Role of occupational and recreational sun exposure as a risk factor for keratinocytic non-melanoma skin cancers: an Italian multicenter case-control study

Abstract

Background: Sun exposure is the main external risk factor for keratinocytic non-melanoma skin cancer (NMSC). Outdoor workers are at increased risk, but the relationship of NMSC with occupational solar exposure is often confounded by concurrent recreational sun exposure. We compared the percentage of outdoor workers in NMSC patients versus controls without history of NMSC and assessed occupational and recreational sun exposure in both groups, evaluating also other risk factors and use of protective measures.

Methods: Adult NMSC patients and controls without history of NMSC or actinic keratoses, matched for sex and age range, were recruited in the Departments of Dermatology of seven Italian University Hospitals, with a 1:2 patient/control ratio whenever possible. Data were collected using specifically designed questionnaires.

Results: Eight hundred thirty-four patients and 1563 controls were enrolled. History of outdoor work was significantly (P=0.033) more frequent in patients. Patients were more sun exposed from outdoor leisure activities (P=0.012) and sunbathed for longer periods (P=0.13) and between 12 pm and 3.30 pm (P=0.011). Cumulative sun exposure during hobbies was similar between patients and controls in outdoor workers, higher (P<0.05) in patients among indoor workers. Patients and controls with history of outdoor work were more sun exposed at work than during leisure activities (P<0.001). Use of sunscreens by outdoor workers was very low, particularly at work (19.9%). Patients used sunscreens more than controls (P=0.002).

Conclusions: Occupational and recreational sun exposure are relevant risk factors for outdoor and indoor workers respectively. Sunscreens are alarmingly underused, particularly at work, and are used mainly by patients.