods, blood mercury concentrations approach levels of concern for fetal protection.

In the course of the "1998 Health and Social Survey", questions were included to verify the prevalence of chronic respiratory diseases and also of wheezing. The objectives of this study were 1) to verify the prevalence of wheezing and its validity as an indicator of chronic respiratory diseases in Québec; and 2) to examine the relationship between chronic respiratory diseases and some of their potential determinants. A total of 30,386 individuals participated in the study. For all ages, the prevalence of wheezing was 5.4%. It was associated with asthma, allergies, chronic bronchitis and emphysema. A low familial income and tobacco smoking were associated with wheezing, asthma, chronic bronchitis and emphysema. Passive smoking was associated with wheezing whereas the presence of carpets was associated with wheezing and asthma. Between 32 and 48% of families with an asthmatic or an allergic member modified their dwelling to alleviate respiratory problems. The prevalence of wheezing documented here was lower than in anglosaxon countries. This result could be explained by a cultural factor (the French translation or the perception of wheezing). This study emphasizes the role of reducing tobacco smoking in the prevention of chronic respiratory diseases.

The authors evaluated lead exposure of Canadians (Montreal) who fished the nearby St. Lawrence River. From screening interviews conducted with 1,118 fishers on-site during the winter and fall of 1996, the authors selected 60 Montrealers who consumed at least one sportfish meal per week and 72 who consumed less than one sportfish meal per week. Fishers at the higher level of sportfish consumption had elevated blood lead concentrations, compared with fishers who ate little sportfish (geometric mean = 57.4 microg/l vs. 48.2 microg/l, respectively; p < .05). This result was surprising inasmuch as fish is not considered a significant source of lead. In addition to sportfish consumption, age, sex, occupation, smoking, and waterfowl consumption also showed independent associations with blood lead levels. Among frequent (i.e., > or = 1 meal/wk) consumers of sportfish, ingestion of waterfowl was associated with higher blood lead levels (geometric mean = 69.4 microg/l vs. 51.8 microg/l, respectively; p < .05); this association was not present for infrequent consumers. In multivariate analysis, the association of higher blood lead levels with sportfish consumption could be accounted for in large part by waterfowl consumption among frequent consumers of sportfish.

Childhood asthma is a chronic inflammatory disorder of the airways. It is a multifactorial disease that has been associated with familial, infectious, environmental, socioeconomic, and psychosocial causes. In the US alone, asthma is the most common chronic disease of childhood. In 1999, the estimated annual cost of treating asthma in children in the US was $3.2 billion. Public health authorities have argued for making childhood asthma a notifiable disease, with the hopes of identifying modifiable sources and reducing adverse consequences. As of the end of the 20th century, however, no jurisdictions in North America require physicians to report pediatric asthma. Would mandatory reporting help public health agencies reduce the asthma burden? What harm might come from obliging physicians to report childhood asthma? In this article we provide a thorough evaluation of these issues, the rationale behind the controversy, and long-awaited answers to these difficult questions.

We assessed levels and determinants of mercury biomarkers among residents of Montreal and surroundings who eat sportfish from the nearby St. Lawrence River. Participants were selected from 1118 adult fishers responding to a 1996 screening questionnaire; the study sample (n=132) overrepresented respondents expected to have the greatest and the least exposure to mercury. Tissue mercury concentrations were associated with sportfish consumption: among participants who ate sportfish at least once weekly, hair geometric mean (GM)=0.82+/-2.54 microg/g and blood mercury GM=3.03+/-2.43 microg/L, compared to hair GM=0.38+/-2.28 microg/g and blood mercury GM=1.44+/-2.23 microg/L for those who ate sportfish less than once weekly. While these levels are somewhat higher than those shown for other Greater Lakes and St. Lawrence River fishers, only one participant surpassed the Canadian recommended population mercury limit of 6 microg/g for hair and 20 microg/L for blood. Consumption of several sportfish species independently explained much of the variation in measured blood mercury; the predatory species pike was the most important in multivariable regression. Coincident consumption of waterfowl, fishing during the longer summer/fall rather than the brief winter season, and fishers' age were independently associated with blood mercury. Serum selenium related neither to the level of fish consumption nor to the participants' blood mercury., (Copyright 2000 Academic Press.)

The objective of this study was to formulate a framework for determining what information to communicate to individual subjects of a study measuring biomarkers of exposure, consistent with the principles of ethical clinical and research practice. Methods consisted of review of the scope of environmental exposure studies, including the use of biomarker measurement in clinical medicine and environmental research and the relevant principles of clinical ethics and research practice. An exposure biomarker study is designed to elucidate constitutional, behavioral, and environmental determinants of tissue concentrations of exogenous substances. Of itself, it is not designed to measure risk relations, those being the relation between biomarker levels and health outcomes. In many settings, measured tissue biomarker concentrations fall below those known or reasonably predicted to cause disease. Ethical clinical and research practice, aiming to maximize autonomy and beneficence and to minimize harm, requires that study findings concerning the determinants of exposure be communicated to study participants. In addition, investigators should reference clinical action levels beyond which individual biomarker results are routinely communicated to participants. When biomarkers have no known relation to risk, or when levels fall below action levels, it may be preferable not to communicate individual results, if this arrangement has been formalized at the time of informed consent., (Copyright 1999 Academic Press.)

