Why are tall people more likely to get cancer?
These results suggest there is a biological reason for link between cancer and height
(Web Desk) - People who are taller are at greater risk of developing cancer. The World Cancer Research Fund reports there is strong evidence taller people have a higher chance of developing cancer of pancreas, large bowel, uterus, ovary, prostate, kidney, skin and breast.
The UK Million Women Study found that for 15 of the 17 cancers they investigated, the taller you are the more likely you are to have them.
It found that overall, each 10-centimetre increase in height increased the risk of developing a cancer by about 16 per cent. A similar increase has been found in men.
Let's put that in perspective. If about 45 in every 10,000 women of average height (about 165 centimetres) develop cancer each year, then about 52 in each 10,000 women who are 175 centimetres tall would get cancer. That's only an extra seven cancers.
So, it's actually a pretty small increase in risk.
Another study found 22 of 23 cancers occurred more commonly in taller than in shorter people.
The relationship between height and cancer risk occurs across ethnicities and income levels, as well as in studies that have looked at genes that predict height.
These results suggest there is a biological reason for the link between cancer and height.
While it is not completely clear why, there are a couple of strong theories.
The first is linked to the fact a taller person will have more cells. For example, a tall person probably has a longer large bowel with more cells and thus more entries in the large bowel cancer lottery than a shorter person.
Scientists think cancer develops through an accumulation of damage to genes that can occur in a cell when it divides to create new cells.
The more times a cell divides, the more likely it is that genetic damage will occur and be passed onto the new cells.
The more damage that accumulates, the more likely it is that a cancer will develop.
A person with more cells in their body will have more cell divisions and thus potentially more chance that a cancer will develop in one of them.
Some research supports the idea having more cells is the reason tall people develop cancer more and may explain to some extent why men are more likely to get cancer than women (because they are, on average, taller than women).
However, it's not clear height is related to the size of all organs (for example, do taller women have bigger breasts or bigger ovaries?).
One study tried to assess this. It found that while organ mass explained the height-cancer relationship in eight of 15 cancers assessed, there were seven others where organ mass did not explain the relationship with height.
It is worth noting this study was quite limited by the amount of data they had on organ mass.
Another theory is that there is a common factor that makes people taller as well as increasing their cancer risk.
