Cancer death is related to high palmitoleic acid in serum and to polymorphisms in the SCD-1 gene in healthy Swedish men

Background: A high proportion of monounsaturated fatty acids (MUFAs) or a high ratio of MUFAs to saturated fatty acids in plasma, reflecting a high activity of the lipogenic enzyme stearoyl-CoA desaturase- 1 (SCD-1), has been shown to be related to cancer death and incidence in some studies. Objectives: The objective was to study whether the serum cholesteryl ester proportion of palmitoleic acid [16:1n-7 (16:1 omega-3)] and the ratio of palmitoleic to palmitic acid (16:1n-7/16:0), as an estimation of the activity of SCD-1, are related to cancer death and to investigate whether polymorphisms in the SCD-1 gene are related to cancer Mortality. Design: A community-based cohort of 50-y-old men was followed for a maximum of >40 y. Survival analysis was used to relate fatty acid composition in serum, analyzed at baseline by gas-liquid chromatography (n = 1981), and single nucleotide polymorphisms in the SCD-1 gene (n = 986) to cancer death. A 7-d dietary record was completed at age 70 y (n = 880). Results: The proportions of 16: 1n-7 and the ratio of 16:1n-7 to 16:0 were associated with cancer mortality during follow-up in a comparison of the highest with the lowest quartile of 16:1n-7 (adjusted HR: 1.37; 95% CI: 1.04, 1.82). Inherited variance of the SCD-1 gene seemed to be related to cancer death, especially among men with a low proportion of PUFA in the diet in a comparison of the highest with the lowest weighted genetic risk score (HR: 2.14; 95% 1.13, 4.04). Conclusion: The findings are compatible with the hypothesis that there is an association between endogenously synthesized MUFAs and cancer death.