A landmark study of children born between 1930 and 1976 in Copenhagen (Baker JA et al, NEJM 2007; 357: 2329-2337), which reviewed 5,063,622 person-years of follow-up, found that the risk of any CHD event, fatal or non-fatal, among adults was positively associated with BMI in boys when aged 7 to 13 years and in girls when aged 10 to 13.
With childhood obesity approaching epidemic levels in countries such as the USA (where 19% of children aged 6-11 years are classified as overweight), it is now a matter of public health urgency that the young are encouraged to keep within an appropriate
weight range.
Dr Peter Whincup and colleagues from UK and Finland found BMI positively related to CHD risk from childhood onwards in a meta-analysis of 15 appropriate studies. Although there was heterogeneity between the studies, the statistical association was just significant. “The associations in young adults are consistent with those observed in middle age,” reported Whincup, who will speak at a Main Session on the childhood initiation of CVD this morning. “The long-term control of BMI from childhood may be important to reduce the risk of CHD.”
Early changes in arterial wall connective tissue and accompanying early lipid deposition have each been associated with cardiovascular risk in children. Similarly, hypertension was detected in 7% of overweight and obese Canadian children (aged 4-17 years) in one study.
But how can that BMI be controlled – and the childhood risks reduced? Professor John Deanfield from the Institute of Child Health in London, who will also speak at this afternoon’s session, has also reported that atherosclerosis begins in early life, and that primary prevention strategies beginning in childhood have great potential.
Governments can also play a part, with statutory controls on junk food and cigarette advertising (and sales to young people), and provision for dietary requirements and games in schools. Other more local recommendations have inc
luded community initiatives for safe walking and bike-riding to school, after-school games and athletic activities, and neighborhood shopping amenities.
A study reported at this year’s EuroPrevent congress suggested that school children as young as 11 can benefit from a daily exercise programme in reducing their levels of several risk factors for CVD. The study, which began four years ago in Leipzig, showed after just one year that the proportion of overweight and obese children decreased from 13% to 9%, but increased in the control group from 11% to 13%. These were statistically significant changes. Moreover, exercise capacity (as measured by VO2max) also improved significantly in the exercise groups by 29%. Similarly, levels of HDL-cholesterol and triglycerides, and systolic blood pressure all improved in the
exercise group.
A review in the BMJ last year (Kipping R et al. BMJ 2008; 337: a1848) found that “few obesity prevention interventions have been shown to be effective in children”, but noted that “comprehensive strategies that tackle diet and physical activity as well as providing psychosocial support and environmental change may help prevent obesity”.
A systematic review of 57 identified studies on interventions in childhood found “some evidence” for potentially effective strategies for increasing physical activity (Ioannidis JPA et al. BMJ 2008; 336: 1413-1415). For adolescents, interventions that included both school and family or community involvement were thought able “to make important differences to levels of physical activity and should be promoted”.