Does the Timing of Puberty Matter?
A live Conversation between Ze’ev Hochberg and Jean-Pierre Bourguignon, moderated by Alan Rogol
Contributors: Cheri Deal, Michael Ranke, Jan-Maarten Wit, Ron Rosenfeld, Alicia Belgorosky, Ivo Arnhold, David Dunger, Martin Ritzen, Leo Dunkel, Raphael Rappaport, Paul Czernichow
Alan Rogol: This session aims for a basic understanding of the issue here, pubertal timing. There are no boundaries for the aspects to be considered, we expect a lively back and forth conversation, although I’m not sure that we have the time for a lot of that. However, if carried out by Internet or Skype, I’m sure we could meet the two goals. Our two protagonists, Ze’ev Hochberg and Jean-Pierre Bourguignon will outline their views and this will be followed by a second shorter second chance to fill in some added information, or as JP just said, directly address a point made by the other.
Remember, this is the alpha presentation; we are not required to answer all questions or solve all dilemmas. We can certainly carry on the conversation over time. What makes this group special is that we are all friends, and that is great to engage with them in these discussions.
Okay, Ze’ev, may we have your first chat. The way it’s going to work is we have 12.5 minutes spread between the first and the second. So, you can have up to 12.5 now, please.
Ze’ev Hochberg: I like to think of adolescence, a broader perspective: it is a life history stage when children prepare for adult roles, in terms of reproduction, independence and caring for a family. So, eventually, at the end of puberty, they will have to become adults. When I think of adolescence, I think of a package that includes puberty and its related neuroendocrine changes, the secondary characteristics of puberty, the growth spurt, the cognitive changes that occur in puberty, and the psychological development that is occurring in puberty, including the acquisition of sexual and reproductive skills. So that in the center is how to become a reproductively competent adult, the so-called ‘coming of age’.
In the last 50 years, and more so in the last two decades, the package of adolescence has disintegrated. The reason is that neuroendocrine maturation and cognitive and psychological skills have developed at different tempos. So, while puberty comes earlier now than it used to about 100-150 years ago, the cognitive and psychological development is slower than it used to be, and the children don’t become mature adults until they’re about 25 or 30. Only then they become economically independent, they start a family, they parent children, and they care for them. I believe that disintegration of adolescence is central to many or the social problems that our youngsters have
I like to think of puberty and adolescence in terms of human biology; I mean fitness goals mostly reproductive fitness in its evolutionary meaning. The life history stage of puberty is part of sapiens’ strategy to become a productive adult. The word strategy is not used much in medicine, but it’s used in the study of evolution. The long-term strategy is to become a reproductively competent adult and propagate one’s DNA. There are different ways to and maybe different trade-offs to do this, and the strategy differs for boys and girls.
If we talk about the importance of the timing of puberty, there are two issues I think that need to be discussed. The first question is what the causes are that determine the timing of puberty, and how these causes change in our modern world. Mostly the causes of concerns are the role of obesity and what is the role of endocrine-disrupting chemicals in determining pubertal onset. I’m mostly interested in the effect of stress on puberty; how much stress has to do with the timing of puberty. The second question deals with the long-term consequences of early or late puberty. The two aspects, both causes and long term consequences have to do with the reproductive goals.
In the medical world we tend to think of different environments as being a good environment and a bad environment, leading to health and pathology, such as, for example, environments with or without endocrine disruptors. But if we think of puberty as a life history reproductive strategy in the world of evolution, then there are different environments, and appreciation of the benefits and the costs of a problematic environment leads to alternative tactics, design, in the evolution jargon. Not good and bad environments but different ones that require different designs. Much of it has to do with energetics and its balance. If this is a girl who lives on the streets of Bombay and she’s malnourished, it makes of course sense for her, in terms of her reproductive strategy do defer her puberty and start it later. The biology behind it is that we evolved to withstand famine by delaying reproduction to the affluent period that would come later. And this is in fact happening in India, where the age of menarche for girls in the slums or who live on the streets is four years later than it is for privileged girls in the same country.
