A combination of plasma phospholipid fatty acids and its association with incidence of type 2 diabetes: The EPIC-InterAct case-cohort study
Authors: Fumiaki Imamura, Stephen J. Sharp, Albert Koulman, Matthias B. Schulze, Janine Kröger, Julian L. Griffin, José M. Huerta, Marcela Guevara, Ivonne Sluijs, Antonio Agudo, Eva Ardanaz, Beverley Balkau, Heiner Boeing, Veronique Chajes, Christina C. Dahm, Courtney Dow, Guy Fagherazzi, Edith J. M. Feskens, Paul W. Franks, Diana Gavrila, Marc Gunter, Rudolf Kaaks, Timothy J. Key, Kay-Tee Khaw, Tilman Kühn, Olle Melander, Elena Molina-Portillo, Peter M. Nilsson, Anja Olsen, Kim Overvad, Domenico Palli, Salvatore Panico, Olov Rolandsson, Sabina Sieri, Carlotta Sacerdote, Nadia Slimani, Annemieke M. W. Spijkerman, Anne Tjønneland, Rosario Tumino, Yvonne T. van der Schouw, Claudia Langenberg, Elio Riboli, Nita G. Forouhi, Nick J. Wareham
Journal: PLoS Medicine (2017)

Background Combinations of multiple fatty acids may influence cardiometabolic risk more than single fatty acids. The association of a combination of fatty acids with incident type 2 diabetes (T2D) has not been evaluated. Methods and findings We measured plasma phospholipid fatty acids by gas chromatography in 27,296 adults, including 12,132 incident cases of T2D, over the follow-up period between baseline (1991–1998) and 31 December 2007 in 8 European countries in EPIC-InterAct, a nested case-cohort study. The first principal component derived by principal component analysis of 27 individual fatty acids (mole percentage) was the main exposure (subsequently called the fatty acid pattern score [FA-pattern score]). The FA-pattern score was partly characterised by high concentrations of linoleic acid, stearic acid, odd-chain fatty acids, and very-long-chain saturated fatty acids and low concentrations of γ-linolenic acid, palmitic acid, and long-chain monounsaturated fatty acids, and it explained 16.1% of the overall variability of the 27 fatty acids. Based on country-specific Prentice-weighted Cox regression and random-effects meta-analysis, the FA-pattern score was associated with lower incident T2D. Comparing the top to the bottom fifth of the score, the hazard ratio of incident T2D was 0.23 (95% CI 0.19–0.29) adjusted for potential confounders and 0.37 (95% CI 0.27–0.50) further adjusted for metabolic risk factors. The association changed little after adjustment for individual fatty acids or fatty acid subclasses. In cross-sectional analyses relating the FA-pattern score to metabolic, genetic, and dietary factors, the FA-pattern score was inversely associated with adiposity, triglycerides, liver enzymes, C-reactive protein, a genetic score representing insulin resistance, and dietary intakes of soft drinks and alcohol and was positively associated with high-density-lipoprotein cholesterol and intakes of polyunsaturated fat, dietary fibre, and coffee (p < 0.05 each). Limitations include potential measurement error in the fatty acids and other model covariates and possible residual confounding. Conclusions A combination of individual fatty acids, characterised by high concentrations of linoleic acid, odd-chain fatty acids, and very long-chain fatty acids, was associated with lower incidence of T2D. The specific fatty acid pattern may be influenced by metabolic, genetic, and dietary factors.