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Table 1 Characteristics of the study population

From: Interaction between ω-6 fatty acids intake and blood cadmium on the risk of low cognitive performance in older adults from National Health and Nutrition Examination Survey (NHANES) 2011–2014

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)   
  1. 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