Table 4.
Among past smokers (reference: 0 to <5 years since quitting), hazard ratios for rheumatoid arthritis serologic phenotypes by smoking status and years since cessation.
| Past, quit ≥30 years ago | Past, quit 20 to <30 years ago | Past, quit 10 to <20 years ago | Past, quit 5 to <10 years ago | Past, quit 0 to <5 years ago | |
|---|---|---|---|---|---|
| HR (95%CI) | HR (95%CI) | HR (95%CI) | HR (95%CI) | HR (95%CI) | |
| All RA | |||||
| Cases/person-years | 123/397,373 | 129/445,185 | 160/551,108 | 90/262,059 | 94/282,440 |
| Age-adjusted model | 0.75(0.56,1.00) | 0.75(0.57,0.99) | 0.86(0.67,1.12) | 1.09(0.81,1.46) | 1.00 (Ref) |
| Multivariable model* | 0.78(0.58,1.05) | 0.78(0.59,1.02) | 0.88(0.68,1.14) | 1.09(0.81,1.46) | 1.00 (Ref) |
| Seropositive RA | |||||
| Cases/person-years | 77/396,579 | 82/443,916 | 99/549,283 | 58/261,118 | 69/281,311 |
| Age-adjusted model | 0.62(0.44,0.88) | 0.62(0.45,0.86) | 0.72(0.53,0.98) | 0.93(0.65,1.32) | 1.00 (Ref) |
| Multivariable model* | 0.63(0.44,0.90) | 0.63(0.45,0.88) | 0.73(0.53,0.99) | 0.91(0.64,1.30) | 1.00 (Ref) |
| Seronegative RA | |||||
| Cases/person-years | 46/396,731 | 47/443,877 | 61/549,236 | 32/261,042 | 25/281,204 |
| Age-adjusted model | 1.11(0.66,1.86) | 1.12(0.68,1.83) | 1.27(0.79,2.04) | 1.54(0.91,2.62) | 1.00 (Ref) |
| Multivariable model* | 1.20(0.71,2.02) | 1.17(0.71,1.93) | 1.30(0.81,2.09) | 1.57(0.92,2.66) | 1.00 (Ref) |
*
Multivariable models were adjusted for age, questionnaire period, cohort, oral contraceptive use (ever, never), parity/breastfeeding in months (nulliparous, parous/<1 month, parous/1–11 months, parous/≥12 months), menopausal status/postmenopausal hormone use (premenopausal, postmenopausal/never, postmenopausal/ever), body mass index category (underweight/normal, overweight, obese), sedentary physical activity, median household income (quartiles), alcohol intake (none/<5 g/day, 5 to <10 g/day, ≥10 g/day).