Abstract Introduction: Nonmelanoma skin cancers (NMSC) including basal cell and squamous cell carcinomas are the most common human cancers. DNA damage can be caused by exposure to solar UV light and other types of radiation, dietary factors, and ageing. The relationship between DNA damage and oncogenesis suggests that diminished DNA repair capacity (DRC) is involved in tumorigenesis. Purpose: The purpose of this study was to identify and assess selected exposures and DRC as predictors for NMSC in Puerto Rico. Methods: An incident-cases case-control study was conducted. A total of 477 NMSC cases and 365 controls were compared regarding DRC levels and other selected factors. Participants with low and high DRC levels were also compared regarding the same factors as in NMSC. DRC was measured using a host-cell reactivation assay with a luciferase reporter gene irradiated with UV light and transfected into human peripheral lymphocytes from participant's blood samples. A standardized epidemiological questionnaire was used to collect data from the participants. The crude and multiple logistic regression adjusted odds ratio was used to assess the associations between NMSC or DRC levels with selected factors after adjusting for age, gender, skin, hair, and eye color, and other potential confounders simultaneously. Results: Exposures increasing the odds for NMSC were being male, aging, light skin, presence of freckles, light hair, light eye color, increased sun exposure, severe insolations, family history of NMSC, and low DRC (p < 0.05). Protective factors found in the study included using sun block, taking aspirin regularly, and multivitamin supplements intake (p < 0.05). Factors associated with low DRC level were aging, light skin, sun exposure, severe insolations and not using sun block regularly. Discussion: The present study identified major epidemiologic factors for NMSC in Puerto Rico that are consistent with similar investigations elsewhere. Low DRC was strongly associated with NMSC (Matta et al, 2003). New unpublished data include the finding of the protective effect of multivitamin supplementation. Light skin, increased sun exposure, severe insolations and not using sun block regularly were associated with low DRC. Conclusions: The protective effect of multivitamins deserves further consideration to confirm our findings. Persons with light skin, increased sun exposure and not using sun block regularly had low DRC levels and increased odds for NMSC. DRC measurements might be used to monitor the potential preventive impact of multivitamins and sun block when used as preventive therapy. Citation Information: Cancer Epidemiol Biomarkers Prev 2010;19(10 Suppl):A90.
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