Body mass index a strong predictor of early puberty

US researchers monitored 1239 girls aged 6–8 years at enrolment from 2004–11 and found the median onset of stage 2 breast development was 8.8, 9.3, 9.7 and 9.7 years for African American, Hispanic, white non-Hispanic and Asian participants respectively.

Body mass index was a stronger predictor of early puberty than race or ethnicity.

The authors said the age of breast development across all groups was younger than in similar studies conducted 10 and 20 years ago,