Follow-up interviews for waves 3 (2001–02; response rate 77.4%) and 4 (2008–09; response rate 80.3%) were conducted with individuals who had participated in wave 1, leaving 12,288 participants who had sampling weight information.
Inverse probability weights for continuing in the study in wave 4 were calculated for all participants conditioned on their participation in wave 3. We created a binary variable for dropping out, D4, in wave 4. If the participant dropped out in wave 4 but participated in wave 3, then D4 = 1, and if they didn't dropout then D4 = 0.
Of these, 8,688 people participated in wave 2 (82%) and 7,433 participants were willing to have a nurse visit.
HCSUS participants were eligible for this follow-up study if they participated in HCSUS' wave 3 and a 1997 1998 follow-up survey [ 23], had a child ≤23 years on 3/1/04, and had seen ≥1 of their children in the past month when they were contacted for participation.
Due to missing contact information, 2550 out of 3302 pupils who participated in wave 3 were invited to participate and 2237 pupils (87.7 %) participated in the follow-up.
Overall, 10,770 participated in wave 1 (response rate 65.7%).
Despite the response rate in wave 1 being quite low, more than 75% of those who participated in wave 1 also participated in wave 3.
The present sample consists of adolescent twins who participated in wave 2 of the G1219 study—a longitudinal study of twins and their families.
For the respondents who had stopped drinking at wave 0 and participated in wave 5, there was a modest reduction in the level of poor self-rated health at wave 5.
First, we limited to females who participated in Wave IV, as that was the Wave when all respondents had completed their teenage years and had complete teen pregnancy data.
