Table 2

Relative risks (RRs) and 95% confidence intervals (95% CIs) for categories of pack-years of smoking
Pack-years RR (95% CI)
Never smokers 1.00
1 to 10 1.26 (1.14 to 1.39)
11 to 20 1.70 (1.44 to 2.01)
21 to 30 1.94 (1.65 to 2.27)
31 to 40 2.02 (1.44 to 2.82)
>40 2.07 (1.15 to 3.73)

Di Giuseppe et al.

Di Giuseppe et al. Arthritis Research & Therapy 2014 16:R61   doi:10.1186/ar4498

Open Data