Table 2.
Participant characteristics by fifth of dietary vitamin C intake derived from food diaries in the UK Dietary Cohort Consortium
| Breast cancer | Dietary vitamin C intake (diary fifths) |
||||||||
|---|---|---|---|---|---|---|---|---|---|
| Covariates (at diary date) | Cases | Controls | 1 | 2 | 3 | 4 | 5 | P* | |
| Cases/controls | 707 | 2144 | 130/440 | 138/432 | 144/426 | 142/428 | 153/418 | ||
| Dietary vitamin C intake (mg/day) | mean (SD) | 98 (56) | 95 (52) | 36.9 (9.9) | 61.9 (6.4) | 85.1 (7.2) | 114.6 (10.0) | 178.4(45.5) | |
| Fruit Intake g/d | mean (SD) | 191 (138) | 185 (135) | 81 (74) | 136 (84) | 188 (105) | 223 (123) | 304 (159) | <0.001 |
| Vegetable intake g/d | mean (SD) | 165 (86) | 158 (82) | 101 (49) | 141 (59) | 161 (65) | 182 (79) | 214 (104) | <0.001 |
| Age at diary completion (yr) | mean (SD) | 55.7 (9.4) | 56.3 (9.6) | 55.5 (10.0) | 55.7 (9.8) | 56.9 (9.6) | 56.8 (9.6) | 56.0 (9.4) | 0.3 |
| Height (cm) | mean (SD) | 163 (7) | 162 (6) | 160.7 (6.5) | 161.5 (6.3) | 161.8 (6.8) | 162.3 (6.4) | 162.9 (6.2) | <0.001 |
| Weight (kg) | mean (SD) | 67.8 (11.8) | 67.2 (12.2) | 67.9 (12.0) | 67.5 (12.6) | 67.8 (12.7) | 66.6 (11.2) | 66.8 (12.0) | 0.1 |
| Energy intake (diary, MJ/day) | mean (SD) | 7.6 (1.7) | 7.4 (1.7) | 6.8 (1.8) | 7.4 (1.6) | 7.4 (1.6) | 7.7 (1.7) | 7.8 (1.7) | <0.001 |
| Alcohol intake (diary, g/day) | mean (SD) | 10.3 (13.6) | 8.7 (12.8) | 7.9 (12) | 8.5 (13) | 10.3 (14) | 9.0 (13) | 9.7 (13) | 0.02 |
| Total fat (g/d) | mean (SD) | 68.9 (21.8) | 67.2 (22.0) | 64.9 (21.3) | 69.5 (21.7) | 66.2 (21.5) | 70.3 (22.5) | 67.6 (21.4) | 0.07 |
| Dietary vitamin E (mg/d) | mean (SD) | 9.9 (4.1) | 9.3 (4.0) | 8.0 (3.8) | 9.2 (3.7) | 9.3 (3.7) | 10.2 (4.2) | 10.6 (4.1) | <0.001 |
| Dietary Iron (mg/d) | mean (SD) | 11.8 (3.5) | 11.3 (3.4) | 9.5 (3.1) | 10.9 (2.9) | 11.5 (3.4) | 12.0 (3.5) | 13.0 (3.5) | <0.001 |
| Parity (number of children) | mean (SD) | 1.8 (1.2) | 1.9 (1.3) | 2.1 (1.3) | 1.9 (1.3) | 1.9 (1.3) | 1.8 (1.3) | 1.6 (1.3) | <0.001 |
| Exercise ( medium - high) | n (%) | 242 (37) | 796 (38) | 162 (30) | 198 (36) | 208 (37) | 230 (42) | 240 (44) | <0.001 |
| HRT use (current user) | n (%) | 122 (18) | 373 (18) | 89 (16) | 94 (17) | 106 (19) | 110 (20) | 96 (17) | 0.4 |
| Menopausal status (post-menopausal) | n (%) | 436 (63) | 1424 (67) | 352 (63) | 368 (66) | 385 (68) | 387 (69) | 367 (65) | 0.2 |
| Never smoked | n (%) | 413 (60) | 1233 (58) | 272 (49) | 316 (56) | 333 (59) | 349 (62) | 376 (67) | <0.001 |
| Education level (degree, HNC, HND) | n (%) | 136 (21) | 313 (15) | 38 (7) | 68 (13 ) | 77 (15) | 113 (21) | 151 (28) | <0.001 |
| Social class (professional or intermediate) | n (%) | 238 (47) | 901 (47) | 187 (37) | 207 (42) | 232 (48) | 254 (53) | 259 (58) | <0.001 |
*
p is Ptrend over continuous variables, and p for χ2 tests for categorical variables