Table 3. Seroprevalence of HBsAg among first-time blood donors according to their socio-demographic characteristics

Independent variables	N	HBsAg (+)	Univariate COR (95% CI)	p-value1)
Sex
Females	862	16 (1.95)	Reference	0.006
Males	776	34 (4.39)	2.31 (1.27–4.23)
Ethnic group
The Kinh	1,546	49 (3.25)	Reference
Other	92	1 (1.15)	0.35 (0.05–2.54)	0.297
Age group
18–24	769	10 (1.34)	Reference
25–35	536	24 (4.58)	3.53 (1.67–7.44)	0.001
36–44	218	12 (5.58)	4.34 (1.85–10.20)	0.001
45–60	115	4 (3.57)	2.72 (0.84–8.83)	0.095
Occupation
Student	511	4 (0.82)	Reference
Officer	331	9 (2.80)	3.49 (1.07–11.44)	0.039
Police – Military	75	1 (1.35)	1.66 (0.18–15.10)	0.651
Worker – Farmer	386	21 (5.53)	7.11 (2.42–20.88)	<0.001
Self-employed – others	335	15 (4.55)	5.79 (1.90–17.59)	0.002

Logistic regression.
COR, crude odds ratio.