Table 2.
Incidence of Diabetes.
| Variable | No. of Participants (%) | Incidence | Reduction in Incidence (95% CI)* | ||||
|---|---|---|---|---|---|---|---|
| PLACEBO | METFORMIN | LIFESTYLE | LIFESTYLE VS. PLACEBO | METFORMIN VS. PLACEBO | LIFESTYLE VS. METFORMIN | ||
| cases/100 person-yr | percent | ||||||
| Overall | 3234 (100) | 11.0 | 7.8 | 4.8 | 58 (48 to 66) | 31 (17 to 43) | 39 (24 to 51) |
| Age | |||||||
| 25-44 yr | 1000 (30.9) | 11.6 | 6.7 | 6.2 | 48 (27 to 63) | 44 (21 to 60) | 8 (-36 to 37)† |
| 45-59 yr | 1586 (49.0) | 10.8 | 7.6 | 4.7 | 59 (44 to 70) | 31 (10 to 46) | 41 (18 to 57)† |
| ≥60 yr | 648 (20.0) | 10.8 | 9.6 | 3.1 | 71 (51 to 83) | 11 (-33 to 41) | 69 (47 to 82)† |
| Sex | |||||||
| Male | 1043 (32.3) | 12.5 | 8.1 | 4.6 | 65 (49 to 76) | 37 (14 to 54) | 46 (20 to 63) |
| Female | 2191 (67.7) | 10.3 | 7.6 | 5.0 | 54 (40 to 64) | 28 (10 to 43) | 36 (16 to 51) |
| Race or ethnic group | |||||||
| White | 1768 (54.7) | 10.3 | 7.8 | 5.2 | 51 (35 to 63) | 24 (3 to 41) | 36 (14 to 52) |
| African American | 645 (19.9) | 12.4 | 7.1 | 5.1 | 61 (37 to 76) | 44 (16 to 63) | 29 (-18 to 58) |
| Hispanic | 508 (15.7) | 11.7 | 8.4 | 4.2 | 66 (41 to 80) | 31 (-9 to 56) | 51 (13 to 72) |
| American Indian | 171 (5.3) | 12.9 | 9.7 | 4.7 | 65 (7 to 87) | 25 (-72 to 68) | 52 (-35 to 83) |
| Asian‡ | 142 (4.4) | 12.1 | 7.5 | 3.8 | 71 (24 to 89) | 38 (-55 to 75) | 52 (-46 to 84) |
| Body-mass index§ | |||||||
| 22 to <30 | 1045 (32.3) | 9.0 | 8.8 | 3.3 | 65 (46 to 77) | 3 (-36 to 30)† | 63 (44 to 76)† |
| 30 to <35 | 995 (30.8) | 8.9 | 7.6 | 3.7 | 61 (40 to 75) | 16 (-19 to 41)† | 53 (28 to 70)† |
| ≥35 | 1194 (36.9) | 14.3 | 7.0 | 7.3 | 51 (34 to 63) | 53 (36 to 65)† | -4 (-47 to 26)† |
| Plasma glucose¶ | |||||||
| In the fasting state | |||||||
| 95-109 mg/dl∥ | 2174 (67.2) | 6.4 | 5.5 | 2.9 | 55 (38 to 68) | 15 (-12 to 36)† | 48 (27 to 63) |
| 110-125 mg/dl** | 1060 (32.8) | 22.3 | 12.3 | 8.8 | 63 (51 to 72) | 48 (33 to 60)† | 30 (6 to 48) |
| Two hours after an oral load | |||||||
| 140-153 mg/dl | 1049 (32.4) | 7.1 | 4.3 | 1.8 | 76 (58 to 86)† | 41 (11 to 61) | 59 (27 to 77) |
| 154-172 mg/dl | 1103 (34.1) | 10.3 | 6.6 | 4.4 | 60 (41 to 72)† | 38 (13 to 56) | 34 (2 to 56) |
| 173-199 mg/dl | 1082 (33.5) | 16.1 | 12.3 | 8.5 | 50 (33 to 63)† | 26 (3 to 43) | 33 (9 to 51) |
*
CI denotes confidence interval.
†
P<0.05 for the test of heterogeneity across strata. Age, body-mass index, and plasma glucose were analyzed as $$Word$$ variables.
‡
This category includes 20 Pacific Islanders.
§
The eligibility criterion was a body-mass index of at least 22 for Asians and at least 24 for all other persons.
¶
To convert the values for glucose to millimoles per liter, multiply by 0.05551.
∥
This category includes American Indian participants who had a fasting glucose concentration that was less than 95 mg per deciliter, according to the eligibility criteria.6