Different environments also explain the secular trend for the age of menarche. The fact that it is so much earlier today that it was only 150 years ago has to do with the different environment of these two societies. Early puberty today is adaptive to the affluent contemporary environment, and present day girls use this environment to gain reproductive advantage by getting into reproductive life earlier. The biology for such an advantage was set during the last two million years of our evolution. The fact that contemporary girls in the industrial society don’t actually marry and reproduce right after menarche relates to the current slower social and behavioral maturation as compared to the rapid neuroendocrine puberty.
On the issue of stress, and I mean chronic rather than acute stress, we see early or late reproductive strategy, depending on severity of the insult. If it is a minor stress, then most of the time the response to would be earlier puberty. In response to a stress such as absence of a father from the family, or the presence of a step-father or a boyfriend of the mother in the family, these stresses would result in earlier puberty. While severe stress, such as malnutrition or war, results in delayed puberty. The theoretical basis for this is the difference between secure and insecure strategy. If the child is born into a secure family, where she is well-nourished, her parents live in harmony and the economy of the family is good, this child will eventually develop a strategy of a secure world. There is no reason to hurry. Such children will have late puberty; they will start a family late to have fewer children than children who develop an insecure strategy. In socioeconomic hardship, significant family conflict, maternal mood disorders, or a poor-quality father – daughter relationship, children develop an insecure strategy and will have an earlier puberty.
This is known as the concept of socialization for the timing of puberty. Maybe we can discuss later on the consequences of later puberty, which have to deal with reproductive cancer, and with a metabolic syndrome and the consequence of growth in starting early or late, and the social effects, but they all, all of them, have to do with human biology, with reproductive strategy within the context of adolescence as a package that deals with cognitive and psychological development.
Rogol: Jean-Pierre Bourguignon will continue on with where we are.
Jean-Pierre Bourguignon: Pierre Bourguignon: Well, thank you. I realized that while thinking about this, I had pointed more precisely the huge 5-year difference in pubertal timing among individuals, which to me is really fascinating. While somehow you have addressed that issue as well, you overall discussed the secular changes in pubertal timing. Should I want to make short my answer to the question “Does pubertal timing matter?”, I would simply say “Yes, for the brain”. I do recognize I’m brain-biased, given my research. I would somehow join what you said, Ze’ev, and put that question in a bio-psychosocial perspective, a concept that is frequently used in adolescent medicine. So, this 5-year time window is huge compared to the life span; if you think of other animal species, only primates and humans have such a huge disparity in timing. Also, if you think about the duration of the pubertal process, it’s just like a race where the first having started has crossed the finish line, while the last has not yet left the start line. So, it is quite intriguing that there is such variability in timing between individuals for a relatively short process. As a matter of fact, variability (5 years) by far exceeds duration of puberty (3 years). Coming to the bio part of my thinking, I think developmental neurobiology has made huge progresses in terms of understanding how brain is reshaped at the time of adolescence; grey matter is lost quite importantly at that time, and the causal involvement of sex steroids seems to be one possible explanation. Again, these changes will happen with some timing disparity among individuals, and that can be important in terms of behavioural consequences. Now, the psychosocial side of that disparity seems important to me. A simplistic representation is to say that children before puberty look all the same, and puberty is really the first time in life when they experience that they are not all the same. If you think further about that, it’s just a transient situation, because after puberty we all reach adulthood. Of course, there are differences remaining, look at Alan and me [Alan: I was the placebo]. Still, this huge difference among individuals that results from disparity in pubertal timing is temporary. Now, coming to the discussion about how puberty makes sense in terms of life history, what you said about nutrition and about stress is challenged by this observation: it is amazing that though we share relatively comparable life conditions (including stress and nutrition) in industrialized countries, there is still such a huge difference in pubertal timing among individuals. I can’t really see the reason behind this. So, that’s one thing I would be really interested to know how you feel.
