Table 1.
Characteristics of the study population
| Characteristics | Total (n = 1,918) | Cognitive performance | Statistics | P | |
|---|---|---|---|---|---|
| Low cognitive performance (n = 467) |
Normal cognitive performance (n = 1,451) | ||||
| Age, years, n (%) | χ2 = 9.584 | 0.008 | |||
| 60–70 | 1,046 (56.41) | 785 (57.69) | 261 (47.93) | ||
| 70–80 | 574 (29.94) | 435 (29.58) | 139 (32.33) | ||
| ≥ 80 | 298 (13.65) | 231 (12.74) | 67 (19.73) | ||
| Gender, n (%) | χ2 = 0.350 | 0.554 | |||
| Male | 954 (46.45) | 687 (46.15) | 267 (48.48) | ||
| Female | 964 (53.55) | 764 (53.85) | 200 (51.52) | ||
| BMI, kg/m2, n (%) | χ2 = 7.156 | 0.067 | |||
| <18.5 | 27 (1.19) | 15 (0.88) | 12 (3.27) | ||
| 18.5–25 | 494 (25.49) | 369 (24.85) | 125 (29.75) | ||
| 25–30 | 653 (35.83) | 499 (36.60) | 154 (30.75) | ||
| ≥30 | 744 (37.48) | 568 (37.67) | 176 (36.24) | ||
| Race, n (%) | χ2 = 195.589 | < 0.001 | |||
| Mexican American | 152 (2.92) | 91 (1.99) | 61 (9.08) | ||
| Non-Hispanic White | 946 (81.49) | 831 (85.77) | 115 (53.05) | ||
| Non-Hispanic Black | 455 (7.46) | 283 (5.45) | 172 (20.88) | ||
| Other race | 365 (8.12) | 246 (6.79) | 119 (16.99) | ||
| Marital status, n (%) | χ2 = 25.228 | < 0.001 | |||
| Married | 1,067 (63.92) | 842 (66.45) | 225 (47.11) | ||
| Widowed/Divorced/Separated | 680 (28.74) | 486 (26.76) | 194 (41.92) | ||
| Never married | 117 (4.34) | 84 (4.01) | 33 (6.54) | ||
| Living with partner | 54 (3.00) | 39 (2.79) | 15 (4.44) | ||
| Educational level, n (%) | χ2 = 212.195 | < 0.001 | |||
| Below high school | 485 (15.59) | 226 (11.05) | 259 (45.81) | ||
| High school/GED | 457 (22.85) | 347 (21.92) | 110 (29.02) | ||
| Above high school | 976 (61.56) | 878 (67.03) | 98 (25.17) | ||
| Annual household income, dollars, n (%) | χ2 = 92.482 | < 0.001 | |||
| <20,000 | 512 (16.49) | 299 (12.73) | 213 (41.47) | ||
| ≥20,000 | 1,406 (83.51) | 1,152 (87.27) | 254 (58.53) | ||
| Trouble sleeping, n (%) | 221 (11.53) | 172 (11.59) | 49 (11.14) | χ2 = 0.044 | 0.834 |
| Sleeping time, hours, Mean (S.E) | 7.12 (0.03) | 7.14 (0.04) | 7.02 (0.08) | t = 1.210 | 0.237 |
| Smoking, n (%) | 975 (50.99) | 715 (50.18) | 260 (56.40) | χ2 = 3.709 | 0.054 |
| Drinking, n (%) | 590 (26.09) | 429 (24.30) | 161 (38.01) | χ2 = 22.038 | < 0.001 |
| Work activity, n (%) | χ2 = 15.971 | < 0.001 | |||
| Vigorous | 216 (13.43) | 179 (14.27) | 37 (7.80) | ||
| Moderate | 399 (23.02) | 334 (24.30) | 65 (14.48) | ||
| Other | 1,303 (63.56) | 938 (61.43) | 365 (77.72) | ||
| Recreational activity, n (%) | χ2 = 61.881 | < 0.001 | |||
| Vigorous | 165 (11.45) | 153 (12.90) | 12 (1.78) | ||
| Moderate | 625 (33.63) | 502 (35.02) | 123 (24.40) | ||
| Other | 1,128 (54.92) | 796 (52.08) | 332 (73.82) | ||
| Depression, n (%) | 148 (5.64) | 82 (4.38) | 66 (14.03) | χ2 = 27.250 | < 0.001 |
| Hypertension, n (%) | 1,177 (56.69) | 872 (55.15) | 305 (66.94) | χ2 = 10.486 | 0.001 |
| Diabetes, n (%) | 458 (19.61) | 300 (17.36) | 158 (34.62) | χ2 = 22.682 | < 0.001 |
| Stroke, n (%) | 129 (6.01) | 79 (5.25) | 50 (11.01) | χ2 = 9.044 | 0.003 |
| CHF, n (%) | 133 (6.82) | 82 (5.80) | 51 (13.61) | χ2 = 21.130 | < 0.001 |
| CHD, n (%) | 167 (8.25) | 125 (8.18) | 42 (8.74) | χ2 = 0.092 | 0.762 |
| Heart attack, n (%) | 166 (8.52) | 117 (7.87) | 49 (12.84) | χ2 = 6.794 | 0.009 |
| TC, mg/dL Mean (S.E) | 195.04 (1.49) | 196.32 (1.58) | 186.52 (2.43) | t = 3.880 | < 0.001 |
| HDL, mg/dL, Mean (S.E) | 55.99 (0.88) | 56.28 (0.97) | 54.04 (1.18) | t = 1.600 | 0.119 |
| GHb, %, Mean (S.E) | 5.94 (0.03) | 5.88 (0.04) | 6.35 (0.12) | t=-3.760 | < 0.001 |
| 25(OH)D, nmol/L, Mean (S.E) | 82.16 (1.30) | 83.52 (1.29) | 73.09 (2.65) | t = 4.310 | < 0.001 |
| Blood cadmium, µg/L, Mean (S.E) | 0.49 (0.02) | 0.47 (0.02) | 0.63 (0.05) | t=-2.890 | 0.007 |
| Blood cadmium, µg/L, n (%) | χ2 = 26.958 | < 0.001 | |||
| Normal-level (< 0.60) | 1,423 (77.77) | 1,112 (79.68) | 311 (65.07) | ||
| High-level (≥ 0.60) | 495 (22.23) | 339 (20.32) | 156 (34.93) | ||
| Total ω-6 fatty acids intake, mg/kcal/day, Mean (S.E) | 8.18 (0.08) | 8.30 (0.09) | 7.34 (0.17) | t = 4.470 | < 0.001 |
| Total ω-6 fatty acids intake, mg/kcal/day, n (%) | χ2 = 9.222 | 0.002 | |||
| Normal-level (≥ 5.92) | 1438 (77.78) | 1,111 (79.11) | 327 (68.89) | ||
| Low-level (< 5.92) | 480 (22.22) | 340 (20.89) | 140 (31.11) | ||
S.E standard error, BMI body mass index, GED general educational development, CHF congestive heart failure, CHD coronary heart disease, TC total cholesterol, HDL high-density lipoprotein, GHb glycated hemoglobin, 25(OH)D 25-hydroxyvitamin D