Tall people are at greater risk of getting cancer, with the danger rising by around 10 per cent for every 10cm above the average height, a study has found.
Researchers said that being taller increases the risk of contracting cancer more for women – by 12 per cent compared to 9 per cent for men.
The findings suggest that having more cells in your body – as tall people do – is the reason for the higher cancer risk.
Meanwhile some types of dwarfism appear to greatly reduce the risk.
The research suggests that the hormone that stimulates growth, called IGF-1, has an effect on triggering cancer.
As IGF-1 speeds up the rate that cells divide as they grow, it also increases the chance that the cells will turn into tumours.
Researchers from the University of California, Riverside, calculated the average male height as 175cm (5ft 9in) and the average female height as 162cm (5ft 4in). They assessed the risk of 23 cancers. For women, the greatest increase in risk was for cancers of the thyroid, skin, lymphoma, colon, ovary, breast and womb.
For men, it was for cancers of the thyroid, skin, lymphoma, colon, kidney, biliary tract and central nervous system. Being taller did not increase the risk of oesophageal, stomach, mouth or cervical cancer in women, while in men it did not increase stomach cancer risk.
Professor Leonard Nunney, of the research team, said: ‘It is possible that the IGF-1 level in adults has a direct effect on cancer risk via an increase in the rate of cell division.’
He added: ‘This association may be responsible for the low cancer rates observed in individuals with growth hormone receptor deficiency.’
These individuals, who have a rare type of dwarfism called Laron syndrome, are on average 118cm (3ft 10in) tall among women sufferers and 124cm (4ft 1in) among men.
They also have a risk of cancer that is typically 50 per cent lower than that of an average person.
The California researchers, who analysed huge sets of data from Korea, Norway, Sweden and Austria, said it was interesting that some cancers were not affected by height – particularly lung cancer and cervical cancer.
While lung cancer is increased by smoking, and cervical cancer by a bacteria called helicobacter pylori, the authors say the question is still an open one.
They stressed the findings do not mean women are more at risk of cancer overall – on average men face a risk up to 55 per cent greater than women.
Georgina Hill, health information officer at Cancer Research UK, said of the findings: ‘A number of studies over the years have shown that taller people seem to have a slightly higher risk of cancer.
‘This study suggests it’s because taller people are made of more cells, so there’s more potential for one of them to go wrong and become cancerous.
‘But the increased risk is small and there’s plenty you can do to reduce the risk of developing cancer such as not smoking and keeping a healthy weight.’
The study was published in the Royal Society journal called Proceedings B.