Obesity is associated with insulin resistance and components of the metabolic syndrome in Lebanese adolescents

Figures & data

Table I.  Baseline characteristics of the adolescent subjects.

	Adolescents
Characteristics	Obese>+2 BMI z-scores (n = 104)	Overweight+1 < BMI z-scores ≥ +2 (n = 78)	Normal weight ≤ +1 BMI z-scores (n = 81)
Age (years), mean ± SD	16.07 ± 1.30	16.39 ± 1.44	16.80 ± 1.27
Anthropometric data, mean ± SD
BMI (Kg/m^2)	32.52 ± 3.39^a	26.38 ± 1.35^b	20.87 ± 1.98^c
Body Fat (DXA) (%)	38.86 ± 5.65^a	32.95 ± 7.29^b	23.60 ± 8.76^c
WC (cm)	97.87 ± 11.57^a	85.16 ± 8.95^b	73.06 ± 8.38^c
Biochemical and blood pressure data, mean ± SD
TC (mg/dL)	156.78 ± 27.34^a	154.19 ± 30.44^a	141.63 ± 21.92^b
HDL (mg/dL)	43.66 ± 10.52^a	46.80 ± 10.33^b	48.10 ± 9.98^b
LDL (mg/dL)	93.84 ± 25.74^a	90.60 ± 26.72^a	79.86 ± 18.69^b
TG (mg/dL)	105.09 ± 50.39^a	85.58 ± 42.76^b	68.31 ± 26.05^c
FBG (mg/dL)	88.62 ± 8.10^a	88.62 ± 7.11^a	89.46 ± 5.48^a
Insulin (μU/mL)	33.55 ± 18.37^a	26.42 ± 14.38^b	10.64 ± 7.89^c
SBP (mmHg)	117.38 ± 11.97^a	113.08 ± 9.98^b	113.65 ± 10.41^b
DBP (mmHg)	70.67 ± 8.16^a	66.99 ± 6.95^b	65.33 ± 5.44^b

^a, ^b, ^c Values in the same row with different superscripts are significantly different, p < 0.05 (one-way ANOVA between normal weight vs overweight vs obese groups).

The definitions of overweight and obesity were based on sex- and age-specific +1 and +2 BMI z-scores, respectively, derived from WHO child growth standards (de Onis et al. 2007).

DBP, Diastolic Blood Pressure; FBG, Fasting Blood Glucose; HDL-C, High Density Lipoprotein-Cholesterol; SBP, Systolic Blood Pressure; TC, Total Cholesterol; TG, Triglycerides; WC, waist circumference.

Table II.  Prevalence of individual metabolic abnormalities by BMI classification.

	Adolescents, n (%)
Individual abnormalities	Obese>+2 BMI z-scores (n = 104)	Overweight+1 < BMI z-scores ≤ +2 (n = 78)	Normal weight ≤ +1 BMI z-scores (n = 81)
Elevated Waist Circumference^a	94 (90.4)	36 (46.2)	3 (3.7)
Low HDL^a	45 (43.3)	29 (37.2)	27 (33.3)
High tryglycerides^a	21 (20.2)	6 (7.7)	1 (1.2)
Hypertension^a	18 (17.3)	5 (6.4)	9 (11.1)
High fasting glucose^a	4 (3.8)	6 (7.7)	3 (3.7)
Insulin resistance^b	92 (88.5)	66 (83.3)	20 (24.7)
Hyperinsulinemia^c	76 (73.1)	45 (57.7)	7 (8.6)

^a As defined by IDF Criteria:

•	Elevated Waist Circumference (WC): For subjects 16 years and older, WC ≥ 94 cm for males and ≥ 80 cm for females. For ages 13–15 years, WC ≥ 90th percentiles or adult cut-off value if lower;
•	Low HDL: For subjects 16 years and older HDL < 40 mg/dL for males and < 50 mg/dL for females. For ages 13–15 years, HDL < 40 mg/dL;
•	High TG: TG ≥ 150 mg/dL;
•	Hypertension: SBP ≥ 130 mmHg or DBP ≥ 85 mmHg; and
•	High Fasting Glucose: ≥ 100 mg/dL.

^b Insulin resistance, HOMA-IR>3.16

^c Hyperinsulinemia, Insulin ≥ 30 μU/ml for Tanner stage 4 and ≥ 20 μU/ml for Tanner stage 5.

Table III.  Number of metabolic syndrome abnormalities, according to IDF 2009 criteria.

