Washington DC – While most cancers increase risk dramatically with age, a recent study has found that having a person's size could make them more susceptible to cancer.
The University of California study was published in the Proceedings of the Royal Society B.
Leonard Nunney examined data from four large-scale surveillance projects in 23 cancer categories. Each of these cancer studies found that large individuals have an increased risk of cancer, with the overall risk increasing by 1
Other researchers have suggested that these factors act early in life – nutrition, health, social conditions – independently affecting height and cancer risk. But Nunney, a professor of biology, questions this hypothesis.
"I tested the alternative hypothesis that height increases cell number and that more cells directly increase cancer risk," he said. "The data strongly supports this simple hypothesis: for most carcinomas, the magnitude of the height effect is predictable from the elevation in cell number."
When Nunney compared the observed effect of altitude on the risk of He found that the effects of high on the risk of thyroid and skin cancer in women were high; Skin cancer stood out in men.
"Large people are at an increased risk for almost all cancers," he said. "But skin cancers – like melanoma – show an unexpectedly strong relationship to height, which may be because the hormone IGF-1 is in higher concentrations in higher adults."
IGF-1 is a growth factor that is particularly important in early development, Nunney explained, but IGF-1 has also been associated with higher cell division rates in large adults.
"Sharing your cells more often increases your cancer risk," he said. "If skin cells divide more quickly in large people due to high levels of IGF-1, this could be responsible for the increased risk of melanoma."