Table 1 Baseline characteristics of participants across tertiles of carbohydrate, and refined grains: Tehran Lipid and Glucose Study

T1

T2

T3

P value

T1

T2

T3

P value

Median intake

44.4

53.1

60.2

2.9

6.7

9.9

Range of intake

≤ 47.5

47.6–56.9

≥ 57.0

≤ 5.4

5.5–8.3

≥ 8.4

n/N

186/640

179/637

226/638

138/638

176/639

277/638

Continuous variables, Mean ± SE

Age at baseline (y)

35.8 ± 0.5

36.0 ± 0.5

37.7 ± 0.5

0.021

35.1 ± 0.5

36.1 ± 0.5

38.2 ± 0.5

< 0.001

Physical activity (MET hour-week)

4.7 ± 0.3

5.2 ± 0.3

5.1 ± 0.3

0.290

4.6 ± 0.3

5.0 ± 0.3

5.4 ± 0.3

0.090

BMI at baseline (kg/m2)

25.1 ± 0.2

25.7 ± 0.2

25.9 ± 0.2

0.011

25.3 ± 0.2

25.1 ± 0.2

26.3 ± 0.2

< 0.001

Weight change (kg)

1.3 ± 0.5

3.2 ± 0.7

5.2 ± 0.8

0.012

2.4 ± 0.7

2.9 ± 0.7

6.3 ± 0.7

< 0.001

Categorical variables, number (%)

Female

349 (54.5)

417 (65.5)

374 (58.6)

< 0.001

501 (78.4)

323 (50.6)

316 (49.5)

< 0.001

Smoker at baseline

126 (19.7)

130 (20.4)

160 (25.0)

0.046

98 (15.3)

152 (23.8)

166 (26.0)

< 0.001

Academic degrees

178 (27.8)

168 (26.4)

151 (23.7)

0.229

173 (27.1)

161 (25.2)

163 (25.5)

0.725

Occupational status, employed

286 (44.7)

251 (39.4)

289 (45.3)

0.065

432 (67.6)

348 (54.5)

309 (48.4)

< 0.001

Family history of diabetes

199 (31.1)

197 (30.9)

224 (35.1)

0.430

229 (35.8)

182 (28.5)

209 (32.8)

0.044

Dietary intake, Mean ± SE

Total energy (Kcal/d)

2240 ± 35

2352 ± 35

2405 ± 35

0.004

2080 ± 34

2329 ± 34

2589 ± 34

< 0.001

Carbohydrate (% of total energy)

44.0 ± 0.2

52.5 ± 0.2

63.2 ± 0.2

< 0.001

53.4 ± 0.3

56.5 ± 0.3

59.7 ± 0.3

0.007

Protein (% of total energy)

14.9 ± 0.3

14.5 ± 0.3

14.5 ± 0.3

0.613

15.4 ± 0.3

14.5 ± 0.3

14.1 ± 0.3

0.009

Fat (% of total energy)

33.8 ± 0.2

30.1 ± 0.2

29.8 ± 0.2

< 0.001

33.7 ± 0.2

32.7 ± 0.2

30.3 ± 0.2

0.034

Total fiber (g/d)

35.7 ± 0.7

41.5 ± 0.7

42.2 ± 0.7

< 0.001

38.0 ± 0.7

41.4 ± 0.7

47.1 ± 0.7

< 0.001

Cholesterol (g/d)

230 ± 8.1

249 ± 8.2

217 ± 8.2

0.021

244 ± 8

236 ± 8

216 ± 8

0.052

Healthy eating index

69.6 ± 0.3

68.1 ± 0.3

67.6 ± 0.3

< 0.001

60.2 ± 0.2

69.4 ± 0.2

57.8 ± 0.2

< 0.001