Artery hardening begins before high school: Australian study
Only a minority of Australian 12-year-olds have ideal cardiovascular health, research shows, with arterial stiffening evident before some children start high school.
A team from Melbourne’s Murdoch Children’s Research Institute assessed the cardiovascular health of 1028 Australian children aged 11-12 using the seven risk factors of the American Heart Association’s Cardiovascular Health (ICVH) score: physical activity, weight, diet, blood glucose, cholesterol, blood pressure and smoking status.
Only 7% of the children (76) had a perfect ICVH score, and only 39% (406) achieved ideal levels in six out of the seven metrics. The median score was 5/7.
For the first time, the researchers demonstrated that ICVH scores in children were associated with vascular function.
Each additional point in a child’s ICVH score was associated with slower carotid-femoral pulse wave velocity (0.07m/s reduction in pulse wave velocity) and greater carotid elasticity (0.009% per mm Hg).
This relationship was largely mediated by BMI and blood pressure, according to the study published this month in the International Journal of Cardiology.
Study co-author, Professor David Burgner of the University of Melbourne told doctorportal: “If parents were aware that even before their child starts high school, risk factors such as increased BMI and raised BP were already associated with stiffer arteries – which increases the chance of heart attack and stroke as adults – then you’d hope that would galvanise families to try to reduce their risk factors.”
“Cardiovascular disease risk occurs from childhood onwards and we already see associations between risk factors and preclinical changes in the arteries by mid-childhood,” he said.
A family problem
The researchers also assessed 1,235 parents of the children – in most cases the mothers.
The median ICVH score in the parents was lower than in children (4/7), and the association with vascular function was stronger, the study found.
ICVH scores in adults were also linked with changes in vascular structure. Each additional point in an adult’s ICVH score was associated with a smaller carotid intima-media thickness (-7.3μm per metric unit), a measure of subclinical atherosclerosis.
The study found children whose parent had non-ideal health in any of the seven metrics had substantially higher odds for non-ideal health in that metric, for all metrics except physical activity and serum glucose. Children typically did more exercise than their parents.
Ideal diet was the metric least likely to be attained by both adults and children.
Professor Burgner said the study highlighted the need for family-based interventions to reduce cardiovascular risk from early on in life.
“Clearly many of the risk factors are shared within families, so considering the family rather than the individual as the unit for interventions that address modifiable environmental risk factors such as increased physical activity or diet may have more impact than just focusing on the adult or child in isolation,” he said.
Professor Burgner said it was unknown whether the poorer vascular function seen in children with lower ICVH scores in the study was reversible.
“The adverse changes in children are smaller than in adults and only relate to the elasticity of the arteries. This likely reflects a longer cumulative exposure to risk factors the older you get,” he said. “Certainly the consensus is that children are physiologically more ‘plastic’, so changes are likely to be reversible, but it is not well understood.”
The study cohort was drawn from the Longitudinal Study of Australian Children and Child Health Checkpoint. The authors cautioned that it was likely to have under-represented socio-economically disadvantaged families.
Dr Richard Liu, another co-author of the study, said that BP measurement should be routine in children. However in practice it was rare.
“Arguably all children with a raised BMI should be screened but it is important that it be done appropriately – that abnormal readings are repeated at least twice, the cuff is appropriately sized and equipment calibrated, and values are measured against established centiles for age, sex and height,” he said.