Factors associated with post-menarcheal growth: results of a longitudinal study in Chilean girls from different socioeconomic statuses.

Background: Menarche is the last stage of pubertal development, which coincides, with the completion of longitudinal growth. Our aim was to evaluate, post-menarcheal growth and clinical variables proposed to be associated with this growth.

Methods: In a prospective fashion, 106 healthy girls attending five different socioeconomic status (SES) schools of Santiago were randomly recruited. A pediatric endocrinologist obtained anthropometrics and registration of date at menarche every 6 months. The evolution of the girls' heights was assessed through mixed models adjusted to the SESes, parental height and body mass index (BMI).

Results: Sixty-three girls from a high socioeconomic status (HSS) and 50 from a low socioeconomic status (LSS) were followed. Four years post menarche, the girls reached a growth plateau and the average height gain was 5.2±2.5 cm. This gain was not associated with SES, BMI, nor with parental height (p=0.744). The only variable that modulated this gain was age at menarche (r=-0.1997, p=0.0332). There was an inverse correlation between height at the moment of menarche and the height reached after 4 years of follow-up adjusted to parental height (r=-0302, p=0.0011).

Conclusions: Post-menarcheal growth ends 4 years post-event and is inversely correlated with the age at menarche and with the height at the moment of menarche independent of BMI, parental height and SES.