UV LIGHT FOR NAIL COSMETICS AND THE RISK OF CANCER
by Prof Dr. rer.Nat.habil.Ralf Janda, director of research and development of the Wilde Group (manufacturer of LCN products)
Light curing units to cure nail resins cause cancer - really?
Title stories of previously published newspapers discussed the risk of UVA-light emitted from light-curing units to cure nails resins. Although some papers cited doctors from the sunny state Texas in the US who have seen skin cancer on the hand of one lady, the readers shall keep in mind that the outer surface of the hand is always completely unprotected against strong sunlight - who is biking with gloves?
Based on these yellow press publications there are many concerns in public about nail cosmetics using light-curing nail resins. However, based on scientific knowledge, all these concerns are absolutely not justified. Reports about the worldwide economic crisis have been stressed for many months and therefore, have now become boring. Other shocking news is needed to keep up papers' sales.
What is the situation?
UVA-light curing devices to cure nail resins have been used in the nail industry for approximately 25 years and millions of women are treated every year with these devices. No articles in medical literature were found reporting about a single case of tumours on women's hands caused by UVA nail resin curing devices.
As it is known to everybody UV-light is always present in our life, the risks of over-exposure are widely discussed and a broad scientific knowledge is available. The effects of UV-light on humans have been well investigated and standard values are defined especially with regard to tanning beds.
UV-light is differentiated in UVA- (wavelength 320-400nm) and UVB-light (wavelength 290-320 nm). It is proven that over-exposure of UV-light can cause different types of skin cancer (melanoma). Whereas UVB-light causes severe sunburn, UVA-light is responsible for pigmenting the skin and therefore, UVA-lamps are used for tanning beds. Since no sunburn is caused by UVA-light, it was considered to be rather safe for a long period of time. However, science learned that UVA-light penetrates skin to much deeper regions and therefore, it represents a high risk for the development of tumours and it is proven that fast skin ageing occurs.
However, UV-light (UVA and UVB) is not only risky but also healthy - the dose is decisive. It is necessary to synthesise vitamin D in our bodies which is important for a sound bone structure. It also positively influences the immune system, the metabolism, blood pressure and other physical and psychical factors. UV-light is also widely used for many medical therapies.
What are the hard facts?
For the nail curing devices only the UVA amount is of interest. The irradiance of an LCN curing device is approximately 70 W/m2 in comparison with a tanning bed performing approximately 300 W/m2.
Literature reports that UVA-radiation doses of around 100.000 Ws/m2 is needed to achieve an even noticeable tanning of the skin. This means you would have to be in a tanning bed performing 300 W/m2 for at least 6 minutes (representing a radiation dose of 108.000 Ws/m2) to see just a little pigmenting. Normally people spend around 20 minutes in a tanning bed to get a nice cosmetic appearance what represents a radiation dose of 360.000 Ws/m2.
Within 2 minutes curing the LCN curing device performs a radiation dose of 8.400 Ws/m2 which is approximately 40 less than 20 minutes tanning bed. It has also to be regarded that the whole body surface (2 m2) is irradiated in a tanning bed in comparison with the irradiation of hand surface 0,015 m2 in a curing device.
Furthermore, literature also reports that European regulatory authorities, including those in the UK and Sweden, have given exposure standards for UVA. For the spectral region of 315-400nm (UVA), the total irradiance incident on unprotected eyes and skin for periods of greater than 1.000 seconds (approximately 16 minutes) should not exceed 10 W/m2, and for exposure times of 1.000 seconds or less the total radiant exposure of unprotected eyes and skin should not exceed 10.000 J/m2.
Comparing the radiation of the LCN curing device with these given standards the situation is as follows:
The irradiance incident is 2 minutes (one curing cycle) and therefore, the exposure is far below the standard. Expressed in J/m2 the LCN device performs 8.400 J/m2 which again is below the standard. Please keep in mind that the standard is also valid for unprotected eyes meaning that the 2 minutes curing cycle does not even damage the eyes. However, LCN instructions for use claim adequate eye protection to make the process absolutely safe.
Hands are normally totally unprotected against sunlight or the lights of tanning beds. Especially during biking or sunbathing the outer surfaces of hands are extremely exposed to UV-radiation. These facts elucidate why skin cancer is observed on hands.
No reports are available proving that tumours are caused by nail curing devices. Compared with tanning beds the LCN curing devices are 40 times safer. Consulting existent standards for UVA irradiance of unprotected eyes and skin the LCN devices can be considered as totally safe when properly used. Moreover, light-curing nail cosmetics have a crucial positive impact on our health when compared with archaic powder/liquid technique. Therefore, it is unjustifiable to strike terror to people.
However, there is an easy way to eliminate peoples' fear completely - use disposable gloves and cut off the fingertips. This is also more hygienic.
However, it is always a concern of research and development to make safe things safer and to improve quality of life. Since 2007 LCN offers the LED curing device skyLED which emits almost no UV-light and in the middle of 2009 LCN will introduce skyLED-2 performing an emission completely above 400nm.
All clients of well-trained nail professionals can be sure and confident that the light-curing technique is the most safe and health oriented nail cosmetic known in our days.