[Disorders of lipid metabolism in adolescents with simple obesity]

Obesity affects approximately 45 millions of children worldwide. Some of them present with secondary dyslipidemia that leads to premature atherosclerosis.

1) Assessment of the frequency and type of dyslipidemia in obese adolescents. 2) An attempt at defining risk factors of atherogenic lipid profile in obese adolescents.

In 146 (84 girls/62 boys) obese (mean BMI SDS 4.95, 95% CI 4.62-5.29) adolescents (age 10-18, mean 14.7 years), the levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDLc), high-density lipoprotein cholesterol (HDLc) and triglicerydes (TG) were measured. Atherogenic dyslipidemia was defined as a high TG level with a concomitant low HDLc level. Standard oral glucose tolerance test was performed with the assessment of fasting and after 120' post-load of 75 g of glucose and insulin levels; the insulin resistance index HOMA-IR was calculated.

The mean values of the lipid fractions were in normal ranges: TC 4.64 mmol/L (95% CI 4.48-4.8), LDLc 2.86 mmol/L (95% CI 2.73-2.99), TG 1.4 mmol/L (95% CI 1.3-1.5), and HDLc 1.16 (95% CI 1.1-1.2). However, in 50.69% of the patients (45.24% girls and 58.06% boys), elevated levels of TC, LDLc, and TG were observed respectively in 23.29%, 17.81% and 37.67%, and low HDLc in 15.07% of patients. A total of 10.96% of the patients presented with coexistence of a low HDLc and a high TG. In 26.7%, dyslipidemia was followed by arterial hypertension. There was a reverse correlation between a low HDLc value and BMI SDS [R (-) 0.22, p < 0.05] and not with TC, LDLc, and TG. The relative risk of abnormal lipid profile occurrence was higher in obese patients with insulin resistance (OR 1.72; 95% CI 0.8-3.4; p = 0.12), being significant only for boys (OR 3.67; 95% CI 1.1-12.1; p = 0.03). There was a reverse correlation between fasting insulin level, HOMA-IR and HDLc [R (-) 0.2; p < 0.05; R (-) 0.2; p < 0.05) respectively], as well as TG (R 0.26 ; p < 0.05; R 0.26; p < 0.05, respectively), and between post-load insulin level and TG (R 0.24; p < 0.05).

1) Lipid disorders occur in about one-half of obese adolescents, of which 10% presents with atherogenic lipid profile. 2) One of the most important risk factors of atherogenic lipid profile occurrence is insulin resistance, especially in boys. The severity of the obesity (BMI-SDS) is of lesser importance.