Characteristics of the unweighed population sample. Continuous data are shown as mean and SD. Categorical data are shown as counts and percentages. The null hypothesis that the mean is the same in those reporting/not reporting respiratory complaints is tested taking full account of the complex survey design
| Characteristics | Respiratory complaints | P value | |
| No | Yes | ||
| N | 6082 | 33 | |
| Age, mean (SD) | 49.8 (17.6) | 62.6 (15.4) | 0.025 |
| Sex | |||
| Men | 2519 (41.4%) | 12 (36.4%) | 0.118 |
| Women | 3563 (58.6%) | 21 (63.6%) | |
| Ethnic group | |||
| White | 3197 (93.8%) | 27 (100.0%) | 0.407 |
| Non-white | 210 (6.2%) | 0 (0.0%) | |
| Cigarette smoking status | |||
| Current smoker | 1402 (23.1%) | 7 (21.2%) | 0.071 |
| Ex-regular cigarette smoker | 1463 (24.1%) | 14 (42.4%) | |
| Never regular cigarette smoker | 3214 (52.9%) | 12 (36.4%) | |
| BMI, mean (SD) | 27.7 (5.4) | 29.3 (7.2) | 0.327 |
| Equivalised income, mean (SD) | 31.4 (23.0) | 28.5 (34.1) | 0.228 |
| Total energy (MJ) diet only, mean (SD) | 7.5 (2.3) | 7.1 (2.6) | 0.564 |
| Vitamin C (mg) diet only, mean (SD) | 78.4 (54.9) | 65.2 (46.4) | 0.048 |
| Vitamin D (mg) diet only, mean (SD) | 2.9 (2.1) | 2.6 (1.9) | 0.789 |
| Vitamin E (mg) diet only, mean (SD) | 9.0 (4.1) | 7.8 (2.9) | 0.004 |
| Vitamin A (μg) diet only, mean (SD) | 949.7 (54.9) | 804.6 (432.6) | <0.001 |
| Vitamin C supplements | |||
| No | 5297 (87.1%) | 33 (100.0%) | <0.001 |
| Yes | 785 (12.9%) | 0 (0.0%) | |
| Vitamin D supplements | |||
| No | 4969 (81.7%) | 27 (81.8%) | 0.001 |
| Yes | 1113 (18.3%) | 6 (18.2%) | |
| Vitamin E supplements | |||
| No | 5034 (82.8%) | 29 (87.9%) | 0.002 |
| Yes | 1048 (17.2%) | 4 (12.1%) | |
| Vitamin A supplements | |||
| No | 5095 (83.8%) | 29 (87.9%) | 0.002 |
| Yes | 987 (16.2%) | 4 (12.1%) | |
Values are displayed for the unweighed sample.
P values take into account complex survey design.
BMI, body mass index.