	Adolescents, n (%)
Metabolic syndrome abnormalities	Obese>+2 BMI z-scores (n = 104)	Overweight+1 < BMI z-scores ≤ +2 (n = 78)	Normal weight ≤ +1 BMI z-scores (n = 81)
One	44 (42.3)	33 (42.3)	32 (39.5)
Two	35 (33.7)	20 (25.6)	4 (4.9)
Three	20 (19.2)	3 (3.8)	1 (1.2)
Four	2 (1.9)	0 (0.0)	0 (0.0)
Metabolic syndrome	22 (21.2)	3 (3.8)	1 (1.2)

Table IV.  Individual abnormalities among subjects with metabolic syndrome (n = 26), according to IDF (2009).

Individual abnormalities	Subjects with the metabolic syndrome, n (%)
Elevated WC^a	25 (96.2)
Low HDL^a	25 (96.2)
High TG^a	19 (73.1)
Hypertension^a	9 (34.6)
High fasting glucose^a	2 (7.7)
Insulin resistance^b	26 (100.0)
Hyperinsulinemia^c	19 (73.1)

^a As defined by IDF Criteria:

•	Elevated Waist Circumference (WC): For subjects 16 years and older, WC ≥ 94 cm for males and ≥ 80 cm for females. For ages 13–15 years, WC ≥ 90th percentiles or adult cut-off value if lower.
•	Low HDL: For subjects 16 years and older HDL < 40 mg/dL for males and < 50 mg/dL for females. For ages 13–15 years, HDL < 40 mg/dL;
•	High TG: TG ≥ 150 mg/dL;
•	Hypertension: SBP ≥ 130 mmHg or DBP ≥ 85 mmHg; and
•	High Fasting Glucose: ≥ 100 mg/dL.

^b Insulin resistance, HOMA-IR>3.16

^c Hyperinsulinemia, Insulin ≥ 30 μU/ml for Tanner stage 4 and ≥ 20 μU/ml for Tanner stage 5.

Table V.  Pearson correlation coefficients of metabolic variables under study in subjects of both genders.

Variable	% BF	BMI	WC	HDL	TG	Glucose	SBP	DBP	Insulin	HOMA
% BF	1.000	0.726	0.453	0.049	0.299^*^*	− 0.163^*^*	0.011	0.130*	0.465^*^*	0.232^*^*
p-value	–	0.000	0.000	0.430	0.000	0.008	0.863	0.035	0.000	0.000
BMI	–	1.000	0.646^*^*	− 0.188^*	0.289^*^*	− 0.111	0.292^*^*	0.225^*^*	0.326^*^*	0.054
p-value	–		0.000	0.011	0.000	0.137	0.000	0.002	0.000	0.470
WC (cm)	–	–	1.000	− 0.155^*	0.344^*^*	0.008	0.343^*^*	0.345^*^*	0.176^*	− 0.007
p-value	–	–		0.037	0.000	0.912	0.000	0.000	0.017	0.922
HDL (mg/dL)	–	–	–	1.000	− 0.336^*^*	− 0.029	− 0.104	− 0.102	− 0.204^*^*	− 0.161^*
p-value	–	–	–		0.000	0.693	0.164	0.169	0.006	0.030
TG (mg/dL)	–	–	–	–	1.000	− 0.006	0.053	0.168^*	0.212^*^*	0.161^*
p-value	–	–	–	–		0.931	0.480	0.023	0.004	0.030
Glucose (mg/dL)	–	–	–	–	–	1.000	0.024	0.122	0.162^*	0.184^*
p-value	–	–	–	–	–		0.745	0.101	0.029	0.013
SBP (mmHg)	–	–	–	–	–	–	1.000	0.474^*^*	0.020	− 0.045
p-value	–	–	–	–	–	–		0.000	0.790	0.548
DBP (mmHg)	–	–	–	–	–	–	–	1.000	0.030	0.038
p-value	–	–	–	–	–	–	–		0.690	0.612
Insulin (μU/mL)	–	–	–	–	–	–	–	–	1.000	0.411^*^*
p-value	–	–	–	–	–	–	–	–		0.000

BF, Body fat; DBP, Diastolic Blood pressure; HDL-C, High Density lipoprotein-Cholesterol; IR, Insulin Resistance; SBP, Systolic blood pressure; TG, Triglycerides; WC, Waist circumference.

^* p < 0.05; ^** p < 0.01.

de Onis M, Onyango AW, Borghi E, Siyam A, Nishida C, Siekmann J. 2007. Development of a WHO growth reference for school-aged children and adolescents. Bull World Health Organ. 85:660–667.

 PubMed Web of Science ®Google Scholar