Table 2.
Estimated differences in systolic and diastolic blood pressure associated with dietary iron intake (mg/4.2 MJ) higher by 2 SD† (mg/4.2 MJ) in 4680 adults
| Model | Difference (99% CI) in | |
|---|---|---|
| Systolic blood pressure (mm Hg) | Diastolic blood pressure (mm Hg) | |
| Total dietary iron (mg/4.2 MJ): | ||
| 1 | −2.06 (−3.06 to −1.07)*** | −1.07 (−1.75 to −0.39)*** |
| 2 | −1.44 (−2.46 to −0.43)*** | −0.71 (−1.41 to −0.02)** |
| 3 | −1.39 (−2.45 to −0.34)** | −0.68 (−1.37 to 0.01) |
| 4a | −1.40 (−2.55 to −0.25)** | −0.73 (−1.51 to 0.06) |
| 4b | −1.17 (−2.32 to −0.02)** | −0.47 (−1.26 to 0.32) |
| 4c | −1.10 (−2.32 to 0.12) | −0.61 (−1.44 to 0.22) |
| 4d | −0.85 (−2.01 to 0.31) | −0.30 (−1.10 to 0.50) |
| 4e | −1.06 (−2.17 to 0.05) | −0.43 (−1.19 to 0.33) |
| 4f | −1.45 (−2.51 to −0.38)** | −0.69 (−1.42 to 0.04) |
| Non-haem iron (mg/4.2 MJ): | ||
| 1 | −2.17 (−3.17 to −1.18)*** | −1.13 (−1.81, −0.45)*** |
| 2 | −1.51 (−2.53 to −0.48)*** | −0.75 (−1.45 to −0.05)** |
| 3 | −1.45 (−2.51 to −0.38)*** | −0.73 (−1.43 to −0.04)** |
| 4a | −1.48 (−2.64 to −0.31)*** | −0.79 (−1.58 to 0.01) |
| 4b | −1.22 (−2.40 to −0.05)** | −0.50 (−1.31 to 0.30) |
| 4c | −1.16 (−2.39 to 0.07) | −0.67 (−1.51 to 0.17) |
| 4d | −0.90 (−2.07 to 0.26) | −0.34 (−1.14 to 0.46) |
| 4e | −1.08 (−2.20 to 0.04) | −0.45 (−1.23 to 0.32) |
| 4f | −1.49 (−2.56 to −0.42)*** | −0.72 (−1.45 to 0.01) |
| Haem iron (mg/4.2 MJ): | ||
| 1 | 0.56 (−0.52 to 1.64) | 0.27 (−0.45 to 0.98) |
| 2 | 0.19 (−0.88 to 1.27) | 0.10 (−0.62 to 0.82) |
| 3 | 0.06 (−1.08 to 1.21) | 0.14 (−0.63 to 0.90) |
| 4a | 0.03 (−1.12 to 1.18) | 0.13 (−0.63 to 0.90) |
| 4b | −0.11 (−1.28 to 1.05) | 0.02 (−0.75 to 0.80) |
| 4c | 0.08 (−1.07 to 1.23) | 0.15 (−0.62 to 0.92) |
| 4d | 0.19 (−0.97 to 1.36) | 0.20 (−0.57 to 0.98) |
| 4e | −0.19 (−1.35 to 0.97) | 0.01 (−0.77 to 0.78) |
| 4f | 0.16 (−1.23 to 1.55) | 0.18 (−0.74 to 1.10) |
1=age, sex, sample, height, weight, special diet, supplement use, physical activity, cardiovascular disease and diabetes, and family history of hypertension; 2=plus urinary sodium, urinary potassium, and alcohol; 3=plus cholesterol, saturated fatty acids, and polyunsaturated fatty acids; 4a=plus fibre; 4b=or plus vegetable protein; 4c=or plus magnesium, 4=or plus phosphorus; 4e=or plus calcium; 4f=or plus animal protein.
***P<0.001.
**P<0.01.
†2 SD difference: 4.20 mg/4.2 MJ (total dietary iron), 4.13 mg/4.2 MJ (non-haem iron), and 0.61 (haem iron) mg/4.2 MJ.