Table 1 Baseline characteristics of the study population, across the quartiles of total iron intake in the Tehran Lipid and Glucose Study
Characteristic | Total iron consumption (mg/day) | ||||
|---|---|---|---|---|---|
Q1 | Q2 | Q3 | Q4 | P | |
Baseline age (years) | 38.19 ± 14.1a | 41.54 ± 14.4 | 42.30 ± 14.6 | 40.42 ± 14.1 | < 0.01 |
Women, % (n) | 27.4 (887) | 24.0 (778) | 22.3 (722) | 26.4 (856) | < 0.01 |
Current smokers (%) | 24.6 | 21.6 | 23.5 | 20.0 | < 0.01 |
Education level (%)†| 22.5 | 27.4 | 30.1 | 32.7 | < 0.01 |
Physical activity (MET/min/week) | 584 ± 891 | 536 ± 837 | 553 ± 805 | 546 ± 834 | 0.34 |
BMI (Kg/m2) | 25.2 ± 4.9 | 25.9 ± 4.8 | 25.8 ± 4.8 | 25.7 ± 4.9 | < 0.01 |
Energy intake (kcal/day) | 2440 ± 715 | 2076 ± 664 | 2346 ± 724 | 2530 ± 698 | < 0.01 |
Carbohydrate (% of energy) | 53.8 ± 6.7 | 58.6 ± 5.7 | 60.5 ± 6.5 | 60.5 ± 10.5 | < 0.01 |
Protein (% of energy) | 13.5 ± 2.2 | 14.4 ± 2.7 | 14.9 ± 3.9 | 15.0 ± 9.4 | < 0.01 |
SFA (% of energy) | 12.1 ± 5.2 | 10.0 ± 2.3 | 9.1 ± 2.9 | 10.0 ± 21.4 | < 0.01 |
Fiber (g/1000 kcal) | 13.5 ± 4.5 | 18.0 ± 6.2 | 21.5 ± 8.9 | 20.2 ± 11.0 | < 0.01 |
Vitamin C (mg/day) | 59.8 ± 32.5 | 67.3 ± 35.0 | 74.8 ± 42.0 | 81.1 ± 50.0 | < 0.01 |
Magnesium (mg/day) | 159 ± 30 | 181 ± 34 | 198 ± 43 | 202 ± 44 | < 0.01 |
Total iron (mg/day) | 12.2 ± 4.0 | 14.9 ± 4.7 | 18.8 ± 5.9 | 23.6 ± 7.9 | < 0.01 |
Haem iron (mg/day) | 0.49 ± 0.29 | 0.53 ± 0.32 | 0.51 ± 0.34 | 0.50 ± 0.30 | < 0.01 |
Non-Haem iron (mg/day) | 10.7 ± 1.7 | 13.2 ± 1.3 | 14.7 ± 2.2 | 15.8 ± 3.4 | < 0.01 |
Red meat (g/day) | 30.5 ± 19.6 | 32.6 ± 18.4 | 31.9 ± 20.4 | 31.1 ± 18.0 | < 0.01 |
Metabolic syndrome (%) | 19.7 | 26.0 | 28.0 | 26.1 | < 0.01 |
Abdominal obesity (%) | 34.0 | 41.0 | 43.8 | 40.5 | < 0.01 |
High blood pressure (%) | 20.1 | 25.5 | 27.9 | 25.6 | < 0.01 |
Low HDL-C (%) | 62.7 | 59.5 | 56.7 | 51.2 | < 0.01 |
Hyperglycemia (%) | 14.3 | 20.6 | 24.5 | 25.5 | < 0.01 |
High triglyceride (%) | 31.3 | 38.3 | 39.2 | 34.9 | < 0.01 |