Challenges to the census: international trends and a need to consider public health benefits.

The Canadian government decision to cancel the mandatory long-form census in 2010 (subsequently restored in 2015), along with similar discussions in the United Kingdom (UK) and the United States of America (USA), have brought the purpose and use of census data into focus for epidemiologists and public health professionals. Policy decision-makers should be well-versed in the public health importance of accurate and reliable census data for emergency preparedness planning, controlling disease outbreaks, and for addressing health concerns among vulnerable populations including the elderly, low-income, racial/ethnic minorities, and special residential groups (e.g., nursing homes). Valid census information is critical to ensure that policy makers and public health practitioners have the evidence needed to: (1) establish incidence rates, mortality rates, and prevalence for the full characterization of emerging health issues; (2) address disparities in health care, prevention strategies and health outcomes among vulnerable populations; and (3) plan and effectively respond in times of disaster and emergency. At a time when budget and sample size cuts have been implemented in the UK, a voluntary census is being debated in the US. In Canada, elimination of the mandatory long-form census in 2011 resulted in unreliable population enumeration, as well as a substantial waste of money and resources for taxpayers, businesses and communities. The purpose of this article is to provide a brief overview of recent international trends and to review the foundational role of the census in public health management and planning using historical and current examples of environmental contamination, cancer clusters and emerging infections. Citing a general absence of public health applications of the census in cost-benefit analyses, we call on policy makers to consider its application to emergency preparedness, outbreak response, and chronic disease prevention efforts. At the same time, we call on public health professionals to improve published estimates of monetary benefit (via either cost-benefit or cost-effectiveness analysis) to a given public health intervention.

Equal treatment: bestowed or earned?

PURPOSE: While the complaint against non-industry employed epidemiologists for holding their industry-based colleagues to a higher level of scrutiny is accurate, this paper shows that there is a sound basis for such treatment. It also shows, however, that a shift towards ongoing vigilance is needed on the part of all epidemiologists to guard against such bias. METHODS: The proposed shift is made possible through the recent incorporation in ethics guidelines of principles that indeed identify the impropriety of any such bias. RESULTS: In the same guidelines, there are principles that require scientific impartiality. Industry-based epidemiologists, by the condition of their employment, may find the avoidance of partiality to the corporate interest more problematic than do non-industry based epidemiologists to their respective sponsors. It is in light of past examples of partiality among industry-based epidemiologists that other epidemiologists may be biased against them. CONCLUSIONS: This paper concludes with the realization that both groups of epidemiologists have the challenge of correcting the biases inculcated over many years. Trust needs to be established between industry and non-industry-based epidemiologists through greater acceptance on the part of the latter and exemplary conduct on the part of the former to overcome past practice records.

Findings from the American College of Epidemiology's survey on Ethics guidelines. The American College of Epidemiology Ethics and Standards of Practice Committee.

PURPOSE: A survey to establish both the need and subject areas for a possible new set of ethics guidelines for epidemiologists was conducted among a random sample of 300 North American (Canada, Mexico, and United States) members of three major United States-based professional epidemiology organizations. METHODS: An 88% response rate revealed wide agreement on topics to be included in any new set of guidelines, but uncertainty prevailed about the need for new guidelines; 41% agreed that there was a need to develop a new set, 43% had no opinion, and 16% disagreed. RESULTS: There was almost no difference in preferences between men and women for topics to be included in a new set of guidelines, or between those aware or unaware of extant ethics guidelines in epidemiology. Fifty-four percent were aware of such guidelines and only 29% of these said they could describe the content of the guidelines. CONCLUSION: More needs to be done to evaluate the utility of ethics codes in epidemiology.

Ethical, social, and legal issues surrounding studies of susceptible populations and individuals.

