HRs (95% CIs) for incident rheumatoid arthritis according to passive smoking in adulthood, overall and after stratified by ever-smoking status among women in the E3N cohort (N=79 806)
| Cases, no/person-years, no | Model 1 HR (95% CI) | Model 2 HR (95% CI) | |
| All population (N=79 806) | |||
| Passive smoking in adulthood | |||
| No | 297/878 178 | Reference | Reference |
| Yes | 401/1 019 405 | 1.24 (1.07 to 1.44) | 1.19 (1.02 to 1.40) |
| P value | 0.005 | 0.025 | |
| Never smokers (N=43 170) | |||
| Passive smoking in adulthood | |||
| No | 175/553 281 | Reference | Reference |
| Yes | 175/472 481 | 1.26 (1.02 to 1.56) | 1.27 (1.02 to 1.57) |
| P value | 0.032 | 0.029 | |
| Ever smokers (N=36 636) | |||
| Passive smoking in adulthood | |||
| No | 122/324 897 | Reference | Reference |
| Yes | 226/546 923 | 1.15 (0.92 to 1.43) | 1.16 (0.93 to 1.44) |
| P value | 0.22 | 0.20 | |
| All population (N=79 806) | |||
| Never smoker, no passive smoking in adulthood | 175/553 281 | Reference | Reference |
| Never smoker, passive smoking in adulthood | 175/472 481 | 1.25 (1.01 to 1.54) | 1.24 (1.00 to 1.53) |
| Ever smoker, no passive smoking in adulthood | 122/324 897 | 1.24 (0.99 to 1.57) | 1.26 (1.00 to 1.59) |
| Ever smoker, passive smoking in adulthood | 226/546 923 | 1.45 (1.18 to 1.76) | 1.46 (1.20 to 1.79) |
Model 1: adjusted for age (as the timescale).
Model 2: adjusted for age (as the timescale), active smoking status (current smoker, non-smoker, former smoker, except for stratified and combined analyses), passive smoking in childhood, body mass index (kg/m²) (<18.5 kg/m², 18.5–25 kg/m², 25–30 kg/m², ≥30 kg/m²), and educational level (<high school, up to two-level university, three/four-level university).
P for interaction between smoking status and passive smoking during adulthood=0.40.
E3N, Etude Epidémiologique auprès des femmes de la Mutuelle générale de l’Education Nationale.