Mediterranean diet, Dietary Approaches to Stop Hypertension, and Pro-vegetarian dietary pattern in relation to the risk of basal cell carcinoma: A nested case-control study within the Seguimiento Universidad de Navarra (SUN) cohort

Background: The association of dietary pattern with the risk of basal cell carcinoma (BCC) is little understood and has scarcely been investigated. Objectives: We assessed the association of several complete dietary patterns [Mediterranean, Dietary Approaches to Stop Hypertension (DASH), and Pro-vegetarian dietary pattern] with the risk of BCC, conducting a nested case-control study (4 controls for each case). Methods: Cases and controls were selected from the SUN (Seguimiento Universidad de Navarra) cohort using risk set sampling. Cases were identified among subjects free of skin cancer at baseline but who later reported a physician-made BCC diagnosis during the follow-up period. In the cohort we identified 101 incident cases of BCC. Results: In multivariable-adjusted conditional logistic regression analyses, better adherence to the Mediterranean diet (highest compared with lowest quintile) was associated with a 72% relative reduction in the odds of BCC (OR: 0.28; 95% CI: 0.10, 0.77; P_trend = 0.014); the DASH diet was associated with a 68% RR reduction (OR: 0.32; 95% CI: 0.14, 0.76; P_trend = 0.013) for the comparison between extreme quintiles. No association was found between a Pro-vegetarian dietary pattern and BCC. Higher fruit consumption (highest compared with lowest quintile, OR: 0.27; 95% CI: 0.11, 0.64; P_trend < 0.001) and low-fat dairy products (OR: 0.39; 95% CI: 0.16, 0.92; P_trend = 0.014) were associated with a lower BCC risk. Conclusions: Our results suggest that Mediterranean and DASH dietary patterns may be associated with a lower risk of BCC, but confirmatory studies are required. Am J Clin Nutr 2020;112:364-372.