There is a second issue I want to pick up from what you said, Ze’ev. You took the example of obesity. To me, this condition raises the question of the difference between association and causation. Especially if we take that example and think about the developmental origin of health and disease concept, it might be that intrauterine conditions have determined a risk of obesity and a change in pubertal timing together. Then, the association is not causal at all. By the end of your discussion, you have mentioned cancer as a possible “consequence” of early pubertal timing. I really doubt that cancer is a consequence of changes in the timing of puberty. I can’t say that’s not true, but I can’t say that it is.
So these are issues for discussion.
Rogol: We are certainly on the right track for having discussions back and forth, the only one comment I wanted to make, is both of you mentioned the issue of adolescence, and if you look over the literature for the last ten years, you don’t go from adolescence to an adult, you go from adolescence to an emerging adult. Then you go to an adult, and the last part of it, from 24-28, is when marriage, finishing school, etc., which we think is a short step, isn’t really such a short step. So, Ze’ev, will you continue please?
Hochberg: I agree Alan with that remark. I call this new life history stage ‘emerging adulthood’. At the end of puberty a child is not an adult. The end of puberty happens around age 15-16 in girls, and 18-19 in boys. By then, they don’t start their reproductive stage, they are not independent and don’t have any family responsibilities. Even the brain isn’t fully mature. The brain gets fully mature at the end of the third decade of life, so also biologically, they are not fully adult yet by the time they finish pubertal maturation. Our colleagues from adolescent medicine have recognized it, and they have developed the concept of pediatrics going through the age of 24.
I’ve tried to look into this question in terms of human and other primate’s evolution, and see if other they have an emerging adulthood. It turns out that even among the great apes, there is a period from the end of puberty to the time they start to give birth (about 2-3 years in chimpanzees and gorillas), and in traditional non-industrial societies, it takes about 4 years from the time the girl is mature to when she starts to give birth. Whereas she looks mature, she doesn’t have effective ovarian cycles yet. So, there is a period of relative sterility after the end of puberty.
And that brings me to the issue of obesity, and why is it that obesity is associated with early puberty. In my view this has also to do with the fitness advantage of having an early puberty, as a step toward reproduction. And this is also why girls have earlier puberty as compared to boys. The reproductive constraint is mostly for females with their long periods of gestation and breast-feeding, which in traditional society take some 3-4 years – the so-called interbirth interval.
Bourguignon: Well you started talking about when adulthood is reached somehow. I understand that, and I think that we as pediatricians and pediatric endocrinologists may be biased because we are much more frequently seeing patients because puberty is starting earlier and rarely because puberty is not ending or because it’s ending later or whatever. This reminds me of a study that was published a few years ago, evaluating different birth cohorts in France. They showed that at the same time that menarche occurred earlier and earlier (this was the secular trend toward earlier menarche), the ovulatory cycles were later and later. And that’s something we couldn’t study any longer now, because contraceptive pills are taken so early that we don’t know about ovulatory cycles at least in our societies. Maybe that could be studied in others. I think this issue, when puberty stops and when it ends, seems very important because we miss information about when puberty ends, and my hypothesis is that puberty ultimately is taking more time now, from the very beginning to the very end, than it was before. That’s what I wanted to add.
Rogol: Okay that will be the end of the formal presentations and now let’s just go ahead and pick up the microphones and ask anybody anything.
Cheri Deal: I’m very intrigued by your comment about the preservation of an enormous inter-individual variability with regard to the timing of puberty, whether you’re looking at a developed nation or a developing nation, regardless of your geographical location. And I hope I don’t sound too teleologic, because I don’t mean to, maybe just the way I’m phrasing it, apart from that question, how it may point to a biomedical perspective to something that is extremely multigenic and epigenetic, which of course opens even an even larger variability from the genomic level. I think it also points to an evolutionary perspective, and probably, the way I see it, is that it was a means of resource-sparing. You couldn’t have all the women born at a certain date becoming fertile at a certain time, because that would stress enormously the village resources or the individual community resources. So, I see this as being carried through by an evolutionary pressure.
