Modelling preventive effectiveness to estimate the equity tipping point: at what coverage can individual preventive interventions reduce socioeconomic disparities in diabetes risk?

INTRODUCTION: Most individual preventive therapies potentially narrow or widen health disparities depending on the difference in community effectiveness across socioeconomic position (SEP). The equity tipping point (defined as the point at which health disparities become larger) can be calculated by varying components of community effectiveness such as baseline risk of disease, intervention coverage and/or intervention efficacy across SEP. METHODS: We used a simple modelling approach to estimate the community effectiveness of diabetes prevention across SEP in Canada under different scenarios of intervention coverage. RESULTS: Five-year baseline diabetes risk differed between the lowest and highest income groups by 1.76%. Assuming complete coverage across all income groups, the difference was reduced to 0.90% (144 000 cases prevented) with lifestyle interventions and 1.24% (88 100 cases prevented) with pharmacotherapy. The equity tipping point was estimated to be a coverage difference of 30% for preventive interventions (100% and 70% coverage among the highest and lowest income earners, respectively). CONCLUSION: Disparities in diabetes risk could be measurably reduced if existing interventions were equally adopted across SEP. However, disparities in coverage could lead to increased inequity in risk. Simple modelling approaches can be used to examine the community effectiveness of individual preventive interventions and their potential to reduce (or increase) disparities. The equity tipping point can be used as a critical threshold for disparities analyses.

TITRE: Modélisation de l'efficacité de la prévention pour estimer le point de bascule de l'équité : quelle couverture des interventions préventives individuelles permet de réduire les effets des disparités socioéconomiques relatives au risque de diabète? INTRODUCTION: La plupart des traitements préventifs individuels peuvent atténuer ou renforcer les disparités en santé selon leur efficacité différentielle dans la collectivité en fonction du statut socioéconomique (SSE). Le point de bascule de l'équité (défini comme le point à partir duquel les disparités en santé augmentent) se calcule en faisant varier les composantes de l'efficacité dans la collectivité, par exemple le risque de base de la maladie, la couverture des interventions ou l'efficacité de ces dernières, en fonction du SSE. MÉTHODOLOGIE: Nous avons utilisé une méthode simple de modélisation pour estimer l'efficacité de la prévention du diabète dans la collectivité au Canada selon le SSE selon divers scénarios de couverture d'intervention. RÉSULTATS: Le risque de base de diabète à cinq ans variait de 1,76 % entre le groupe ayant le revenu le plus faible et celui ayant le revenu le plus élevé. Lorsqu'on supposait que la couverture était complète dans toutes les tranches de revenu, l'écart diminuait, passant à 0,90 % (prévention de 144 000 cas) à la suite d'interventions sur le mode de vie et à 1,24 % (prévention de 88 100 cas) au moyen de la pharmacothérapie. Le point de bascule de l'équité a été estimé comme étant un écart de couverture de 30 % dans le cas des interventions de prévention (100 % de couverture dans le groupe ayant le revenu le plus élevé et 70 % de couverture dans le groupe ayant le revenu le plus faible). CONCLUSION: Les disparités relativement au risque de diabète pourraient être sensiblement réduites si les interventions étaient adoptées de manière égale dans tous les groupes indépendamment du SSE. Cependant, les disparités en matière de couverture sont susceptibles d'entraîner une plus grande inégalité du risque. Des méthodes simples de modélisation peuvent servir à déterminer l'efficacité des interventions de prévention individuelles dans la collectivité et leur potentiel à réduire (ou augmenter) les disparités. Le point de bascule de l'équité peut être utilisé comme seuil critique dans l'analyse des disparités.

Health behavior associated with influenza vaccination among healthcare workers in long-term-care facilities.

OBJECTIVE: To investigate the health behavior associated with influenza vaccination among healthcare workers (HCWs) in long-term-care facilities. DESIGN: A cross-sectional, self-administered survey of HCWs, augmented with focus groups to further examine attitudes toward influenza vaccination. SETTING: Two long-term-care facilities participated in the survey. The focus groups were held at one of the two facilities. PARTICIPANTS: All HCWs were invited to participate in the survey and all nonmanagerial staff members were invited to participate in the focus groups. The response rate for the survey was 58% (231 of 401). RESULTS: Vaccinated HCWs had a more positive attitude toward influenza vaccination and a greater belief that the vaccine is effective. This was not accompanied by differences in vaccine knowledge or values of potential preventive outcomes. Nonvaccinated respondents were more likely to believe that other preventive measures, such as washing hands, taking vitamins and supplements, eating a nutritious diet, exercising, and taking homeopathic or naturopathic medications, were more effective than vaccination. Additional findings from the focus groups suggest that HCWs believe that the main purpose of influenza vaccination programs is to protect residents' health at the expense, potential harm, and burden of responsibility of the staff. CONCLUSIONS: This study identifies challenges to and opportunities for improving vaccination rates among HCWs. A message that emphasizes the health benefits of vaccination to staff members, such as including vaccination as part of a staff "wellness" program, may improve the credibility of influenza immunization programs and coverage rates.

