Response rates to each data collection are summarized in Supplementary Table S1 (available as Supplementary data at IJE online) and Figures 4 and 5. Attrition rates were at their greatest when the child was in infancy and are increasing again as the children enter adulthood. The response rates suggest selective participation among respondents with a larger group of ‘active’ participants than the response to any single data collection would suggest; e.g. the average response rate to the 12 measures during the ‘adolescence’ phase is 6155 (48.2% of the 12 776 eligible for follow-up during this phase); however, 9600 (75% of 12 776) individuals responded at least once during this phase (Supplementary Table S1, available as Supplementary data at IJE online).
