Background: Atherosclerosis is a leading cause of death worldwide. Progression of the disease is long term; even though the first signs are known to be present already in childhood symptoms do not usually appear until middle age or later. 

Aims: The aim of the present thesis was to investigate tracking of cardiovascular risk factors from childhood to adult age spanning several decades. Also the aim of this thesis was to study a combination of childhood risk factors to predict adult outcomes (obesity and hypertension) controlling for multiple confounding and new genetic factors. In addition, the effect of child and adult blood pressure (BP) on subclinical atherosclerosis in adult age was examined. 

Participants and Methods: This study is part of the Cardiovascular Risk in Young Finns Study launched in 1980, which is a multicentre follow-up study from childhood to adult age to evaluate risk factors and precursors of cardiovascular disease. The findings of the present study are based on data from the 21- and 27-year follow-ups in 2001 and 2007 when a total of 2,283 and 2,204 participants aged 24 to 45 years were re-examined. In addition, data for 1,987 participants from similar contemporary cohort studies in United States of America and Australia were used in the analyses. 

Results: In a multivariable analysis the independent predictors of adult elevated BP included parental hypertension (P<0.0001), childhood systolic BP (P<0.0001), a genetic risk score (P<0.0001), parental occupational status (P=0.02), and childhood overweight/obesity (P=0.001). A non-laboratory risk score composed of childhood body mass index (BMI), maternal BMI, and family income predicted adult obesity in all age groups between 3-18 years (P <0.001 for all groups). Inclusion of genetic variants of obesity in the analyses did not significantly improve the prediction of adult obesity (AUC (0.779, P=0.16)). In contrast, genetic markers of BP improved the prediction of adult elevated BP with and without a family history of hypertension. Individuals with persistently elevated BP from childhood to adult age as well as individuals with normal childhood BP but elevated adult BP had an increased risk of high carotid artery intima-media thickness (cIMT) RR 1.82[1.47–2.38] and 1.57[1.22–2.02], respectively) (relative risk [95% confidence interval]) in comparison with persistently normotensive. In contrast, individuals with elevated BP during childhood but normal BP during adulthood did not have significantly increased risk of high cIMT (RR 1.24[0.92–1.67]) in comparison with persistently normotensive. In addition, these individuals had a lower risk of increased carotid artery IMT (RR 0.66[0.50–0.88]) compared with those with persistently elevated BP. 

Conclusions: Tracking of cardiovascular risk factors from childhood to adult age is strong. Multiple childhood risk factors including genetic markers predict adult hypertension. Thus, a multifactorial approach may be useful in identifying children at risk for hypertension later in life. The increased risk of subclinical atherosclerosis associated with elevated childhood BP was reduced if BP was normal in adult age. A simple risk score based on childhood risk factors (child BMI, maternal BMI and low socioeconomic status) was superior in predicting adult obesity compared with the currently recommended approach of using child BMI only.