Damage to 'heart health' may start in childhood

"Children are suffering damage to their hearts as early as 12 due to poor diets," the Mail Online reports.

A US study has found high levels of known risk factors for heart disease in children. The study has not shown the direct effect these risks have in this age group, but it has raised concerns that they may affect the heart from childhood.

The study looked at four related risk factors known to contribute towards heart disease in adults:

They are:

Researchers surveyed 8,961 children and found that less than 1% of children aged two to 11 ate a healthy diet. Nearly a third of the children were overweight or obese.

80% of the children only met one of the five elements considered to be part of an "ideal" diet:

four or five portions of fruit and vegetables a day
fish twice a week
low salt
low added sugar in drinks
regular wholegrains

While heart damage in later life was not directly assessed in this study, it does highlight the need for further health promotion strategies. Heart disease has now overtaken cancer as the leading cause of death in developed countries.

While it is not clear to what extent these US findings relate to the UK population, the UK is in the midst of its own obesity epidemic. The latest figures suggest that the UK is now the "fat man of (Western) Europe", with one in four British adults now obese.

Where did the story come from?

The study was carried out by researchers from Northwest University in Chicago, the University of North Carolina at Chapel Hill and the University of Colorado School of Medicine. No external funding was reported.

The study was published in the peer-reviewed medical journal Circulation: Cardiovascular Quality and Outcomes.

On the whole, the Mail Online reported the story well, but there were some inaccuracies. The headline that stated damage to the heart starts before the age of 12 was not confirmed by the study. While it is likely that the increased cholesterol, BMI, poor diet and high blood pressure in this age group may be bad for the heart, the study did not directly check for any damage to the heart. They did point out some of the limitations of the study – specifically, using adult dietary recommendations for children and not adjusting this for the amount of exercise they take.

What kind of research was this?

This was a cross-sectional study, which measured how common risk factors for cardiovascular disease are in childhood.

Cardiovascular diseases (which affect the heart and blood vessels) are the leading cause of death globally. There are several known risk factors for cardiovascular disease, which are smoking, high blood pressure, obesity, high cholesterol, diabetes, low levels of physical activity and poor diet. Previous research has shown that managing these risk factors from adolescence is associated with reduced risk of cardiovascular disease.

This research aimed to provide a national reference point for these risk factors in children under the age of 12 in the US. This will help researchers to assess how successful future strategies are in tackling childhood obesity, by looking for changes in these measures over time.

What did the research involve?

The researchers used information from a large US study called The National Health and Nutrition Examination Survey (NHANES). These surveys collect data from adults and children across the US every two years, using a home interview and a health examination.

This study looked at four cardiovascular risk factors for 8,961 children who had participated between 2003 and 2010. These were:

diet
cholesterol level
blood pressure
BMI

Dietary intake was assessed by two interviews with the child’s carer (parent or guardian) and recorded dietary intake over the previous 24 hours. An "ideal diet" was considered to meet the following five criteria:

4.5 or more cups of fruit and vegetables per day
two or more servings of fish per week
three or more servings of wholegrains per day
less than 1.5 grams of salt per day
less than 450 calories of added sugar in drinks per week

This broadly matches current UK recommendations for a healthy diet for children.

Children were then classified into three groups, according to how many of these criteria they fulfilled:

"ideal diet" – meeting four or five criteria
"intermediate diet" – meeting two or three criteria
"poor diet" – meeting none or one of the criteria

Similarly, they also classed the children’s other measurements (such as BMI, blood pressure and cholesterol) as "ideal", "intermediate" or "poor", based on standard criteria.

What were the basic results?

The main results were:

99.9% of children did not have an ideal healthy diet, with most (over 80%) having a poor diet
38% did not have an ideal cholesterol level
about 8% did not have ideal blood pressure
about 30% of children did not have an ideal BMI (were overweight or obese)

When combining the results for children aged eight to 11:

no children had ideal levels for all four cardiovascular health measures (diet, cholesterol, BMI and blood pressure)
39% of boys and 38% of girls had three ideal measures
all children had ideal levels for at least one measure

How did the researchers interpret the results?

The researchers concluded that "with the exception of diet rated as intermediate or poor for nearly all children, the majority of children observed from ages two to 11 years had ideal CVH [cardiovascular health] for BMI, total cholesterol and blood pressure, thereby starting life with generally favourable CVH metrics". However, they are concerned about the rise in obesity and the effect this has on cardiovascular health. They say that "promoting the recommended dietary habits, physical activity as part of daily life, and arresting the growing trend of obesity are keys to achieving more favourable CVH metrics and long-term freedom from cardiovascular disease".

Conclusion

This large US survey has found high rates of poor diet, as well as overweight and obesity in children, some of whom also had high blood pressure and cholesterol. The data was collected over a number of years, and should be nationally representative, but may not be representative of each year individually.

Other limitations acknowledged by the researchers include the following:

Potential inaccuracies in parental reporting of the children’s diet over the previous 24 hours. This could be due to poor recall or being unaware of food the child consumed outside of the home.
An average ideal dietary intake for adults was used, rather than individual estimates of the required dietary intake per child according to their level of energy expenditure, height, weight, growth rate and age.
Some children participated in each of the two-yearly surveys, so their results will be included at each age group. This may have affected the results.
The survey did not collect data on smoking or secondhand smoke exposure, physical activity level or type 2 diabetes.

While the study did not directly assess heart damage, as might be assumed from the news coverage, it does suggest that children in the US frequently have risk factors for developing cardiovascular disease. It is not clear whether the results are representative of what might be seen in the UK, but it is known that overweight and obesity are becoming more common.

Overall, the study highlights the need for measures to encourage healthy diet and lifestyle from an early age. Installing healthy habits at a young age may make it more likely that said habits will persist into adulthood.