Evo-devo of human adolescence: beyond disease models of early puberty

Despite substantial heritability in pubertal development, much variation remains to be explained, leaving room for the influence of environmental factors to adjust its phenotypic trajectory in the service of fitness goals. Utilizing evolutionary development biology (evo-devo), we examine adolescence as an evolutionary life-history stage in its developmental context. We show that the transition from the preceding stage of juvenility entails adaptive plasticity in response to energy resources, other environmental cues, social needs of adolescence and maturation toward youth and adulthood. Using the evolutionary theory of socialization, we show that familial psychosocial stress fosters a fast life history and reproductive strategy rather than early maturation being just a risk factor for aggression and delinquency. Here we explore implications of an evolutionary-developmental-endocrinological-anthropological framework for theory building, while illuminating new directions for research

Distinctions between short- and long-term human growth studies

It is known what the aim is in a complete long-term growth study; the final height is the outcome measure, although the annual height velocity values provide additional information. Strictly, short-term growth studies are also defined in terms of minimum length of observation, i.e. one month, as well as the type of measurement errors to be considered. The poor correlation between short- and long-term growth velocity values has led to the conclusion that the short-term study cannot be interpreted in long-term perspectives, and vice versa. There is a need to debate the way in which results of short-term studies should be interpreted. This is especially important when short-term growth is taken as the outcome measure in a controlled study. Our proposal is that such studies must include information about the growth achieved for a period after the treatment has ended in order to describe possible compensatory growth. Without weighing in some long-term consequences, we may incorrectly document short-term growth as a positive or negative effect of a certain treatment.link_to_subscribed_fulltex

Final height after combined growth hormone and GnRH analogue treatment in adopted girls with early puberty

Background: Girls adopted from developing countries often have early or precocious puberty, requiring treatment with gonadotrophin-releasing hormone (GnRH) analogues. During such treatment, decreased growth velocity is frequent. Aim: To study whether the addition of growth hormone (GH) to GnRH analogue treatment improves final height in girls with early or precocious puberty. Methods: Forty-six girls with early or precocious puberty (age less than or equal to9.5 y) adopted from developing countries were randomized for treatment for 2-4 y with GnRH analogue, or with a combination of GH and GnRH analogue. Results: During treatment, the mean growth velocity in the GH/GnRH analogue group was significantly higher compared to the control group. Combined GH/GnRH analogue treatment resulted in a higher final height: 158.9 cm compared to 155.8 cm in the GnRH analogue-treated group. Three out of 24 girls (13%) in the combined group and nine of the 22 girls (41%) treated with GnRH analogue alone attained a final height below -2 standard deviation scores (SDS). Conclusion: The difference between the two groups is statistically significant, and possibly of clinical importance. A future challenge is to identify a subgroup with clinically significant advantage of GH addition to GnRH analogue treatment. Being very short on arrival in Sweden and being short and young at start of treatment are possible indicators