Background to study
The Child Heart and Health Study in England (CHASE)
The Child Heart And Health Study in England (CHASE) is a detailed investigation of patterns of risk factors for cardiovascular disease and type 2 diabetes of UK children of South Asian, black African-Caribbean and white European origin. CHASE is based in 200 Primary Schools in London, Birmingham and Leicester, which were sampled to allow the invitation of balanced numbers of South Asians (including similar numbers of Indian, Pakistani and Bangladeshi origin), black African-Caribbeans (including similar numbers of African and Caribbean origin) and white Europeans. Recruitment of 5000 participants began in late 2004; fieldwork was completed in mid 2008, with an overall 69% participation rate (similar in all major ethnic groups). More details of the data collected in CHASE are provided in (Appendix 2). The study can best be understood in 3 parts:-
- a study of heart disease risk factors, carried out in approximately 5000 children (CHASE-5000)
- a study of heart disease risk factors and health behaviours, carried out in approximately 2000 children (CHASE-2000)
- a study of heart disease risk factors, health behaviours and measurements of vascular structure and function, carried out in approximately 1000 children (CHASE-1000)
CHASE main risk factor study in 5000 children in 200 schools (CHASE-5000 Study)
In this study, standardized measurements of height, weight, waist and hip circumference, abdominal diameter, bioelectrical impedance, skinfold thickness, pubertal status and blood pressure were made. Participants provided fasting blood for measurement of plasma glucose, glycated haemoglobin (HbA1c), serum insulin and lipids (total, LDL and HDL cholesterol and triglyceride) and plasma vitamin C. Detailed information on ethnicity (self-defined ethnicity; place of birth, language and religion of child, parents and grand-parents) has been sought from participants and parents. Data on individual social markers (parental occupation, housing tenure, car ownership, household amenities) has been collected.
CHASE health behaviour study in 2000 children in 80 schools (CHASE-2000 Study)
In a sub-study of 2,000 participants in the main risk factor study (examined 2006-2007), detailed additional assessments of physical activity, physical fitness and diet were made. Objective assessment of physical activity was carried out over a one week period using an Actigraph GT1M accelerometer, which has been validated against gold standard methods of assessment for energy expenditure. Physical fitness was assessed using a submaximal ramped exercise step test, with continuous heart rate monitoring to a maximal workload of approximately 30 ml/kg/min. Dietary habits, nutritional composition were assessed in detail using 24 hour recalls and 4-day diaries. Supplementary studies examined short-term variation in physical activity, physical fitness and nutritional composition over periods between one month and one year.
CHASE vascular study in 1,000 children in 40 schools (CHASE-1000 Study)
In 1000 CHASE-2000 participants, objective markers of vascular structure and function which are predictors of later cardiovascular outcomes, including common carotid intimal-medial thickness, carotid arterial distensibility, carotid-femoral pulse wave velocity were measured; measurements of retinal arterial and venous tortuosity have also been made.