TABLE 2.
Baseline characteristics of UK Biobank participants according to level of tea consumption1
| Characteristic | Tea consumption, cups/day | ||||||
|---|---|---|---|---|---|---|---|
| None | <1 | 1 | 2–3 | 4–5 | 6–7 | ≥8 | |
| N = 65,808 | N = 13,657 | N = 36,403 | N = 128,122 | N = 115,520 | N = 54,087 | N = 32,189 | |
| Age, y | 55.5 ± 8.2 | 55.6 ± 8.2 | 55.8 ± 8.3 | 56.9 ± 8.1 | 57.2 ± 7.9 | 57.3 ± 7.7 | 56.6 ± 7.8 |
| Male, n (%) | 28,444 (43.2) | 6590 (48.3) | 17,247 (47.4) | 58,293 (45.5) | 51,284 (44.4) | 23,768 (43.9) | 16,052 (49.9) |
| Current smoker, n (%) | 8973 (13.6) | 1710 (12.5) | 3790 (10.4) | 10,830 (8.5) | 9974 (8.6) | 5788 (10.7) | 6061 (18.8) |
| BMI, kg/m2 | 28.1 ± 5.3 | 27.6 ± 5.1 | 27.3 ± 4.8 | 27.1 ± 4.6 | 27.2 ± 4.6 | 27.3 ± 4.6 | 27.6 ± 4.8 |
| Income, £<18,000, n (%) | 12,583 (19.1) | 2064 (15.1) | 5462 (15.0) | 21,423 (16.7) | 22,075 (19.1) | 11,424 (21.1) | 7934 (24.7) |
| College or university degree, n (%) | 19,810 (30.1) | 6160 (45.1) | 13,996 (38.5) | 44,632 (34.8) | 35,681 (30.9) | 15,266 (28.2) | 8586 (26.7) |
| Currently employed, n (%) | 40,289 (61.2) | 8586 (62.9) | 22,490 (61.8) | 73,910 (57.7) | 64,612 (55.9) | 30,426 (56.3) | 18,198 (56.5) |
| Townsend deprivation score | −1.24 ± 3.07 | −1.32 ± 3.01 | −1.44 ± 2.99 | −1.62 ± 2.91 | −1.63 ± 2.89 | −1.52 ± 2.94 | −1.02 ± 3.20 |
| Homeowner, n (%) | 57,790 (87.8) | 12,318 (90.2) | 32,855 (90.3) | 117,082 (91.4) | 105,083 (91.0) | 48,601 (89.9) | 27,418 (85.2) |
| Moderate to vigorous physical activity, minutes/week | 73 ± 99 | 67 ± 82 | 74 ± 91 | 75 ± 91 | 78 ± 96 | 79 ± 103 | 82 ± 112 |
| Hypertension, n (%) | 34,629 (52.6) | 7082 (51.9) | 18,788 (51.6) | 68,141 (53.2) | 62,114 (53.8) | 29,228 (54.0) | 16,903 (52.5) |
| Diabetes, n (%) | 3875 (5.9) | 690 (5.1) | 1661 (4.6) | 5568 (4.4) | 5037 (4.4) | 2399 (4.4) | 1661 (5.2) |
| Poor overall health rating, n (%) | 3211 (4.9) | 515 (3.8) | 1210 (3.3) | 3770 (3.0) | 3845 (3.3) | 2191 (4.1) | 2086 (6.5) |
| Alcohol, drinks/week | 1.21 ± 1.58 | 1.38 ± 1.60 | 1.36 ± 1.51 | 1.27 ± 1.42 | 1.15 ± 1.34 | 1.07 ± 1.31 | 1.08 ± 1.51 |
| Fish, servings/week | 0.30 ± 0.23 | 0.31 ± 0.22 | 0.32 ± 0.22 | 0.33 ± 0.22 | 0.33 ± 0.22 | 0.32 ± 0.23 | 0.31 ± 0.24 |
| Red, meat servings/week | 0.50 ± 0.33 | 0.51 ± 0.32 | 0.50 ± 0.31 | 0.50 ± 0.30 | 0.51 ± 0.31 | 0.52 ± 0.32 | 0.55 ± 0.34 |
| Fruit, servings/week | 2.85 ± 2.61 | 2.87 ± 2.56 | 2.99 ± 2.45 | 3.05 ± 2.40 | 3.07 ± 2.43 | 3.03 ± 2.51 | 2.96 ± 2.80 |
| Vegetable, servings/week | 0.79 ± 0.58 | 0.78 ± 0.56 | 0.80 ± 0.54 | 0.80 ± 0.51 | 0.80 ± 0.51 | 0.80 ± 0.51 | 0.82 ± 0.60 |
| Regular coffee, cups/day | 2.8 ± 2.7 | 2.8 ± 2.4 | 2.3 ± 2.1 | 1.7 ± 1.7 | 1.2 ± 1.5 | 0.9 ± 1.4 | 1.0 ± 2.0 |
| Coffee-/tea-derived caffeine, mg/day | 210 ± 204 | 229 ± 177 | 212 ± 154 | 226 ± 127 | 265 ± 111 | 320 ± 109 | 466 ± 178 |
| Recent caffeine drinking, n (%) | 1337 (2.2) | 283 (2.2) | 729 (2.2) | 2377 (2.0) | 2118 (2.0) | 1030 (2.1) | 721 (2.5) |
| CMSG2 | 1.71 ± 0.93 | 1.66 ± 0.92 | 1.65 ± 0.92 | 1.67 ± 0.92 | 1.72 ± 0.92 | 1.79 ± 0.92 | 1.86 ± 0.93 |
| APOE ε4 carriers, n (%) | 15,279 (28.6) | 3238 (28.6) | 8559 (28.7) | 29,520 (28.2) | 26,619 (28.5) | 12,576 (28.9) | 7350 (28.5) |
1Data drawn from 2006–2010 for self-described white participants with information on coffee and tea intake and who completed ≥1 of the cognitive function tests. Values are mean (±SD) unless stated otherwise. All characteristic values are significantly different across tea categories (P < 0.0001) with the exception of APOE (P = 0.11).
2CMSG: caffeine metabolism score; derived by summing the number of single-nucleotide polymorphism alleles multiplied by their β-coefficients and recalibrated such that it ranged from 0 to 4, with higher scores predicting faster caffeine metabolism.