N° 75 | February 2013

Obesity and cardiovascular risk in children and adolescents

The world wide prevalence of childhood overweight and obesity is projected to reach 9.1% in 2020. Obesity in childhood and adolescence is associated with established risk factors for Cardiovascular Diseases (CVD) like elevated blood pressure, abnormal levels of blood lipids and blood glucose, metabolic syndrome, type II diabetes mellitus, structural and functional changes of the heart and sleep disorders.

Cardiovascular health in children and adolescents worsen with an increase in Body Mass Index (BMI), a marker of obesity. The worsening of cardiovascular health with increases in BMI is dramatic above the 85th percentile of BMI, a level at which CVD risk factors start to show rapid increases with increasing levels of BMI. The spectrum of atherosclerotic CVD process begins early in childhood and evolves during later life.

Obesity related hypertension in childhood and adolescence

The relationship of childhood obesity with Blood Pressure (BP) was examined and confirmed by many previous studies. In a large multi center European cohort of 26,000 children, more than a third had high BP (i.e., BP>95th percentile). Data from a recent study covering 25,000 school children (5–16 years) reported that 17% of overweight children and 18% of obese children had abnormally high BP compared to only 10% among non-overweight children.

Metabolic syndrome among obese children

The metabolic syndrome is a clustering of components including higher levels of insulin, obesity, high BP and abnormal levels of blood lipids. Subjects with metabolic syndrome anytime during life have a higher risk of CVD in future. The primary cause of the syndrome appears to be obesity, which leads to excess insulin production that in turn leads to an increase in BP and altered levels of blood lipids. In a recent cross-sectional survey done on school children (12–17 years), the criteria for metabolic syndrome were met by 37% of the overweight adolescents and 12% of at-risk-foroverweight adolescents. Only 2% of the remaining normalweight adolescents met the same diagnostic criteria.

Insulin resistance (resistance to the normal action of insulin in the body due to several reasons) is a well-known cardiovascular risk factor. This condition has a strong association with childhood obesity. In a recently published study conducted among obese children and adolescents, the rate of insulin resistance was higher among both pre-pubertal (37% in boys and 28% in girls) and pubertal obese subjects (62% among boys and 67% among girls). Insulin resistance frequently leads to the development of type II diabetes. In a recent study among obese children, the researchers reported that 2% of obese children had type II diabetes and 20% had pre-diabetes (a forerunner of diabetes).

Dyslipidemia and accelerated atherosclerosis among obese children

Dyslipidemia (abnormal levels of blood lipids) is strongly associated with obesity during childhood and adolescence. In a recent study done among 26,000 overweight children, concentrations of one or more of the lipids were abnormal in 32%: total cholesterol in 14%, LDL-Cholesterol in 16%, HDLCholesterol in 11%, and triglycerides in 14% of subjects.

Autopsy studies done on children and adolescents who died of non-cardiac causes suggest that there exists an accelerated atherosclerotic process among obese children.

Sleep disordered breathing in obese children

Sleep Disordered Breathing (SDB) and Obstructive Sleep Apnea Syndromes (OSAS) are associated with childhood obesity. In a recent study, the researchers reported that childhood obesity was associated with a 4.7-times higher likelihood of SDB. The risk of having moderate OSAS increased 12% with each unit of BMI above the mean levels for the subjects included in the study. Both SDB and OSAS are well known cardiovascular risk factors.

Conclusion

Among the modifiable CVD risk factors currently known, obesity is the major contributor for CVD as well as the one which is most amenable to modification. The opportunity to reduce cardiovascular risk by modifying obesity levels during childhood and adolescence through focused interventions (dietary and physical activity based) should be used to the highest possible extent. Most risk factor excesses that are related to increased obesity during childhood can be reversed to a significant extent by reducing obesity levels through appropriate interventions.

  • Raj M. Obesity and cardiovascular risk in children and adolescents. Indian J Endocrinol Metab. 2012 Jan;16(1):13-9. (Review article)
  • Raj M, Kumar RK. Obesity in children & adolescents. Indian J Med Res. 2010 Nov;132:598-607. (Review article)
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