Actinic damage on the back is significantly determined by MC1R variants and previous sun exposure compared with other body sites in a multivariate analysis.

BACKGROUND: Only recently, site-dependent associations of actinic damage with melanoma were identified in our study population. OBJECTIVES: To elucidate the diverse aetiologies for actinic damage at different body sites. METHODS: We performed multivariate logistic regression analyses to identify independent risk factors for actinic damage on the face, hands and the back in 2112 participants of central European origin. RESULTS: For actinic damage on the face, age was the only risk factor that remained consistently significant in a multivariate analysis, whereas actinic damage on the back was predominantly associated with number of sunburns, freckles in childhood, holiday weeks and male sex. Moreover, we identified a particular significance of MC1R variants and dorsal actinic skin damage. CONCLUSIONS: The particular effect of MC1R variants and sun exposure during recreational time on dorsal actinic damage indicates that actinic damage on the back is more informative regarding susceptibility to sunlight and past sun exposure associated with melanoma risk.