Table 1. Characteristics of all study participants, cases and those with low and high levels of radon at the residences.
| Characteristic | Cohort | Cases | Radone,c <67.6 Bq/m3 | Radone,c <67.6 Bq/m3 | ||||
| No. (%) | Median (5–95 percentile) | No. (%) | Median (5–95 percentile) | No. (%) | Median (5–95 percentile) | No. (%) | Median (5–95 percentile) | |
| All participants | 51 674 (100) | 121* (100) | 38 763 (75.0) | 12 911 (25.0) | ||||
| Age at enrolment | 56.1 (50.7–64.2) | 57.2 (50.9–64.2) | 56.1 (50.7–64.2) | 56.5 (50.9–64.2) | ||||
| Sex | ||||||||
| Male | 24 533 (47.5) | 56 (46.3) | 18 067 (46.6) | 6 466 (50.1) | ||||
| Female | 27 141 (52.5) | 65 (53.7) | 20 696 (53.4) | 6 445 (49.9) | ||||
| Occupational status | ||||||||
| Employed | 40 314 (78.0) | 89 (73.5) | 30 010 (77.4) | 10 306 (79.8) | ||||
| Unemployed | 11 360 (22.0) | 32 (26.5) | 8 753 (22.6) | 2 605 (20.2) | ||||
| School attendance (years) | ||||||||
| <8 | 16 924 (33.0) | 54 (44.6) | 13 130 (33.9) | 3 794 (29.4) | ||||
| ≥8 | 34 750 (67.0) | 67 (55.4) | 25 633 (66.1) | 9 117 (70.6) | ||||
| Marital status | ||||||||
| Single | 3 028 (5.9) | 10 (8.3) | 2 832 (7.3) | 196 (1.5) | ||||
| Married/living de facto | 37 225 (72.0) | 87 (71.9) | 26 180 (67.5) | 11 045 (85.6) | ||||
| Divorced | 8 581 (16.6) | 17 (14.1) | 7 510 (19.4) | 1 071 (8.3) | ||||
| Widowed | 2 840 (5.5) | 7 (5.8) | 2 241 (5.8) | 599 (4.6) | ||||
| Fruit and vegetable intake (g/day) | 312 (96–735) | 282 (75–617) | 308 (91–744) | 322 (115–713) | ||||
| Enployment in chemical industrya | ||||||||
| No | 51 446 (99.6) | 119 (98.4) | 38 587 (99.6) | 12 859 (99.6) | ||||
| Yes | 228 (0.4) | 2 (1.6) | 176 (0.4) | 52 (0.4) | ||||
| Radon at the addressb,c (Bq/m3) | 40.5 (9.1–91.0) | 41.8 (8.8–92.2) | ||||||
| NOx at front doord (µg/m3) | 21.6 (14.8–67.7) | 22.0 (15.2–92.9) | 23.1 (15.3–76.6) | 17.5 (14.4–31.8) | ||||
aEver employed in the chemical industry for at least 1 year.
b
Time-weighted average radon.
c
For the period 1 January 1971, to censoring date with inclusion of a 10-year latency period relevant for brain tumour.
d
Time-weighted average NOx, we focused on the concentration of NOx as an indicator for particular matter (PM) from traffic because NOx correlates strongly with ultrafine particles in Danish streets [35].
e
Cut-off based on the 75th percentile for time-weighted average radon concentrations.
*
Including 11 cases of benign tumours.