Table 1 Flow of participants

1993

1198

Random sample (4–18 y)

19

Did not fulfill inclusion criteria

113

Incorrect address provided

1066

Eligible

2003

1066

Target sample (14–28 y)

Loss to follow-up (9% of 1066)

72

Tracing unsuccessful

2

Deceased

18

Moved out of region

974

Approached (91% of 1066)

6

Did not meet inclusion criteria

968

Eligible

Non-response

168

Refusal

97

Unreachable ^a

64

Incorrect address

18

Other reasons

621

Respondents (14–28 y) (64% of 968)

184

14–17 years old

437

Respondents (18–28 y)