TABLE 1.
Baseline characteristics of men and women from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial by energy-adjusted total dietary folate intake on the basis of values before folic acid fortification (1998–2005)1
| Quartiles of energy-adjusted total folate intake in women (n = 57,187) |
Quartiles of energy-adjusted total folate intake in men (n = 51,988) |
|||||||||
| 1 | 2 | 3 | 4 | P for trend | 1 | 2 | 3 | 4 | P for trend | |
| n | 14,296 | 14,297 | 14,297 | 14,297 | — | 12,997 | 12,997 | 12,997 | 12,997 | — |
| Total folate intake (μg/d) | ≤238.9 | 239.0–399.0 | 399.1–534.2 | ≥534.3 | — | ≤186.9 | 187.0–280.6 | 280.7–413.5 | ≥413.6 | — |
| Age2 (y) | 62.0 | 62.2 | 62.4 | 63.0 | <0.0001 | 62.0 | 62.7 | 62.5 | 63.2 | <0.0001 |
| Race (%) | ||||||||||
| Black | 4.5 | 4.6 | 2.8 | 2.9 | <0.0001 | 3.0 | 3.2 | 2.3 | 2.3 | <0.0001 |
| White | 92.1 | 90.0 | 93.4 | 90.4 | 0.25 | 93.6 | 90.1 | 91.4 | 89.0 | <0.0001 |
| Asian | 1.4 | 3.5 | 2.4 | 4.9 | <0.0001 | 1.1 | 4.0 | 4.0 | 6.4 | <0.0001 |
| Other | 1.9 | 2.0 | 1.4 | 1.8 | 0.10 | 2.3 | 2.7 | 2.3 | 2.3 | 0.52 |
| Postsecondary education (%) | 60.6 | 68.0 | 70.2 | 69.8 | <0.0001 | 67.8 | 75.5 | 77.9 | 80.7 | <0.0001 |
| Folate intake3 (μg/d) | ||||||||||
| Natural folate4 | 132.4 | 160.9 | 159.5 | 186.0 | <0.0001 | 109.6 | 141.5 | 140.3 | 161.6 | <0.0001 |
| Fortified folic acid5 | 61.7 | 75.2 | 73.5 | 87.2 | <0.0001 | 53.8 | 78.8 | 77.2 | 95.5 | <0.0001 |
| Food folate6 | 181.6 | 223.8 | 220.8 | 262.3 | <0.0001 | 150.1 | 204.7 | 202.7 | 242.0 | <0.0001 |
| Supplemental folic acid7 | 9.1 | 184.8 | 378.3 | 415.5 | <0.0001 | 4.7 | 64.4 | 314.5 | 403.9 | <0.0001 |
| Total folate8 | 185.9 | 316.3 | 465.6 | 674.0 | <0.0001 | 151.8 | 227.5 | 346.6 | 541.9 | <0.0001 |
| Multivitamin use, recent (%) | 13.7 | 24.6 | 34.9 | 34.8 | <0.0001 | 8.3 | 14.4 | 29.7 | 32.9 | <0.0001 |
| Height (cm) | 163.4 | 163.4 | 163.5 | 162.8 | <0.0001 | 178.1 | 178.0 | 178.2 | 177.4 | <0.0001 |
| Current BMI (kg/m2) | 27.5 | 27.1 | 26.6 | 26.3 | <0.0001 | 28.0 | 27.6 | 27.4 | 27.0 | <0.0001 |
| Self-reported diabetes (%) | 6.3 | 6.3 | 4.9 | 6.0 | 0.0003 | 6.8 | 9.6 | 8.1 | 9.6 | <0.0001 |
| Family history of pancreatic cancer (%) | 2.9 | 3.1 | 3.3 | 2.9 | 0.69 | 2.0 | 2.1 | 2.1 | 2.3 | 0.22 |
| Smoking status (%) | ||||||||||
| Never | 55.3 | 56.8 | 56.4 | 58.3 | <0.0001 | 33.1 | 39.5 | 37.9 | 39.4 | <0.0001 |
| Former | 32.6 | 34.2 | 36.6 | 35.2 | <0.0001 | 51.2 | 51.3 | 52.8 | 54.4 | <0.0001 |
| Current | 12.0 | 8.9 | 7.0 | 6.5 | <0.0001 | 15.7 | 9.2 | 9.3 | 6.2 | <0.0001 |
| Daily intakes3 | ||||||||||
| Energy (kcal) | 1610.4 | 1760.0 | 1585.6 | 1090.4 | <0.0001 | 2178.9 | 2073.4 | 2166.8 | 1484.1 | <0.0001 |
| Alcohol (g) | 6.6 | 5.9 | 5.4 | 3.4 | <0.0001 | 21.0 | 14.4 | 13.2 | 7.7 | <0.0001 |
| Fruit (servings) | 1.0 | 1.3 | 1.3 | 1.5 | <0.0001 | 0.6 | 1.0 | 0.9 | 1.2 | <0.0001 |
| Vegetables (servings) | 1.1 | 1.3 | 1.3 | 1.5 | <0.0001 | 0.8 | 1.0 | 1.0 | 1.1 | <0.0001 |
| Saturated fat (g) | 12.2 | 11.0 | 10.8 | 9.5 | <0.0001 | 13.1 | 11.2 | 11.5 | 10.0 | <0.0001 |
| Vitamin B-6 (mg) | 1.0 | 1.2 | 1.2 | 1.3 | <0.0001 | 0.9 | 1.1 | 1.1 | 1.3 | <0.0001 |
| Vitamin B-12 (μg) | 2.4 | 2.5 | 2.5 | 2.7 | <0.0001 | 2.6 | 2.7 | 2.7 | 2.8 | <0.0001 |
1
All values are means. Generalized linear models and the Cochran-Armitage test were used to test for trend associations of continuous and categorical baseline characteristics.
2
Age at randomization.
3
All folate variables, nutrients, and foods are energy adjusted except for supplemental folic acid and alcohol.
4
Polyglutamates found naturally in food.
5
Folic acid added to food.
6
Natural folate and fortified folic acid combined.
7
Folic acid from vitamin supplements.
8
Food folate and supplemental folic acid combined.