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The risks of using sunbeds far outweigh the rewards, according to new research.
Tanning machines expose users to more damaging ultraviolet (UV) radiation and less beneficial vitamin D than natural sunlight, according to scientists from the National Institute of Water and Atmospheric Research (Niwa).
The study of 500 people of different skin types, age, and gender, was part of ongoing research to determine the relationship between vitamin D in the blood and past personal exposure to UV radiation from various sources, including sunlight and sunbeds.
Vitamin D, acquired by exposure to sunlight, is crucial in skeletal development, immune function, and blood cell formation, has also been implicated in a wide range of ailments, including cancer and heart disease.
The study aimed to identify seasons and regions where various groups were at risk, and what steps should be taken to reduce the risk.
Researchers found the average UV index for the sunbeds was similar to New Zealand summer sunlight. But the same exposure in a sunbed makes less vitamin D than natural sunlight, based on knowledge of the wavelengths that produce vitamin D and sunburn.
"More disturbingly, the intensity of radiation at some wavelengths from these sunbeds was several times higher than ever occurs in sunlight at the earth's surface," said Dr Richard McKenzie, Niwa principal scientist in atmospheric radiation.
"By using these sunbeds, we expose ourselves to unknown risks. Our skins may not be able to cope well with this sort of stress."
The research was part of a collaborative study between Niwa, Otago University, and Auckland University. It is funded by the Health Research Council.