TABLE 5.
Regression to predict Pubertal Development Trajectory Class based on HAZ and BMIZ at ages 5 and 8 y by sex, Birth-to-Twenty study1
| Age 5 y |
Age 8 y |
|||||||
| Girls (n = 808) |
Boys (n = 734) |
Girls (n = 526) |
Boys (n = 500) |
|||||
| Adjusted RRR2 | 95% CI | Adjusted RRR2 | 95% CI | Adjusted RRR3 | 95% CI | Adjusted RRR3 | 95% CI | |
| HAZ | ||||||||
| Pubic hair4 | ||||||||
| Class 3 vs. class 1 | 1.57 | (1.22, 2.03) | 1.78 | (1.35, 2.34) | 1.03 | (0.57, 1.86) | 1.57 | (0.80, 3.07) |
| Class 2 vs. class 1 | 1.34 | (1.13, 1.59) | 1.32 | (1.10, 1.60) | 0.93 | (0.65, 1.34) | 1.07 | (0.68, 1.67) |
| Breast/genital5 | ||||||||
| Class 4 vs. class 1 | 1.78 | (1.37, 2.33) | 2.19 | (1.41, 3.40) | 0.95 | (0.52, 1.74) | 1.99 | (0.62, 6.37) |
| Class 3 vs. class 1 | 1.39 | (1.13, 1.72) | 1.68 | (1.19, 2.38) | 0.83 | (0.52, 1.32) | 1.24 | (0.51, 3.05) |
| Class 2 vs. class 1 | 0.97 | (0.77, 1.22) | 1.28 | (0.90, 1.81) | 0.74 | (0.46, 1.20) | 0.68 | (0.28, 1.66) |
| BMIZ | ||||||||
| Pubic hair4 | ||||||||
| Class 3 vs. class 1 | 1.51 | (1.17, 1.96) | 1.43 | (1.11, 1.85) | 2.06 | (1.10, 3.87) | 1.00 | (0.56, 1.79) |
| Class 2 vs. class 1 | 1.09 | (0.91, 1.30) | 1.15 | (0.96, 1.37) | 1.58 | (1.06, 2.34) | 0.70 | (0.46, 1.05) |
| Breast/genital5 | ||||||||
| Class 4 vs. class 1 | 1.65 | (1.25, 2.17) | 1.49 | (0.99, 2.26) | 3.35 | (1.74, 6.46) | 1.40 | (0.50, 3.94) |
| Class 3 vs. class 1 | 1.25 | (1.01, 1.55) | 1.19 | (0.85, 1.66) | 2.56 | (1.52, 4.33) | 1.56 | (0.68, 3.56) |
| Class 2 vs. class 1 | 1.00 | (0.79, 1.27) | 1.31 | (0.93, 1.85) | 1.75 | (1.03, 2.97) | 1.48 | (0.64, 3.41) |
Higher class numbers represent children who were at a more advanced stage of pubertal development by age 16 y, either because they started out at a more advanced stage at age 9 y, or because they progressed through pubertal development more quickly (or both). BMIZ, BMI-for-age z score; HAZ, height-for-age z score; RRR, relative risk ratio.
Adjusted for ethnicity and quintiles of maternal monthly income. BMIZ at age 5 y is adjusted for HAZ at age 5 y.
Adjusted for HAZ and BMIZ at age 5 y, ethnicity, and quintiles of maternal monthly income. HAZ at age 8 y is included in the model as the residual produced when HAZ at age 8 y is regressed on HAZ at age 5 y. BMIZ at age 8 y is included in the model as the residual produced when BMIZ at age 8 y is regressed on BMIZ at age 5 y.
Multinomial logistic regression with the outcome being the growth trajectory groups for pubic hair development.
Multinomial logistic regression with the outcome being the growth trajectory groups for breast development in girls and genital development in boys.