Introduction
Cardiovascular disease (CVD) affects seven million people in the UK and is the leading cause of death in the Western world.1 CVD risk factors should be low in young people, but the rise in childhood inactivity and poor fitness levels has led to an increase in prevalence and potential impact on lifetime CVD risk.2 3 Identifying and addressing important CVD risk factors in early life could prevent symptoms in later life. Pathological changes in the arterial wall are well recognised to begin in childhood.4
Positive associations have been shown between a child’s body mass index and CVD risk in adulthood, particularly among those from lower socioeconomic status.5 Deprivation has been associated with poorer cardiovascular fitness levels, higher obesity levels and consequently higher CVD risk.6 Young people with lower socioeconomic status are less likely to engage in activity in the form of structured activities and competitive sports7 and are subsequently at an increased risk of more sedentary lifestyles. These traits may also cluster with other health behaviours (eg, diet) which could also contribute to CVD risk when a child is older. Consequently, prevention strategies that decrease sedentary behaviour and improve nutrition have been designed to combat this issue.6 8–10
Early life behaviours may also contribute, for example, breastfeeding may protect against hypertension,11–13 although this relationship has been described as modest. Less is known about the relationship between early life exposures and subsequent cardiovascular phenotype in young people and longer-term CVD risk. Therefore, increased study of these relationships in early life may provide important insights into how best to implement interventions in young people to prevent CVD.
This paper aims to identify predictors of cardiovascular health in teenagers (aged 13–14 years) which is an under-researched area of teenage health. Cardiovascular phenotype data were collected as part of baseline data collection from the Active Children through Individual Vouchers—Evaluation (ACTIVE) project, a mixed method randomised control trial (RCT) based in south Wales, UK. The ACTIVE RCT aimed to improve the cardiovascular fitness, cardiovascular health and motivation of teenagers to be active10 and, therefore, included measures of augmentation index (AIx), blood pressure and fitness. This paper is a cross-sectional analysis of baseline measures linked with routinely collected data from the National Community Child Health Database (NCCHD) and the Tagged Electronic Cohort Cymru (TECC). These databases include data from the child health system in Wales, including birth registration, maternal health and monitoring of child health examinations.
The relationships between arterial stiffness, blood pressure and fitness with important early life influences (eg, deprivation and maternal influences) at population level are less well known and exploring these will add to knowledge and inform novel approaches to clinical practice regarding CVD risk. Furthermore, findings can inform early public health intervention approaches in this area. This paper assessed if there are any early life indicators that make teenagers more vulnerable to cardiovascular risk.