TABLE 1.
Characteristics of study participants by TCN2 776C→G genotype1
| Characteristic | Total (n = 171) | CC (n = 79) | CG (n = 61) | GG (n = 31) | P |
| Age, y | 73.5 ± 8.02 | 73.2 ± 7.9 | 73.8 ± 8.3 | 73.8 ± 8.0 | 0.90 |
| Women, n (%) | 121 (70.8) | 55 (69.6) | 41 (67.2) | 25 (80.7) | 0.39 |
| BMI, kg/m2 | 31.9 ± 8.6 | 32.6 ± 9.9 | 31.7 ± 7.1 | 30.5 ± 7.7 | 0.50 |
| Education, n (% within genotype) | 0.66 | ||||
| Kindergarten through grade eight | 21 (12.3) | 10 (12.7) | 7 (11.5) | 4 (12.9) | |
| Grades 9–11 | 19 (11.1) | 11 (13.9) | 6 (9.8) | 2 (6.5) | |
| Grade 12 or high school | 47 (27.5) | 25 (31.7) | 17 (27.9) | 5 (16.1) | |
| Any undergraduate | 70 (40.9) | 28 (35.4) | 26 (42.6) | 16 (51.6) | |
| Any graduate | 14 (8.2) | 5 (6.3) | 5 (8.2) | 4 (12.9) | |
| Race or ethnicity, n (% within genotype) | <0.001 | ||||
| American Indian or Alaskan Native | 3 (1.8) | 3 (3.8) | 0 (0) | 0 (0) | |
| Asian | 3 (1.8) | 1 (1.3) | 0 (0) | 2 (6.5) | |
| Non-Hispanic black | 58 (33.9) | 39 (49.4) | 16 (26.2) | 3 (9.7) | |
| Hispanic | 2 (1.2) | 0 (0) | 1 (1.6) | 1 (3.2) | |
| Non-Hispanic white | 105 (61.4) | 36 (45.6) | 44 (72.1) | 25 (80.7) | |
| Current smoker, n (%) | 39 (22.8) | 18 (22.8) | 14 (23.0) | 7 (22.6) | 1.00 |
| Alcohol, g/d | 2.0 ± 5.4 | 1.3 ± 4.3 | 3.2 ± 7.2 | 1.4 ± 3.2 | 0.11 |
| Vitamin B-12 intake, μg/d | 16.6 ± 16.6 | 14.8 ± 16.8 | 18.2 ± 16.0 | 17.8 ± 17.5 | 0.44 |
| Folate intake, μg DFE/d | 928.3 ± 576.0 | 863.5 ± 616.0 | 985.4 ± 543.0 | 980.8 ± 531.5 | 0.40 |
| Plasma metabolites | |||||
| Folate, nmol/L | 32.0 ± 19.7 | 31.0 ± 18.8 | 31.5 ± 21.1 | 34.4 ± 20.2 | 0.71 |
| Pyridoxal 5′-phosphate, nmol/L | 79.7 ± 83.34 | 76.5 ± 89.0 | 82.9 ± 76.9 | 82.1 ± 83.8 | 0.89 |
| Creatinine, μmol/L | 78.7 ± 26.5 | 79.6 ± 26.5 | 77.8 ± 35.4 | 75.1 ± 26.5 | 0.68 |
| Diabetes, n (%)3 | 49 (28.7) | 20 (25.3) | 20 (32.8) | 9 (29.0) | 0.54 |
| Hypertension, n (%)3 | 142 (83.0) | 68 (86.1) | 53 (86.9) | 21 (67.7) | 0.21 |
1
Between-genotype differences were analyzed with the use of Pearson’s chi-square test for categorical variables and a 1-factor ANOVA for continuous variables. DFE, dietary folate equivalent; TCN2, transcobalamin gene.
2
Mean ± SD (all such values).
3
ANCOVA adjusted for age, sex, and race or ethnicity.