Table 2.

General characteristics of the study population.

	Northern Italy	Southern Italy	p-value
N	1,290	774
Sex			0.317
Females	800 (62.0)	497 (64.21)
Males	490 (38.0)	277 (35.79)
Age, years	15.3 ± 2.2	15.7 ± 1.8	0.0001
Age groups			<0.0001
11–13 years	287 (22.2)	87 (11.2)
14–19 years	1,003 (77.8)	687 (88.8)
School			<0.0001
Professional institute	158 (12.2)	222 (28.7)	<0.0001
Technical institute	144 (11.2)	124 (16.0)	0.01
High school-liceo	660 (51.2)	325 (42.0)	<0.0001
Middle school	328 (25.4)	103 (13.3)	<0.0001

Percentages in parentheses.