Bourguignon: Well I agree with that, but I would just like to add something about epigenetic and genetic control. While presumably epigenetics would play a more important role in early phase of life. Quite intriguingly, if you take two examples, nutritional restriction and stress, when they are imposed during pregnancy (so during fetal life, or around birth), they result in advancement of puberty. If they are imposed closer to the time of puberty, they result in delaying puberty, and that’s interesting because you take the same environmental issues and they have an opposing effect depending on the time in life. That difference comes to possible epigenetic versus genetic mechanisms.
Hochberg: I think that we are talking of two different phenomena. The one is early programming for the best fitness strategy, which involves an epigenetic mechanism, and happens during gestation, but also postnatally at critical transition points between life history stages. At the transition from infancy to childhood, around the end of the first year of life, the child programs for his growth trajectory based on his energetic environment, but this is also the first hit for programming for a secure (late puberty) or insecure strategy – early puberty based on his or her attachment environment. This is known as Bowlby attachment theory. The second hit becomes functional at the transition from childhood to juvenility around age 6-7. A very different phenomenon is the response to a major stress, such as war or famine that would delay puberty based on factors of the stress and energy mechanisms.
Michael Ranke: It is of course important to focus on a specific subject, particularly if one starts something of which one doesn’t actually know where it’s going to and choses a discussion forum which someone has compared with a “salon littéraire” . You have rightly proposed puberty as a target. The problem that I see is that we primarily need to talk about evolution. This means the adaptation of a race to the environment in order for the survival of the fittest, as our thinking has been formed by the experience made in the animal world. Puberty in humans has very specific problems related to the man-made environment. So, what we have and see is puberty in its time variability. This variability in the human effects – like in other species – sexual activity. However, at the same time, reproduction in humans today is actually separated from the course of physical pubertal development. Reproduction in humans is influenced strongly by social factors, not by the optimal time of human natural fertility. The female would probably have the best reproductive ages at the age of 18-20, not at 30+ as today. And finally there is the even more complex issue of individual maturation. Perhaps maturation is not even the right word for the becoming of a “complete” individual in an enormously complex man-influenced environment. I think altogether the problems related to puberty, growth and maturation are enormously complex and I wonder how the human species is going to come out of this – and what EDGE will be able to unravel.
Rogol: Precisely why we are having these discussions.
Jan-Maarten Wit: I was astonished a little bit by a comment by Ze’ev that psychological development would be slower now than before. I was thinking what indicator are you using in this comparison, and how do we know that? Because of course society was quite different then, so who to compare with another 150 years ago; what are the data that psychological development is slower?
Hochberg: There is a big body of data comparing children from the ages of 18-20 to young adults beyond age 25 (Behav Sci Law, 18:741, 2000). The young kids are not fully mature in terms of decision making. They are not mature enough to take full responsibility of their own life, let alone of the life of children. They are still dependent or their parents economically and mentally, and they function accordingly. They stay at their parents until they get to be 30, until they are mature enough to leave home.
Wit: Yes, but is that psychological development, or is that another thing?
Ron Rosenfeld: My thoughts are like Michael Ranke’s. I like to view such processes as evolution and growth from an evolutionary perspective. Ze’ev made a point and I agree with it, if you look at human or primate puberty compared to other species, there are several totally distinguishing features. One is the prolonged childhood phase, or the long lag before the onset of puberty, and the second is the fact that homo sapiens is the only species that has a pubertal spurt in skeletal growth. Other species will gain weight during puberty, but only Homo sapiens has the pubertal growth spurt. And one can ask, why from an evolutionary perspective has this benefitted the species? And Cheri is right in saying that we should be careful in thinking teleologically, but the arguments are that a prolonged childhood had several advantages. First, it made male children less threatening to adult males. They weren’t rivals for reproduction. Secondly, smaller children required fewer resources in terms of food, but perhaps, most importantly for humans is the argument that prolonged childhood gives you a prolonged period of psychological and intellectual nurturing that allows you to develop hopefully into a mature adult. And that the pubertal growth spurt that Homo sapiens has is then a way of compensating in terms of growth for the prolonged childhood. Now there’s nothing biologically imperative about a girl having menarche at 11 rather than 15, I mean, there’s nothing written in scripture saying that 15 is the right age. And what is really striking is that in spite of the marked earlier puberty, it hasn’t affected adult height. Even though one may have argued that epiphyses are going to fuse earlier, we’re going to end up shorter, in fact the secular trend has been to increasing height, despite your earlier puberty. Probably both reflecting better nutrition and better general health. I don’t think there’s anything necessarily biologically problematic about early puberty, I think the implications, Michael was suggesting, and Ze’ev also, are psychological and societal in terms of the implications of reproductive capabilities, sexual capability, at an earlier and earlier age, but I think those are societal issues or sociological issues, or psychological issues, not necessarily biological issues.
