Development of cardiometabolic risk in childhood and adolescence: The PIAMA birth cohort study

The atherosclerotic process leading to cardiovascular disease begins early in life and is influenced over time by several risk factors. Investigating determinants that contribute to an unfavourable cardiometabolic profile in childhood and adolescence is important for specifying time windows suitable for prevention or intervention early in the process of cardiovascular disease development, and ultimately for improving cardiovascular health of the population. The aim of this thesis was to identify and characterize determinants of an unfavourable cardiometabolic profile in childhood and adolescence. The cardiometabolic profile was characterized by indicators of adiposity, levels of total cholesterol (TC), HDL cholesterol (HDLC), total/HDL cholesterol ratio, blood pressure and glycated haemoglobin (HbA1c). As indicators of adiposity, body mass index (BMI), waist circumference and waist-to-height ratio were used. The individual studies presented in this thesis were embedded in the Prevention and Incidence of Asthma and Mite Allergy (PIAMA) birth cohort study; an ongoing population based prospective study in the Netherlands that has followed children from before birth until young adulthood.
This thesis shows that already in adolescence (ages 12 and 16 years), there was variation in levels of cardiometabolic markers that could partly be explained by determinants in childhood, which are well-known risk factors for adult cardiovascular disease. These determinants were familial factors (family history of cardiovascular disease or diabetes), lifestyle factors (sleep, sedentary behaviour, physical activity, and snack consumption), and biological factors (patterns of overweight development and pubertal timing). In general, children with a strong family history of cardiovascular disease or diabetes, those with less physical activity, those with gradually developing or persistent overweight in childhood, girls with lower sleep quality, and girls with early pubertal timing had unfavourable levels of cardiometabolic markers in childhood and adolescence. Of all these determinants, developing overweight in childhood and a strong family history of diabetes may be most unfavourable for future cardiovascular disease risk because these factors were associated with a wider range of cardiometabolic markers. Lifestyle factors (sleep, screen time and physical activity) were associated with the cardiometabolic profile mainly through higher adiposity, suggesting that adiposity is an important mediator in the pathway of unfavourable lifestyle behaviours to cardiovascular outcomes. Although the observed effect sizes of determinants investigated in this thesis were modest, the high prevalence of these determinants in the general populations may lead to a relevant contribution to the future burden of cardiovascular disease at a population level. With population strategies for prevention of overweight and unfavourable lifestyle behaviours starting early in life, the long-term cardiovascular health of the entire population may be improved.