Tendencia del desarrollo puberal en escolares de la Región Metropolitana de Chile: Menor edad de presentación, mayor duración y dimorfismo sexual en la estatura

Abstract

Background: There is a worldwide tendency towards an earlier appearance of puberal development among children, associated with an increase in weight and height. Aim: To study the trends in puberal development in Chilean school age children, between the years 1986 and 2001 and correlate it with weight and height changes. Subjects and Methods: In two representative samples of school age children, collected between years 1985 and 1987 (m-1986) and another between years 2000 and 2002 (m-2001), girls between 7 and 15 years (958 and 935, respectively) and boys between 9 and 15 years (842 and 870 respectively), were selected. Breast development (B) in females and genital development (G) in males were classified according to Tanner stages. Weight, height, body mass index (BMI) and nutritional status (according to Centers for Disease Control/ National Center for Health Statistics (CDC/NCHS) standards) were assessed. Results: The prevalence of obesity increased four fold between 1986 and 2001. The 2001 generation had a significantly higher degree of puberal development than their counterparts studied in 1986. Compared to m-1986, m-2001 subjects had a lower mean age at puberal development stage 2 and 3, but no differences at puberal stages 4 and 5. BMI of m-2001 subjects was significantly higher than that of m-1986 subjects at all puberal stages. The m-2001 males showed highest stature than m-1986 in all puberal stage, however, in females there is no difference in height between m-2001 and m-1986. Conclusions: The highest BMI observed in the cohort of 2001, could be facilitating an earlier puberal development and ethnic factors could explain the sexual dimorphism in stature.