Tall People Shouldn't Worry Too Much About High Cancer Risk, Says Scientist
"There’s absolutely nothing they can do about it."
In late October, a study published in the Proceedings of the Royal Academy B struck fear into the hearts of the vertically unchallenged. Tall people, the paper reported, have a greater risk of cancer than their shorter peers. The science is sound, but even so, Tim Cole, Ph.D., a professor of medical statistics at University College London, doesn’t think tall folks should be too worried.
The paper, written by Leonard Nunney, Ph.D., a University of California Riverside professor of biology, puts forth a simple explanation for previous observations that, for every 10 centimeters of height in humans, cancer risk increases by roughly 10 percent. This relationship is referred to in the paper as the “cell-number hypothesis.” Comparing data from four large-scale surveillance surveys against prediction rates based on this hypothesis, Nunney came to a simple conclusion: Cancer rates are higher in taller people simply because they have more cells. And having more cells means more opportunities to become cancerous.
The paper, Cole tells Inverse, “provides good evidence that taller people, by virtue of having more cells in their body, are slightly more likely to get cancer than shorter people. The same also applies to weight, but more so, as the variation in weight between individuals, and hence the variation in the number of cells, is much greater than for height.”
There's nothing you can do about height, but weight is a different story.
This link may seem counterintuitive when considering that large animals, like elephants and hippos, don’t seem to be any more cancer-prone than smaller animals, like mice. In biological circles, this conundrum is addressed by Peto’s paradox, which refers to the “lack of correlation between body size and cancer risk.” The leading explanation for the paradox is that large animals have evolved more natural mechanisms to fight cancer. Despite this explanation, argues Nunney, Peto’s paradox doesn’t say anything about individuals within a single species — say, taller and shorter folks within Homo sapiens.
Nunney’s analysis of the four data sets, which covered 23 categories of cancer, showed that the hazard ratio for overall cancer risk per 10 centimeter increase in human height is 1.12 (that is, a 12 percent increase) for women and 1.09 (a 9 percent increase) for men. The cell-number hypothesis predicted increases of 13 percent for women and 11 percent for men.
The various types of cancer had differing relationships with height, with melanoma (skin cancer) having a particularly strong link in men and women. But overall, 18 of the 23 cancer types Nunney looked at had a significant increase in risk with height.
Nunney’s analysis and argument are solid, says Cole, but he doesn’t seem too concerned for tall folks.
"I don’t think tall people should be particularly worried about the link.
“I don’t think tall people should be particularly worried about the link,” he says. “There’s absolutely nothing they can do about it, and the risk is in any case small.” He iterates a point he made to the BBC in 2015, when a similar study came out: “[Taller] people are on average healthier than shorter people, so this small extra risk needs to be set against that.”
Besides, he says, far more important than the role of height in cancer risk is the role of weight and obesity.
“People have more control over their weight than their height, and there is already established a strong relationship between obesity and increased cancer risk,” says Cole. “So if people are going to worry, it should be on account of their weight rather than their height. And that as a message is far from new.”
