Table 1: Age and sex distribution of the study population and the response rate of the questionnaires.

Number of participating familiesResponse rate,
AgeTotalFemaleMaleChildrenFemaleMaleParents

8–1142251741251642
12–1510467371026537100
16–18141311312110

Total16010555156a10254152b

aOne questionnaire was broken and three parents came to the clinic without their children.
bEight adolescents visited the clinic without their parents.