Plasma Omega-3 and Omega-6 Concentrations and Risk of Cutaneous Basal and Squamous Cell Carcinomas in Australian Adults

Abstract

Laboratory-based evidence suggests that omega-3 and omega-6 polyunsaturated fatty acids may affect skin photocarcinogenesis, but epidemiologic evidence is inconsistent. In 1,191 White Australian adults, we prospectively investigated associations between baseline plasma concentrations of omega-3 and omega-6 fatty acids and cutaneous basal cell carcinomas (BCC) and squamous cell carcinomas (SCC). Relative risks (RR) and 95% confidence intervals (CI) were estimated on the basis of number of histologically confirmed tumors diagnosed during follow-up (1997-2007). Plasma eicosapentaenoic acid (EPA) concentrations and omega-3/-6 ratio showed significant inverse associations with SCC tumors, comparing higher tertiles with the lowest, in age-and sex-adjusted models (P trend ¼ 0.02 and 0.03, respectively) which weakened after adjustment for past sun exposure. Associations between EPA and SCC were stronger among participants with a history of skin cancer at baseline (n ¼ 378; highest vs. lowest tertile: RR ¼ 0.50; 95% CI, 0.28-0.92; P trend ¼ 0.01). Total omega-6 was inversely associated with BCC tumors in multivariate models (P ¼ 0.04; highest vs. lowest tertile: RR ¼ 0.71; 95% CI, 0.51-0.99), and more strongly in the subgroup with past skin cancer. Linoleic and linolenic acids were also inversely associated with BCC occurrence in this subgroup. When fatty acids were analyzed as continuous variables, however, there was no evidence of any linear or nonlinear associations. This study provides some support for reduced skin cancer risk with high plasma concentrations of omega-3 and omega-6 fatty acids, but results depended on how fatty acid data were modeled. Further investigation of these associations in larger datasets is needed. Cancer Epidemiol Biomarkers Prev; 22(10); 1900-5. Ó2013 AACR.

N-6 Polyunsaturated Fatty Acids and Risk of Cancer: Accumulating Evidence from Prospective Studies

“…The detailed process of study selection is presented in Supplementary Figure S1. Forty-one articles reported RRs for n-6 PUFA intake only [ [24,53,58,75,80], endometrium (3 articles and 1756 cases) [31,36,85], skin (3 articles and 36,819 cases) [23,39,44], and others (ovarian, lung, liver, lymphoma, and gastric; 6 articles and 2958 cases) [25,30,47,51,83,90]. Three articles provided RRs of any type of cancer [22,38,73].…”

“…Summary of pooled relative risks (RR) of cancer risk for n-6 polyunsaturated fatty acid (PUFA) intake. PUFAs and the risk of cancer[24,[26][27][28]32,35,38,39,[41][42][43]47,51,52,55,56,61,62,67,68,70,71,73,74,76,82,84,88,89] (Supplementary…”

Bioactive Compounds Isolated from Microalgae in Chronic Inflammation and Cancer

“…A prospective cohort study evaluated associations between plasma phospholipid levels of n -3 and n -6 PUFAs and the development of NMSC. The results showed a reduced risk of SCC in patients with high EPA concentrations and omega-3/-6 ratio and an inverse association of total omega-6 and BCC risk [ 354 ]. However, a study of over 40,000 American male health professionals failed to find a link between n -3 PUFA intake and BCC risk [ 355 ].…”

Erythrocyte Membrane Unsaturated (Mono and Poly) Fatty Acids Profile in Newly Diagnosed Basal Cell Carcinoma Patients

“…The higher composition of 18:2 n-6 and n-6 PUFAs were associated with increased risk for prostate cancer and breast cancer, but that of AA had no association [ 19 ]. Animal studies indicate that n-6 PUFA increase carcinogenesis [ 23 ]. Adds to evidence from animal studies, our results are consistent with a case-control study which reported a significantly higher risk of SCC with greater AA concentrations in erythrocytes membranes [ 20 ].…”

“…A decrease in risk of SCC with increased intake of diets with a high n-3/n-6 ratio was reported in a population-based case-control study [ 20 ]. Ratio of n-3/n-6 in circulation plays a key role in determining the overall effect on skin photocarcinogenesis [ 23 ].…”