Table 1.

Demographic characteristics of study participants.

Variable	Category	Frequency	Percentage (95%CI)
Sex	Male	179	46.0 (40.6–50.9)
	Female	210	54.0 (49.1–59.4)
Age group	6–9 years	165	42.4 (37.3–47.3)
	10–12 years	169	43.5 (38.6–48.6)
	13–15 years	55	14.1 (10.8–18.0)
School	Mbaju	78	20.1 (15.9–23.7)
	Chigugu	78	20.1 (16.5–24.2)
	Mbemba	77	19.8 (15.9–24.2)
	Lukuledi	78	20.1 (16.2–23.9)
	Mkululu	78	20.1 (16.2–24.2)
Class	I	65	16.7 (12.9–20.3)
	II	64	16.5 (12.6–20.1)
	III	65	16.7 (13.1–20.6)
	IV	65	16.7 (13.1–20.6)
	V	65	16.7 (13.1–20.6)
	VI	65	16.7 (13.1–20.8)