Summary of selected studies
| Authors, year (ref no) | Gender | RR or OR (95% CI) | Adjustment | Smoking rate (%) | ||||||||
| Ever smokers | Current smokers | Past smokers | Cases/controls or cohort size | Ever smokers | Current smokers | Past smokers | Study design | Study quality | Study area | |||
| Vessey et al, 19875 | Female | 1.50 (0.93 to 2.44) | 1.66 (1.00 to 2.78) | 1.15 (0.54 to 2.43) | (No) | 78/600 | 47.5 | 33.8 | 13.6 | Cohort | 5 | Europe |
| Hazes et al, 199034 | Female | 0.61 (0.42 to 0.89) | Year of birth, age at onset of symtoms, | 135/378 | 43.9 | |||||||
| parity, alcohol consumption, oral cotraceptive, | Case–control | 10 | Europe | |||||||||
| marital status, menopause | ||||||||||||
| Heliovaara et al, 200038 | Both | 512/52 809 | 47.6 | 35.6 | 12.1 | |||||||
| RF+ cases | 1.85 (1.26 to 2.70) | 1.93 (1.14 to 3.28) | 1.76 (0.92 to 3.38) | Consumption of coffee, age, BMI, serum cholesterol, sex, | ||||||||
| level of education, smoking, intake of alcohol | ||||||||||||
| Heliovaara et al, 19937 | Male | 2.04 (1.10 to 3.79) | 1.60 (0.70 to 3.80) | 1.40 (0.50 to 3.80) | Age | 161/28 364 | 69.7 | 51.1 | 18.7 | |||
| RF+ cases | 3.86 (2.71 to 5.49) | 4.31 (2.87 to 6.50) | 2.80 (1.40 to 5.60) | Cohort | 13 | Europe | ||||||
| RF− cases | 0.81 (0.49 to 1.34) | 0.66 (0.34 to 1.27) | 1.10 (0.50 to 2.40) | |||||||||
| Female | 1.06 (0.84 to 1.35) | 1.10 (0.84 to 1.44) | 0.92 (0.53 to 1.58) | Age | 351/24 445 | 22.1 | 17.7 | 4.5 | ||||
| RF+ cases | 1.04 (0.78 to 1.40) | 1.10 (0.80 to 1.52) | 0.80 (0.40 to 1.70) | |||||||||
| RF− cases | 1.10 (0.73 to 1.66) | 1.10 (0.70 to 1.80) | 1.10 (0.50 to 2.60) | |||||||||
| Voigt et al, 19948 | Female | 1.31 (1.07 to 1.60) | 1.33 (1.00 to 1.77) | 1.28 (0.96 to 1.71) | Age, BMI | 349/1457 | 50.9 | 26.0 | 24.9 | Case–control | 10 | USA |
| PY <20 | 1.49 (1.06 to 2.10) | |||||||||||
| PY >20 | 1.16 (0.90 to 1.50) | |||||||||||
| Symmons et al, 19979 | Both | 1.66 (0.95 to 3.06) | 0.95 (0.56 to 1.61) | Sex,social class | 90/93 | 54.5 | ||||||
| RF+ cases | 2.92 (0.92 to 9.21) | Case–control | 12 | Europe | ||||||||
| RF− cases | 1.20 (0.70 to 2.09) | |||||||||||
| Uhlig et al, 199911 | Both | 1.46 (1.10 to 1.94) | Age, sex, education, marital status, employment, BMI | 361/5469 | 32.9 | |||||||
| Male | 2.38 (1.45 to 3.92) | Age,education, marital status, employment, BMI | 99/2626 | 33.4 | ||||||||
| RF+ cases | 4.77 (2.09 to 10.90) | |||||||||||
| RF− cases | 1.57 (0.80 to 3.06) | Case–control | 13 | Europe | ||||||||
| Female | 1.14 (0.8 to 1.62) | Age, education, marital status, employment, BMI | 262/2843 | 32.2 | ||||||||
| RF+ cases | 0.67 (0.37 to 1.20) | |||||||||||
| RF− cases | 1.54 (0.99 to 2.39) | |||||||||||
| Karlson et al, 199910 | Female | 1.13 (1.08 to 1.18) | 1.18 (1.07 to 1.31) | 1.06 (0.96 to 1.13) | Age, race, education, age at menarche, pregnancy history, | 7697/37 7481 | 45.2 | 13.2 | 32.0 | Cohort | 13 | USA |
| menopausal status, postmenopausal HRT | ||||||||||||
