Cambios en la edad de inicio de la pubertad en niñas de la comuna de Santiago: Implicancias para el diagnóstico de la pubertad precoz

Abstract

Introduction : recent evidence suggests that the onset of puberty among girls is occurring earlier than previously considered in the northern hemisphere. However, this observation might not be applicable to populations of different ethnic origins, such as Chilean children. Objective : to determine the age of onset of puberty in boys and girls attending 3 primary schools in downtown Santiago. The criteria for the determination of puberal development was the prescence of palpable mammary tissue in girls, and a testicular volume of at least 4 ml in boys. Only children with a MBI between the 10th and 95th percentile were analyzed. Subjects and methods : of 332 children recruited, 80 (24%) were excluded because their BMI was above the 95th percentile. Of the remaining 252, 131 were girls. Among girls aged 7 to 7.49 yrs 10% (2/20) had palpable breast tissue, aged 7.5-7.99 25% (4/16), aged 8-8.99 25% (9/36). Among boys the first signs of testicular growth were observed between 9 and 9.49 years as previously described. Conclusion : the onset of puberty among this group of Chilean girls occurs earlier than in the classical literature, but there was no difference in boys. These results suggest that the development of breast tissue in girls between the ages of 7 and 8 years should not be considered necessarily pathological and that the definition of precocious puberty should be re-evaluated.