Background: Cardiac left ventricular mass and arterial stiffness are subclinical markers of cardiovascular disease which are associated with cardiovascular disease and clinical events in adulthood. 

Aims: The aim of this thesis was to study left ventricular mass and arterial stiffness in childhood and their determinants in terms of cardiometabolic risk factors and ideal cardiovascular health. This thesis also aimed to investigate the effect of a dietary and lifestyle intervention on ideal cardiovascular health and subclinical markers of cardiovascular disease. 

Subjects and methods: This thesis is a part of the prospective, randomized Special Turku Coronary Risk Factor Intervention Project (STRIP) that has followed initially over 1,000 children for 27 years. Their cardiometabolic risk factors have been repeatedly measured from childhood to adulthood. Children in the intervention group (n=540) have received dietary and lifestyle counseling aimed at improving the quality of dietary fat. Subclinical markers of atherosclerotic cardiovascular disease were examined using noninvasive ultrasonic measurements of carotid and aortic distensibility, pulse wave velocity, carotid intima-media thickness and cardiac left ventricular mass. This study analyses the data of the children who participated in the arterial ultrasound evaluations from the age of 11 to 19 years (n=420–503), and in the cardiac ultrasound assessments from the age of 15 to 19 years (n= 394–420). 

Results: Cardiac left ventricular mass and arterial stiffness increased with increasing age from childhood to early adulthood. In boys, the arterial stiffness increased more than in girls. It was found that current pulse pressure, weight and physical activity along with birth weight were associated with left ventricular mass in adolescence; overall these factors explained nearly 50% of the variation in left ventricular mass. Childhood blood pressure, body mass index, LDL cholesterol concentration and insulin resistance were associated with arterial stiffness. The dietary and lifestyle intervention was associated with ideal cardiovascular health in adolescence, however, it had no effect on left ventricular mass or arterial stiffness.