.001), and had more parent-reported externalizing problems at baseline (0.27 ± 0.23 vs 0.23 ± 0.19, t (df = 857) = 2.54, P < .001). Table 1.Participants in the population and clinical cohort of TRAILS across the data collection wavesWavePopulation cohortClinical cohortN (retention ratea)Mean age, years (SD)% femalesN (retention ratea)Mean age, years (SD)% females1223011.1 (0.6)51%54311.1 (0.5)34%22149 (96%)13.6 (0.5)51%462 (85%)12.8 (0.6)34%31816 (81%)16.3 (0.7)52%419 (77%)15.9 (0.7)34%41881 (84%)19.1 (0.6)52%422 (78%)19.1 (0.7)34%51778 (80%)22.3 (0.6)53%aRetention rate refers to the proportion of the baseline sample participating in each subsequent wave.