Calls for professional accountability have resulted in the development of ethics guidelines by numerous specialty and subspecialty groups of scientists. Indeed, guidelines among some health professions now address vulnerable and dependent groups: but these are silent on issues related to biomarkers. In parallel, attention has been drawn to human rights concerns associated with attempts to detect hypersusceptible workers, especially in democratic countries. Despite this, concern for vulnerable populations grows as advances in biomarker technology make the identification of genetic predisposition and susceptibility markers of both exposure and outcome more attainable. In this article, the principles derived from the ethical theory of utilitarianism provide the basis for principle-based ethical analysis. In addition, the four principles of biomedical ethics--respect for autonomy, beneficence, nonmaleficence, and social justice--are considered for biomarker studies. The need for a context in which ethical analysis is conducted and from which prevailing social values are shown to drive decisions of an ethical nature is emphasized; these include statutory regulation and law. Because biomarker studies can result in more harm than good, special precautions to inform research participants prior to any involvement in the use of biomarkers are needed. In addition, safeguards to maintain the privacy of data derived from biomarker studies must be developed and implemented prior to the application of these new technologies. Guidelines must be expanded to incorporate ethical, social, and legal considerations surrounding the introduction of new technologies for studying susceptible populations and individuals who may be vulnerable to environmental exposures.

Ethical decision-making in epidemiology: the case study approach.

The experience of other health professions that have been concerned with professional ethics over the past number of years can be directly applied in epidemiology. A schematicized model, adapted from Storch and based on the nursing experience, provides a synthesis of those considerations necessary for ethical decision-making. An example demonstrates the process by which the model can be used. While a checklist procedure is regarded as neither useful nor appropriate for making an ethical decision, the existence of professional ethics guidelines is deemed a prerequisite, because it embodies the profession's values and social responsibilities. The place of professional ethics guidelines in making an ethical decision is central to the model and is shown to be fundamental to continued ethical conduct among epidemiologists.

Prevalence and determinants of tuberculin reactivity among physicians in Edmonton, Canada: 1996-1997.

BACKGROUND: Health care workers (HCW) have historically borne a heavy burden of tuberculosis (TB) infection and disease. Unfortunately, physicians are rarely included in HCW surveys of tuberculin exposure and infection. METHODS: The prevalence and risk factors for tuberculin reactivity were determined for a sample of the 1732 licensed physicians in Edmonton. Stratified random sampling was used to select 554 specialists and 219 general practitioners. These physicians were contacted by means of an introductory letter and a follow-up telephone call to solicit participation. All eligible physicians were asked to complete a questionnaire and those with either no recorded positive tuberculin test or a previously negative result were two-step tuberculin skin tested. RESULTS: In total, 560 physicians (72.4 %) participated in the study. The overall tuberculin reactivity for this population was 45.9%. Using logistic regression analysis, we determined that risk factors for reactivity were aged over 45 years, of foreign-birth, previous Bacillus Calmette-Guérin (BCG) vaccination, foreign practice experience, and being a respiratory medicine specialist. CONCLUSION: The prevalence of tuberculin reactivity among physicians is considerably higher than estimates for the general Canadian population. This observed excess risk may be associated with factors linked to their medical practice. The high participation rate suggests physician willingness to participate in this type of research, and emphasizes the need to include them in routine HCW surveillance.

Mortality and institutionalization following hip fracture.

OBJECTIVES: To identify determinants of mortality and institutionalization after hip fracture and to identify those older hip fracture patients at high risk of death or institutionalization after hip fracture. DESIGN: Population-based prospective inception cohort study of hip fracture patients; patients were assessed in the hospital and at 3 months following the hip fracture. SETTING: Edmonton area hip fracture patients admitted to one of two Edmonton, Alberta, Canada, acute care centers between July 10, 1996, and August 31, 1997. PARTICIPANTS: Patients were residents of the Edmonton area and over the age of 64. Those who had previously fractured the same hip within the past 5 years or had some pathological condition underlying the hip fracture were excluded. Of 610 eligible patients, 558 contributed some baseline information and were included in the mortality analysis; the institutionalization analysis was restricted to the 338 patients who lived in the community before fracture, survived the 3-month period postfracture, and had completed a 3-month follow-up interview. MEASUREMENTS: The baseline interview was done in the hospital to assess mental status, prefracture physical function, prefracture health perception, and prefracture social support. The 3-month follow-up interview was done by phone to assess physical function, health perception, and social support 3 months postfracture. Demographic and comorbidity information was collected from medical records. RESULTS: Low mental status in hospital was found to increase the chances of mortality and institutionalization, and male gender was found to increase mortality risk fourfold. Each additional 10 years of age increased the risk of institutionalization approximately 2.5 times. Patients with lower postfracture physical function had at least five times the risk of institutionalization compared to patients with high postfracture physical function. CONCLUSIONS: Cognitive impairment, older age, and gender were associated with increased risk of poor outcome following hip fracture. The socioeconomic variables--social support and health perception--did not contribute significant additional information in explaining mortality or institutionalization risk. While demographic factors cannot be modified, physical function 3 months postfracture may be amenable to intervention and may reduce the risk of institutionalization. Intervening to increase postfracture physical function may be particularly beneficial to older patients, or to those who are cognitively impaired.

