Syndromes

Control

N = 43

Welders

N = 32

p

Proximal obstruction n (%)

1 (2.32)

5 (15.62)

0.09

Distal obstruction n (%)

0 (0)

8 (25)

0.001

Central Obstruction n (%)

0 (0)

12 (37.5)

4.8 × 10⁻⁵

Restriction n (%)

0 (0)

6 (18.75)

0.01