Fishing and fish consumption are widely practiced among members of certain ethnocultural groups. Informal assessment led us to ascribe high levels of consumption of locally caught sportfish to Montrealers of Asian origin and to hypothesize that their choices of species and fish organs differ from those of the majority group. An exploratory assessment of contaminant bioindicators reflective of St. Lawrence River fish consumption was conducted in late 1995 among nine Vietnamese and nine Bangladeshi Montreal sportfishers identified by community contacts. Vietnamese participants, six men and three women, were 27-70 (median 36) years of age and had immigrated to Canada 3-20 (median 7) years earlier. In contrast, the nine Bangladeshi males aged 28-41 (median 34) years had been in Canada for 2-13 (median 4) years. Bio-indicator concentrations among Bangladeshi and Vietnamese participants are compared to those found for majority-community Montreal-area high-level consumers recruited on the St. Lawrence River during winter 1995. All results are presented as the median and 90th percentile. Hair mercury concentrations were higher for both Vietnamese (1.2, 4.6 microgram/g) and Bangladeshis (1.1, 2.3 microgram/g) than for majority-community sportfishers (0.7, 1.9 microgram/g). Certain organochlorine levels, specifically total PCB (estimated by plasma Aroclor 1260), p,p'-DDT, p,p'-DDE, and B-BHC, were highest in the Bangladeshis compared to Vietnamese and to majority-community sportfishers. In contrast, plasma levels of other pesticides were low in all three groups, including mirex, chlordane, and cis-nonachlor. A correlation between plasma p,p'-DDT levels and recency of arrival in Canada was found for the Bangladeshis. These data suggest a distinct pattern of tissue organochlorines, which we postulate relates to exposure prior to arrival in Canada and perhaps to the ongoing consumption of foods (other than St. Lawrence River sportfish) specific to these groups., (Copyright 1999 Academic Press.)

A 1995 pilot study assessed sport fish consumption and contaminant exposure among Montreal-area residents fishing the frozen St. Lawrence River. Interviews conducted among 223 ice fishers met on-site were used to create an index of estimated exposure to fish-borne contaminants. A second-stage assessment of sport fish consumption and tissue contaminant burdens included 25 interviewees at the highest level of estimated contaminant exposure (of 38, or 66% of those solicited) and 15 low-exposure fishers (of 41, or 37% of those solicited). High-level fisher-consumers reported eating 0. 92+/-0.99 sport fish meals/week during the previous 3 weeks compared to 0.38+/-0.21 (P<0.05) for the low-level group. Based on the product of consumption frequency times mass of sport fish meals consumed, high-level consumers ate a mean of 18.3 kg of sport fish annually versus 3.3 kg for the low-level consumers. Tissue contaminant assessments showed significant (P<0.05) groupwise differences: 0-1 cm hair mercury (median 0.73 microgram/g for the high versus 0.23 microgram/g for the low group), lipid-adjusted plasma PCB congeners (Aroclor 1260: median 0.77 microgram/g versus 0.47 microgram/g), and lipid-adjusted plasma DDE (median 0.35 microgram/g versus 0.26 microgram/g). No participant had a hair mercury or plasma DDE concentration above Health Canada recommendations but 2/25 high-level participants (8%) had plasma Aroclor 1260 concentrations above recommended limits. The results of this pilot study suggest that a small number of Montreal-area sportfishers consume their catch as often as three times weekly and that those consuming sport fish frequently have significantly higher tissue levels of mercury, PCBs, and DDE than do infrequent consumers. On the other hand, compared to other groups in Quebec, such as the Inuit or commercial fishers on the North Shore of the Gulf of St. Lawrence, Montreal-area sportfishers eat less fish and have lower tissue concentrations of fish-related contaminants., (Copyright 1999 Academic Press.)

Lack of demonstrated neurotoxicity among fish-eating populations has been cited by the World Health Organization and others as supporting an adult LOEL (lowest observed effect level) of > or = 200 ppb blood mercury equivalent. We reviewed 13 published evaluations of neurologic status as related to tissue mercury or methylmercury concentration in long-term fish-eating populations. Review criteria included study size, design (sampling strategy, characterization of exposure, characterization of outcome) and data analysis. No case of classic Minimata disease is described in the 13 studies. Also, no study clearly shows a threshold tissue level above which any form of neurologic dysfunction occurs. A study by Valciukas et al. shows no evidence of neurologic impairment in groups with blood mercury of 10-20 ppb. Studies by Spitzer et al. and McKeown-Eyssen and Reudy suggest correlation of neurologic dysfunction with rising blood mercury concentrations in the 60-120 ppb range. While other studies show no effects associated with rising mercury dose, numbers are small, participant self-selection likely and the clinical assessment limited. Together the 13 studies describe neurologic examinations in approximately 50 fish eaters having a blood mercury equivalent above 200 ppb; of these subjects, neurologic dysfunction consistent with methylmercury exposure was found in as few as six and as many as 15. We conclude that the oft-cited LOEL for (methyl)mercury of 200 ppb in blood is not supported by these studies.

