Table 3

Adjusted odds ratios for developing rheumatoid arthritis according to smoking and rheumatoid factor status in men

Number of observations entering the multivariable model

Parameter

RA cases

Controls

Odds ratio* (95% CI)

All RA

Current smoking

306

418

1.2 (0.7–2.0)

Past smoking

234

306

2.0 (1.2–3.2)

RF-positive RA

Current smoking

181

418

1.5 (0.8–2.6)

Past smoking

140

306

2.3 (1.3–3.9)

RF-negative RA

Current smoking

125

418

0.8 (0.3–1.8)

Past smoking

94

306

1.5 (0.7–3.0)

*Odds ratios are expressed as the expected probability of having rheumatoid arthritis (RA) as compared with those who did not smoke. The confounders adjusted for in the multivariable logistic regression models included age, body mass index, number of years of education, Health Assessment Questionnaire disability index, general health assessment, and pain. CI, confidence interval.

Krishnan et al. Arthritis Res Ther 2003 5:R158   doi:10.1186/ar750