TABLE 1

Metformin and placebo group characteristics at baseline (in the combined groups) and, on average, up to the time of diabetes onset or the final visit during 3.2 years of follow-up

Baseline
Follow-up
Metformin and placebo combined*Placebo (change from baseline)Metformin (change from baseline)P
n2,1551,0821,073
Weight (kg)94.30 ± 0.430.29 ± 0.16−1.72 ± 0.15<0.001
BMI (kg/m2)34.02 ± 0.140.11 ± 0.06−0.62 ± 0.06<0.001
Waist circumference (cm)105.02 ± 0.31−0.23 ± 0.18−1.63 ± 0.19<0.001
Waist-to-hip ratio0.9238 ± 0.0018−0.0037 ± 0.0015−0.0078 ± 0.00150.036
Fat per day (g)82.00 ± 1.03−11.66 ± 0.93−13.23 ± 0.910.230
Calories per day (kcal)2,121.21 ± 22.14−252.36 ± 20.10−287.32 ± 19.830.216
Percent of calories from fat34.05 ± 0.15−0.77 ± 0.18−0.84 ± 0.170.783
MAQ: leisure MET h/week16.73 ± 0.591.01 ± 0.541.26 ± 0.610.751
LoPAR: recreational MET h/week66.96 ± 0.892.46 ± 0.951.06 ± 0.860.244
A1C (%)5.91 ± 0.010.11 ± 0.010.03 ± 0.01<0.001
Glucose (mmol/l)
    Fasting5.92 ± 0.010.13 ± 0.01−0.08 ± 0.01<0.001
    30-min postload9.44 ± 0.030.36 ± 0.040.25 ± 0.040.043
    120-min postload9.15 ± 0.02−0.23 ± 0.06−0.31 ± 0.060.302
Insulin (pmol/l)
    Fasting161.19 ± 1.946.02 ± 2.45−13.01 ± 2.17<0.001
    30-min postload606.54 ± 8.492.92 ± 9.34−36.67 ± 8.32<0.001
Fasting proinsulin (pmol/l)18.29 ± 0.310.80 ± 0.39−2.45 ± 0.34<0.001
IGR (pmol/mmol)133.92 ± 2.17−6.94 ± 3.89−12.87 ± 2.390.190
  • Data are means ± SE.

  • *

    * There were no significant differences (P < 0.10) between the metformin and placebo participants in any variables at baseline.

  • Mean change from baseline within a group is significantly different from zero at P < 0.05.

  • IGR = (I30I0)/(G30G0) using the baseline (0) and 30-min insulin and glucose values from the OGTT. MAQ, Modifiable Activity Questionnaire; LoPAR, Low-Level Physical Activity Recall.