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

July 28, 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 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 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 , 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 are another reason to take action against childhood obesity ".

Explore further: Early poor mental health link to early puberty

Related Stories

Early poor mental health link to early puberty

April 2, 2013
(Medical Xpress)—Children who have an earlier onset of puberty have poorer mental health from as early as preschool age, a new study by Murdoch Childrens Research Institute has found.

Early periods may signal greater diabetes risk, study suggests

October 25, 2013
(HealthDay)—Girls who start menstruating earlier than most may be more likely to develop type 2 diabetes in adulthood, a new study suggests.

Faulty gene can delay or block puberty

March 26, 2014
More than 4% of adolescents suffer from early or late-onset puberty, which is associated with health problems including obesity, type-2 diabetes, heart disease and cancer. The findings of the study will make diagnosis easier ...

The brain's reaction to male odor shifts at puberty in children with gender dysphoria

May 28, 2014
The brains of children with gender dysphoria react to androstadienone, a musky-smelling steroid produced by men, in a way typical of their biological sex, but after puberty according to their experienced gender, finds a study ...

Age of puberty in girls influenced by which parent their genes are inherited from

July 23, 2014
(Boston)—The age at which girls reach sexual maturity is influenced by 'imprinted' genes, a small sub-set of genes whose activity differs depending on which parent passes on that gene, according to new research published ...

Recommended for you

Schoolchildren who use e-cigarettes are more likely to try tobacco

August 17, 2017
Vaping - or the use of e-cigarettes - is widely accepted as a safer option for people who are already smoking.

Study shows cigarette makers shifted stance on nicotine patches, gum

August 17, 2017
The use of nicotine patches, gum, lozenges, inhalers or nasal sprays—together called "nicotine replacement therapy," or NRT—came into play in 1984 as prescription medicine, which when combined with counseling, helped ...

Federal snack program does not yield expected impacts, researchers find

August 17, 2017
A well-intentioned government regulation designed to offer healthier options in school vending machines has failed to instill better snacking habits in a sample of schools in Appalachian Virginia, according to a study by ...

In a nutshell: Walnuts activate brain region involved in appetite control

August 17, 2017
Packed with nutrients linked to better health, walnuts are also thought to discourage overeating by promoting feelings of fullness. Now, in a new brain imaging study, researchers at Beth Israel Deaconess Medical Center (BIDMC) ...

Energy dense foods may increase cancer risk regardless of obesity status

August 17, 2017
Diet is believed to play a role in cancer risk. Current research shows that an estimated 30% of cancers could be prevented through nutritional modifications. While there is a proven link between obesity and certain types ...

Technology is changing Generation smartphone, and not always for the better

August 16, 2017
It's easy to imagine some graybeard long ago weighing in on how this new generation, with all its fancy wheels, missed out on the benefits of dragging stuff from place to place.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.