Table 1: Baseline characteristics of participants of the Swedish Mammography Cohort with or without RA diagnosis between 1997 and 2009.

Characteristics
(1997)
RA
(n=191)
No RA
(n=21,411)
p value1

Age (yrs), mean ± SD59 ± 759 ± 8N.S.
BMI (Kg/m2), mean ± SD24.5 ± 3.625.0 ± 3.8N.S.
Alcohol (g/day), mean ± SD4.9 ± 5.24.8 ±5.2N.S.
Smoking, %<0.001
 (i) Never33.952.8
 (ii) Former31.725.5
 (iii) Current34.421.7
Education, %N.S.
 (i) Less than high school33.034.8
 (ii) High school46.141.6
 (iii) University20.923.6

BMI: body mass index; N.S.: not significant; RA: rheumatoid arthritis; SD: standard deviation.
1The significance level is 0.05.