Table 2.
Characteristics of Study Population According to Quartiles of Homocysteine Levels (N = 1677)
| Quartiles of Homocysteine (μmol/L) | ||||||
|---|---|---|---|---|---|---|
| Characteristics | Q1 (<7.42)
N = 421 |
Q2 (7.42–9.06)
N = 420 |
Q3 (9.07–11.25)
N = 418 |
Q4 (>11.25)
N = 418 |
Total | p Value |
| Continuous variables* | ||||||
| Age, y | 67.2 (6.4) | 69.0 (6.7) | 71.2 (7.4) | 73.4 (8.0) | 70.2 (7.5) | <.001 |
| Body mass index, kg/m2 | 27.9 (5.2) | 28.4 (5.1) | 27.9 (4.8) | 27.6 (4.7) | 28.0 (5.0) | .245 |
| Vitamin B12, pg/mL† | 574 (302) | 513 (280) | 447 (264) | 374 (245) | 477 (287) | <.001 |
| Folate, ng/mL† | 18.8 (11.3) | 16.1 (9.4) | 15.4 (11.7) | 13.3 (10.7) | 16.1 (11.3) | <.001 |
| Serum creatinine, mg/dL | 0.7 (0.2) | 0.8 (0.2) | 0.9 (0.2) | 1.2 (0.9) | 0.9 (0.5) | <.001 |
| Isokinetic peak quadriceps strength, Newtons | 330 (107) | 347 (111) | 339 (104) | 320 (106) | 334 (108) | .094 |
| Habitual gait speed, m/s | 1.028 (0.257) | 1.016 (0.216) | 0.960 (0.219) | 0.918 (0.238) | 0.980 (0.237) | <.001 |
| Categorical variables‡ | ||||||
| Female | 272 (64.6) | 209 (49.8) | 162 (38.8) | 138 (33.0) | 781 (46.6) | <.001 |
| Non-Hispanic white | 229 (54.4) | 243 (57.9) | 240 (57.4) | 278 (66.5) | 990 (59.0) | .001 |
| Education more than high school | 180 (42.8) | 154 (36.7) | 166 (39.7) | 124 (29.7) | 624 (37.2) | <.001 |
| Hypertension | 257 (61.1) | 271 (64.5) | 285 (68.2) | 309 (73.9) | 1122 (66.9) | .001 |
| Diabetes mellitus | 70 (16.6) | 57 (13.6) | 58 (13.9) | 74 (17.7) | 259 (15.4) | .261 |
| Current smoker | 54 (12.8) | 48 (11.4) | 57 (13.6) | 63 (15.1) | 222 (13.2) | .468 |
| Alcohol intake > 12 drinks per year | 240 (57.0) | 266 (63.3) | 271 (64.8) | 276 (66.0) | 1053 (62.8) | .082 |
| Self-reported functional disability | ||||||
| Activities of daily living | 47 (11.2) | 56 (13.3) | 68 (16.3) | 90 (21.5) | 261 (15.6) | <.001 |
| Instrumental activities of daily living | 75 (17.8) | 65 (15.5) | 77 (18.4) | 107 (25.6) | 324 (19.3) | .002 |
| Leisure and social activities | 44 (10.5) | 45 (10.7) | 52 (12.4) | 75 (17.9) | 216 (12.9) | .004 |
| Lower extremity mobility | 108 (25.7) | 101 (24.1) | 112 (26.8) | 151 (36.1) | 472 (28.2) | <.001 |
| General physical activities | 203 (48.2) | 209 (49.8) | 228 (54.6) | 245 (58.6) | 885 (52.8) | .01 |
*
Values in the continuous variables were expressed as mean (standard deviation) unless otherwise specified.
†
Values were expressed as median (interquartile range) due to right skewness.
‡
Values in the categorical variables were expressed as number (percentage).