John W. Frank

Modelling psychosocial effects of exposure to solid waste facilities

A parallel case study design was used to investigate psychosocial effects in populations exposed to solid waste facilities. Psychosocial effects were defined as a complex of distress, dysfunction and disability, manifested in a range of psychological, social and behavioural outcomes, as a consequence of actual or perceived environmental contamination. This paper presents the results of logistic regression analyses designed to identify determinants of psychosocial effects of exposure. The data come from an epidemiologic survey of residents (N = 696) living within a prescribed radius from each of three solid waste facilities in southern Ontario. The analytical model has three main components: external variables (e.g. individual and exposure-related variables); mediating variables (e.g. social network membership and involvement, general health status measures); and outcome variables (e.g. concern, effects and actions). Results for a series of site specific analyses show that outcome measures can be successfully explained by a combination of external and mediating factors. In general, variables from each of the three main components enter the concern-related models while the action models are clearly dominated by social network variables. Analyses using data from all three sites indicate the explanatory power of site-related characteristics. However, given the number and diversity of variables in the models, there is no support for a simple cause and effect relationship. The implication is that strategies aimed to address and alleviate psychosocial effects need to be specific to the characteristics of the populations in particular settings.

Do coronary heart disease risk factors measured in the elderly have the same predictive roles as in the middle aged comparisons of relative and attributable risks

Risk factors for the 12-year incidence of definite coronary heart disease (CHD) among 3440 men who were middle-aged (51 to 59 years old) and 1419 men who were elderly (65 to 74 years old) at baseline examination were examined for differences in predictive values in terms of both relative risk and attributable (excess) risk of the highest versus the lowest quartile or appropriate categories. In multivariate models using Cox life-table regression procedures, serum cholesterol level, cigarette smoking, systolic blood pressure, and history of treatment for diabetes were significant predictors of incident CHD for both age groups. Alcohol consumption when modeled as drinker versus nondrinker showed a protective effect in both younger and older men. There was no dose relationship, however, among elderly drinkers. While the relative risks for the variables studied were similar between the two age groups, the excess risk was typically between 1.5 to 2.0 times higher for the older than the middle-aged men. In contrast, the detrimental effect of adiposity as measured by body mass index appeared to decline after age 65 for both measures of risk. This may partly be attributed to diminished adiposity overall in the older age group. The implications of these results are that serum cholesterol level, smoking, hypertension, diabetes, and possibly alcohol consumption continue to be important predictors for CHD when measured after age 65, and that the public health impact of these risk factors, in terms of excess risk, may be more important in the elderly.

Psychosocial impacts in populations exposed to solid waste facilities

This interdisciplinary study uses a parallel case study design to investigate psychosocial impacts in populations exposed to three solid waste facilities in Southern Ontario. Impacts are examined at three social scales: individual, social network and community levels. The objectives and design derive from a feasibility study recently completed by the same research team. A two stage approach is adopted. The first is an epidemiologic survey to determine the prevalence of psychosocial impacts in the populations within a prescribed area around each site. A disproportionate stratified (by distance) random sample of 250 households is surveyed at each site. Data on awareness, knowledge, concern and action regarding the site are also obtained. Scores on pre-validated health measurement scales will be compared with population norms to determine the frequency distribution above, within and below the range of normal. The second stage involves the use of qualitative methodologies to provide an in-depth analysis of the individual, social network and community level factors affecting psychosocial impacts and reactions to the situation. Depth interviews with a sub-sample of survey respondents explore individual perceptions, attitudes and actions. Focus groups composed of members of relevant organizations and discussion groups comprising non-members uncover social network and community perspectives in an interactional setting. Interviews and group sessions are taped and transcribed for content analysis of salient themes. Textual analysis of media reports and other relevant documentation provide insights regarding the informational environment and the community context of the issues.

