Table 1.
Baseline characteristics of study population according to the quartiles of dietary inflammatory index
| Characteristics | Overall | Dietary inflammatory indexa | P valueb | |||
|---|---|---|---|---|---|---|
| First quartile (n = 41,587) | Second quartile (n = 41,607) | Third quartile (n = 41,587) | Fourth quartile (n = 41,596) | |||
| Age (mean ± SD) | 55.91 ± 7.98 | 56.91 ± 7.83 | 56.20 ± 7.91 | 55.71 ± 7.95 | 54.82 ± 8.08 | < 0.001 |
| Female sex (%) | 88,802 (53.4) | 20,653 (49.7) | 21,656 (52.0) | 22,474 (54.0) | 24,019 (57.7) | < 0.001 |
| Ethnic (%) | < 0.001 | |||||
| White | 159,256 (95.7) | 39,970 (96.1) | 40,324 (96.9) | 40,060 (96.3) | 38,902 (93.5) | |
| Asian | 2398 (1.4) | 489 (1.2) | 397 (1.0) | 546 (1.3) | 966 (2.3) | |
| Black | 2018 (1.2) | 457 (1.1) | 328 (0.8) | 377 (0.9) | 856 (2.1) | |
| Chinese | 470 (0.3) | 125 (0.3) | 94 (0.2) | 112 (0.3) | 139 (0.3) | |
| Mixed | 1037 (0.6) | 249 (0.6) | 232 (0.6) | 209 (0.5) | 347 (0.8) | |
| Other | 1198 (0.7) | 297 (0.7) | 232 (0.6) | 283 (0.7) | 386 (0.9) | |
| Education level (%) | < 0.001 | |||||
| Higher education qualifications/professional qualifications | 118,527 (71.2) | 30,727 (73.9) | 30,822 (74.1) | 29,621 (71.2) | 27,357 (65.8) | |
| Others | 47,850 (28.8) | 10,860 (26.1) | 10,785 (25.9) | 11,966 (28.8) | 14,239 (34.2) | |
| TDI (mean ± SD) | − 1.58 ± 2.86 | − 1.68 ± 2.81 | − 1.75 ± 2.76 | − 1.62 ± 2.84 | − 1.27 ± 3.02 | < 0.001 |
| Smoking status (%) | < 0.001 | |||||
| Never | 93,931 (56.5) | 23,560 (56.7) | 23,926 (57.5) | 23,408 (56.3) | 23,037 (55.4) | |
| Previous | 59,476 (35.7) | 15,501 (37.3) | 15,008 (36.1) | 14,953 (36.0) | 14,014 (33.7) | |
| Current | 12,970 (7.8) | 2526 (6.1) | 2673 (6.4) | 3226 (7.8) | 4545 (10.9) | |
| Drinking status (%) | < 0.001 | |||||
| Never | 5097 (3.1) | 1132 (2.7) | 1052 (2.5) | 1158 (2.8) | 1755 (4.2) | |
| Previous | 4955 (3.0) | 1140 (2.7) | 1056 (2.5) | 1159 (2.8) | 1600 (3.8) | |
| Current | 156,325 (94.0) | 39,315 (94.5) | 39,499 (94.9) | 39,270 (94.4) | 38,241 (91.9) | |
| BMI (%) | < 0.001 | |||||
| Health weight | 61,871 (37.2) | 16,472 (39.6) | 16,114 (38.7) | 15,205 (36.6) | 14,080 (33.8) | |
| Underweight | 908 (0.5) | 236 (0.6) | 247 (0.6) | 194 (0.5) | 231 (0.6) | |
| Overweight | 69,587 (41.8) | 17,196 (41.3) | 17,443 (41.9) | 17,551 (42.2) | 17,397 (41.8) | |
| Obesity | 34,011 (20.4) | 7683 (18.5) | 7803 (18.8) | 8637 (20.8) | 9888 (23.8) | |
| Diabetes (%) | 6847 (4.1) | 1742 (4.2) | 1570 (3.8) | 1671 (4.0) | 1864 (4.5) | < 0.001 |
| Blood pressure status (%) | < 0.001 | |||||
| Normal | 27,949 (16.8) | 6415 (15.4) | 6873 (16.5) | 6964 (16.7) | 7697 (18.5) | |
| Elevated | 22,181 (13.3) | 5527 (13.3) | 5671 (13.6) | 5485 (13.2) | 5498 (13.2) | |
| Hypertension stage 1 | 45,944 (27.6) | 11,271 (27.1) | 11,392 (27.4) | 11,664 (28.0) | 11,617 (27.9) | |
| Hypertension stage 2 | 70,303 (42.3) | 18,374 (44.2) | 17,671 (42.5) | 17,474 (42.0) | 16,784 (40.4) | |
| Achieve the recommended physical activity level (%) | 136,169 (81.8) | 35,905 (86.3) | 34,399 (82.7) | 33,445 (80.4) | 32,420 (77.9) | < 0.001 |
| Energy, kcal/day (mean ± SD) | 2075.06 ± 606.00 | 2477.95 ± 666.68 | 2189.28 ± 498.79 | 1977.78 ± 448.94 | 1655.27 ± 461.69 | < 0.001 |
| Family history of dementia (%) | 21,800 (13.1) | 5782 (13.9) | 5603 (13.5) | 5369 (12.9) | 5046 (12.1) | < 0.001 |
TDI Townsend deprivation index, BMI Body mass index, SD Standard deviation
aQuartiles of dietary inflammation index. The cutoff points of the quartiles are − 1.799, − 0.395, 0.985
bAnalysis of variance or χ2 test where appropriate