TABLE 2.
RRs (and 95% CIs) of T2D by quintiles of carbohydrate, starch, and total, cereal, fruit, and vegetable fiber intake1
| Quintile of energy-adjusted intake |
||||||
| Variable | 1 | 2 | 3 | 4 | 5 | P-trend2 |
| Carbohydrates | ||||||
| Median, g/d | 159 | 181.0 | 195 | 208.3 | 228.4 | |
| Cases/person-years | 1390/283,174 | 1508/299,048 | 1465/299,859 | 1381/303,398 | 1190/298,735 | |
| Model 1 | 1.00 (Ref) | 1.02 (0.95, 1.10) | 0.97 (0.90, 1.04) | 0.90 (0.84, 0.97) | 0.77 (0.71, 0.83) | <0.0001 |
| Model 2 | 1.00 (Ref) | 0.94 (0.87, 1.01) | 0.92 (0.85, 0.99) | 0.93 (0.86, 1.00) | 0.89 (0.82, 0.97) | 0.007 |
| Model 3 | 1.00 (Ref) | 0.96 (0.89, 1.04) | 0.96 (0.89, 1.04) | 0.99 (0.91, 1.08) | 0.98 (0.89, 1.08) | 0.84 |
| Starch | ||||||
| Median, g/d | 45.4 | 55.6 | 62.2 | 69.3 | 79.6 | |
| Cases/person-years | 1241/272,607 | 1464/298,842 | 1445/303,906 | 1456/310,195 | 1328/298,664 | |
| Model 1 | 1.00 (Ref) | 1.07 (0.99, 1.15) | 1.04 (0.96, 1.12) | 1.03 (0.95, 1.11) | 0.98 (0.91, 1.06) | 0.37 |
| Model 2 | 1.00 (Ref) | 1.04 (0.96, 1.12) | 1.00 (0.93, 1.08) | 0.99 (0.92, 1.07) | 0.98 (0.90, 1.06) | 0.28 |
| Model 3 | 1.00 (Ref) | 1.11 (1.03, 1.20) | 1.12 (1.03, 1.22) | 1.17 (1.07, 1.27) | 1.23 (1.12, 1.35) | <0.0001 |
| Total fiber | ||||||
| Median, g/d | 12.2 | 14.9 | 17.0 | 19.3 | 23.3 | |
| Cases/person-years | 1488/288,459 | 1551/302,435 | 1446/304,094 | 1357/293,442 | 1092/295,783 | |
| Model 1 | 1.00 (Ref) | 0.97 (0.90, 1.04) | 0.88 (0.82, 0.94) | 0.83 (0.77, 0.90) | 0.65 (0.60, 0.70) | <0.0001 |
| Model 2 | 1.00 (Ref) | 0.95 (0.88, 1.02) | 0.89 (0.82, 0.95) | 0.89 (0.82, 0.96) | 0.76 (0.70, 0.82) | <0.0001 |
| Model 3 | 1.00 (Ref) | 0.96 (0.89, 1.03) | 0.90 (0.83, 0.98) | 0.91 (0.84, 1.00) | 0.80 (0.72, 0.89) | <0.0001 |
| Cereal fiber | ||||||
| Median, g/d | 2.40 | 3.43 | 4.28 | 5.36 | 7.40 | |
| Cases/person-years | 1537/275,155 | 1621/304,468 | 1430/299,750 | 1360/303,460 | 986/301,381 | |
| Model 1 | 1.00 (Ref) | 0.93 (0.87, 1.00) | 0.82 (0.77, 0.89) | 0.76 (0.71, 0.82) | 0.54 (0.50, 0.59) | <0.0001 |
| Model 2 | 1.00 (Ref) | 0.90 (0.83, 0.96) | 0.83 (0.77, 0.89) | 0.81 (0.75, 0.87) | 0.69 (0.63, 0.74) | <0.0001 |
| Model 3 | 1.00 (Ref) | 0.90 (0.84, 0.97) | 0.84 (0.78, 0.91) | 0.82 (0.76, 0.89) | 0.71 (0.65, 0.78) | <0.0001 |
| Fruit fiber | ||||||
| Median, g/d | 1.45 | 2.55 | 3.55 | 4.69 | 6.68 | |
| Cases/person-years | 1504/296,218 | 1446/299,737 | 1485/304,047 | 1324/296,519 | 1175/287,692 | |
| Model 1 | 1.00 (Ref) | 0.93 (0.86, 1.00) | 0.91 (0.85, 0.98) | 0.82 (0.76, 0.88) | 0.73 (0.68, 0.79) | <0.0001 |
| Model 2 | 1.00 (Ref) | 0.90 (0.84, 0.97) | 0.91 (0.85, 0.98) | 0.83 (0.77, 0.90) | 0.79 (0.72, 0.85) | <0.0001 |
| Model 3 | 1.00 (Ref) | 0.90 (0.84, 0.97) | 0.92 (0.85, 0.99) | 0.85 (0.78, 0.92) | 0.80 (0.73, 0.88) | <0.0001 |
| Vegetable fiber | ||||||
| Median, g/d | 3.69 | 4.92 | 5.94 | 7.10 | 9.24 | |
| Cases/person-years | 1299/288,921 | 1409/304,811 | 1437/302,276 | 1440/291,878 | 1349/296,326 | |
| Model 1 | 1.00 (Ref) | 1.01 (0.93, 1.09) | 1.04 (0.97, 1.12) | 1.06 (0.98, 1.14) | 0.98 (0.91, 1.06) | 0.78 |
| Model 2 | 1.00 (Ref) | 1.01 (0.94, 1.09) | 1.07 (0.99, 1.15) | 1.08 (1.00, 1.16) | 1.00 (0.92, 1.08) | 0.86 |
| Model 3 | 1.00 (Ref) | 1.03 (0.96, 1.12) | 1.12 (1.03, 1.21) | 1.15 (1.06, 1.24) | 1.09 (1.00, 1.19) | 0.02 |
RRs and 95% CIs were calculated with the use of the Cox proportional hazards regression model. Model 1 was age-adjusted. Model 2 was adjusted for age, BMI, family history of diabetes, postmenopausal status, smoking status, alcohol intake, physical activity level, multivitamin use, race, and total energy intake. Model 3 additionally was adjusted for red meat, coffee, magnesium, ratio of polyunsaturated fat to saturated fat, and trans fat (dietary variables all in quintiles). Model for starch additionally was adjusted for cereal fiber, sugar-sweetened beverages, and fruit and vegetables. Model for total fiber additionally was adjusted for glycemic load. Models for cereal, fruit, and vegetable fibers additionally were adjusted for glycemic load and the other 2 subtypes of fiber. Ref, reference; T2D, type 2 diabetes.
Test for trend based on variable containing median value for each quintile.