Table 1.

Baseline characteristics of the study population

Characteristic	N = 2200 (%)
Age (median) years	43 [18–87]
Sexe
Male	886 (40.3)
Female	1314 (59.7)
Occupation
Unemployed	1247 (56.7)
Working class	508 (23.1)
Farmers	103 (4.7)
Middle/senior management	125 (5.7)
Retired	217 (9.9)
Risk factors
Past surgery	619 (28.1)
Endoscopy	584 (27.5)
Using drugs	13 (0.6)
Intravenously	1 (0.0)
Nasal way	12 (0.6)
Tatoo	216 (10.0)
Piercing	95 (4.4)
Shaving hair or beard	352 (16.3)
Unknown	321 (14.6)