Age group (years) | Sample size (n), N=70 | No of observations | APHV (median, range) | Time to APHV (median, range) |

Girls (10–12) | 10 | 10 | 11.7 (10.7–12.5) | 0.15 (−0.6–0.6) |

Girls (13–15) | 17 | 17 | 12.5 (12.0 –13.3) | 2.3 (0.9–2.3) |

Girls (16–18) | 10 | 5 | 12.8 (12.5–13.8) | 3.7 (3.1–4.0) |

Boys (10–12) | 12 | 1 | – | – |

Boys (13–15) | 12 | 12 | 13.6 (12.5–14.8) | 0.75 (−0.8–2.5) |

Boys (16–18) | 9 | 9 | 14.4 (12.9 –15.1) | 3.1 (2.2–3.7) |