Table 3.
Diabetes risk according to quintiles of cumulative average dietary intakes of heme, nonheme, and total iron in men (n = 8,346) and women (n = 8,680)
| Quintiles of intake in men | Quintiles of intake in women | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 (n = 1,669) | 2 (n = 1,669) | 3 (n = 1,669) | 4 (n = 1,669) | 5 (n = 1,669) | P- trend | 1 (n = 1,736) | 2 (n = 1,736) | 3 (n = 1,736) | 4 (n = 1,736) | 5 (n = 1,736) | P- trend | |
| Heme iron | ||||||||||||
| Median intake (mg/day)* | 0.07 | 0.4 | 0.75 | 1.21 | 2.16 | 0.06 | 0.33 | 0.63 | 1.01 | 1.76 | ||
| Cases/person-years | 115/21,486 | 124/22,053 | 106/20,463 | 112/19,477 | 90/17,287 | 152/21,389 | 115/22,202 | 118/20,725 | 102/19,484 | 90/17,569 | ||
| Model 1 | 1 (ref) | 0.96 (0.75–1.24) | 0.90 (0.69–1.17) | 1.02 (0.79–1.33) | 0.96 (0.73–1.27) | 0.97 | 1 (ref) | 0.77 (0.61–0.98) | 0.84 (0.66–1.08) | 0.73 (0.57–0.95) | 0.91 (0.70–1.18) | 0.518 |
| Model 2 | 1 (ref) | 0.89 (0.69–1.15) | 0.78 (0.59–1.03) | 0.84 (0.63–1.12) | 0.78 (0.57–1.05) | 0.167 | 1 (ref) | 0.72 (0.56–0.92) | 0.75 (0.58–0.96) | 0.64 (0.49–0.84) | 0.76 (0.57–1.02) | 0.118 |
| Model 3 | 1 (ref) | 0.86 (0.64–1.15) | 0.75 (0.53–1.07) | 0.77 (0.53–1.14) | 0.68 (0.44–1.05) | 0.155 | 1 (ref) | 0.74 (0.56–0.97) | 0.78 (0.56–1.07) | 0.68 (0.47–0.98) | 0.84 (0.56–1.26) | 0.982 |
| Nonheme iron | ||||||||||||
| Median intake (mg/day) | 17 | 19.91 | 22.02 | 24.48 | 29.29 | 14.97 | 17.39 | 19.14 | 21.26 | 25.38 | ||
| Cases/person-years | 95/17,678 | 104/21,419 | 110/21,397 | 107/21,754 | 131/18,518 | 106/17,324 | 99/21,069 | 105/22,265 | 133/22,193 | 134/18,518 | ||
| Model 1 | 1 (ref) | 0.78 (0.59–1.03) | 0.75 (0.57–1.00) | 0.69 (0.52–0.92) | 1.02 (0.78–1.34) | 0.486 | 1 (ref) | 0.67 (0.51–0.88) | 0.65 (0.50–0.86) | 0.72 (0.56–0.94) | 1.00 (0.77–1.29) | 0.247 |
| Model 2 | 1 (ref) | 0.76 (0.58–1.01) | 0.73 (0.55–0.97) | 0.68 (0.51–0.90) | 0.99 (0.76–1.30) | 0.615 | 1 (ref) | 0.65 (0.49–0.86) | 0.62 (0.47–0.82) | 0.71 (0.55–0.93) | 0.98 (0.76–1.27) | 0.257 |
| Model 3 | 1 (ref) | 0.77 (0.58–1.02) | 0.72 (0.54–0.97) | 0.63 (0.46–0.85) | 0.87 (0.64–1.19) | 0.683 | 1 (ref) | 0.63 (0.48–0.84) | 0.57 (0.43–0.76) | 0.58 (0.43–0.77) | 0.67 (0.49–0.91) | 0.080 |
| Total iron | ||||||||||||
| Median intake (mg/day) | 17.92 | 20.86 | 23.03 | 25.43 | 30.6 | 15.7 | 18.17 | 19.95 | 22.05 | 26.45 | ||
| Cases/person-years | 106/18,038 | 101/21,223 | 103/21,882 | 110/21,647 | 127/17,976 | 112/17,628 | 82/21,216 | 130/22,417 | 123/22,372 | 130/17,736 | ||
| Model 1 | 1 (ref) | 0.73 (0.56–0.97) | 0.66 (0.50–0.87) | 0.69 (0.53–0.91) | 1.00 (0.77–1.29) | 0.505 | 1 (ref) | 0.57 (0.43–0.77) | 0.78 (0.61–1.01) | 0.70 (0.54–0.91) | 1.03 (0.80–1.33) | 0.150 |
| Model 2 | 1 (ref) | 0.73 (0.55–0.96) | 0.65 (0.49–0.85) | 0.67 (0.51–0.88) | 0.94 (0.73–1.23) | 0.793 | 1 (ref) | 0.55 (0.42–0.74) | 0.75 (0.58–0.96) | 0.69 (0.53–0.90) | 0.99 (0.77–1.28) | 0.198 |
| Model 3 | 1 (ref) | 0.73 (0.55–0.96) | 0.61 (0.46–0.82) | 0.60 (0.44–0.80) | 0.81 (0.60–1.11) | 0.513 | 1 (ref) | 0.54 (0.41–0.72) | 0.68 (0.52–0.89) | 0.57 (0.43–0.76) | 0.70 (0.52–0.96) | 0.203 |
Data are HR (95% CI) calculated by using Cox proportional hazards analyses. Model 1: adjusted for age, BMI, dietary intake of TE. Model 2: model 1 + residence area, highest education level, household income level, PAL, smoking status, alcohol consumption, and history of hypertension at baseline. Model 3: model 2 + dietary intake of carbohydrates, protein, ratio of MUFA-to-SFA intake, ratio of PUFA-to-SFA intake, cholesterol, magnesium, cereal fiber, vegetables, and fruits. Mutual adjustment was performed for dietary heme iron and nonheme iron. Tests for linear trend for HRs were conducted using the median value for each quintile of intake as a continuous variable. ref, reference.
Intakes were estimated as energy-adjusted cumulative average intake from baseline and follow-up periods.