Study shows new link between obesity in the young and the lowering of age of puberty

July 27, 2014

A new link has been identified between obesity in childhood and the lowering of the age of puberty.

The research which discovered the link, carried out at Plymouth University Peninsula Schools of Medicine and Dentistry, is published in the Journal of Clinical Endocrinology and Metabolism.

The study focuses on a protein called sex hormone-binding globulin (SHBG), the regulation and role of which in children are poorly defined. SHBG binds to the sex hormones androgen and oestrogen. SHGB levels are initially high in childhood but decline significantly before puberty, in essence 'allowing' puberty to happen.

The research team analysed data from the EarlyBird longitudinal measurement of 347 schoolchildren in Plymouth, UK, aged five to 15 years.

The findings of this study showed that a child who is heavier at age five tends to have lower levels of SHBG throughout childhood and reaches puberty sooner. The tendency was more striking in girls than in boys.

The study suggested that a combination of hormonal disturbances that are associated with weight gain and obesity, together with inflammation, might be the biological mechanism that explains the observed relationship between weight gain and the declining age of puberty.

It is not known why increasing body weight is associated with earlier puberty, especially in girls, but one possible explanation for this is that humans, like all mammals, require large amounts of energy to reproduce. Throughout most of evolution, a well-nourished state would have greatly favoured successful pregnancy in a world with high perinatal mortality. Conversely, a state of poor nutrition and low body weight, is disadvantageous to reproduction, and slows down reproductive maturation or leads to infertility. Deliberate weight control in female athletes and dancers, or the state of anorexia nervosa, still result in the same phenomenon of infertility. Thus, the hormones that control appetite and body weight interact closely with those that allow fertility. The new findings show that SHBG is part of an interaction between the body's systems for controlling energy balance and reproduction.

The findings are of additional interest because they might go some way to answering the question of why, historically, the age of puberty has declined over the past century. For example, the onset of puberty in girls in 1920 was 14.6 years; in 1950 13.1; in 1980 12.5; and in 2010 10.5. In boys puberty has always tended to occur a year or so later than in girls.

The findings also open a debate about the role of the worldwide obesity epidemic in the general lowering of the age of puberty. The World Health Organization recognises childhood obesity as one of the most serious global health challenges for the 21st century. Figures from the UK's National Child Measurement Programme 2012/13 show that almost a third of 10 to 11 year olds and over a fifth of four to five year olds were either obese or overweight.

Worryingly, as well as now identified as contributing to the lowering age of puberty, obesity in childhood also increases the risk of heart disease and diabetes in later life.

The study was led by Professor Jonathan Pinkney, Professor of Endocrinology and Diabetes at Plymouth University Peninsula Schools of Medicine and Dentistry. He said: "There are critical windows early in life which the die is cast for our long term health. We know that weight gain often begins early and we wanted to investigate how early weight gain might be linked to earlier puberty."

He added: "Here we have found compelling evidence that hormonal effects of obesity, and associated inflammation, affect levels of SHBG and hence the age when puberty commences. As a higher proportion of youngsters around the world have become obese, so has the age of puberty dropped. We now know that the relation between these issues is more than coincidental."

He concluded: "These findings have significant implications for children's development and public health around the world. Reduction in the age of puberty, as a result of early weight gain, expedites physical and psychosocial development at a younger age, and this potentially means an earlier ability to reproduce as well as poorer long term adult health. The observed effects on puberty are another reason to take action against childhood obesity ".
-end-
Notes

EarlyBird Diabetes Study

The study is a 12-year prospective analysis of body composition, physical activity and metabolic health of a single cohort of children, randomly recruited from Plymouth primary schools in 2000-2001 at age five years. Insulin resistance, related largely to obesity, is believed to underlie diabetes and heart disease, and EarlyBird aims to establish why some children, and not others, develop insulin resistance. EarlyBird is able to exploit its longitudinal design to detect previously unrecognised trends and interactions, some of them counterintuitive. It appears that the trajectory which leads to obesity is established early in life, and involves principally offspring whose same sex-parent is obese. Inactivity does not appear to be the cause of obesity, rather obesity the cause of inactivity. Modelling of the longitudinal data should allow us to determine - crucially - to what extent insulin resistance and diabetes risk are directly attributable to obesity, or to the reduction in physical activity that results from obesity.

