N° 22 | April 2008

Consequences of childhood obesity

The growing epidemic of childhood obesity draws the attention to accompanying risk factors and co-morbidities. According to the most recent data, 22 million children in Europe are overweight and 5 million obese, increasing yearly by 300 000 children. The importance and significance of childhood obesity is indicated by the increasing societal and health burdens.

Traditional cardiovascular risk factors associated with obesity are frequently detected in children and especially in adolescents. Odds ratios for these risk factors are the following: 2.4 for raised diastolic blood pressure, 3.0 for raised low density lipoprotein cholesterol, 3.4 for low high density lipoprotein cholesterol, 4.5 for elevated systolic blood pressure, 7.1 for elevated triglycerides and 12.6 for high fasting insulin . In another study from Europe obese children had a 19.35 times higher risk of developing at least one risk factor, including increased blood pressure, hyperinsulinaemia/insulin resistance, impaired glucose tolerance/type 2 diabetes mellitus, increased LDL-cholesterol, decreased HDL-cholesterol or increased triglyceride level. They had 6.29 times higher risk of having more than one risk factor as compared to normal weight controls.

Overweight and obesity in youth also plays a central role in the development of the metabolic syndrome (MS), defined as clustering of the above listed risk factors2. A recent publication estimated the prevalence of MS in Europe on the basis of data obtained from a literature search and extrapolated them to the 25 member states. According to this study, the prevalence of MS among obese European children and adolescents is 23.9% (1.21 million children)1.

Population-based data suggest that the epidemic of adult obesity is being followed by an epidemic of type 2 diabetes mellitus (T2DM). In recent years, type 2 diabetes has increasingly been reported among overweight and obese children and adolescents. Currently, children with T2DM are usually diagnosed over the age of 10 years during middle to late puberty. As the childhood population becomes increasingly overweight, the occurrence of T2DM may be expected to shift to younger, prepubertal children. However, the prevalence of T2DM is still less than 2% in European obese children.3

Unfavourable psychosocial consequences, as a result of altered physical appearance and physical handicap, are also common4. Children as young as 6 years may be labelled negatively, suffer rejection, have poorer interpersonal relationship and become socially isolated, or acquire a distorted body image. Obese children show depressive symptoms and signs. These psychosocial and psychological problems can persist into adulthood.

The social burden of obesity also affects educational attainment: learning difficulties5 (due to night hypoventilation or sleep apnoea and malnutrition due to energy-dense, nutrient-poor foods) may lead to completing fewer years of schooling and decreased socio-economic status in adulthood.

Hormonal and pubertal developmental alterations may be the most distressing problems: pseudogynecomastia and pseudohypogenitalism for obese boys; hirsutism and increased acne formation in obese girls, which can be aggravated by early menarche, irregular cycles or polycystic ovary syndrome. Well-known and obvious orthopaedic complications, pseudotumor cerebri, skin alterations and impaired antioxidant status6 are also observable in obese children.

The fast track of childhood obesity shown by epidemiological data from all over the word underscores that effort should be concentrated on determining the proper assessment of risk status and defining screening criteria. However, the dynamics of pathogenesis demonstrates that growing severity and /or prolonged duration of obesity leads to the increasing number of unfavourable parameters. Thus even the less pathological findings in early childhood carry increased risk of the development of obesity-associated diseases in early adulthood.

Furthermore, childhood obesity tends to persist to later life: the risk of adult obesity is twice as great for overweight as compared to non-overweight children. A review of the persistence of obesity in children indicated that 26-41% of obese preschoolers and 42-63% of obese school-age children became obese adults. Taking all this into account, the growing body of convincing evidence suggests that attention should be focused on early childhood screening and prevention, and this is a shared responsibility of parents, caregivers and medical society.

  1. Lobstein T, Jackson-Leach R. Estimated burden of paediatric obesity and co-morbidities in Europe. Part 2. Numbers of children with indicators of obesity-related disease. J Pediatr Obesity 2006; 1:33-41.
  2. Molnár D. Prevalence of the metabolic syndrome and type 2 diabetes mellitus in obese children and adolescents. Int J Obesity 28(Suppl 3): S70-S74, 2004
  3. Malecka-Tendera E, Erhardt E, Molnar D. Type 2 diabetes mellitus in European children and adolescents. Acta Paediatrica 94: 543-6, 2005.
  4. Török K, Szelényi Z, Pórszász J, Molnár D. Low physical performance in obese boys with multimetabolic syndrome. Int J Obesity 25: 966-70, 2001
  5. Cserjési R, Molnár D, Luminet O, Lénárd L. Is there any relationship between obesity and mental flexibility in children? Appetite. 49: 675-8, 2007
  6. Molnár D, Decsi T, Koletzko B. Reduced antioxidant status in obese children with multimetabolic syndrome. In J Obesity 28: 1197-1202, 2004