Baseline characteristics of employed individuals (n=25 029) in the Swedish National March Cohort, stratified by job strain
| Low strain job | Passive job | Active job | High strain job | |
| Number of participants | 5882 | 7402 | 6334 | 5411 |
| Sex | ||||
| Female | 3737 (64%) | 5200 (70%) | 4085 (64%) | 3827 (71%) |
| Male | 2145 (36%) | 2202 (30%) | 2249 (36%) | 1584 (29%) |
| Age (years) | 46.3 (35.8–53.9) | 46.5 (34.8–54.4) | 47.2 (38.1–53.6) | 46.6 (34.4–54.0) |
| Body mass index (kg/m2) | 23.9 (22.0–26.3) | 23.8 (22.0–26.2) | 24.2 (22.2–26.4) | 23.9 (22.0–26.3) |
| Missing (n) | 207 | 290 | 228 | 250 |
| Education | ||||
| Compulsory school | 628 (11%) | 1563 (21%) | 563 (9%) | 1098 (20%) |
| High school | 2130 (36%) | 4209 (57%) | 1978 (31%) | 3034 (56%) |
| University/PhD | 3118 (53%) | 1623 (22%) | 3785 (60%) | 1274 (24%) |
| Missing (n) | 6 | 7 | 8 | 5 |
| Smoking | ||||
| Non-smoker | 3443 (62%) | 4391 (63%) | 3631 (62%) | 3114 (62%) |
| Former smoker | 1643 (30%) | 1941 (28%) | 1722 (29%) | 1357 (27%) |
| Current smoker | 444 (8%) | 591 (9%) | 522 (9%) | 537 (11%) |
| Missing (n) | 352 | 479 | 459 | 403 |
| Alcohol consumption | ||||
| None | 452 (8%) | 710 (10%) | 469 (7%) | 479 (9%) |
| Low | 2865 (49%) | 3879 (52%) | 2807 (45%) | 2894 (54%) |
| Medium/high | 2552 (43%) | 2783 (38%) | 3035 (48%) | 2016 (37%) |
| Missing (n) | 13 | 30 | 23 | 22 |
| Charlson’s comorbidity index | ||||
| 0 | 5519 (94%) | 6906 (93%) | 5952 (94%) | 5044 (93%) |
| 1 | 159 (3%) | 200 (3%) | 158 (2%) | 149 (3%) |
| ≥2 | 204 (3%) | 296 (4%) | 224 (4%) | 218 (4%) |
| Missing (n) | 0 | 0 | 0 | 0 |
| Physical activity (MET*hours/day)* | ||||
| Low (<32 (F); <35 (M)) | 2053 (35%) | 2647 (36%) | 2053 (32%) | 1587 (29%) |
| Medium (32 to 39 (F); 35 to 46 (M)) | 2093 (36%) | 2385 (32%) | 2223 (35%) | 1638 (30%) |
| High (>39 (F); >46 (M)) | 1735 (29%) | 2365 (32%) | 2056 (33%) | 2182 (41%) |
| Missing (n) | 1 | 5 | 2 | 4 |
| Shift work | ||||
| Daytime | 5006 (87%) | 5726 (79%) | 5277 (85%) | 3902 (74%) |
| Shiftwork | 717 (13%) | 1477 (21%) | 944 (15%) | 1364 (26%) |
| Missing (n) | 159 | 199 | 113 | 145 |
| Sleep duration | ||||
| ≤6 hours | 1516 (26%) | 2196 (30%) | 2137 (34%) | 2027 (38%) |
| 7 hours | 2917 (50%) | 3395 (47%) | 2942 (47%) | 2252 (42%) |
| ≥8 hours | 1401 (24%) | 1709 (23%) | 1180 (19%) | 1046 (20%) |
| Missing (n) | 48 | 102 | 75 | 86 |
| Sleep quality | ||||
| Medium/good | 3597 (61%) | 3985 (54%) | 3406 (54%) | 2542 (47%) |
| Bad | 2267 (39%) | 3396 (46%) | 2912 (46%) | 2854 (53%) |
| Missing (n) | 18 | 21 | 16 | 15 |
| Restorative sleep (yes) | 3680 (63%) | 4299 (58%) | 3262 (52%) | 2565 (48%) |
| Missing (n) | 18 | 22 | 16 | 16 |
| Income† | ||||
| First quartile (≤85 200 SEK) | 1446 (25%) | 2085 (28%) | 1262 (20%) | 1478 (27%) |
| Second quartile (85 300 to 111 500 SEK) | 1444 (24%) | 1954 (27%) | 1459 (23%) | 1399 (26%) |
| Third quartile (111 600 to 142 400 SEK) | 1335 (23%) | 1936 (26%) | 1537 (24%) | 1442 (27%) |
| Fourth quartile (≥142 500 SEK) | 1655 (28%) | 1425 (19%) | 2075 (33%) | 1089 (20%) |
| Missing (n) | 2 | 2 | 1 | 3 |
| White-collar profession | 4037 (76%) | 3606 (53%) | 4805 (82%) | 2613 (53%) |
| Missing (n) | 548 | 655 | 489 | 490 |
Results are given as numbers (%) for categorical variables and as median (IQR) for continuous variables.
*Sex-specific tertiles of total physical activity MET*hours/day. MET, Metabolic Equivalent for Task; F, females; M, males.
†Yearly disposable income (after taxes) split between family members. The information was retrieved from the Longitudinal Integrated Database for Health Insurance and Labour Market Studies database in 1997.