Table 1

 Participation by wave of data collection

n
Baseline
    Successfully contacted116
    Number eligible104
    Number ineligible8
    Refused4
    Both interview and saliva sample68
    Both interview and saliva sample (<15 ng/ml)53
    Both interview and saliva sample (>15 ng/ml)15
3 month follow up
    Successfully contacted (out of 68 from baseline)65
    Number eligible54
    Number ineligible9
    Refused2
    Both interview and saliva sample47
    Both interview and saliva sample (<15 ng/ml)41
    Both interview and saliva sample (>15 ng/ml)6
6 month follow up
    Successfully contacted (out of 68 from baseline)42
    Number eligible38
    Number ineligible4
    Refused0
    Both interview and saliva sample38
    Both interview and saliva sample (<15 ng/ml)35
    Both interview and saliva sample (>15 ng/ml)3
12 month follow up
    Successfully contacted (out of 68 from baseline)36
    Number eligible35
    Number ineligible1
    Refused0
    Both interview and saliva sample32
    Both interview and saliva sample (<15 ng/ml)29
    Both interview and saliva sample (>15 ng/ml)3
Completed all interviews and saliva samples30
    Completed all interviews and saliva samples (<15 ng/ml)24
    Completed all interviews and saliva samples (>15 ng/ml)6