Why was the cohort set up?
Cardiovascular disease (CVD) including ischaemic heart disease and cerebrovascular disease is among the leading causes of mortality worldwide,1 and in Ireland, coronary heart disease death rates are among the highest in Europe.2 Although it has previously been reported that only 50% of CVD can be attributed to traditional risk factors,3,4 it is now recognized that these factors occur much more frequently in people with CVD,5,6 with most of the population attributable risk of myocardial infarction due to risk factors such as smoking, hypercholesterolaemia, diabetes mellitus, hypertension and obesity.7 To date, much of the focus in CVD prevention has been on determining the individual contribution of risk factors to the development of CVD and targeting individual risk factors.8 However, it is increasingly recognized that it is the effect of these risk factors in combination and the consequent potential for prevention in terms of lifestyle changes that address these factors simultaneously that should be prioritized.9–11 The original Cork and Kerry Diabetes and Heart Disease Study—Phase I, which was undertaken in 1998, was at that time, one of the first large population-based observational studies in Ireland.12The primary aim of the study was to estimate the prevalence of major CVD risk factors in a middle-aged population in Ireland and to estimate the proportion of the population at high risk according to Framingham criteria. The study included measurement of diet and physical activity and assessed the impact of these lifestyle factors on traditional CVD risk factors including hypertension and dyslipidaemia.13–15
Phase II of the Cork and Kerry Diabetes and Heart Disease Study began in 2008, with support from the Health Research Board Centre for Health and Diet Research.16 The centre provided funding for long-term follow-up of the original Cork and Kerry cohort, including assessment of vital status and a rescreen of surviving cohort members as well as recruitment of a new cohort, the Mitchelstown cohort. Although the original cohort was recruited from across 17 different general practices in Cork and Kerry, the new cohort was recruited from a single large primary care centre, the Livinghealth Clinic in Mitchelstown, county Cork (Figure 1).
The aim of the Cork and Kerry Study—Phase II (Mitchelstown cohort recruited 2010–11) is to provide an updated profile of glucose tolerance status, cardiovascular health and their related factors in an Irish adult general population sample and to compare the findings with those obtained during baseline assessment of Phase I of the Cork and Kerry study (1998) and the rescreen (2008) and (2015). Additional objectives include determining the prevalence of proximal risk factors, such as hypertension, dyslipidaemia, body mass index (BMI) and insulin resistance as well as of more distal risk factors of diet, smoking, alcohol consumption and physical activity, and the association between cardiovascular health and its risk factors with general measures of well-being and mental health. The new cohort includes collection of qualitative and quantitative data in an effort not only to describe the current health status of the cohort and assess individual level determinants but also to provide the appropriate context to interpret the role of behavioural factors and social circumstances on health.