About Plymouth University

We are one of the leading modern universities in the UK, ranked in the top seven institutions under the age of 50 by Times Higher Education. Awarded the Queen's Anniversary Prize for Higher and Further Education in 2012 for marine and maritime teaching and research, we have won numerous awards and accolades, and are the only university in the world to be awarded the Social Enterprise Mark.

Our 30,000 students, which include those at our partner colleges across the South West, are enrolled on courses from farming to pharmacy, business to biology, and design to dentistry. And the 12,000 paid internships we provide every year for our students is just one of the many ways that we help them to develop new skills and graduate ready-for-work.

We have invested more than £150 million in our campus over the past seven years and are the first modern university to launch a medical school. And through our £100 million network of support facilities and services, we are growing hundreds of businesses across the region and beyond. To find out how Plymouth is making a difference to its communities, please visit http://www.plymouth.ac.uk

University of Plymouth

Related Obesity Articles from Brightsurf:

11 years of data add to the evidence for using testosterone therapy to treat obesity, including as an alternative to obesity surgery
New research covering 11 years of data presented at this year's European and International Congress on Obesity (ECOICO 2020) show that, in obese men suffering from hypogonadism (low testosterone), treatment with testosterone injections lowers their weight and improves a wide range of other metabolic parameters.

Overlap between immunology of COVID-19 and obesity could explain the increased risk of death in people living with obesity, and also older patients
Data presented in a special COVID-19 session at the European and International Congress on Obesity (ECOICO 2020) suggests that there are overlaps between the immunological disturbances found in both COVID-19 disease and patients with obesity, which could explain the increased disease severity and mortality risk faced by obese patients, and also elderly patients, who are infected by the SARS-CoV-2 virus that causes COVID-19 disease.

New obesity guideline: Address root causes as foundation of obesity management
besity management should focus on outcomes that patients consider to be important, not weight loss alone, and include a holistic approach that addresses the root causes of obesity, according to a new clinical practice guideline published in CMAJ (Canadian Medical Association Journal) http://www.cmaj.ca/lookup/doi/10.1503/cmaj.191707.

Changing the debate around obesity
The UK's National Health Service (NHS) needs to do more to address the ingrained stigma and discrimination faced by people with obesity, says a leading health psychologist.

Study links longer exposure to obesity and earlier development of obesity to increased risk of type 2 diabetes
Cumulative exposure to obesity could be at least as important as actually being obese in terms of risk of developing type 2 diabetes (T2D), concludes new research published in Diabetologia (the journal of the European Association for the Study of Diabetes [EASD]).

How much do obesity and addictions overlap?
A large analysis of personality studies has found that people with obesity behave somewhat like people with addictions to alcohol or drugs.

Should obesity be recognized as a disease?
With obesity now affecting almost a third (29%) of the population in England, and expected to rise to 35% by 2030, should we now recognize it as a disease?

Is obesity associated with risk of pediatric MS?
A single-center study of 453 children in Germany with multiple sclerosis (MS) investigated the association of obesity with pediatric MS risk and with the response of first-line therapy in children with MS.

Women with obesity prior to conception are more likely to have children with obesity
A systematic review and meta-analysis identified significantly increased odds of child obesity when mothers have obesity before conception, according to a study published June 11, 2019 in the open-access journal PLOS Medicine by Nicola Heslehurst of Newcastle University in the UK, and colleagues.

Obesity medicine association announces major updates to its adult obesity algorithm
The Obesity Medicine Association (OMA) announced the immediate availability of the 2019 OMA Adult Obesity Algorithm, with new information for clinicians including the relationship between Obesity and Cardiovascular Disease, Diabetes Mellitus, Dyslipidemia, and Cancer; information on investigational Anti-Obesity Pharmacotherapy; treatments for Lipodystrophy; and Pharmacokinetics and Obesity.

Read More: Obesity News and Obesity Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.