Copenhagen Airport Cohort: baseline characteristics with information from registers and survey
| Variables | Air pollution | Manual lifting | Non-respondents in survey | |||
|---|---|---|---|---|---|---|
| Data from registers | Reference* | Exposed* | Reference† | Exposed† | Respondents | Non-respondents |
| N | 62 546 | 6629 | 65 702 | 3473 | 3749 | 1725 |
| Age, median (Q1–Q3) | 31 (24–43) | 28 (24–35) | 31 (24–43) | 27 (23–33) | 29 (24–36) | 28 (24–35) |
| Risk time, person-years | 679385.0 | 51314.2 | 703235.6 | 27463.4 | ||
| Danish country of origin, n (%) | 51 345 (83.7) | 5529 (88.0) | 53 839 (83.9) | 3067 (89.9) | 3357 (89.8) | 1386 (80.8) |
| Educational level, n (%) | ||||||
| Elementary school | 35 664 (57.0) | 3132 (47.3) | 37 221 (56.65) | 1575 (45.35) | 1614 (43.1) | 873 (50.6) |
| High school | 8821 (14.1) | 904 (13.6) | 9225 (14.0) | 500 (14.4) | 565 (15.1) | 213 (12.4) |
| Vocational education | 16 742 (26.8) | 2487 (37.5) | 17 872 (27.2) | 1357 (39.1) | 1494 (39.9) | 610 (35.4) |
| Higher education | 1319 (2.1) | 106 (1.6) | 1384 (2.11) | 41 (1.18) | 76 (2.0) | 29 (1.7) |
| Marital status, n (%) | ||||||
| Married | 19 663 (31.4) | 1783 (26.9) | 20 603 (31.36) | 843 (24.27) | 1169 (31.2) | 433 (25.1) |
| Unmarried | 36 438 (58.3) | 4459 (67.3) | 38 428 (58.49) | 2469 (71.09) | 2357 (62.9) | 1185 (68.7) |
| Divorced | 5712 (9.1) | 379 (5.7) | 5932 (9.03) | 159 (4.58) | 221 (5.9) | 102 (5.9) |
| Widower | 733 (1.2) | 8 (0.1) | 739 (1.12) | 2 (0.06) | 2 (0.1) | 5 (0.3) |
| Average pollution at residence | ||||||
| Major road within 50 m of residence, n (%)‡ | 5593 (11.3) | 600 (10.3) | ||||
| Data from survey | Reference | Exposed | Reference | Exposed | ||
| N | 1473 | 2276 | 1963 | 1786 | ||
| Smoking, n (%) | ||||||
| No | 485 (32.9) | 887 (38.5) | 680 (34.8) | 682 (38.5) | ||
| Former | 507 (34.4) | 773 (34.0) | 674 (34.5) | 606 (34.2) | ||
| Current | 473 (32.1) | 609 (26.8) | 598 (30.6) | 484 (27.3) | ||
| Missing | 8 (0.54) | 17 (0.75) | 11 (0.56) | 14 (0.78) | ||
| Units of alcohol per week, n (%) | ||||||
| 0 | 355 (24.1) | 582 (25.6) | 502 (25.8) | 435 (24.7) | ||
| 1–21 | 999 (67.8) | 1567 (68.9) | 1318 (67.8) | 1248 (70.7) | ||
| >21 | 106 (7.2) | 101 (4.4) | 125 (6.4) | 82 (4.7) | ||
| Missing | 13 (0.88) | 26 (1.14) | 18 (0.92) | 21 (1.18) | ||
| BMI, n (%) | ||||||
| <18.5 | 8 (0.5) | 2 (0.1) | 9 (0.47) | 1 (0.1) | ||
| 18.5–25 | 507 (34.4) | 795 (34.9) | 685 (35.5) | 617 (35.0) | ||
| 25.1–30 | 664 (45.1) | 1087 (47.8) | 892 (46.2) | 859 (48.7) | ||
| >30 | 267 (18.1) | 366 (16.1) | 345 (17.9) | 288 (16.3) | ||
| Missing | 27 (1.83) | 26 (1.14) | 32 (1.63) | 21 (1.18) | ||
| Leisure time physical activity hours/week, n (%) | ||||||
| Sedentary | 188 (12.8) | 242 (10.6) | 255 (13.0) | 175 (9.8) | ||
| Low | 535 (36.3) | 786 (34.5) | 697 (35.5) | 624 (34.9) | ||
| Medium | 540 (36.7) | 878 (38.6) | 707 (36.0) | 711 (39.8) | ||
| High | 187 (12.7) | 347 (15.3) | 280 (14.26) | 254 (14.2) | ||
| Missing | 23 (1.56) | 23 (1.01) | 24 (1.22) | 22 (1.23) | ||
*Descriptive statistics at baseline, the first year during follow-up that a person is an employee in Copenhagen Airport in a job function with tasks outdoors on the apron (exposed group) or the first year during follow-up for workers who are never employees in Copenhagen Airport in job functions with tasks outdoors on the apron (reference group).
†Descriptive statistics at baseline, the first year during follow-up that a person is employed as baggage handler in Copenhagen (exposed group) or first year during follow-up for workers who are never employed as baggage handler in Copenhagen (reference group).
‡Major road >10 000 vehicles/day.
BMI, body mass index.