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.
