Case-cohort design in practice – experiences from the MORGAM Project

When carefully planned and analysed, the case-cohort design is a powerful choice for follow-up studies with multiple event types of interest. While the literature is rich with analysis methods for case-cohort data, little is written about the designing of a case-cohort study. Our experiences in designing, coordinating and analysing the MORGAM case-cohort study are potentially useful for other studies with similar characteristics. The motivation for using the case-cohort design in the MORGAM genetic study is discussed and issues relevant to its planning and analysis are studied. We propose solutions for appending the earlier case-cohort selection after an extension of the follow-up period and for achieving maximum overlap between earlier designs and the case-cohort design. Approaches for statistical analysis are studied in a simulation example based on the MORGAM data

European Health Examination Survey - towards a sustainable monitoring system

Background: Health examination surveys (HESs), including both questionnaire and physical measurements, and in most cases also collection of biological samples, can provide objective health indicators. This information complements data from health interview surveys and administrative registers, and is important for evidence-based planning of health policies and prevention activities. HESs are valuable data sources for research. The first national HESs in Europe were conducted in the late 1950s and early 1960s. They have recently been carried out in an increasing number of countries, but there has been no joint standardization between the countries. Methods: The European Health Examination Survey Pilot Project was conducted in 2009–2012. The European Health Examination Survey Pilot Reference Centre was established and pilot surveys were conducted in 12 countries. Results: European standardized protocols for key measurements on main chronic disease risk factors (height, weight, waist circumference, blood pressure, blood lipids and fasting glucose or HbA1c) were prepared. European-level training and external quality assessment were organized. Although the level of earlier experience, infrastructures, economic status and cultural settings varied between the pilot countries, it was possible to standardize measurements of HESs across the populations. Obtaining high participation rates was challenging. Conclusion: HESs provide high-quality and representative population data to support policy decisions and research. For future national HESs, centralized coordination, training and external quality assessment are needed to ensure comparability of the results. Further studies on effects of different survey methods on comparability of the results and on recruitment and motivation of survey participants are needed.peer-reviewe

World Health Organization definition of myocardial infarction: 2008-09 revision

Background WHO has played a leading role in the formulation and promulgation of standard criteria for the diagnosis of coronary heart disease and myocardial infarction since early 1970s. Methods The revised definition takes into consideration the following: well-resourced settings can use the ESC/ACC/AHA/WHF definition, which has new biomarkers as a compulsory feature; in resource-constrained settings, a typical biomarker pattern cannot be made a compulsory feature as the necessary assays may not be available; the definition must also have provision for diagnosing non-fatal events with incomplete information on cardiac biomarkers and the ECG; to facilitate epidemiologic monitoring definition must recognize fatal events with incomplete or no information on cardiac biomarkers and/or ECG and/or autopsy and/or coronary angiography. Results Category A definition is the same as ESC/ACC/AHA/WHF definition of MI, and can be applied to settings with no resource constraints. Category B definition of MI is to be applied whenever there is incomplete information on cardiac bio-markers together with symptoms of ischaemia and the development of unequivocal pathological Q waves. Category C definition (probable MI) is to be applied when individuals with MI may not satisfy Category A or B definitions because of delayed access to medical services and/or unavailability of electrocardiography and/or laboratory assay of cardiac biomarkers. In these situations, the term probable MI should be used when there is either ECG changes suggestive of MI or incomplete information on cardiac biomarkers in a person with symptoms of ischaemia with no evidence of a non-coronary reason. Conclusions This article presents the 2008-09 revision of the World Health Organization (WHO) definition of myocardial infarction (MI) developed at a WHO expert consultatio