Carcinogenic potential of fluorescent UV tanning sources can be estimated using the CIE erythema action spectrum

In legislation the CIE human erythema action spectrum is used to assess the risk of UV radiation appliances for household use. The most popular type of UV radiation source for private use is the low pressure 'UVA' radiation source, which mainly emits in the UVA area, but also has some emission in the UVB area. Recently reports have raised doubt whether the CIE erythema action spectrum is a good approximation for the carcinogenic risk. Therefore, it was investigated whether the carcinogenic potential of differing UV tanning sources, which mainly emit in the UVA area, could be assessed by using the CIE erythema spectrum. Two groups of lightly pigmented C3H/Tif mice were initially exposed to broad spectrum UV radiation with a high output of UVB (UVB emission 16.7%) during 84 days, in a daily dose of 4.67 Basic minimal erythema doses (Basic-MED). Subsequently, one group was exposed to Bellarium-S SA-1-12 (UVB emission 6.9%), the other to Philips TL 09R (UVB emission 2.2%), in a daily dose of 1 Basic-MED. The time to occurrence of seven tumour end-points was almost identical in the two groups, p > 0.4. To obtain further information on the relationship between the daily dose of common UV tanning sources measured in Basic-MED and tumour development, we combined the result of this experiment with the results of two others. There existed a negative correlation between the daily exposure dose measured in Basic-MED and the tumour induction time, p < or = 0.05. This inverse relationship was observed both when the UV tanning sources were administered with or without a prior exposure to broad spectrum UV irradiation. Our results indicate that the carcinogenic risk of UV tanning sources in the hairless C3H/Tif mouse can be estimated by the CIE erythema action spectrum.