From: Cigarette smoking and smoking cessation in relation to risk of rheumatoid arthritis in women
 | Person-years1 | Cases, number1 | Age-adjusted relative risk | 95% CI | Multivariable relative risk3 | 95% CI |
---|---|---|---|---|---|---|
Smoking status | ||||||
Never | 137,162 | 79 | 1.00 (ref) | Â | 1.00 (ref) | Â |
Former | 59,466 | 60 | 1.65 | 1.17, 2.32 | 1.68 | 1.19, 2.38 |
Current | 58,368 | 80 | 2.24 | 1.63, 3.07 | 2.20 | 1.58, 3.04 |
Intensity, cigarettes/day 2 | ||||||
Never | 137,162 | 79 | 1.00 (ref) | Â | 1.00 (ref) | Â |
1 to 7 | 34,032 | 47 | 2.23 | 1.54, 3.21 | 2.31 | 1.59, 3.36 |
8 to 14 | 32,010 | 45 | 2.23 | 1.54, 3.24 | 2.19 | 1.50, 3.21 |
> 14 (median 18) | 35,586 | 33 | 1.45 | 0.96, 2.20 | 1.46 | 0.96, 2.23 |
Duration, years | ||||||
Never | 137,162 | 79 | 1.00 (ref) | Â | 1.00 (ref) | Â |
1 to 25 | 39,634 | 39 | 1.55 | 1.05, 2.30 | 1.60 | 1.07, 2.38 |
25 to 40 | 53,219 | 68 | 2.01 | 1.43, 2.83 | 1.99 | 1.40, 2.82 |
> 40 (median 45) | 23,528 | 32 | 2.36 | 1.55, 3.58 | 2.33 | 1.52, 3.57 |
Pack-years | ||||||
Never | 137,162 | 79 | 1.00 (ref) | Â | 1.00 (ref) | Â |
1 to 5 | 27,534 | 28 | 1.67 | 1.08, 2.58 | 1.72 | 1.11, 2.67 |
6 to 13 | 30,613 | 40 | 2.13 | 1.45, 3.13 | 2.19 | 1.48, 3.25 |
14 to 22 | 36,990 | 35 | 2.10 | 1.40, 3.14 | 2.04 | 1.35, 3.09 |
> 22 (median 28) | 27,628 | 31 | 1.81 | 1.19, 2.76 | 1.82 | 1.19, 2.79 |