Risk of surgery for varicose veins among men in relation to occupational mechanical exposures and covariates
| Person-years | Cases | HRcrude | 95% CI | HRadj* | 95% CI | |
|---|---|---|---|---|---|---|
| Standing/walking (hours/day) | ||||||
| <4 | 68 394 | 38 | 1.00 | – | 1.00 | – |
| ≥4–<6 | 14 805 | 20 | 2.48 | 1.44 to 4.27 | 2.65 | 1.52 to 4.62 |
| ≥6–≤7.3 | 86 603 | 178 | 3.78 | 2.36 to 4.84 | 3.17 | 2.06 to 4.89 |
| p for trend <10−3 | p for trend <10−3 | |||||
| Lifting (kg/day) | ||||||
| 0 | 51 384 | 26 | 1.00 | – | 1.00 | – |
| >0–<1000 | 58 961 | 70 | 2.33 | 1.48 to 3.66 | 2.65 | 1.63 to 4.32 |
| ≥1000–≤4900 | 59 457 | 140 | 4.25 | 2.76 to 6.54 | 3.95 | 2.32 to 6.73 |
| p for trend <10−3 | p for trend <10−3 | |||||
| Age at baseline (years) | ||||||
| <36 | 61 972 | 83 | 1.00 | – | 1.00 | – |
| ≥36–<45 | 43 659 | 43 | 0.81 | 0.56 to 1.17 | 1.11 | 0.66 to 1.86 |
| ≥45–<56 | 46 237 | 81 | 1.46 | 1.07 to 2.00 | 2.01 | 1.28 to 3.18 |
| ≥56 | 17 935 | 29 | 1.48 | 0.96 to 2.28 | 2.25 | 1.28 to 3.96 |
| Body mass index (kg/m2) | ||||||
| <25 | 62 656 | 61 | 1.00 | – | 1.00 | – |
| ≥25–<30 | 57 412 | 66 | 1.21 | 0.86 to 1.72 | 1.04 | 0.72 to 1.49 |
| ≥30–≤63 | 12 722 | 14 | 1.16 | 0.65 to 2.07 | 1.06 | 0.59 to 1.91 |
| Missing | 37 013 | 95 | – | – | – | – |
| Leisure time physical activity (hours/week) | ||||||
| Light activity <2 | 30 687 | 32 | 0.91 | 0.59 to 1.41 | 0.72 | 0.45 to 1.16 |
| Light activity ≥2–≤4 | 45 982 | 58 | 1.00 | - | 1.00 | – |
| Light activity >4 or strenuous activity ≥2–≤4 | 43 938 | 42 | 0.78 | 0.53 to 1.16 | 0.84 | 0.55 to 1.27 |
| Strenuous activity >4 | 10 982 | 14 | 1.03 | 0.57 to 1.85 | 1.20 | 0.66 to 2.19 |
| Missing | 38 213 | 90 | – | – | – | – |
| Smoking status | ||||||
| Never smoker | 52 816 | 52 | 1.00 | – | 1.00 | – |
| Ex-smoker | 34 786 | 48 | 1.40 | 0.95 to 2.08 | 1.18 | 0.78 to 1.78 |
| Smoker | 47 334 | 50 | 0.99 | 0.67 to 1.47 | 0.75 | 0.49 to 1.14 |
| Missing | 34 867 | 86 | – | – | – | – |
*Number of person-years in the adjusted model: 128 752. Standing/walking and lifting are adjusted for age, body mass index, leisure time physical activity, smoking and baseline year; occupational mechanical exposures are not mutually adjusted. Age, body mass index, leisure time physical activity and smoking are adjusted for standing/walking and baseline year; the estimates changed minimally if adjusted for lifting instead (results not shown).