TABLE 1.
Descriptive statistics for individuals with complete data on key exposures and outcomes versus those in two main analysis samples for mortality and incident cardiovascular disease (CVD)
| Factor | Level | Complete outcome data # | Mortality analysis sample | Level |
CVD analysis (mortality
and incidence) sample |
| Individuals | 316 893 | 208 998 | 199 577 | ||
| Outcome | Alive | 309 419 (97.6) | 204 756 (98.0) | No CVD | 189 654 (95.0) |
| Died (other cause) | 6301 (2.0) | 3594 (1.7) | Incident CVD | 9923 (5.0) | |
| Died (CVD) | 1173 (0.4) | 648 (0.3) | |||
| FEV1 (L) | 2.8±0.8 (n=316 893) |
2.9±0.8 (n=208 998) |
2.9±0.8 (n=199 577) |
||
| FVC (L) | 3.7±1.0 (n=316 893) |
3.7±1.0 (n=208 998) |
3.7±1.0 (n=199 577) |
||
| FEV1/FVC | 0.8±0.1 (n=316 893) |
0.8±0.1 (n=208 998) |
0.8±0.1 (n=199 577) |
||
| COPD (GOLD stage) | No COPD | 272 468 (86.0) | 182 930 (87.5) | No COPD | 175 326 (87.8) |
| Stage 1 | 20 610 (6.5) | 12 850 (6.1) | Stage 1 | 12 247 (6.1) | |
| Stage 2 | 20 994 (6.6) | 11 818 (5.7) | Stage 2 | 10 793 (5.4) | |
| Stage 3 | 2608 (0.8) | 1287 (0.6) | Stage 3 | 1119 (0.6) | |
| Stage 4 | 213 (0.1) | 113 (0.1) | Stage 4 | 92 (<1) | |
| PM10, 2010 (μg·m−3) | 16.0 (15.2–17.0) (n=316 893) |
16.0 (15.2–17.0) (n=208 998) |
16.0 (15.2–16.9) (n=199 577) |
||
| PM2.5, 2010 (μg·m−3) | 9.9 (9.3–10.5) (n=316 893) |
9.9 (9.2–10.5) (n=208 998) |
9.9 (9.2–10.5) (n=199 577) |
||
| NO2, 2010 (μg·m−3) | 25.9 (21.1–30.9) (n=316 893) |
25.6 (21.0–30.7) (n=208 998) |
25.6 (21.0–30.7) (n=199 577) |
||
| Sex | Female | 176 405 (55.7) | 116 341 (55.7) | Female | 113 452 (56.8) |
| Male | 140 488 (44.3) | 92 657 (44.3) | Male | 86 125 (43.2) | |
| Age (years)¶ | 56.3±8.1 (n=316 893) |
55.9±8.0 (n=208 998) |
55.6±8.0 (n=199 577) |
||
| Age group¶ | <45 years | 33 520 (10.6) | 23 177 (11.1) | <45 years | 23 018 (11.5) |
| ≥45 and <55 years | 92 690 (29.2) | 64 090 (30.7) | ≥45 and <55 years | 62 926 (31.5) | |
| ≥55 and <65 years | 133 931 (42.3) | 87 247 (41.7) | ≥55 and <65 years | 82 801 (41.5) | |
| ≥65 years | 56 752 (17.9) | 34 484 (16.5) | ≥65 years | 30 832 (15.4) | |
| BMI (kg·m−2) | 27.3±4.7 (n=316 623) |
27.3±4.7 (n=208 998) |
27.2±4.7 (n=199 577) |
||
| BMI category+ | Normal | 106 648 (33.7) | 70 757 (33.9) | Normal | 68 989 (34.6) |
| Overweight | 134 951 (42.6) | 88 967 (42.6) | Overweight | 84 822 (42.5) | |
| Obese | 75 294 (23.8) | 49 274 (23.6) | Obese | 45 766 (22.9) | |
| Height (cm) | 168.4±9.2 (n=316 893) |
168.6±9.1 (n=208 998) |
168.5±9.1 (n=199 577) |
||
| Education§ | None | 48 954 (15.4) | 26 351 (12.6) | None | 23 867 (12.0) |
| O Level/CSE/GCSE | 54 517 (17.2) | 35 019 (16.8) | O Level/CSE/GCSE | 33 634 (16.9) | |
| A2/AS/NVQ/HNDC/Other | 106 745 (33.7) | 71 546 (34.2) | A2/AS/NVQ/HNDC/Other | 68 345 (34.2) | |
| Degree | 103 894 (32.8) | 76 082 (36.4) | Degree | 73 731 (36.9) | |
| Missing | 2783 (0.9) | ||||
| Income | <GBP 31 000 | 125 953 (39.7) | 92 645 (44.3) | <GBP 31 000 | 86 623 (43.4) |
| ≥GBP 31 000 | 148 228 (46.8) | 116 353 (55.7) | ≥GBP 31 000 | 112 954 (56.6) | |
| Missing | 42 712 (13.5) | ||||
| Smoking status | Never-smoker | 173 669 (54.8) | 145 776 (69.7) | Never-smoker | 141 055 (70.7) |
| Ever-smoker | 143 224 (45.2) | 63 222 (30.3) | Ever-smoker | 58 522 (29.3) | |
| Passive smoke exposure | None | 272 715 (86.1) | 198 511 (95.0) | None | 189 756 (95.1) |
| Any | 15 032 (4.7) | 10 487 (5.0) | Any | 9821 (4.9) | |
| Missing | 29 146 (9.2) | ||||
| Asthma | Never had asthma | 280 868 (88.6) | 184 892 (88.5) | Never had asthma | 176 542 (88.5) |
| Ever had asthma | 35 564 (11.2) | 23 953 (11.5) | Ever had asthma | 22 897 (11.5) | |
| Missing | 461 (0.1) | 153 (0.1) | Missing | 138 (0.1) | |
| Occupation | Non “at-risk” occupation | 311 072 (98.2) | 205 730 (98.4) | Non “at-risk” occupation | 196 463 (98.4) |
| “At-risk” occupation | 5821 (1.8) | 3268 (1.6) | “At-risk” occupation | 3114 (1.6) |
Data are presented as n, n (%), mean±sd or median (interquartile range). For continuous variables, numbers with non-missing data are given in brackets after the mean or median values (e.g. 2.9±0.8 (n=208 998)); for categorical variables, numbers missing are given as a separate category. FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; GOLD: Global Initiative for Chronic Obstructive Lung Disease; PM10: particulate matter <10 µm; PM2.5: particulate matter <2.5 µm; NO2: nitrogen dioxide; BMI: body mass index. #: numbers of participants with incomplete covariate data; ¶: at recruitment; +: normal <25 kg·m−2, overweight 25–29.9 kg·m−2 and obese ≥30 kg·m−2; §: the four categories correspond (approximately) to less than secondary education, secondary education, further education (usually 16–18 years) and degree level education (usually ≥18 years).