Table 1 Characteristics of inflammatory bowel disease patients and controls in the case-control study

Total (n)^b

1392

1392

–

Male (n)

634

658

0.362

Age (years)^b

37.0 ± 5.8

36.7 ± 5.8

0.454

BMI (kg/m²)^a

23.2 ± 4.3

22.4 ± 4.3

< 0.001

History of smoking (n)

604

296

< 0.001

History of drinking (n)

410

395

0.531

History of iodized salt intaking (n)

754

708

0.081

History of radiation exposure (n)

251

14

< 0.001

History of benign thyroid nodule (n)

1064

570

< 0.001

Family history of TC (n)^a

135

22

< 0.001

Age at diagnosis of IBD (years)^a

26.9 ± 6.3

–

–

Duration of IBD on admission (years)

10.1 ± 2.8

–

–

Extraintestinal manifestations (n)

708

–

–

5-ASA treatment (n)^a

1334

–

–

PTC development (n)^a

11

3

0.032