Table 1.
Characteristics of baseline demographic and lifestyle factors and cumulative average food and nutrient intake according to quintiles of dietary intake of heme iron and nonheme iron in men (n = 8,346)*
| Quintiles of heme iron intake | Quintiles of nonheme iron intake | |||||||
|---|---|---|---|---|---|---|---|---|
| 1 | 3 | 5 | P-trend† | 1 | 3 | 5 | P-trend† | |
| Age (years) | 38.8 ± 15.6 | 39.9 ± 15.7 | 39.4 ± 14.8 | 0.475 | 40 ± 15.8 | 39 ± 14.7 | 40.1 ± 15.7 | 0.538 |
| BMI (kg/m2) | 21.8 ± 2.9 | 22.3 ± 3.3 | 22.8 ± 3.4 | <0.0001 | 22 ± 3.4 | 22.3 ± 3 | 22.6 ± 3.4 | <0.0001 |
| PAL (× BMR) | 1.96 ± 0.26 | 1.74 ± 0.32 | 1.64 ± 0.28 | <0.0001 | 1.77 ± 0.31 | 1.77 ± 0.32 | 1.76 ± 0.32 | 0.690 |
| Urban residence area | 237 (7.7) | 669 (21.8) | 903 (29.4) | <0.0001 | 494 (16.1) | 680 (22.1) | 698 (22.7) | <0.0001 |
| Education level | <0.0001 | 0.869 | ||||||
| Low | 867 (29.9) | 535 (18.4) | 365 (12.6) | 600 (20.7) | 561 (19.3) | 564 (19.4) | ||
| Medium | 773 (16.0) | 989 (20.4) | 1,107 (22.9) | 931 (19.2) | 987 (20.4) | 972 (20.1) | ||
| High | 29 (4.8) | 145 (24.0) | 198 (32.8) | 138 (22.8) | 121 (20.0) | 134 (22.2) | ||
| Household income level | <0.0001 | 0.0002 | ||||||
| Low | 890 (37.0) | 419 (17.4) | 242 (10.1) | 455 (18.9) | 466 (19.4) | 523 (21.7) | ||
| Medium | 453 (20.4) | 468 (21.1) | 377 (17.0) | 432 (19.4) | 436 (19.6) | 406 (18.3) | ||
| High | 218 (11.5) | 413 (21.7) | 447 (23.5) | 363 (19.1) | 412 (21.7) | 361 (19.0) | ||
| Very high | 108 (6.0) | 369 (20.3) | 604 (33.3) | 419 (23.1) | 355 (19.6) | 380 (20.9) | ||
| Former or current smoker | 1,087 (20.9) | 1,008 (19.4) | 1,060 (20.4) | 0.242 | 1,039 (20.0) | 1,061 (20.4) | 1,033 (19.9) | 0.475 |
| Alcohol consumer | 969 (18.6) | 1,049 (20.2) | 1,081 (20.8) | 0.002 | 1,023 (19.7) | 1,065 (20.5) | 1,009 (19.4) | 0.734 |
| Hypertension | 327 (18.8) | 351 (20.2) | 346 (19.9) | 0.963 | 331 (19.0) | 344 (19.8) | 380 (21.8) | 0.001 |
| TE (kcal) | 2,509.2 ± 591.3 | 2,417.6 ± 539.7 | 2,378.4 ± 564.6 | <0.0001 | 2,409.9 ± 572.7 | 2,436.8 ± 525.3 | 2,460.7 ± 616.5 | 0.0002 |
| Carbohydrates (%TE) | 69.1 ± 8.3 | 56.6 ± 8.1 | 50.1 ± 9.8 | <0.0001 | 55.8 ± 11.9 | 57.9 ± 9.9 | 59.4 ± 11.4 | <0.0001 |
