Increased risk of cancer in tall people up to the number of cells: study

Tall people have a higher risk of "induced" cancer in part because they have more cells to target, a study said Wednesday.

US researchers have examined populations from three continents and found that the risk of contracting cancer in men and women increased by 10% every 10 centimeters.

Cancer develops when the body's normal controls on cell growth stop functioning, leading to the uncontrolled creation of abnormal cells that manifest as tumors.

A study published in the journal Proceedings of the Royal Society B suggests that the risk of several types of cancer is probably higher in tall humans simply because they have more cells and therefore more chances for these cells become cancerous.

"This means that this extra risk is" wired "and can not be reduced in an obvious way," said AFP Leonard Nunney, senior author of the study, the study.

It is thought that some large mammals, such as elephants and giraffes – whose bodies contain a much larger number of cells than smaller creatures – have put in place additional protective mechanisms against cancer.

But nothing indicates that it works the same way in individuals of the same species, such as man.

The average size varies from one region to another, but in the United States men average 176 cm (five feet nine inches) and women 162 cm (five feet four inches).

Although scientists have long known that tall people tend to be at higher cancer risk, Nunney's study of human populations in the United States, Europe, and South Korea found that perhaps because they have more cells in which something is wrong.

In particular, tall people had an increased risk of melanoma because they had a higher rate of cell division – and, simply, more skin – than people of average height.

However, the risk of cancer of the stomach, mouth and cervix in women does not seem to be affected by size.

– Nature vs feed –

Although the size is largely determined by an individual's genes, Nunney said that the environment of childhood also had an effect and that it therefore likely had an impact on the associated cancer risks.

"Environmental and genetic factors acting during childhood both have a significant effect on adult height," he said.

"There is no reason to think that their effects on cancer risk would be different because the determining factor is the number of cells, not why or how an individual ended up with a given number of cells. "

It is known that obesity in adults increases the risk of cancer, but for a very different reason, size.

As a person's cell count increases as he grows up, obesity changes the size of these cells rather than creating more.

"So we can expect that the cause of the increase in cancer risk related to obesity is different from the effect of height," Nunney said.

He suggested that more research be done on why large mammals do not appear to be at high cancer risk to determine if they have built-in cellular protection that could be replicated in humans.

Although the results show that a person's risk of cancer increases to about the same degree as its size, Nunney said that tall people should not panic, their height being far from being the only risk factor for the disease.

"I do not think that extreme measures are needed in general: the effect is statistical and relatively low for most people," he said.

He added, however, that "exceptionally large" people could benefit from additional screening: a 229 cm (7 feet 2 inches) man is twice as likely to develop cancer as a 5-year-old man. feet 2 inches.