TABLE 1

BCERP Puberty Study Population Characteristics

CharacteristicNew York CityCincinnatiSan Francisco Bay AreaTotal Study Population
n%n%n%n%
Total no. of participants4163437931444361239100
Age group at enrollment
 6.0–6.9 y1543715441882039632
 7.0–7.9 y13633187493347565753
 ≥8.0 y12630381022518615
Mean age at enrollment, (y)7.4 (0.9)7.1 (0.6)7.4 (0.4)7.3 (0.7)
Mean age at end of follow-up, (y)11.2 (2.2)11.5 (1.9)12.0 (1.4)11.6 (1.9)
Mean length of follow-up, (y)3.8 (2.1)4.4 (1.8)4.6 (1.3)4.3 (1.8)
Race/Ethnicitya
 Black1684012734962239132
 Asian00515212575
 Hispanic248601541082437130
 White00232611884242034
Education of family provider
 Grade School (1-8), Some High School (9-11) or High School Diploma/GED232583510832035031
 Some College/technical/trade/vocational school or associate’s degree11429119351363436932
 Bachelor’s degree3910106311283227324
 Master’s degree or greater1338424551415213
BMI% group at enrollmentb
 >95th97235214671521617
 85th–94.9th66166216651519316
 50th–84.9th13532122321633742034
 <50th11628143381493440833
 No BMI data20000020
Median BMI percentile at enrollmentc74.464.069.170.1
BMI% group during follow-upd,e
 >95th102255815671522718.3
 85th–94.9th64156918721620516.5
 50th–84.9th12831112301543539431.8
 <50th12029140371513441133.2
 No BMI data20000020.2
Median BMI% during follow-upd
 All girlsf76.365.866.470.9
 Girls at/above the 85th percentile onlyg96.594.294.895.3
 Girls below the 85th percentile onlyh52.744.950.148.7
Thelarche
 Breast stage 2+ at enrollment90225515337%17814
 Breast stage 2+ observed during study244592787335981%88171
 Not attained breast stage 2+ by end of follow-up822046125212%18015
  • a Racial distributions were significantly different across sites (P < .0001).

  • b BMI percentile groups were significantly different across sites (P = .0021); Greater Cincinnati (P = .0013) and the San Francisco Bay Area (P = .0107) were significantly different from New York City, but not each other (P = .4125).

  • c Median BMI at enrollment in Cincinnati was significantly lower than New York City (P = .0095), but not the San Francisco Bay Area (P = .3095); New York City and the San Francisco Bay Area were not significantly different (P = .1013).

  • d For girls who were breast stage 2+ at enrollment, BMI% during follow-up is BMI% at enrollment. For girls in whom breast stage 2+ was first observed during the study, BMI% during follow-up is the BMI% at the last exam with data before thelarche. For girls who had not attained breast stage 2+ by the end of follow-up, BMI% during follow-up is the BMI% at their last exam.

  • e Distribution of BMI percentile groups for all girls at end of follow-up were significantly different across sites (P = .0021); Greater Cincinnati (P = .0039) and the San Francisco Bay Area (P = .0055) were significantly different from New York City, but not each other (P = .4502).

  • f Median BMI percentile for all girls at end of follow-up in New York City was significantly higher than Cincinnati (P = .0062), and the San Francisco Bay Area (P = .0041); Cincinnati and the San Francisco Bay Area were not significantly different (P = .9699).

  • g Median BMI percentile for girls at/above the 85th percentile at end of follow-up in New York City was significantly higher than Cincinnati (P = .0018), but not the San Francisco Bay Area (P = .0576); Cincinnati and the San Francisco Bay Area were not significantly different (P = .7132).

  • h Median BMI percentile for girls below the 85th percentile at end of follow-up were not significantly different across sites (.0669 ≤ P ≤ .5817).