[Assessment of the secular trend in puberty in boys and girls]

Objective: Changes in the onset of puberty have been reported in the last few years. The aim of this study is to determine pubertal trends in boys and girls.

Method: Longitudinal study was conducted on 310 caucasian children. We analysed birth weight (BW), weight (kg), height (cm) and body mass index (BMI) (%), bone age, duration of puberty growth and pubertal height spurt.

Results: For boys the mean age at stage 2 was 12.4 (1.5) years with a bone age of 11.9 (1.3) years, and stage 5: 15.6 (1.5) with a bone age of 14.5. Mean age (years) (SD) for girls stage 2 was 10.1 (1.4), with a bone age of 10.3 (1.1). Age at menarche was 12.0 (1.3), with a bone age of 13.2 (0.9). Duration of puberty growth for boys was 3 years (1.2), and for girls 2.5 years (1.1). Pubertal height spurt in boys was 19.5cm (7.6) and for girls was 15.7cm (5.0). Girls with puberty onset<9 years of age show a greater pubertal height gain (19.7cm (4.3)) than girls >9 years of age [14.4 (4.5) (P<0.0001)] and a longer period of pubertal growth 3.1 years (0.8) versus 2.3 (0.9) (P<0.0001). Boys with puberty onset <11 years of age had a greater pubertal height gain [27.3cm (7.9)] than boys > 11 years of age [17.4 (5.9) (P<0.0001)] and a longer period of puberty growth of 3.9 years (1.2) versus 2.7 (1.1) (P<0.001).

Conclusions: Boys presented secondary sex characteristics at the same age as other studies, but the girls reached puberty and menarche at a younger age than previous studies in the Mediterranean area. Bone age correlates with chronological age for both sexes at the beginning of puberty but not at the end. Early onset of puberty was associated with a greater pubertal height gain and a longer period of pubertal growth. There was no correlation between BW or BMI with onset of puberty.