Table 3.
Relative risk of rheumatoid arthritis by different activity status among women from the Swedish Mammography Cohort, follow-up 2003 to 2010
| Person-years | Number of cases a /women in the cohort | Age-adjusted relative risk | 95% CI | Multivariable b relative risk | 95% CI | |
|---|---|---|---|---|---|---|
| Leisure-time activity | ||||||
| Walking/bicycling | ||||||
| <20 minutes/day | 64,615 | 69/8,769 | 1.00 | 1.00 | ||
| ≥20 minutes/day (median 40 to 60) | 161,862 | 132/21,343 | 0.91 | 0.76 to 1.08 | 0.91 | 0.77 to 1.09 |
| Exercise | ||||||
| <1 hour/week | 42,398 | 46/5,770 | 1.00 | 1.00 | ||
| 1 hour/week | 54,190 | 48/7,150 | 0.80 | 0.54 to 1.20 | 0.83 | 0.55 to 1.25 |
| ≥2 hours/week (median 2 to 3) | 129,889 | 107/17,192 | 0.77 | 0.55 to 1.10 | 0.80 | 0.56 to 1.14 |
| Leisure-time inactivity | ||||||
| Watching television/sitting | ||||||
| <1 hour/day | 25,361 | 21/3,280 | 1.00 | 1.00 | ||
| 1 to 2 hours/day | 104,213 | 93/13,665 | 1.15 | 0.71 to 1.84 | 1.11 | 0.69 to 1.78 |
| >2 hours/day (median 3 to 4) | 95,068 | 87/12,922 | 1.37 | 0.84 to 2.24 | 1.27 | 0.77 to 2.08 |
| Other daily physical activities | ||||||
| Home/household work | ||||||
| <2 hours/day | 86,311 | 83/11,364 | 1.00 | 1.00 | ||
| 3 to 4 hours/day | 77,696 | 74/10,344 | 1.05 | 0.76 to 1.43 | 1.04 | 0.75 to 1.43 |
| 5 to 6 hours/day | 33,313 | 24/4,458 | 0.84 | 0.53 to 1.33 | 0.84 | 0.53 to 1.35 |
| >6 hours/day (median 7 to 8) | 22,131 | 13/2,981 | 0.67 | 0.37 to 1.22 | 0.68 | 0.37 to 1.24 |
| Work/occupation | ||||||
| Sitting | 107,145 | 103/14,290 | 1.00 | 1.00 | ||
| Walking/standing | 105,432 | 87/13,917 | 0.86 | 0.64 to 1.14 | 0.85 | 0.63 to 1.13 |
| Total energy expenditure (24 hours) | ||||||
| <38.8 MET-hours per day | 48,847 | 45/6,567 | 1.00 | 1.00 | ||
| 38.8 to 42.2 MET-hours per day | 51,492 | 47/6,792 | 1.00 | 0.66 to 1.50 | 1.01 | 0.67 to 1.53 |
| 42.2 to 45.9 MET-hours per day | 51,285 | 44/6,800 | 0.94 | 0.62 to 1.43 | 0.96 | 0.63 to 1.46 |
| ≥45.9 MET-hours per day | 52,099 | 46/6,851 | 0.97 | 0.64 to 1.46 | 0.97 | 0.64 to 1.47 |
CI, confidence interval; MET, metabolic equivalent (kcal/kg per hour). aNumber of cases do not add to the total (n = 201) due to missing values for information about the single physical activities. bAdjusted for age (continuous), smoking status (categorised as never, former, current ≤10 cigarettes per day or >10 cigarettes per day), alcohol intake (never, former, current <2 drinks per week, ≥2 drinks per week), body mass index (quartiles) and educational level (<10 years, 10–12 years, >12 years, other).