A Swedish study of five million people appears to support the theory that height and cancer risk are linked.
The study found that taller people had a slightly higher risk of breast cancer and skin cancer, among other cancers.
Its results found that for every extra 10cm (4in) of height, when fully grown, the risk of developing cancer increased by 18% in women and 11% in men.
But experts said the study did not take into account many risk factors and that tall people should not be worried.
To reduce risk of cancer, the most important things to do are:
- give up smoking
- cut down on alcohol
- adopt a healthy diet and lifestyle
Previous studies have shown a link between height and an increased risk of developing cancer, although why it exists is not known.
In a preliminary report of the study, presented at the European Society for Paediatric Endocrinology conference, researchers from the Karolinska Institute in Stockholm describe how they tracked a large group of Swedish adults for more than 50 years.
Taller women had a 20% greater risk of developing breast cancer, they said, while taller men and women increased their risk of skin cancer (or melanoma) by 30%.
This study’s early findings are very similar in size to those found by other studies.
Dr Emelie Benyi, who led the study, said the results could help to identify risk factors that could lead to the development of treatments.
But she added: “As the cause of cancer is multi-factorial, it is difficult to predict what impact our results have on cancer risk at the individual level.”
Although it is clear that adult height is not a cause of cancer, it is thought to be a marker for other factors related to childhood growth.
Scientists say taller people have more growth factors, which could encourage cancer development, they have more cells in their body because of their size, which increases the risk of one of them turning cancerous, and a higher food intake, which also makes them more at risk of cancer.
Prof Dorothy Bennett, head of the molecular cell sciences research centre, St George’s, University of London, said it was “very plausible” that the risk of cancer in a person should be related to the number of cells in their body
“A cancer arises by mutations from a single normal cell. Bigger people have more cells (not bigger cells),” she said.
“So melanoma risk, for example, might be expected to increase with surface area (amount of skin), which is related to the square of height.”
Sarah Williams, health information manager at Cancer Research UK, said the study did not take into account factors such as smoking or whether women went for breast screening.
She added: “Whatever your height, there are lots of things you can do to reduce the risk of cancer – not smoking, cutting down on alcohol, eating healthily, being active, having a healthy weight and enjoying the sun safely can each help you stack the odds against the disease.”