Table 2.
Baseline Characteristics of Elderly Participants in Third National Health and Nutrition Examination Survey According to Cognitive Status*
| Characteristic | All Participants (n = 3,396) | Cognitively Normal (n = 3,056) | Cognitively Impaired (n = 340) | p† |
| Serum 25-hydroxyvitamin D (nmol/L) | ||||
| ≥75 | 1,104 (37.5) | 1,019 (37.9) | 85 (30.1) | <.001 |
| ≥50 < 75 | 1,306 (39.0) | 1,194 (39.4) | 112 (31.3) | |
| ≥25 < 50 | 894 (21.8) | 770 (21.2) | 124 (31.7) | |
| <25 | 92 (1.8) | 73 (1.5) | 19 (7.0) | |
| Age (y), M (SD) | 73.7 (10.9) | 72.6 (11.3) | 76.6 (12.6) | <.001 |
| Women | 1,736 (55.2) | 1,571 (55.4) | 165 (52.7) | .4 |
| Race/ethnicity | ||||
| White | 2,744 (90.9) | 2,521 (91.9) | 223 (74.0) | <.001 |
| Black | 594 (7.6) | 488 (6.7) | 106 (23.0) | |
| Other | 58 (1.5) | 47 (1.4) | 11 (3.0) | |
| Education (y), M (SD) | 10.7 (8.1) | 11.3 (8.2) | 7.7 (7.9) | <.001 |
| Season tested | ||||
| December to February | 700 (13.4) | 615 (13.4) | 85 (13.8) | .04 |
| March to May | 898 (29.5) | 823 (29.7) | 75 (25.6) | |
| June to August | 824 (31.5) | 780 (32.1) | 44 (21.9) | |
| September to November | 974 (25.6) | 838 (24.9) | 136 (38.8) | |
| Current smoker | 424 (12.8) | 379 (12.7) | 45 (14.8) | .6 |
| Body mass index (kg/m2), mean (SD) | 26.6 (6.7) | 26.8 (9.1) | 25.2 (8.0) | .001 |
| Alcohol consumption | ||||
| 0 drinks/mo | 2,314 (62.0) | 2,049 (61.4) | 265 (72.1) | .03 |
| 1–10 drinks/mo | 571 (18.4) | 523 (18.6) | 48 (16.2) | |
| ≥11 drinks/mo | 511 (19.6) | 484 (20.1) | 27 (11.8) | |
| Serum vitamin E (μmol/L), mean (SD) | 32.8 (20.8) | 33.4 (21.1) | 27.6 (18.8) | <.001 |
| Combined annual family income | ||||
| <$20,000 | 2,137 (52.6) | 1,855 (51.4) | 282 (74.6) | <.001 |
| $20,000–34,999 | 781 (26.8) | 742 (27.4) | 39 (15.2) | |
| ≥$35,000 | 478 (20.6) | 459 (21.2) | 19 (10.2) | |
| Impaired mobility | 289 (5.9) | 213 (5.1) | 76 (20.7) | <.001 |
| Physically inactive | 1,107 (25.9) | 949 (24.9) | 158 (44.2) | <.001 |
| Stroke | 245 (6.2) | 211 (6.1) | 34 (8.3) | .1 |
| Diabetes | 695 (16.7) | 612 (16.3) | 83 (24.0) | .02 |
| Hypertension | ||||
| Untreated | 1,109 (30.9) | 982 (30.7) | 127 (34.1) | .6 |
| Treated with antihypertensive drugs | 1,207 (34.6) | 1,098 (34.8) | 109 (31.8) | |
Notes: *Data are expressed as number and percentage unless otherwise indicated. Means and percentages are weighted to adjust for the sampling design.
†
p Value for χ2 test for categorical variables and analysis of variance for continuous variables.