Table 3: Bivariate analysis of continuous variables.

Characteristic RA with AITD RA without AITD P Mean ± SD Mean ± SD Age 52.26 ± 12.39 51.88 ± 12.24 0.029 Median ± IQR Median ± IQR Educational level (y) 14 ± 7 11 ± 9 0.006 Body mass index 25.5 ± 6.3 23.9 ± 5.9 0.006

AITD: autoimmune thyroid disease; IQR: interquartile range; RA: rheumatoid arthritis; SD: standard deviation.