Known and potential new risk factors for skin cancer in European populations: a multicentre case-control study

Background During recent years numerous studies have suggested that personal and environmental factors might influence cancer development. Objectives To investigate environmental and personal characteristics associated with skin cancer risk. Methods A multicentre hospital-based casecontrol study was performed in Finland, Germany, Greece, Italy, Malta, Poland, Scotland and Spain, including 409 patients with squamous cell carcinoma (SCC), 602 with basal cell carcinoma (BCC) and 360 with cutaneous malignant melanoma (CMM) and 1550 control persons. Exposures were assessed by questionnaires that were partly self-administered, partly completed by dermatologists. Unconditional logistic regression modelling was used to assess associations including the influence of certain drugs and food items on skin cancer risk. Results The usual associations were observed for sun exposure and pigmentation characteristics, with chronic sun exposure being most strongly associated with SCC risk, and naevi and atypical naevi with CMM risk. Use of ciprofloxacin was associated with a decreased risk of BCC [odds ratio (OR) 0.33] and use of thiazide diuretics was associated with an increased risk of SCC (OR 1.66). Ciprofloxacin was also associated with SCC (OR 0.34) and thiazines with BCC (OR 2.04), but these associations lost significance after correction for multiple testing. Consumption of pomegranate, rich in antioxidants, was associated with decreased BCC and SCC risk, also after correcting for multiple testing. Recent experience of stressful events was associated with increased risk, particularly of CMM. Conclusions In this large casecontrol study from across Europe the expected associations were observed for known risk factors. Some new potential protective factors and potential risk factors were identified for consumption of certain food items, medication use and stress, which deserve further investigation in future studies.