TABLE 2.
Baseline characteristics of study participants stratified by tertile of baseline plasma selenium concentrations1
| Tertile of mean ± SD plasma selenium concentration at baseline | |||
|---|---|---|---|
| Characteristic | 113.5 ± 9.7 ng/mL (n = 572) | 135.4 ± 5.9 ng/mL (n = 571) | 168.7 ± 23.4 ng/mL (n = 571) |
| Age, y | 63.0 ± 9.3 | 63.3 ± 9.0 | 63.0 ± 8.8 |
| Male, n (%) | 360 (62.9) | 374 (65.5) | 380 (66.6) |
| BMI (kg/m2), n (%) | |||
| <25 | 129 (22.6) | 110 (19.3) | 101 (17.7) |
| 25 to <30 | 246 (43.0) | 236 (41.4) | 264 (46.2) |
| ≥30 | 197 (34.4) | 224 (39.3) | 206 (36.1) |
| Race, n (%) | |||
| White | 540 (94.6) | 534 (93.7) | 538 (94.2) |
| Black | 18 (3.2) | 19 (3.3) | 12 (2.1) |
| Asian | 2 (0.4) | 5 (0.9) | 10 (1.8) |
| American Indian/Alaskan | 4 (0.7) | 2 (0.4) | 2 (0.4) |
| Mixed or other | 7 (1.2) | 10 (1.8) | 9 (1.6) |
| Hispanic ethnicity (yes), n (%) | 21 (3.7) | 27 (4.8) | 29 (5.1) |
| Cigarette smoking status, n (%) | |||
| Never | 236 (42.1) | 237 (42.5) | 226 (40.4) |
| Former | 266 (47.5) | 266 (47.7) | 292 (52.1) |
| Current | 58 (10.4) | 55 (9.9) | 42 (7.5) |
| Education, n (%) | |||
| Less than high school | 14 (2.5) | 8 (1.4) | 10 (1.8) |
| High school or GED | 116 (20.3) | 118 (20.7) | 101 (17.7) |
| Some college | 170 (29.7) | 155 (27.2) | 180 (31.6) |
| Bachelor's degree | 118 (20.6) | 126 (22.1) | 119 (20.9) |
| Graduate/professional | 154 (26.9) | 164 (28.7) | 160 (28.1) |
| Dietary intake | |||
| Energy, kcal/d | 1859 ± 876 | 1883 ± 936 | 1849 ± 853 |
| Protein, g/d | 75 ± 39 | 76 ± 39 | 76 ± 35 |
| Carbohydrate, g/d | 248 ± 123 | 250 ± 131 | 247 ± 125 |
| Total fat, g/d | 62 ± 36 | 63 ± 36 | 61 ± 33 |
| Total fiber, g/d | 20 ± 11 | 21 ± 12 | 21 ± 12 |
1
Values are means ± SDs unless otherwise indicated; n = 1714. Missing values for baseline characteristics are as follows: BMI (n = 1), race (n = 2), ethnicity (n = 2), cigarette smoking (n = 37), and education (n = 1). GED, General Educational Development.