Alicia Belgorosky: I would like to comment on what Jean-Pierre Bourguignon said, because I think that the maturation of the brain is something very important. In poor countries, the association between maturation of the brain, and earlier puberty and reproductive capacity might be influenced by the fact that females are less able to take care of their own body, with the consequent increment of the incidence of early pregnancies. So, I think this is a very important point that you have mentioned. Sexual intercourse is now very early, and that is a problem, at least in poor counties. The second point that I would like to comment on is a very recent paper from Almastrup K et al (Scientific Report, Doi 101038, 2016), where they found maturation changes in female, and in males, during the transition time between pre-puberty and puberty. They have observed that using elastic model net prediction models methylation patterns predicted pubertal development more accurately than chronological age, and they have proposed to consider the biological age instead of chronological age. Finally, the authors have raised the concept that the modulations of the epigenome might be involved in the regulation of pubertal timing. So, as Cheri has mentioned about epigenetic changes, it also occurs in this transition period. I think that perhaps it’s a new way to analyze childhood maturation.
Rogol: Thank you and I think I want to clear up one point. Many of us in this room have talked about transitions. Most of them are the transitions from the adolescent to the emerging adult or adult, but there’s an important transition from prepuberty to puberty.
Ivo Arnhold: I’m thinking out loud, but I think maybe society wants to know from us 1) if our prepubertal body is prepared to the psychosocial changes that are happening, and this mismatch between content to which the young girl or boy is exposed to through communication much earlier than the brain exposure to sex steroids. So, I wanted to know from Jean Pierre if it would help to have the sexual hormones earlier to understand earlier the communication that society is bringing and 2) if we should also look at extending the biological reproductive life of women, if this is a societal need. And because I think evolution changes much slower than the societal pressures, so I’m just bringing up these questions. The question is: if children are exposed to communication at a younger age of sexual life and of being a young adult and how much are hormones important to understand this type of communication or should we even induce puberty earlier because of this?
Bourguignon: It’s really hard to address that question specifically because I think it’s a whole set of things that appear. I think we know more about what could drive the changes in behavior than how children entering puberty would perceive some messages from the society, from the media, and whatever. Parenthetically, there is some evidence that the first places in the brain to change are in the hippocampus, the limbic system, where emotions are controlled. And the last change is in the frontal region where social control is happening and some people tend to think that the dissociation between change in the hippocampus and change in the frontal region could explain this eruption of behaviour at the time of adolescence.
David Dunger: I’m not quite sure I follow what you’re saying about strategies, you make it sound like a continuous process through childhood, there’s very good evidence that after prenatal growth restraint, you get catch-up growth with adequate nutrition and that has been shown in endless studies now, and that appears to program for early puberty and rapid weight gain, obesity later on. That’s been shown in 20-30 different populations. Does it matter? Well probably in the study we did in Bristol, it didn’t matter a great deal the girls go into puberty a bit earlier, they’re a bit plumper, so obesity is a risk and maybe long term metabolic risk. I kind of disagree with you about cancer, I think long term exposure to sex steroids does increase cancer risk. Does it matter in other populations? So, we did studies in South Africa. There it does matter, because these children are born very small, they come out, they’re in a different environment where they put on weight, they become obese, and they go into puberty early. They have early pregnancies, they have an increased rate of metabolic disease, and this is going to be a disaster going forward. Africa is estimated to have the highest numbers of Type II Diabetes in the world in 2020. So, it does matter. Mid-childhood, there’s very little evidence of plasticity at all, I’m very interested in all this business about stress bringing about puberty, I don’t know anything about that. The only one bit of evidence there is, is migration, which is very curious, the way these girls move from Romania to the UK, and that’s very interesting , I don’t know what the mechanism is. It’s probably nutritionally related, because they put on a lot of weight. But on the other hand, years and years ago, people looked at putting upon weight between the ages of 2 and 10, and it did nothing to rate of entry into puberty. Putting on weight between 0-2 does make a difference, but between 2 and 10 it does not.
