A large systematic review and meta-analysis, published in the BMJ, has shown an association between body mass index (BMI) and cardiovascular disease risk parameters in school age children.

A total of 63 studies carried out after 1990 were analysed. They covered 49,220 healthy children, aged 5 to 15, in 23 highly developed countries including the UK.

The studies used prospective or retrospective cohort, cross-sectional, case-control, or randomised clinical trial designs in school, outpatient, or community settings. All reported an objective measure of weight and at least one risk parameter for cardiovascular disease.

Systolic blood pressure was higher by 4.54 mmHg (99% CI: 2.44-6.64, p < 0.001) in overweight children compared with those of normal weight and by 7.49 mmHg (99% CI: 3.36-11.62, p < 0.001) in obese children. Diastolic blood pressure was increased by 2.57 mmHg (99% CI: 1.55-3.58, p < 0.001) and 4.06 mmHg (99% CI: 2.05-6.08, p < 0.001) in overweight and obese children respectively. This association extended to 24 hour ambulatory systolic blood pressure.

There were similar findings with lipids. Total cholesterol was 0.15 mmol/L (99% CI: 0.04-0.25, p < 0.001) and triglycerides 0.26 mmol/L (99% CI: 0.13-0.39, p < 0.001) higher in obese children compared with those of normal weight.

No significant effect was seen in overweight children for total cholesterol but triglycerides were higher in overweight children by 0.21 mmol/L (99% CI: 0.14-0.27,p < 0.001).

Fasting insulin and insulin resistance were significantly higher in obese children, but not in those classed as overweight. LV mass was 19.12g (99% CI: 12.66-25.59, p < 0.001) greater in obese compared with normal weight children.

The authors conclude that a BMI outside the normal range significantly worsens risk parameters for cardiovascular disease in school age children. This appears to be a graded risk with obese children faring worse than their overweight peers. ‘The exact ages at which changes in a child’s risk parameters begin needs to be established. Risk parameters could then be targeted before abnormal levels are reached and treatment could be preventative,’ they state.

Childhood obesity is an ever increasing problem and it seems inevitable that such a trend will manifest as increasing cardiovascular morbidity and mortality in adult life. This study provides further evidence of the ticking time bomb that is increasingly prevalent in children of the developed world.

There is a greater need than ever to motivate and encourage our children to be more active and eat sensibly. Perhaps the recent London Olympics will galvanise them into action.

Dr Peter Savill