Empirical assessment of the effect of different summary worklife exposure measures on the estimation of risk in case-referent studies of occupational cancer.

The effect of different summary measures of worklife exposure on the estimation of risk is reported. Two matched case-referent studies associating sulfuric acid exposure and cancer from Baton Rouge and southern Ontario were used. Five summary exposure measures were converted to discrete levels of exposure through the selection of equivalent percentile points on each measure's respective percentage frequency distribution for logistic regression modeling purposes. The southern Ontario data set exhibited only minor differences across all five exposure measures. The Baton Rouge data set, however, produced different results, and the time-dependent measures appeared to underestimate risk. It is possible, therefore, to obtain different estimates of risk depending on the exposure measure selected. It is recommended that, in the absence of proved models for assessing exposure, a variety of summary measures be used to estimate risk. This approach would facilitate the comparison of findings across studies.

Occupational exposure to sulfuric acid in southern Ontario, Canada, in association with laryngeal cancer.

A case-referent study, designed to test associations between asbestos, nickel, and the development of laryngeal cancer, was conducted in southern Ontario in 1977-1979. The cases were individually matched to neighborhood referents for gender and age. This constituted the primary study. Personal interviews had secured tobacco, alcohol, and detailed work histories. To 183 of the male pairs was added retrospective assessments of sulfuric acid exposure for each job, blind of disease status; this constituted the data base for an augmented secondary analysis. Logistic regression revealed statistically significant odds ratios when tobacco and alcohol were controlled. Exposure-response gradients were strongly positive with odds ratios in the range of 1.97 [95% confidence interval (95% CI) 0.63-6.13] for short duration-low level exposure through 6.91 [95% CI 2.20-21.74] for long duration-higher level exposure employing progressively more specific definitions of exposure. Asbestos as a confounder and the interaction terms examined were nonsignificant. These findings are corroborative of those of other studies.

Lack of associations between air emissions from sour-gas processing plants and beef cow-calf herd health and productivity in Alberta, Canada.

This paper describes a large-scale investigation into the effects of licensed air emissions from sour-gas processing plants on the health and productivity of beef cow-calf herds in the province of Alberta, Canada. In conjunction with a geographical information system, two atmospheric-dispersion models were used to assess historical exposures at 5726 beef cow-calf farm-sites from 1987 to 1990. We did secondary analyses of health, productivity, and management data, from a government-extension survey previously administered to beef cow-calf producers across the province. Statistical models (adjusted for potential confounding and clustering within herd and over time) were used to determine associations with estimates of sour-gas emission exposure. All analyses were conducted at the herd-level. There were no significant (P>0.05) detrimental associations of exposure and the annual herd risk for culling, calf-crop delivered, calf-crop season profile, stillbirth and twinning, calfhood mortality, or calf-crop weaned.

Air emissions from sour-gas processing plants and dairy-cattle reproduction in Alberta, Canada.

