Esmaillzadeh A, Mirmiran P, Azadbakht L, Azizi F,
Volume 63, Issue 4 (13 2005)
Abstract
Background: No evidence exists regarding the prevalence of the hypertriglyceridemic waist phenotype in adolescents. We aimed to evaluate the prevalence of this phenotype in a representative sample of Tehranian adolescents.
Materials and Methods: Anthropometry and biochemical measurement were assessed in a population-based cross-sectional study of 3036 Tehranian adolescents (1413 male and 1623 female) aged 10-19 years. Hypertriglyceridemic waist phenotype was defined as concurrently having serum triglyceride concentration ≥110 mg/dl and waist circumference ≥90th percentile for age and sex. Overweight (≥95th percentile) and at risk for overweight (≥85th-<95th percentile) was defined based on the standardized percentile curves of body mass index suggested for Iranian adolescents.
Results: The prevalence of the hypertriglyceridemic waist phenotype was 6.4% (95%CI: 5.5-7.2) among Tehranian adolescents (males: 7.3%, 5.9-8.7 and females: 5.6%, 4.4-6.7). Overweight subjects had the highest proportion of hypertriglyceridemic waist phenotype than those at risk for overweight and those with normal-weight (male: 42.9 vs 2.9 and 0.0%, respectively, P<0.01 female: 32.5 vs 11.3 and 1.3%, respectively, P<0.01).
Conclusion: This study provides evidence showing high prevalence of the hypertriglyceridemic waist phenotype in Tehranian adolescents, particularly among overweight adolescents. This finding highlights the need for effective preventive and therapeutic strategies relying on diet, physical activity and lifestyle modification.
Azadbakht L, Mirmiran P, Hedayati M, Esmaillzadeh A, Shiva N, Azizi F,
Volume 64, Issue 10 (2 2006)
Abstract
Background: The NCEP step II diet produced a desirable lipoprotein response in hypercholesterolemia. A relation between plasma concentrations of small dense LDL and cardiovascular risk factors has also been mentioned in children. This study was conducted to determine the effects of the National Cholesterol Education Program (NCEP) step 2 diets on the low density and high density lipoprotein particle size in dyslipidemic adolescents.
Methods: Forty- four dyslipidemic adolescents, aged 10-18 years, participated in this case-control study. The control group was not given a diet prescription and was simply instructed to “eat as usual”. Their eating patterns reflected the consumption of macronutrients, fruit, vegetables and dairy products, typical of what many Tehranian eat. NCEP step 2 diets was a diet with 30% of calories as total fat, less than 7% saturated fat, less than 200 mg cholesterol, less than 15% of calories as monounsaturated fat and less than 10% as polyunsaturated fat per day. Lipoprotein particle size was the major outcome variables, which was measured after 3 months of intervention. Lipoprotein particle size was estimated by nondenaturing polyacrylamide gradient gel electrophoresis using Krauss and Burke methodtion.
Results: The mean body mass index was 26.3±4.2 kg/m2. Baseline characteristics of these adolescents did not differ significantly across the NCEP step 2 and control diet groups. The NCEP diet resulted in higher reduction in total cholesterol (-13±4 vs –2±0.3 mg/dl, p<0.001), LDL (-9±2 vs 3±0.6 mg/dl, p<0.01) and higher increase in size of the LDL (1.7±0.4 vs 0.1±0.4 mg/dl, p<0.001). HDL particle size did not change significantly. The prevalence of hypercholesterolemia decreased significantly (p<0.05) in NCEP step 2 group (68% in NCEP step 2 vs 100% in the control group) after 3 months.
Conclusion: NCEP step 2 diet not only reduces the serum LDL concentration of hypercholesterolemic adolescents but also has a favorable effect on the LDL particle size distribution. The related mechanism needs to be studied in future experimental designs.