| Protein (%TE) | 11.1 ± 1.6 | 12 ± 1.7 | 14.3 ± 2.7 | <0.0001 | 11.4 ± 2.2 | 12.3 ± 2 | 13.4 ± 2.6 | <0.0001 |
| SFA (%TE) | 3.8 ± 2 | 7.2 ± 2.4 | 8.5 ± 2.7 | <0.0001 | 7.4 ± 3.4 | 6.7 ± 2.6 | 6.2 ± 2.8 | <0.0001 |
| PUFA (%TE) | 5.9 ± 3.7 | 6.9 ± 3.7 | 7.1 ± 3.9 | <0.0001 | 6.6 ± 4.3 | 6.9 ± 3.4 | 6.2 ± 3.6 | 0.002 |
| MUFA (%TE) | 6.6 ± 3.2 | 12.3 ± 3.6 | 14.5 ± 4.4 | <0.0001 | 13.2 ± 4.9 | 11.5 ± 4.4 | 10.3 ± 4.7 | <0.0001 |
| PUFA/SFA | 1.7 ± 0.8 | 1.1 ± 0.5 | 0.9 ± 0.5 | <0.0001 | 1.1 ± 0.6 | 1.2 ± 0.7 | 1.2 ± 0.6 | <0.0001 |
| MUFA/SFA | 1.9 ± 0.7 | 1.8 ± 0.4 | 1.8 ± 0.4 | <0.0001 | 2 ± 0.6 | 1.8 ± 0.4 | 1.8 ± 0.5 | <0.0001 |
| Heme iron (mg/day) | 0.07 (0.00, 0.15) | 0.75 (0.66, 0.85) | 2.16 (1.82, 2.82) | <0.0001 | 0.85 (0.45, 1.32) | 0.76 (0.34, 1.46) | 0.70 (0.20, 1.56) | <0.0001 |
| Nonheme iron (mg/day) | 24.2 ± 8.7 | 22.1 ± 6 | 23.9 ± 7.7 | 0.259 | 16.4 ± 2.1 | 22 ± 0.6 | 32.6 ± 11.8 | <0.0001 |
| Iron (mg/day) | 24.2 ± 8.7 | 22.9 ± 6 | 26.6 ± 8.2 | <0.0001 | 17.4 ± 2.3 | 23.1 ± 1.1 | 33.8 ± 12 | <0.0001 |
| Magnesium (mg/day) | 379.9 ± 85 | 328.5 ± 60.3 | 326.7 ± 67.3 | <0.0001 | 298.4 ± 72 | 334.2 ± 51.2 | 391.6 ± 86.2 | <0.0001 |
| Cereals fiber (g/day) | 7.6 (4.4, 11.9) | 3.7 (3.0, 5.3) | 2.8 (2.2, 3.6) | <0.0001 | 3.3 (2.6, 4.2) | 3.9 (2.9, 6.3) | 4.3 (2.8, 8.5) | <0.0001 |
| Cholesterol (mg/day) | 62.5 (17.2, 147.1) | 211.0 (140.3, 313.7) | 320.6 (238.3, 439.2) | <0.0001 | 194.1 (110.4, 301.1) | 229.9 (135.7, 337.9) | 208.3 (84, 344.9) | 0.006 |
| Vegetables (g/day) | 323.5 ± 187.9 | 318 ± 169.5 | 318.7 ± 168.2 | 0.963 | 278 ± 115.2 | 323.8 ± 133.1 | 372.8 ± 272.1 | <0.0001 |
| Fruits (g/day) | 0.0 (0.0, 0.0) | 0.0 (0.0, 40.6) | 3.1 (0.0, 48.5) | <0.0001 | 0.0 (0.0, 18.8) | 0.0 (0.0, 40.9) | 0.0 (0.0, 30.8) | 0.0003 |
Data are mean ± SD, n (%), or median (IQR).
*
Information on nondietary factors was collected at baseline, and dietary data were estimated as energy-adjusted cumulative average intake from baseline and follow-up periods.
†
We used linear regressions to test the linear trends for continuous variables (with the median intake of heme or nonheme iron as continuous variables included in the regression models). We used χ2 with linear-by-linear association tests to test the linear trends for categorical variables.