The dispersion of air pollutants from all 231 licensed sour-gas processing plants in Alberta, Canada, was modeled on a monthly basis over a 10-year period (1985-1994). Exposure estimates for sulfur dioxide (SO(2)-used as a surrogate for exposure to combusted emissions) then were assigned to 1382 provincial dairy farms using a geographical-information system. Individual average and peak exposure for periods prior to each of 15 months of age and conception (four exposure-averaging periods for each of two dispersion models) were estimated for 163,988 primiparous female dairy-cattle between 1986 and 1994. Monthly or annual average farm-site exposure estimates likewise were assigned to associated herd-level data sets for the biologically relevant period of interest for each of three additional reproductive outcomes: monthly herd-average calving interval, stillbirth risk, and twinning risk. In one of the main-effects models, the maximum (i.e., peak) monthly sour-gas exposure experienced by individual-animals from birth to conception was associated with an increased time to first-calving in the very-highest exposure category (hazard ratio=0.86, 95% CI=0.80, 0.92). This equates to a decreased hazard (lambda) of calving (in each month subsequent to 22 months of age) for the highest-exposure animals (lambda=0.170) versus the zero-exposure animals (lambda=0.198) in a model with referent values for agro-ecological region and season of birth. The dose-response was not consistent across the full range of exposure categories. There was significant (P=0.003) interaction of emissions with agro-ecological region. After accounting for the interaction, a more-consistent dose-response was evident for some (but not all) agro-ecological regions. This suggests that any effect of emissions on dairy-heifer reproduction is subject to modification by features of soil type, vegetative cover, and/or climate. The increase in monthly herd-average calving interval on farms exposed to the very-highest levels of emissions appeared quite small and of limited practical importance within the range of expected exposures. There was no association between exposure and the risk for twinning. Herds exposed to higher emissions exhibited a slight decrease in risk for stillbirth.

A preventive response to AIDS in a low prevalence region: a multisectoral, multistrategy approach.

The public health response to AIDS has been neglectful. Successive windows of opportunity for primary prevention have been lost, especially in low prevalence regions. However, an early response to preventing HIV infection is reported from Edmonton, a centre estimated as being 2-3 years behind larger North American cities in terms of its phase on the AIDS epidemic curve. In October, 1985, an Interagency Council was established. The Council is multisectoral, composed of professionals and lay people who contribute equally. Lay groups extend public health's reach, while health professionals add legitimacy to health promotion efforts. It is multistrategy by ensuring that both the felt needs of the lay community and the perceived needs of the professionals are incorporated; behaviour change theory is applied in all programming. The Council operationalizes some of the basic tenets of health promotion.

Infant and preschool immunization delivery in Alberta and Ontario: a partial cost-minimization analysis.

This paper is a partial cost-minimization analysis of preschool immunization delivery in Alberta and Ontario. Public health nurses deliver such immunization in Alberta while in Ontario it is usually provided by private physicians. In constant 1986 dollars, labour costs were 2.9 times higher in Ontario than in Alberta. Alberta and Ontario achieved equal success in preventing diphtheria, tetanus and poliomyelitis in the target population of zero to four years of age. Ontario's pertussis rates were higher than Alberta's from 1980 to 1986 inclusive (p less than 0.01). Rubella rates were higher in Alberta from 1980 to 1986 inclusive (p less than 0.05) but the congenital rubella rates for the same period were not. During 1980, Ontario's measles rate was higher (p less than 0.01) while for 1982 and 1986, Alberta's measles rates were higher. In 1986, Alberta's mumps rate was higher than Ontario's (p less than 0.01). The findings argue in favour of the less costly public health nurse approach to immunization delivery. A more definitive conclusion could have been reached had the provinces maintained more detailed age-specific disease incidence data.

Epidemiologic and toxicologic evidence for chronic health effects and the underlying biologic mechanisms involved in sub-lethal exposures to acidic pollutants.

Since the 1880s, a disparate and extensive literature has evolved examining the biologic effects of acidification on cells. More recently, effects on the health of human and other species of acidic agents contained, for example, in pollutants have been suggested, particularly relating to long-term exposures. This paper provides a review of the epidemiologic and toxicologic evidence concerning health effects--particularly carcinogenicity--attributable to sub-lethal acid exposure. Underlying biologic mechanisms that explain adverse health outcomes include pH modulation of toxicity for a number of xenobiotics (including carcinogens, genotoxins, and teratogens), and low-pH-induced changes of cells involving, for example, alterations in mitotic and enzyme regulation. More focused research is recommended to test the relationship between long-term exposures to acidic agents (with a consequent lowered cellular pH) and various health effects.