There is another area of plasticity that is during puberty that has been shown in a couple of studies, and that is if you are one of those thin girls who go into puberty very late, you have to put on a lot of weight, because reproductive capacity requires a certain fat mass in a woman, they can’t have a pregnancy with no fat mass. A couple of studies have shown that late developing girls have low leptin levels and they have put on proportionally more weight during puberty than the others. And then the last comment is just a question. You talked about the variation in the timing of puberty, but you can go through puberty in 2 years or 5 years, there’s another variation in there which I’ve never understood, and what’s the significance of that?
Deal: In terms of the plasticity pre-pubertally, I thought some of the evidence was also that when you had reconstituted families, where young girls were no longer living with a biologic father, but with an adoptive father, that that was another trigger for onset of puberty (1). I wanted to pick up on one more comment about what are important questions and I think prolonging reproductive potential in women is a very important question. Only humans and whales (a few species of whales) have menopause. I think we need to work that understanding as well in our comprehension of earlier puberty, and what this means for total reproductive function, because it’s not just becoming reproductively functional, but it’s also how long is the woman going to be reproductively functional.
Martin Ritzen: I’m going to be very practical. I think we’re going to end up the discussion saying more research is needed, as always [laughter]. But for future projects, I see a different approach from authors of papers on early or late puberty, and my own practice when I see a patient. One of my first questions is: When did the mother have menarche, what do we know about the father’s pubertal development, what about the sibling’s pubertal development? What is the overriding influential factor for pubertal development, genetic background or the fine tuning by endocrine disruptors, or other environmental factors? If you are going to set up a new study, I suggest that you divide the subjects into different groups depending on family background. The mother almost always knows when she had menarche; this is a good staging parameter. You will probably get different results depending on whether the mother´s menarche was early, middle or late, because (epi)genetics is so important. There are very few papers that distinguish girls or boys depending on the pubertal development of their parents.
Leo Dunkel: Eighty percent of the variation in puberty is genetically determined, and of course there must be this type of environmental cues, otherwise we wouldn’t have for instance this secular change in the timing of puberty. And I think that’s quite important, really, to have this type of biological architecture, otherwise we wouldn’t be able to have these strategies to select what is the optimal way to develop and so forth. But really, we don’t understand what the genetic core is, and really to make a steep change in this area of investigation we would really have to first understand what are the genes that are ultimately determining the timing of puberty. Practically we know nothing about those. If we look at the 200, 000 women and age of menarche for instance, based on this, we have hundreds of SNPs which explain like 3% of all this variation. So we have typical case of missing heritability and really to understand the gene environment interactions, we would really have to first understand the genetic core, and then really understand what is interacting.
Dunger: I was just going to make a comment that in a big population study in Bristol, we did look at that, we followed the mothers up until early, late and middle gestation, and when you look at their offspring, the mothers with early puberty had babies that were born smaller who showed rapid catch up growth, who then went into puberty earlier, and the mothers who had late puberty had children who did the reverse. So it may be genes but it may be much more complicated than that, maybe much more epigenetic.