Following the identification of high levels of lead in the soils of residences near two abandoned Montreal metal-recovery plants, blood lead concentrations were analyzed for children living or cared for in the affected neighbourhood. Overall, the distribution of blood lead levels (geometric mean = .27 mumol/L, range .11-1.01) among the 52 children sampled was similar to those of children of other Quebec localities without known point sources of lead. Nevertheless, multiple regression analysis did suggest a modest influence of the concentration of lead in children's own yards (as measured by actual soil samples or as estimated by a geostatistical modeling procedure) on their blood lead level (.05 mumol/l rise for a 1000 ppm increase in soil lead, 95% C.I.-.01, .11). This estimate of the influence of soil on blood lead is at the lower end of the range reported by others. We suggest that these Montreal results demonstrate the modest effects of lead-contaminated soil when its access is limited by grass cover and/or when the emissions which produced it have ceased.

At the request of Cree political and health authorities and using indirect measures of exposure, we estimated the risk to the James Bay Cree of renal impairment related to the long-term consumption of the liver and kidney of moose and caribou contaminated by environmental cadmium. The low risk of disease was weighed against the possible detriment from activities to convince the Crees to avoid a traditional albeit occasional component of their subsistence diet. Our approach to the assessment and management of this specific environmental hazard is of general interest.

In Canada in late 1987 there was an outbreak of an acute illness characterized by gastrointestinal symptoms and unusual neurologic abnormalities among persons who had eaten cultivated mussels. Health departments in Canada solicited reports of this newly recognized illness. A case was defined as the occurrence of gastrointestinal symptoms within 24 hours or of neurologic symptoms within 48 hours of the ingestion of mussels. From the more than 250 reports received, 107 patients met the case definition. The most common symptoms were vomiting (in 76 percent of the patients), abdominal cramps (50 percent), diarrhea (42 percent), headache, often described as incapacitating (43 percent), and loss of short-term memory (25 percent). Nineteen patients were hospitalized, of whom 12 required intensive care because of seizures, coma, profuse respiratory secretions, or unstable blood pressure. Male sex and increasing age were associated independently with the risks of hospitalization and memory loss. Three patients died. Mussels associated with this illness were traced to cultivation beds in three river estuaries on the eastern coast of Prince Edward Island. Domoic acid, which can act as an excitatory neurotransmitter, was identified in mussels left uneaten by the patients and in mussels sampled from these estuaries. The source of the domoic acid appears to have been a form of marine vegetation, Nitzschia pungens, also identified in these waters in late 1987. The contaminated mussels from Prince Edward Island were removed from the market, and no new cases have occurred since December 1987. We conclude that the cause of this outbreak of a novel and severe intoxication was the ingestion of mussels contaminated by domoic acid, a potent excitatory neurotransmitter.

Outbreaks of hepatitis A among patrons and employees of two food service establishments in Anchorage, Alaska, in November 1982 and April 1983 were linked to male food handlers infected with the virus. By case finding and contact tracing, we established that the food handlers in both outbreaks were associated with an epidemic of hepatitis A that was transmitted among Anchorage homosexual men for more than six months. Lacking specific serologic findings, physicians treating several of these homosexual men had incorrectly diagnosed the illness as hepatitis B, delaying recognition of the epidemic.

In an outbreak of folliculitis in Alaska among bathers in a contaminated hot tub, one person was found in whom follicular lesions were preceded by deep, tender, peripheral nodules. Of nine affected bathers, five showed inflammation of Montgomery's follicles of the breast. Bathing longer in the tub and later in the day was associated with increased risk of disease. This investigation added serotype O-7,8 to the list of pseudomonads associated with hot tub infections.

An outbreak of 8 cases of hepatitis A among the 36-member crew of an offshore Alaska petroleum production platform was linked to a previous outbreak in an urban day-care center. Transmission of hepatitis A on the platform related most plausibly to refrigerated food items contaminated by a cook with mild disease. Control efforts included identifying and treating contacts of case patients who had traveled far from the platform before becoming ill. Early serologic confirmation of diagnosed cases and rapid reporting to public health authorities are essential to prevent disease transmission. Timely investigation can limit the administration of immune globulin to persons at high risk of contracting the disease.

An outbreak of febrile respiratory disease occurred over 11 days among thirteen adults in Nova Scotia, all members of an extended family and their friends. Signs of illness included bradycardia at the same time as fever, palatal petechiae, and rapidly enlarging bilateral pulmonary infiltrates. Ten of the patients had a four-fold rise in antibody to phase-2 Q-fever antigen as determined by complement fixation on acute and 4-week-convalescent serum samples. Six children of the extended family for whom a four-fold titre rise was shown had slight or no disease. Investigations showed that the illness related to having entered the home of four of the patients on 1 of 2 consecutive days. On the first day the family cat, subsequently found to have antibody to Q fever, gave birth to kittens which she nursed in a basket kept inside the entry way. Q fever has been associated with parturient cattle, sheep, and goats but family pets, particularly cats, have not previously been implicated in human illness.