Methodological issues in assessing reproducibility—A comparative study of various indices of reproducibility applied to repeat ELISA serologic tests for Lyme disease

This study applies and evaluates a variety of different measures of reproducibility. As an example, repeat enzyme-linked immunosorbent assays (ELISA) for antibodies to Borrelia burgdorferi, the etiologic agent of Lyme disease, are used. These repeat tests were part of the 1991 Quality Control Assessment of provincial laboratories that was carried out by the Laboratory Centre for Disease Control (Ottawa). Twenty-seven sera from cases and non-cases were tested by three laboratories, and two laboratories repeated the tests once. Methodological issues discussed include: different methods of assessing reproducibility in the continuous scale; whether reproducibility should be assessed with data in continuous or categorical form; problems assessing the reproducibility of data that has been standardized using a calibration-regression line; and problems with external generalizability of reproducibility studies of rare diseases. The authors conclude that the statistical method used to assess the reproducibility of a test must be adjusted to suit individual study designs and data, and the usage of the test.

Making health data maps: a case study of a community/university research collaboration.

This paper presents the main findings from a collaborative community/university research project in Canada. The goal of the project was to improve access to community health information, and in so doing, enhance our knowledge of the development of community health information resources and community/university collaboration. The project built on a rich history of community/university collaboration in Southeast Toronto (SETO), and employed an interdisciplinary applied research and action design. Specific project objectives were to: (1) develop via active community/university collaboration a geographic information system (GIS) for ready access to routinely collected health data, and to study logistical, conceptual and technical problems encountered during system development; and (2) to document and analyze issues that can emerge in the process of community/university research collaboration. System development involved iteration through community user assessment of need, development or refinement of the GIS, and assessment of the GIS by community users. Collaborative process assessment entailed analysis of archival material, interviews with investigators and participant observation. Over the course of the project, a system was successfully developed, and favorably assessed by users. System development problems fell into four main areas: maintaining user involvement in system development, understanding and integrating data, bringing disparate data sources together, and making use of assembled data. Major themes emerging from the community/university collaborative research process included separate community and university cultures, time as an important issue for all involved, and the impact of uncertainty and ambiguity on the collaborative process.

Cost-effectiveness studies of medical and chiropractic care for occupational low back pain ☆: a critical review of the literature

BACKGROUND CONTEXT Back pain is the single most costly work-related injury. Chiropractors and physicians are the main primary care providers for occupational low back pain (OLBP), but there is no consensus regarding the relative cost-effectiveness of these two modes of care. PURPOSE To critically appraise and synthesize recent literature on the cost-effectiveness of medical and chiropractic care for OLBP, and to propose a cost-effectiveness methodology that integrates epidemiologic and economic methods for future studies. STUDY DESIGN Literature review. MEDLINE was searched from 1990 through 1999. Nine articles that met the inclusion criteria were reviewed. The methodological quality of the articles was critically appraised independently by two epidemiologists using standardized review criteria. Two health economists reviewed the studies on cost-effectiveness. RESULTS The current literature suggests that chiropractors and physicians provide equally effective care for OLBP but that chiropractic patients are more satisfied with their care. Evidence on the relative costs of medical and chiropractic care is conflicting. Several methodological deficiencies limit the validity of the reviewed studies. No studies combine high-quality cost data with adequate sample sizes and controls for confounding factors. CONCLUSION Existing studies fail to clarify whether medical or chiropractic care is more cost effective. We suggest that future studies must combine epidemiologic and economic methods to answer the question adequately.

Low Back Pain Prognosis: Structured Review of the Literature

The purpose of this paper was to review and appraise pertinent articles to gain a better understanding of critical methodological issues necessary to properly design a high-quality back pain prognosis study. The review concentrated on back pain prognosis studies with epidemiologically sound designs focusing on work-disability outcomes and utilizing survival analytic methods. Nine papers were reviewed. There were few well-designed studies that achieved good scientific quality with minimal flaws. The outcomes were well defined in each paper. The age and sex characteristics of the cohorts were described in six papers and an adequate description of the study site occurred in five papers. All papers employed suitable mathematical/statistical techniques, but only one paper discussed accuracy and predictive value. No paper addressed the issue of reproducibility of the predictor variables or the final model. Most papers derived models that were clinically sensible, and the ease of use for clinicians was high. A recommended course of action for use by future patients/therapists in prognostication was rarely documented. To date, prognosis has been an inadequately studied aspect of the continuum from back injury to recovery. Researchers and clinicians interested in prognosis research need to overcome the limitations of past designs and address the methodological guidelines outlined to improve the quality of future prognosis studies.