Ralph Rappaport: It’s just a very stimulating and interesting discussion, I’ve learned a lot and I just want to take the point of view of age, just to finish the discussion, because you say that age is aiming at putting science, not only science but something in addition to it, which is social, humanistic, or whatever it is, but we did not really do away with discussing and with our many more issues. I just wanted to raise one issue, aiming at something else different, and it’s not scientific, but all issues of puberty puts us in one difficult questioning which we are facing in practice and daily life, which is what is normal? And when is normal beginning, early puberty, what is early, and what is late? And this is probably not only decided by us, according to the criteria we have somebody has put up 40 years ago, it’s only depending on the view of the society, and just for an instant, I’m told that now in many clinics, at least in our country, I believe, in many other places, doctors are overloaded by questions about puberty, early puberty, much more than about short or tall. It used to be the first problem of the society that we generated perhaps, but perhaps not. I’m not clear about this. It was height and now it is according to what I hear and what I read, it is puberty. So let us ask why all of a sudden, the society grasps the issue of puberty and 3-4 years ago I like to quote a very nice paper that you may have read eventually, in the New York Times, it was 5-6 columns about early puberty in New York, and the way the mother’s behaved with girls having early breasts, and being all of a sudden just becoming just like young ladies and this is a very interesting paper to see how the society reacts to changes which are apparently certainly occurring. So, there are so many other ways to look at that issue.
Paul Czernichow: Ze’ev, you started your interesting speech by saying that there is a lack of exchange between humanities and the sciences and lay people. Speaking about the problem of variability in puberty it is striking that people in the educations system, they are not very interested by this problem. I think that the timing of puberty has an enormous impact on how the children understand the enormous amount of knowledge they need to learn and digest, and I wonder if this has been studied. In face of the large variability in puberty, we demand from the children so much learning, at least in France, but probably also in other parts of Europe. It is a very rigid system, where you enter high school at a certain age and this problem of puberty age is not taken into account.
Hochberg: I wanted to finish with the issues that Paul Czernichow raised. Does it matter to the patients and their families whether they start puberty early or late? Of course, it matters a lot to them. They come to ask us to modify it, to start it earlier, to start it later; they come with precocious or late puberty and the misery of the child himself. This is an important issue that we will not have time to discuss today.
- Webster GD1, Graber JA1, Gesselman AN1, Crosier BS1, Schember TO. A life history theory of father absence and menarche: a meta-analysis. Evol Psychol. 2014 Apr 29;12(2):273-94.
ECGM Club Discussion:
Martin Ritzen, MD, PhD, Prof. emeritus of Pediatrics, Karolinska Institute, Sweden
I would like to draw your attention to a remarkable long term follow-up study that enrolled a cohort of all healthy girls in a geographical area in Sweden (n=466) when they were 13 years old and followed them until they were 43 years of age. The results what concerns the influence of early puberty on later development has been published in psychology journals by the Swedish professor of psychology, Håkan Stattin and his group (1). More references can be found at Web of Science. I summarized the data for a conference on pubertal development back in 2005 (2).
Several differences in somatic and psychosocial behaviour were noted when the original cohort of 466 girls was divided into three groups, depending on the age of menarche; those with early puberty (menarche before age 11), middle (age 11-13) and late puberty (menarche later than at age 13). At age 15-16, girls with menarche before age 11 (early) were more problematic, including delinquency, in several contexts. By adult age, all adverse behaviours had disappeared. Thus, the effects of early pubertal timing on psychosocial adjustment seem to be adolescence-limited. However, at age 27 the early group had lower academic degrees, which was also the case at age 43. Regarding somatic development, at age 43, women with early menarche were shorter and heavier, had worse physical fitness, and dieted more frequently than others did. However, no difference in quality of life was found. In searching for causes of the antisocial behaviour in adolescence and the lower educational levels, early heterosexual relations seem to be the most decisive. The early girls had older boyfriends, and copied some of their adverse behaviour.
Although none of these girls had true precocious puberty, the results indicate that even early normal puberty might influence important behavioural issues in adolescence leading to lower future educational level, shorter stature and increased body weight in adulthood. This should be considered when counselling parents of girls with early puberty.
COMMENTS TO THIS CONVERSATION ARE TO BE MAILED TO JEAN PIERRE BOURGUIGNON [jpbourguignon@ulg.ac.be].