Demographics by individual at each age in the younger and older cohorts.

a<p>Participants transitioned from Tanner 1 to 2 at 10 years (n = 5), 11 years (n = 6), and 12 years (n = 5).</p>b<p>Participants transitioned from Tanner 1 to 3 at 11 years (n = 1).</p>c<p>Participants transitioned from Tanner 2 to 3 at 12 years (n = 1) and 13 years (n = 1).</p>d<p>Participants transitioned from Tanner 3 to 4 at 11 years (n = 2), 13 years (n = 1), and 15 years (n = 1).</p>e<p>Participants transitioned from Tanner 3 to 5 at 11 years (n = 2).</p>f<p>Participants transitioned from Tanner 4 to 5 at 15 years (n = 3) and 16 years (n = 1).</p><p>Notes: if more than one Morningness/Eveningness score was collected at each age, then the mean score was used; Tanner stage was unavailable for 1 participant at ages 9, 11, and 13 years, and for 2 participants at age 15 years.</p><p>Demographics by individual at each age in the younger and older cohorts.</p

Modeled developmental trajectories (bold line) and individual trajectories (thin lines) for actigraphically estimated sleep onset and offset on weekdays (A and D) and weekends (B and E) in the proximal 7 days before DLMO phase was measured in both cohorts.

<p>Sleep onset and offset differences between weekends and weekdays (C and F) illustrate when participants slept earlier (<0) or later (>0) on weekends compared to weekdays. The younger cohort (9–13 years) is on the left and the older cohort (15–19 years) is on the right of each plot.</p

Means (SDs) for actigraphic sleep and circadian outcomes by age in the younger and older cohorts.

<p>Notes: These data are from 94 participants (N = 38 in the younger cohort; N = 56 in the older cohort) who contributed on average 4.29 assessments range (1 to 6). Three observations at age 19 were included in the 18+ category.</p><p>Means (SDs) for actigraphic sleep and circadian outcomes by age in the younger and older cohorts.</p

Modeled developmental trajectories (bold line) and individual trajectories (thin lines) for DLMO phase (A), DLMO phase angle to sleep onset (B), and DLMO phase angle to sleep offset (C).

<p>A negative DLMO phase angle to sleep onset indicates when the DLMO occurred after weekday sleep onset.</p