UK - Heightened risk of cancer for tall people?

Ever wanted to be taller?

Well, it turns out the tall tribe may not have it that good after all.

A study of more than one million women, published in The Lancet Oncology, suggests that chemicals that control growth might also affect tumours.

Though the study concerned women only, researchers at Oxford University say that being tall for men has been also linked to a greater risk of cancers.

The study followed 1.3 million middle-aged women in the UK between 1996 and 2001.

It linked 10 cancers to height - colon, rectal, malignant melanoma, breast, endometrial (uterus), ovarian, kidney, lymphoma, non-Hodgkin lymphoma and leukaemia.

Those in the tallest group (175cm and above) were 37 per cent more likely to have developed a tumour than those in the shortest group, under 152cm.

Dr Jane Green, lead researcher from Oxford University, told the BBC: "Obviously height itself cannot affect cancer, but it may be a marker for something else."

They think, but have not proved, that growth hormones - such as insulin-like growth factors - may be the explanation.

Higher levels of growth factors could do two things. They could result in more cells - taller people are made of more stuff so there are more cells which could mutate and become tumours.

Alternatively, they could increase the rate of cell division and turnover, increasing the risk of cancer.

Another study published in the journal PLoS Medicine suggests that height is also linked to ovarian cancer in women with taller women being at most risk.

Questions remain on why the connection

Researchers looked at 47 studies in 14 countries, including about 25,000 women with ovarian cancer and more than 80,000 women without ovarian cancer.

There was a slight increase in the risk of developing ovarian cancer for every 5cm increase in height (taking into account other factors such as age, smoking and alcohol consumption) Researchers caution against over-reacting. Height is not a universally bad thing - it is believed that people worldwide are becoming taller due to better nutrition and fewer diseases in childhood.

In Europe, average height is thought to have increased by around 1cm every decade during the 20th century.

But the research means that height might one day help doctors screen for cancer risk. It is hoped that by furthering the understanding of cancers, the study will help researchers discover treatments.

Dr Caitlin Palframan, policy manager at Breakthrough Breast Cancer, said: "The big question is why this connection exists. If we can unravel why height affects the risk of cancer, it will lead us closer to understanding how some cancers develop."

But before the tall ones among you panic, it is also not the biggest contributor to cancer. Smoking is still the greater threat.

Obesity is also a big factor - a 10 point increase in Body Mass Index increases the risk of breast cancer by around 40 per cent.

But as Dr Green admitted: "The point is we don't know."

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