Associations of Relative Pubertal Timing and Pubertal Tempo with Body Mass Index in a Sample of Youth Adopted at Birth

Abstract

Most research on puberty has focused on pubertal timing and its correlates. Less research has examined how timing and tempo relate to each other despite how both relate to health outcomes. We examined timing (relative to same-age/sex-peers) and tempo with each other and body-mass-index (BMI) during adolescence. Data came the Early Growth and Development Study, a sample of youth adopted-at-birth (N=361;57% male). We present correlations between timing and tempo from youth self-reported puberty using the Pubertal Development Scale at age 9, 11, and 15, and BMI at 7, 9, and 15 for girls and boys separately. For girls and boys, earlier timing at 9 was associated with earlier timing at 11 (r=.20-.22), but neither was associated with timing at 15. Tempo between 9-15 was associated with tempo from 9-11 and 11-15 (r=.32-.56). Tempo from 9-11 was negatively associated with tempo from 11-15 (r=-.47to-.72). Earlier timing at 9 was associated with slower tempo at all timepoints (r=-.24to-.85). Earlier timing at 11 was associated with slower tempo between 11-15 (r=-.66to-.86), but faster tempo between 9-11. Earlier timing at 15 was associated with faster tempo between 11-15 and 9-15 (r=.21-.77). In boys, higher BMI at 7 was associated with earlier timing at 11 and slower tempo 9-15 (r=.20;r=-.28). There was stability in timing early in adolescence, moderate-high associations of tempo, differential associations between timing and tempo, and sparse associations of BMI and puberty.