Tanning beds, sunlamps, and risk of cutaneous malignant melanoma

Background: A number of studies have been conducted evaluating the risk of cutaneous malignant melanoma after exposure to sunlamps and/or sunbeds. The proportion of subjects in the individual studies who have reported exposure has, in general, been modest, and the resulting risk estimates for melanoma have been unstable with wide 95% confidence intervals (95% CI). The inconclusive results seen in individual studies have resulted in confusion as to the carcinogenicity of these devices. Methods: We conducted a systematic review and metaanalysis of these studies. A review of the literature from Jan 1, 1984 to April 2004 using MEDLINE identified 12 case-control studies and I cohort study which quantitatively evaluated the use of sunlamps and/or sunbeds and subsequent melanoma. After applying exclusion/inclusion criteria, 9 case-control and 1 cohort study provided data for the analysis. Summary odds ratios (OR) and 95% CIs for sunlamp/sunbed use and subsequent melanoma were calculated using a random-effect model. Results: Ten studies provided data for assessment of melanoma risk among subjects who reported "ever" being exposed compared with those "never" exposed. A positive association was found between exposure and risk (summary OR, 1.25; 95% CI, 1.05-1.49). Significant heterogeneity between studies was present. Evaluation of the metrics "first exposure as a young adult" (5 studies) and "longest duration or highest frequency of exposure" (6 studies) also yielded significantly elevated risk estimates (summary OR, 1.69; 95% CI, 1.32-2.18, and 1.61; 95% Cl, 1.21-2.12, respectively, with no heterogeneity in either analysis). Conclusions: Results indicate a significantly increased risk of cutaneous melanoma subsequent to sunbed/sunlamp exposure.