Forty years ago, Frisch and Revelle [38] put forward the “critical weight” hypothesis suggesting that a minimum weight (48 kg) or body fat (22%) should be attained to trigger the complex series of events leading to the development of secondary sexual features. More recently, some but not all epidemiologic

studies from the United States of America [39] indicated that the secular trend of earlier puberty in girls would coincide with the progressing prevalence of overweight and obesity in children [40, 41]. Nevertheless, when this association was found, the question remained whether earlier pubertal timing was the result or cause of higher body fat [42]. Among putative nutrition or fat mass-related mediators, leptin was specially taken into account. From the analysis of experimental and clinical evidence, it

emerges that leptin could not be considered as a critical factor Selleckchem Sotrastaurin [43] that would determine the wide interindividual variability in pubertal timing, as repeatedly observed in a large number of healthy adolescent populations [37, 44], as well as in our cohort with menarcheal age ranging from 10.2 to 16.0 years. Leptin should rather be considered as playing a permissive role in the triggering of the pubertal maturation process [43]. The secular trend in earlier puberty check details was also observed in a very large longitudinal multi-cohort study from Denmark with annual measurements of BW and H in 156,835 school children born Immune system from 1930 to 1969 [45, 46]. However, this trend was recorded irrespective of the BMI level as assessed at 7 years of age [45, 46]. Thus, there is no evidence that fat mass would be an essential physiological factor causally implicated in the marked variability of pubertal maturation onset, as worldwide monitored in healthy children. In our study, the difference in BMI gain between healthy, non-obese girls who will experience their first menses relatively earlier (12.1 years) and later (14.0 years), was already significant from 1.0 to

8.9 years of age. In absolute terms at 8.9 years of age, BW was 31.6 ± 5.0 and 28.1 ± 4.0 kg in the earlier and later groups, respectively. The corresponding BMI values were 17.4 ± 2.2 and 16.4 ± 1.8 kg/m2 in the earlier and later subgroup, respectively. In a previous UK study in healthy girls of similar age (8.6 ± 0.2 year), BW (29.5 ± 5.7 kg), and H (1.31 ± 0.05 m), with BMI of 16.9 kg/m2, fat mass was estimated from total body water measurement by deuterium dilution [47]. Using this validated method for measuring children body composition [48], fat mass amounted to 8.0 ± 3.7 kg corresponding to 27% of BW [47]. In our study, the increased BW from 1.0 to 8.9 years of age was 22.1 and 18.9 kg in earlier and later maturers, respectively.