Avaliação do Desenvolvimento Físico e Idade de Início da Puberdade em Crianças Normais na cidade de Uberaba

Abstract

It is a cross-sectional study conducted in the city of Uberaba from February 2012 to September 2013. The purpose of the survey was to understand the adequacy of physical and pubertal development of participants, age of onset of puberty in both genders, age of menarche in girls, possible correlations and associations of pubertal events among themselves and among individual variables, including those related to fathers and mothers of the participants and verify validation of the instrument used for staging puberty. A sample consisting of 1095 school 665 (60.7%) girls and 430 boys was evaluated. Obtained the weight, height and 6 skinfold measure, by physical examination. The classification of pubertal stage was performed by self-assessment by participants or their guardians through the use of photographs of the stages suggested by Marshall and Tanner for the breasts and genitals and orchidometer in ring adapted to measure testicles. The validity of self-assessment was measured by comparison with physical examination performed by an experienced endocrinologist in 35 girls and 37 boys in the study. The weighted Kappa concordance index between subject and examiner were found in boys 0.817 for pubic hair, 0.533 for genitals and 0.495 for orchidometer and between girls were 0.610 for breasts and 0.772 for pubic hair (p<0,05). As for the physical development, overweight and obesity was found in 33.8% of boys and 31.3% girls. The average age of thelarche and menarche occurred at 9.8 ± 1.4 years and11.7 ± 1.3 years, respectively . Considering the 2.5 and 97.5 percentiles, 95% of participants showed the first sign of puberty (thelarche or pubarche) in the range 7-13 years old. Among boys the average age at the G2 stage and pubarche was 11.2 ± 1.8 and 11.0 ± 1.6 years old, respectively, while 95% presented this event in the period from 8.0 to 14.0years old and the G2 stage between 9.2 and 13.4 years. The presence of obesity was associated with early onset of hair, breasts and menarche before 10 years of age. Found positive correlations on pubertal events among themselves and between pubarche age of fathers and mothers as well as menarche of mothers in the group of girls. Among boys, the same correlations were found, except in relation to their parents pubarche. However, the age of pubertal events reported by the parents was higher than age of their sons and daughters, although z scores for height, do not show differences between generations when considering the last stage of puberty participants of both genders. The findings of this research indicate a secular trend to reduce the age of menarche and earlier onset of puberty, especially in the group of girls. It was not found a secular trend of increase in stature between parents and children, but we identified high prevalence of overweight, a factor possibly associated with the onset of puberty earlier events. The knowledge of these parameters is of paramount importance for the realization of public policies aiming prevention plans on lowering the age of onset of puberty as well as attention to its consequences from the risk of teen pregnancy and infection with11 sexually transmitted diseases in an age of such vulnerability and even the increased likelihood of cancer of the reproductive system, psychosocial and metabolic disorders.