Relationships between the development of biological risk factors for coronary heart disease and lifestyle parameters during adolescence: The NorthernIreland Young Hearts Project

The purpose of this study was to examine relationships between the longitud inal development of biological risk factors for coronary heart disease (CHD ) (namely, serum lipids, body fatness, blood pressure and cardiorespiratory fitness) and the development of lifestyles considered to be atherogenic. T he study was conducted in a representative sample of adolescents from North ern Ireland, a region of high coronary mortality, and atherogenic aspects o f lifestyle such as cigarette smoking, physical inactivity and selected asp ects of diet were examined. Repeated measurements were made at 12 and 15 y of age on 229 boys and 230 girls. Longitudinal relations were analysed with generalised estimating equations, and the following longitudinal relations were found: for boys diastolic blood pressure was positively associated wi th vitamin C intake (P = 0.014), and inversely with energy intake (P = 0.00 6), and smoking (P = 0.048). Systolic blood pressure was inversely related to physical activity (P = 0.012), and smoking (P = 0.000). Body fatness was also inversely related to smoking (P = 0.006). Total cholesterol (TC) was positively related to physical activity (P = 0.044) and the TC:HDL choleste rol ratio positively to vitamin C intake (P = 0.008). Cardiorespiratory fit ness was positively related to physical activity (P = 0.000) and inversely to smoking (P = 0.031). For girls, systolic blood pressure was positively r elated to vitamin C intake (P = 0.042); HDL cholesterol inversely to carboh ydrate intake (P = 0.014), fat intake (P = 0.031), cholesterol intake (P = 0.042) and smoking (P = 0.035) and positively to energy intake (P = 0.035). The TC:HDL cholesterol ratio was inversely related to energy intake (P = 0 .038) and finally, cardiorespiratory fitness positively to physical activit y (P = 0.001). These results offer additional evidence that changes in life style are associated with changes in biological risk factors in adolescents . Education and intervention at this stage, particularly in relation to cig arette smoking, physical activity and certain aspects of diet appear justif ied as part of a preventative strategy for CHD.