TABLE 1

Baseline participant characteristics

MetforminPlacebo
N5347
Age (years)10.1 ± 1.610.4 ± 1.4
Female sex (%)5764
Race/ethnicity (%)
 Non-Hispanic white4249
 Non-Hispanic black4238
 Hispanic white1111
 Other (Native American, Asian, or Pacific Islander)52
Family history of type 2 diabetes (%)8172
Parent with type 2 diabetes (%)3428
Pubertal status
 Percentage prepubertal (%)35.834.0
 Boys’ testis volume (cc)3.9 ± 1.94.2 ± 1.5
 Girls’ breast stage [median (range)]II (I–III)II (I–III)
Skeletal age (years)*11.6 ± 1.911.9 ± 1.4
Weight (kg)76.4 ± 23.180.1 ± 20.5
BMI (kg/m2)34.2 ± 6.834.6 ± 6.2
BMI range (kg/m2)23.0–55.024.7–57.5
BMI SD score for age and sex2.56 ± 0.272.58 ± 0.24
Fat mass by DEXA (kg)‡33.9 ± 11.835.2 ± 10.0
Fat mass by air displacement plethysmography (kg)39.0 ± 16.939.1 ± 14.2
Waist circumference (cm)105.4 ± 15.1106.1 ± 14.2
Presence of acanthosis nigricans (%)6468
Systolic blood pressure (mmHg)115.5 ± 15.1116.8 ± 1.5
SD score for age, sex, and height0.76 ± 2.031.02 ± 1.28
Diastolic blood pressure (mmHg)65.6 ± 9.864.3 ± 10.2
SD score for age, sex, and height0.17 ± 1.170.13 ± 0.92
Fasting plasma glucose (mg/dL)92 ± 892 ± 8
Fasting serum insulin (mIU/mL)19.8 ± 8.921.7 ± 13.5
HOMA-IR index†4.5 ± 2.24.9 ± 3.3
Insulin sensitivity (from hyperglycemic clamp) (mg/kg/min per μIU/mL)4.9 ± 3.24.4 ± 2.4
Serum triglycerides (mg/dL)97.2 ± 44.693.5 ± 42.8
Total cholesterol (mg/dL)162.8 ± 30.1151.1 ± 34.9
LDL/HDL cholesterol ratio2.92 ± 0.962.78 ± 0.75
HDL cholesterol (mg/dL)40.2 ± 9.040.2 ± 7.8
LDL/HDL cholesterol ratio2.92 ± 0.962.78 ± 0.75
Diagnosis of pediatric metabolic syndrome (%)§26.431.9
AST (U/L)23.8 ± 8.326.0 ± 12.5
ALT (U/L)24.8 ± 5.524.7 ± 6.3
High-sensitivity C-reactive protein (mg/dL)0.56 ± 0.430.74 ± 1.03
Serum vitamin B12 (pg/mL)683 ± 270694 ± 265
  • Data are means ± SD unless otherwise indicated. At baseline, there were no significant differences between treatment groups (all P > 0.32). Race and ethnicity were self-reported.

  • *Skeletal age according to Greulich and Pyle method.

  • †HOMA-estimated insulin resistance.

  • ‡Two subjects, one from each group, weighed >136 kg and could not be scanned using DEXA.

  • §Diagnosis of pediatric metabolic syndrome was made when three or more components were present from among the following: waist circumference, blood pressure, and triglycerides ≥90th percentile for age and sex, HDL cholesterol ≤10th percentile for age and sex, and fasting glucose ≥100 mg/dL (44).