Insulin sensitivity, lipids, and body composition in childhood: is "syndrome X" present?

Abstract

Syndrome X, or the syndrome of insulin resistance, is a cluster of related metabolic abnormalities of hyperinsulinemia, glucose intolerance, increased very low density lipoprotein (VLDL), decreased high density lipoprotein (HDL), and hypertension in nonobese adults and plays an important role in the genesis of cardiovascular disease. The aim of the present study was to examine the relationships among insulin sensitivity, plasma lipid levels, and body composition in the pediatric age group to determine whether these associations are present in childhood. Twenty healthy Caucasian Tanner stage I (TI) children (age, 10.7 +/- 0.3 yr; body mass index, 18.9 +/- 0.8 kg/m2) and 22 pubertal Tanner stage II-IV (TII-IV) adolescents (age, 14.0 +/- 0.3 yr; body mass index, 20.0 +/- 0.4 kg/m2) were studied. In vivo insulin-mediated glucose disposal (Rd) was evaluated during a 40 mu/m2. min hyperinsulinemic-euglycemic clamp. Body composition was assessed isotopically by the H218O dilution principle. Fasting blood was obtained for cholesterol, triglyceride (TG), VLDL, low density lipoprotein (LDL), and HDL determinations. In both groups, the strongest correlation of Rd was with percent body fat (%BF) (TI: r = -0.82; P < 0.001; TII-IV: r = -0.73; P < 0.001). In addition, in TI, Rd was correlated with TG (r = 0.64; P = 0.001), VLDL (r = 0.64; P = 0.001), and diastolic blood pressure (r = -0.50; P = 0.01). There were no such correlations in TII-IV. In TI, % BF correlated positively with LDL and negatively with TG and VLDL. In TII-IV, % BF correlated positively with cholesterol and LDL. After correcting for %BF, partial correlation analysis revealed no relationship between Rd and lipid levels in either group. This suggests that the relationship of insulin sensitivity to lipid levels was secondary to the effect of body composition on lipid levels. However, regardless of body composition, the basal insulin level was correlated with TG (r = 0.38; P = 0.04) and VLDL (r = 0.40; P = 0.04) in TII-IV subjects. We conclude that 1) the primary correlate of insulin sensitivity is %BF in both prepubertal and pubertal subjects, with no relationship to plasma lipids; 2) in prepubertal children, diastolic blood pressure is negatively correlated with insulin sensitivity and positively with insulin levels, independent of adiposity; and 3) after the onset of puberty, basal insulin levels are positively correlated with VLDL and TG regardless of the degree of adiposity. This observation could be a very early manifestation of the genesis of syndrome X in childhood.

Pathophysiology of type 2 diabetes mellitus in youth: the evolving chameleon

“…It is well established that obesity is associated with IR in all ethnic groups (28). It accounts for 55% of the variance in insulin sensitivity among Caucasians (29), and it was the most important risk factor for IR independent of age, sex or ethnicity in the National Health and Nutrition Examination Survey (NHANES) 1999-2002 data, explaining 29.1% of the variance in homeostasis assessment model of IR (HOMA-IR) (30). …”

Type 2 Diabetes Mellitus in Children

“…25 This syndrome may be present in children before and during puberty. 26 Conventional diabetes therapy aimed at improving glycemic control does not address these important pathophysiological features of type 2 diabetes mellitus and may actually cause weight gain and increase insulin levels. 16 …”

Metabolic syndrome in adults: relation with diet and other lifestyle factors

“…Findings of the study revealed that those who were in the lower tertile of birth weight (1,250-3,209 and 3,210-3,649 g) had 1.8 times greater risk of developing MetS compared to those in the highest tertile (3,650-5,500 g). The syndrome is on the rise among young adults [158,159], with its roots embedded early in life [160][161][162][163][164]. A cohort of healthy young individuals in Amsterdam was followed for 24 years from the age of 13 years to 36 years to ascertain the prevalence of MetS (NCEP-ATPIII criteria) in relation to fatness, fitness and lifestyle.…”