Changes to sleep-wake behaviors are associated with trajectories of pubertal timing and tempo of secondary sex characteristics.

We examined relations between sleep-wake behaviors and pubertal development from age 8.5 through 15.5 years in a US-based sample of 488 boys (75% White) and 478 girls (78% White). Applying conditional nonlinear growth models to 7-waves of longitudinal data, we examined how sleep-wake behaviors are related to individual differences in the developmental timing and tempo of secondary sex characteristics. For girls, results supported the hypothesis that circadian changes in bedtimes, wake times, sleep duration, and eveningness preference were uniquely related to development of discrete aspects of secondary sex characteristics. For boys, the hypothesis was generally not supported. Different endocrine systems related to discrete secondary sex characteristics may be responsible for more relations between sleep and pubic hair development than for breast or genital development. Further research into associations between adrenarche and sleep during puberty may help researchers understand more about the origins and timing of adolescent sleep changes. [ABSTRACT FROM AUTHOR]