New research shows that there are up to 19 per cent more skin melanomas on the left sides of people in Britain than on the right.
Similar differences were also found in four other countries by the researchers who looked at the sites of almost 100,000 tumours.In the first study of its kind, researchers from the from the NHS, the US National Institutes
In England, there were 10,345 on the left side, and 9,267 on the right in England, showing a 12 per cent left side bias. In Scotland, there were 19 per cent more cases on the left - 1,667 compared to 1,410. Australia and the US were lowest, with an eight per cent left side bias
In all countries they found a left side bias in melanoma, the most serious form of skin cancer whose incidence has doubled in the last 20 years to around 8,000 cases, with 1,800 deaths linked to spread of the disease. The research, being published in the European Journal of Cancer this week, shows that, overall, there were 51,338 melanomas on the left, and 46,883 on the right. The difference are found in both sexes.
Ultraviolet light exposure is the major cause of all types of skin cancer, but why there should be more melanomas on the left than the right is not clear.
The researchers say there are several possible reasons for such a bias. They reject the idea that it is a chance findings because the same trend was found in all cancer registries, and for the same reason they reject a possibly of reporting errors.
They looked at the idea that handedness - 11.5 per cent of the population are left handed - might have an effect on the way sunblocks are applied, but reject that too: "While handedness might result in differential application of sunscreen to the arms, this argument is unlikely to apply to the legs or to young children who have sunscreen applied by their parents," they say.
"The fact that there is an excess of left-sided melanomas on the lower as well as the upper limb makes handedness a less convincing explanation."
Source - Independent