Measuring the health burden of chronic disease and injury using health adjusted life expectancy and the Health Utilities Index.

OBJECTIVES: To estimate the burden of illness from chronic disease and injury using a population based health survey, which contains both measures of chronic disease and a utility based health related quality of life (HRQOL) measure. DESIGN: An adapted Sullivan method was used to calculate cause deleted health adjusted life expectancies for chronic conditions. SETTING: Ontario, Canada, 1996/97. SUBJECTS: The 1996/97 Ontario Health Survey (n=35 527) was used to estimate the prevalence of chronic conditions. A cause deleted approach was used to estimate the impact of these conditions on the Health Utilities Index (HUI). Cause deleted probabilities of dying were derived with the cause eliminated life table technique and death data from vital statistics for Ontario 1996/97 (n=156 610). RESULTS: Eliminating cardiovascular disease and cancer will cause an "expansion of morbidity", while eliminating mental conditions and musculosketal disorders will result in a "contraction of morbidity". The HUI score varies depending on chronic condition, age, and sex-most of which were assumed not to vary in previous summary measures of population health. CONCLUSIONS: Health adjusted life expectancy estimated for chronic conditions using a utility based measure of health related quality of life from population health surveys addresses several limitations of previous studies that estimate the burden of disease using either a categorical measure of disability or expert opinion and related epidemiological evidence.

Health-adjusted life expectancy at the local level in ontario.

Health expectancy measures are becoming a common method of combining information on mortality and health-related quality of life into one summary population health measure. However, health expectancy measures are infrequently measured at the local level, despite a shift toward health service planning to that level. Using a modified Sullivan method, we calculated health-adjusted life expectancy (HALE) for the 42 public health units in Ontario using life tables that were derived from mortality and population data for 1988-1992 and the Health Utilities Index from the 1990 Ontario Health Survey. There were large variations among health units in HALE at age 15 for both men (range: 51.3-58.2 years) and women (range: 56.6-62.9 years). Generally, rural and northern areas had the lowest HALE. Local differences in male HALE were greater than for life expectancy (7.1 versus 6.0 years). Despite a relatively large health survey (45,583 respondents, range: 729-1,746 per health unit), few HALE differences deviated significantly from the Ontario mean, raising concerns about the feasibility of estimating local health expectancy measures with adequate precision. Nevertheless, the wider local differences and different geographic distribution of local HALE compared with mortality measures, along with the additional benefit of being able to model the complex interaction of mortality and morbidity, suggest that HALE may be a useful population health measure.

The first reported cluster of food-borne cyclosporiasis in Canada.

INTRODUCTION: Prior to 1996, sporadic cases of cyclosporiasis in Canada were most often associated with foreign travel and outbreaks throughout the world were associated with contaminated drinking water. In May 1996, the North York Public Health Department was notified of three laboratory-confirmed cases of cyclosporiasis among persons who attended a luncheon at a religious institution. A ceremonial bath (mikvah) was initially identified as a possible source of exposure to contaminated water. METHODS: Guests of a luncheon were interviewed regarding food, beverage and water exposure. The institution kitchen and water sources were inspected and environmental testing was performed. RESULTS: Eating strawberry flan, decorated with rasberries and blueberries, was associated with developing illness (relative risk = 2.13, p = 0.02). There was no evidence that water exposure was associated with illness. DISCUSSION: This event was the index Canadian cluster of a widespread North American outbreak associated with imported Guatemalan raspberries. The local investigation highlights the role of public health departments in multijurisdictional food-borne outbreaks of emerging pathogens.

The derivation of life tables for local areas.

Life tables are seldom derived at the local level, despite a shift toward health service planning to that level. We calculated life tables by sex for the 42 public health units in Ontario, using 1988 1992 mortality files. Traditional methods of life table construction were compared and validated. Data quality, particularly geographical coding of death certificates, poses the greatest difficulty in deriving accurate life tables for comparison between areas. Migration will affect estimates, but it is best considered during the interpretation of results. Except for the final age interval, methods of modelling life tables have little impact on final life expectancy estimates. It is feasible to calculate local level life tables with data and tools that are readily available. The results highlight the importance of examining such life tables, as variations within a province in life expectancy at birth may be as important as the differences between provinces.