Table 2.
Hazard ratios for rheumatoid arthritis serologic phenotypes by smoking status and intensity.
| Never | Past | Current, 1–14 cigarettes/day | Current, 15–24 cigarettes/day | Current, ≥25 cigarettes/day | |
|---|---|---|---|---|---|
| HR (95%CI) | HR (95%CI) | HR (95%CI) | HR (95%CI) | HR (95%CI) | |
| All RA | |||||
| Cases/person-years | 675/3,262,927 | 597/1,946,910 | 80/316,907 | 111/330,369 | 65/180,038 |
| Age-adjusted model | 1.00 (Ref) | 1.35(1.20,1.51) | 1.19(0.94,1.50) | 1.58(1.28,1.94) | 1.69(1.30,2.19) |
| Multivariable model* | 1.00 (Ref) | 1.36(1.21,1.53) | 1.23(0.97,1.55) | 1.60(1.30,1.97) | 1.69(1.30,2.20) |
| Seropositive RA | |||||
| Cases/person-years | 415/3,254,327 | 386/1,940,936 | 52/315,778 | 73/329,167 | 43/179,214 |
| Age-adjusted model | 1.00 (Ref) | 1.44(1.25,1.66) | 1.29(0.97,1.73) | 1.75(1.35,2.25) | 1.86(1.35,2.58) |
| Multivariable model* | 1.00 (Ref) | 1.48(1.28,1.71) | 1.36(1.01,1.82) | 1.80(1.39,2.34) | 1.92(1.39,2.66) |
| Seronegative RA | |||||
| Cases/person-years | 260/3,254,901 | 211/1,940,814 | 28/315,756 | 38/328,645 | 22/178,974 |
| Age-adjusted model | 1.00 (Ref) | 1.20(1.00,1.44) | 1.03(0.70,1.53) | 1.32(0.94,1.88) | 1.42(0.91,2.21) |
| Multivariable model* | 1.00 (Ref) | 1.18(0.98,1.43) | 1.03(0.69,1.53) | 1.31(0.92,1.86) | 1.36(0.86,2.12) |
*
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).