Trends in UV Irradiance of Tanning Devices in Norway: 1983-2005

Photochemistry and Photobiology, Sep/Oct 2008 by Nilsen, Lill Tove N, Hannevik, Merete, Aalerud, Tommy N, Johnsen, Bj�rn, Friberg, Eva G, Veier�d, Marit B

ABSTRACT

Indoor tanning increases skin cancer risk, but the importance of different parts of the UV spectrum is unclear. We assessed irradiance of tanning devices in Norway for the period 1983-2005. Since 1983, all tanning models needed approval before being sold or used. UV Type 3 limits were valid from late 1992 (

INTRODUCTION

The first commercial tanning devices were single mercury arc lamps, often causing severe sunburn and acute eye damage. Fluorescent tube tanning beds became popular during the 1980s, and indoor tanning has become widely used in many countries during the recent two decades (1). Use may be associated with adverse health effects. Immediate effects include sunburn, phototoxic and photoallergic reactions and eye damage, while later effects include skin aging and skin cancer (1-3).

A handful of studies have described UV output and spectral characteristics from indoor tanning devices (4-11). Yet, aside from the general knowledge about the change over time from predominantly UVB (280-315 nm) to UVA (315-400 nm), little data are available about the time trends. As regards skin cancer, UVB is important for squamous cell carcinoma development, but both UVB and UVA may play a role for cutaneous malignant melanoma and basal cell carcinoma where more knowledge is needed concerning the action spectrum (1,2,12). Experimental models mimicking the induction of skin cancer are still not satisfactory (1), therefore epidemiologic studies are important. To date, these have typically investigated the effects of solar and artificial UV exposure without considering spectra. Indoor tanning has been an important source of UVA since the early 1980s and calendar year of use of tanning devices was discussed in the first prospective study relating malignant melanoma to indoor tanning (13-15) and in a recent review (1,2). Moreover, exposure to solar UVB initiates the synthesis of vitamin D in the skin, and the wavelength distribution of sunbed UV irradiance is of importance in the ongoing discussion of positive and negative effects of sunbed use (16-18).

Norway and Sweden were among the first countries to implement national regulations for indoor tanning devices (19,20). Since 1983, all models are required to have an approval from the Norwegian Radiation Protection Authority (NRPA) before being sold, used or advertised in Norway. The approval is based on UV measurements from accepted laboratories, and these data have been recorded since 1983. In addition, the regulations include requirements for user instructions and labeling (19).

The few studies that have assessed compliance with regulations suggest poor compliance, but more knowledge is required (1,9,10). In 1998-1999 and 2003, NRPA performed inspection surveys in Norway to study compliance with regulations and to assess sunbed irradiance. This study focuses on irradiance of approved and inspected tanning devices in Norway and these data provide a unique opportunity to assess UV radiation from indoor tanning devices in use from 1983 to 2005. Comparisons with irradiance of natural sun are also performed.

MATERIALS AND METHODS

The first Norwegian regulation of indoor tanning devices was implemented in 1983 (19) and UV Type 3 requirements took effect in late 1992. A UV Type 3 appliance is provided with a UV emitter such that the biologic effect is caused by radiation having wavelengths both shorter and longer than 320 nm (the cutoff point for UV Types 1-4) and characterized by a limited irradiance over the whole UV radiation band (

Indoor tanning devices approved for side or use. A total of 496 models of indoor tanning devices were approved in 1983-2005, but irradiance data were not available for 50 models as approvals were based on Swedish endorsements (equal irradiance limits). The 446 models with available irradiance data include 41 models approved with several lamp types and thereby different spectral output. All approvals are based on type testing performed by European laboratories, including NRPA's laboratory from 1995. Since 1997, the approval was based on the maximum UV irradiance measured anywhere in the device (25). Previously, the mean irradiance was usually recorded, i.e. the mean irradiance measured over the surface of the device or at a distance stated in the instructions for use. Values for each part of the device (bench, canopy, face) are presented when available.

Inspection surveys in tanning establishments. The inspection survey in 1998-1999 included 130 establishments along the coastal road from Bergen (western Norway) via the southern coast to Drammen (southeast Norway). The survey in 2003 included 52 establishments in five municipalities on the east side of the lake Mj�sa (eastern Norway) and the cities Trondheim (central Norway) and Troms� (northern Norway). All establishments that could be identified in the selected regions were inspected, including tanning salons, fitness centers, hairdressing or beauty salons, kiosks and hotels. They were identified from the regional phone catalogs in advance. A few were identified by information from rival establishments throughout the inspections. No announcements were made in advance. We included all tanning devices found in the inspected establishments, 1034 in 1998-99 and 307 in 2003. Compliance was recorded according to the following criteria: tanning models were approved, sunlamps were in accordance with the approvals, user instruction with exposure schedule followed each tanning device, poster with precaution text was present, and warning and approval labels were present on each device.