Does cigarette smoking have an independent effect on coronary heart disease incidence in the elderly

In order to evaluate the effects of cigarette smoking on coronary heart disease (CHD) in elderly persons in the Honolulu Heart Program, 1,394 men between ages 65 and 74 were followed during an average 12-year period for new cases of nonfatal myocardial infarction and fatal CHD. Incidence rates increased progressively in individuals classified at baseline as never, former, and current smokers, respectively. The absolute excess risk associated with cigarette smoking was nearly twice as high in elderly compared with middle-aged men.

Screening for hypercholesterolaemia in primary care: randomised controlled trial of postal questionnaire appraising risk of coronary heart disease

Abstract Objectives: To validate a self administered postal questionnaire appraising risk of coronary heart disease. To determine whether use of this questionnaire increased the percentage of people at high risk of coronary heart disease and decreased the percentage of people at low risk who had their cholesterol concentration measured. Design: Validation was by review of medical records and clinical assessment. The questionnaire appraising risk of coronary heart disease encouraged those meeting criteria for cholesterol measurement to have a cholesterol test and was tested in a randomised controlled trial. The intervention group was sent the risk appraisal questionnaire with a health questionnaire that determined risk of coronary heart disease without identifying the risk factors as related to coronary heart disease; the control group was sent the health questionnaire alone. Setting: One capitation funded primary care practice in Canada with an enrolled patient population of about 12 000. Subjects: Random sample of 100 participants in the intervention and control groups were included in the validation exercise. 5686 contactable patients aged 20 to 69 years who on the basis of practice records had not had a cholesterol test performed during the preceding 5 years were included in the randomised controlled trial. 2837 were in the intervention group and 2849 were in the control group. Main outcome measures: Sensitivity and specificity of assessment of risk of coronary heart disease with risk appraisal questionnaire. Rate of cholesterol testing during three months of follow up. Results: Sensitivity of questionnaire appraising coronary risk was 87.5% (95% confidence interval 73.2% to 95.8%) and specificity 91.7% (81.6% to 97.2%). Of the patients without pre-existing coronary heart disease who met predefined screening criteria based on risk, 45 out of 421 in the intervention group (10.7%) and 9 out of 504 in the control group (1.8%) had a cholesterol test performed during follow up (P<0.0001). Of the patients without a history of coronary heart disease who did not meet criteria for cholesterol testing, 30 out of 1128 in the intervention group (2.7%) and 18 out of 1099 in the control group (1.6%) had a cholesterol test (P=0.175). Of the patients with pre-existing coronary heart disease, 1 out of 15 in the intervention group (6.7%) and 1 out of 23 in the control group (4.3%) were tested during follow up (P=0.851, one tailed Fishers exact test). Conclusions: Although the questionnaire appraising coronary risk increased the percentage of people at high risk who obtained cholesterol testing, the effect was small. Most patients at risk who received the questionnaire did not respond by having a test. Key messages Of patients at high risk of coronary heart disease, 10.7% who received a risk appraisal questionnaire with a general health questionnaire and 1.8% of those who received the general health questionnaire alone had a cholesterol test within the following three months Of patients at low risk, 2.7% of patients receiving the risk appraisal questionnaire and 1.6% of control subjects had a cholesterol test Most patients at risk who received the risk appraisal questionnaire did not seek a test Further research is needed to identify factors contributing to low uptake of cholesterol testing among people at high risk of coronary heart disease even when encouragement is given

Integrating qualitative research into occupational health: a case study among hospital workers.

Objective: We sought to better use qualitative approaches in occupational health research and integrate them with quantitative methods. Methods: We systematically reviewed, selected, and adapted qualitative research methods as part of a multisite study of the predictors and outcomes of work-related musculoskeletal disorders among hospital workers in two large urban tertiary hospitals. Results: The methods selected included participant observation; informal, open-ended, and semistructured interviews with individuals or small groups; and archival study. The nature of the work and social life of the hospitals and the foci of the study all favored using more participant observation methods in the case study than initially anticipated. Conclusions: Exploiting the full methodological spectrum of qualitative methods in occupational health is increasingly relevant. Although labor-intensive, these approaches may increase the yield of established quantitative approaches otherwise used in isolation.