| Hutchinson et al, 200112 | Both | 1.81 (1.22 to 2.19) | (Not clearly shown) | 239/239 | 58.3 | 31.8 | 26.6. | Case–control | 10 | Europe | ||
| Olsson et al, 200119 | Male | 1.97 (1.18 to 3.29) | 2.20 (1.10 to 4.20) | Age, socioeconomic status | 91/203 | 65.6 | ||||||
| RF+ cases | 2.42 (1.36 to 4.32) | |||||||||||
| PY <20 | 1.39 (0.56 to 3.44) | |||||||||||
| PY >20 | 2.70 (1.20 to 5.80) | Case–control | 12 | Europe | ||||||||
| female | 1.61 (1.06 to 2.45) | Age, socioeconomic status | 154/222 | 38.0 | ||||||||
| RF+ cases | 1.94 (1.24 to 3.01) | |||||||||||
| PY <20 | 1.57 (0.99 to 2.50) | |||||||||||
| PY >20 | 1.80 (0.70 to 4.60) | |||||||||||
| Criswell et al, 200239 | Female | 1.70 (1.02 to 2.85) | 2.20 (1.40 to 3.30) | 1.30 (0.80 to 2.00) | Age, alcohol use, coffee consumption, marital status, | 154/31 336 | 33.0 | 13.4 | 17.1 | Cohort | 13 | USA |
| PY <20 | 1.10 (0.60 to 1.80) | BMI, age at menopause, oral contraceptives, HRT | ||||||||||
| PY >20 | 1.99 (1.41 to 2.81) | |||||||||||
| Krishnan et al, 200331 | Male | 1.56 (0.95 to 2.58) | 1.20 (0.70 to 2.00) | 2.00 (1.20 to 3.20) | Age, BMI, education, HAQ index, | 318/426 | 76.5 | 19.7 | 56.8 | |||
| RF+ cases | 1.88 (1.24 to 2.86) | 1.50 (0.80 to 2.60) | 2.30 (1.30 to 3.90) | general health assessment, pain | ||||||||
| RF− cases | 1.16 (0.63 to 2.22) | 0.80 (0.30 to 1.80) | 0.90 (0.40 to 1.90) | Case–control | 12 | Europe | ||||||
| female | 0.81 (0.60 to 1.09) | 0.70 (0.40 to 1.00) | 0.90 (0.60 to 1.30) | Age, BMI, education, HAQ index, | 777/1104 | 30.6 | 11.1 | 19.5 | ||||
| RF+ cases | 0.74 (0.53 to 1.02) | 0.60 (0.30 to 1.00) | 0.80 (0.60 to 1.30) | general health assessment, pain | ||||||||
| RF− cases | 0.90 (0.63 to 1.28) | 0.84 (0.50 to 1.50) | 0.94 (0.60 to 1.50) | |||||||||
| Krishnan, 200335 | Both | 1.34 (1.00 to 1.81) | 1.42 (1.13 to 1.80) | 1.08 (0.87 to 1.34) | No | 644/1509 | 49.5 | 20.9 | 28.9 | |||
| Male | 2.29 (1.35 to 3.90) | Age, race, education, income, living alone | 203/543 | 68.3 | Case–control | 10 | USA | |||||
| Female | 0.98 (0.67 to 1.42) | Age, race, education, income, living alone | 441/946 | 39.2 | ||||||||
| Stolt et al, 200320 | Male | 1.40 (0.80 to 2.30) | 1.30 (0.70 to 2.40) | 1.40 (0.80 to 2.50) | Age, residential area | 190/245 | 74.7 | 37.0 | 37.7 | |||
| RF+ cases | 1.90 (1.00 to 3.50) | 1.80 (0.80 to 4.10) | 1.90 (0.90 to 3.80) | |||||||||
| RF− cases | 0.80 (0.40 to 1.60) | 0.70 (0.30 to 1.60) | 0.90 (0.40 to 1.90) | Case–control | 13 | Europe | ||||||
| Female | 1.30 (1.00 to 1.70) | 1.40 (1.00 to 2.00) | 1.20 (0.90 to 1.70) | Age, residential area | 489/602 | 64.4 | 33.6 | 19.1 | ||||
| RF+ cases | 1.70 (1.20 to 2.30) | 1.80 (1.30 to 2.60) | 1.60 (1.10 to 2.30) | |||||||||
| RF− cases | 0.80 (0.60 to 1.20) | 0.90 (0.50 to 1.40) | 0.80 (0.50 to 1.30) | |||||||||
| Padyukov et al, 200422 | Both | 1.50 (1.20 to 2.00) | Age(10 strata), sex, residential area | 858/1048 | 23.6 | |||||||
| RF+ cases | 2.20 (1.70 to 3.00) | |||||||||||
