Onset of puberty at eight years of age in girls determines a specific tempo of puberty but does not affect adult height

Aims: To analyse the effect of early puberty (onset between 7.5 and 8.5 y) on pubertal growth and adult height in girls, and the implications of this effect for the age limit for normal onset of puberty. Methods: Longitudinal study in Reus (Spain) of 32 girls with early puberty until they reached adult height. Data from these girls were compared with longitudinal data from girls (116) from the same population with normal onset at 10 (n = 37), 11 (n = 47), 12 (n = 19) and 13 (n = 13) y. We analysed height, target height, adult height, pubertal height increase, duration of pubertal growth, age at menarche and time to menarche. Results: The adult height of girls with early puberty (160.9 5.4 cm) was similar to that of girls with onset at later ages (p = not significant). In these girls, puberty lasted 5.4 0.7 y and the mean growth during puberty was 31.1 3.5 cm. As the age of onset of puberty increases, the duration of puberty and mean growth during puberty progressively decreased (p < 0.001). Girls with early puberty reached menarche at a mean age of 10.9 1.0 y, 3.2 0.9 y after onset of puberty, and this time span was greater than in the other groups. Conclusion: Girls with onset of puberty at 8 y show all the compensatory phenomena related to height at onset, pubertal duration and height increase during puberty. These phenomena cause their adult height to be similar to that of girls who begin puberty at the age of 10 to 13 y

Body fat at pubertal genital stage 2: A comparison between Spanish and Mexican boys

Background/Objectives: To compare body fat mass at the same stage of pubertal maturation, genital stage 2 (G2), in a Spanish and in a Mexican sample of boys. Subjects/Methods: Data from Spain (n = 177) were from aprevious longitudinal clinical follow-up and data from Mexico (n = 91) from a cross-sectional study. Subjects were grouped according to the presence of G2 at similar ages. Spanish sample was divided into boys with G2 at age 12 (n = 60), 13 (n = 74) and 14 (n = 43). In Mexican sample, 23 boys were at G2 at 12 years, 38 at age 13 and 30 at 14 years. Height, weight, upper arm circumference and four skinfold thicknesses were recorded. Genital development was assessed (Tanner scale). Sum of four skinfolds (SUM), body mass index (BMI), percentage of body fat (%BF) and extremity/ trunk skinfold ratio (ETR = (triceps+biceps)/(subscapular+suprailiac)) was calculated. Results: When comparing subjects with different ages at G2 from the same country, or with the same age at G2 from different countries, no significant differences were found in adiposity variables (%BF, SUM), nor in BMI. Nevertheless, there were differences in body fat distribution: ETR was higher in Spanish boys (P < 0.001), because of their greater triceps skinfold thickness (P = 0.013), and due to the greater trunk fat stores in Mexican boys (P < 0.01, subscapular and suprailiac skinfolds). Conclusions: There is a subcutaneous fat mass store characteristic of G2 in boys, which is not only independent of age, but is also observable in two different populations