Table 1 Age-standardized characteristics of the subjects in the Nurses' Health Study in 1990
From: Protein, iron, and meat consumption and risk for rheumatoid arthritis: a prospective cohort study
Total protein (g/day) | Heme iron (g/day) | |||||
|---|---|---|---|---|---|---|
Quintile | 1 | 3 | 5 | 1 | 3 | 5 |
Intake (mean) | 60.1 | 74.1 | 90.7 | 0.77 | 1.20 | 1.81 |
Number of women | 15,836 | 15,822 | 15,824 | 15,843 | 15,996 | 15,649 |
Age (mean; years)) | 56.4 | 56.3 | 57.1 | 57.3 | 56.4 | 56.3 |
Body mass index (mean; kg/m2) | 24.7 | 25.5 | 27.1 | 24.6 | 25.8 | 26.6 |
Current smoker (%) | 23 | 16 | 14 | 14 | 17 | 21 |
Age at menarche (mean; years) | 12.6 | 12.5 | 12.3 | 12.5 | 12.5 | 12.4 |
Breastfeeding ≥12 months among parous women (%) | 14 | 17 | 17 | 18 | 17 | 13 |
Very regular menses (%)a | 53 | 56 | 54 | 56 | 57 | 50 |
Mean nutrient intakes | ||||||
Protein (g/day) | - | - | - | 67.1 | 74.6 | 82.5 |
Animal protein (g/day) | 42.4 | 55.8 | 73.0 | 47.3 | 56.5 | 66.7 |
Vegetable protein (g/day) | 17.7 | 18.2 | 17.7 | 19.8 | 18.1 | 15.7 |
Heme iron (g/day) | 0.98 | 1.25 | 1.50 | - | - | - |
Total iron (g/day) | 14.0 | 15.5 | 16.5 | 15.8 | 15.6 | 14.8 |