| RF− cases | 0.80 (0.60 to 2.20) | |||||||||||
| Male | 1.70 (1.00 to 2.90) | Age(10 strata), residential area | 246/312 | 19.7 | ||||||||
| RF+ cases | 3.30 (1.70 to 6.30) | Case–control | 13 | Europe | ||||||||
| RF− cases | 0.60 (0.30 to 1.30) | |||||||||||
| Female | 1.50 (1.10 to 2.00) | Age(10 strata), residential area | 612/736 | 25.5 | ||||||||
| RF+ cases | 2.20 (1.60 to 3.00) | |||||||||||
| RF− cases | 0.80 (0.60 to 1.30) | |||||||||||
| Olsson et al, 200421 | Male | 2.54 (1.55 to 4.16) | 2.90 (1.40 to 6.40) | 2.30 (1.20 to 4.40) | Age | 74/382 | 63.8 | 22.2 | 44.3 | Case–control | 11 | Europe |
| RF+ cases | 4.60 (2.20 to 9.60) | 5.80 (1.90 to 17.10) | 3.80 (1.40 to 10.20) | |||||||||
| PY <20 | 2.20 (1.15 to 4.22) | |||||||||||
| PY >20 | 2.50 (1.20 to 5.10) | |||||||||||
| Female | 1.52 (1.09 to 2.12) | 1.80 (1.10 to 2.90) | 1.30 (0.80 to 2.00) | Age | 159/368 | 52.8 | 19.7 | 30.8 | Case–control | 11 | Europe | |
| RF+ cases | 1.56 (1.03 to 2.36) | 1.80 (1.00 to 3.50) | 1.40 (0.80 to 2.40) | |||||||||
| PY <20 | 1.33 (0.86 to 2.04) | |||||||||||
| PY >20 | 1.60 (0.90 to 3.10) | |||||||||||
| Costenbader et al, 200637 | Female | 1.46 (1.24 to 1.71) | 1.43 (1.16 to 1.75) | 1.47 (1.24 to 1.71) | BMI, alcohol intake, father’s occupation, | 680/103 818 | 55.5 | 17.5 | 38.1 | |||
| RF+ cases | 1.59 (1.29 to 1.97) | 1.58 (1.21 to 2.06) | 1.60 (1.27 to 2.02) | age at menarche, regularity of menses, | Cohort | 14 | USA | |||||
| RF− cases | 1.28 (1.00 to 1.65) | 1.23 (0.88 to 1.70) | 1.31 (1.00 to 1.73) | duration of breastfeeding, postmenopausal HRT | ||||||||
| PY <20 | 1.19 (0.95 to 1.50) | |||||||||||
| PY >20 | 1.72 (1.41 to 2.11) | |||||||||||
| Pedersen et al, 200636 | Both | 1.70 (1.38 to 2.10) | 1.80 (1.37 to 2.36) | 1.57 (1.13 to 2.19) | Birth year, year of diagnosis | |||||||
| CCP+ cases | 1.66 (1.23 to 2.24) | 1.73 (1.17 to 2.56) | 1.57 (0.99 to 2.48) | Sex,birth year, year of diagnosis,residence area, | ||||||||
| history of urinary tract infection, maritul status, | 515/769 | 64.7 | 44.2 | 28.9 | ||||||||
| CCP− cases | 1.04 (0.65 to 1.68) | 0.83 (0.49 to 1.39) | 1.35 (0.76 to 2.39) | coffee consumption, alcohol consumption, BMI | ||||||||
| Physical activity, pets as adult, asthma, | ||||||||||||
| schizophrenia among 1st degree relatives | ||||||||||||
| Male | 1.75 (1.15 to 2.65) | 1.89 (1.09 to 3.30) | 1.58 (0.84 to 2.97) | Birth year, year of diagnosis | 149/291 | 77.0 | 50.0 | 27.0 | Case–control | 12 | Europe | |
| PY <20 | 1.63 (0.99 to 2.70) | |||||||||||
| PY >20 | 2.00 (1.12 to 3.58) | |||||||||||
| Female | 1.78 (1.38 to 2.97) | 1.84 (1.33 to 2.54) | 1.69 (1.12 to 2.55) | Birth year, year of diagnosis | 366/478 | 58.4 | 41.4 | 30.0 | ||||
| PY <20 | 1.68 (1.27 to 2.26) | |||||||||||
| PY >20 | 2.07 (1.35 to 3.16) | |||||||||||
BMI, body mass index; CCP, citrulline protein/peptide; HRT, hormone replacement therapy; OR, odds ratio; PY, pack-years smoked; RF, rheumatoid factor; RR, relative risk.