Children who develop early have greater risk of cancer

Chances of disease can rise 28%

GOING through puberty early puts us at greater risk of cancer.

Girls typically start their periods at 12 or 13 while boys tend to see their voice break at 13 or 14.

For every year a child starts puberty before this point, their cancer risk rises dramatically, a study has found.

A girl of 11 going through puberty has a 28 per cent higher chance of getting endometrial cancer, affecting the lining of the womb, than a girl of 12.

The danger of getting breast cancer later in life rises six per cent for each early year, while boys see their risk of prostate cancer go up by nine per cent.

The figures, from a University of Cambridge study, raise concern because many overweight children are now entering puberty early.

The average age of puberty in the west is five years earlier than a century ago, with hormones feared to be triggered by modern fatty diets.

Senior author Dr John Perry said: ‘We have the best evidence yet that, broadly speaking, early puberty is bad for health.

‘It leads to higher risks for breast cancer and may cause ovarian and prostate cancer too. That is because, when girls go through puberty early, typically age nine or ten, this increases their lifetime exposure to circulating sex hormones like oestrogen. We think it is these hormones that fuel the growth of certain types of tumours and cause people to develop cancer.’

The study, published in the journal Nature Genetics, identified 389 genetic signals associated with puberty – four times the number previously known. Scientists mapped genetic variants from nearly 370,000 women and 110,000 men to discover the link with cancer. Women are at risk of three types of cancer if they have their first period early, possibly due to hormones such as oestrogen.

Longer hormone exposure is also why women who go through the menopause later are at greater risk of cancer. The study, also by scientists from the Reproductive Genetics Consortium, puts the risk of ovarian cancer up eight per cent for every year.

Dr Perry said the findings should encourage parents to take action to make sure their children develop at an appropriate time.

He said: ‘ From a public health point of view, we aim to develop future guidance to prevent children from entering puberty early with better nutrition and exercise. The body appears to go through this transition when it believes it has enough of an energy supply – this is the reason why teenage girls with anorexia may not start their periods.

‘But obese children have lots of energy reserves, so can trick their body into thinking they are ready to make the transition to puberty when in fact they are too young.’

The study is the largest genomic analysis of puberty timing in men and women to date. It found that puberty timing often runs in families.

While an earlier transition to adulthood may have advantages, such as for sports, previous studies show it also raises the risk of diabetes and heart disease.

Dr Richard Berks, of charity Breast Cancer Now, said: ‘We already know that early puberty can slightly increase a woman’s risk of developing breast cancer later in life.

‘However, lifestyle factors could have a much bigger influence on a woman’s breast cancer risk – and everyone can help reduce their risk of the disease by maintaining a healthy weight, being more physically active and cutting down on alcohol.’

‘Triggered by fatty diets’