Plasma Industrial and Ruminant Trans Fatty Acids and Incident Type 2 Diabetes in the EPIC-Potsdam Cohort
While dietary intake of trans fatty acid (TFA) is a major public health concern as it raises the risk of cardiovascular events, it remains unclear whether TFA also impact risk of type 2 diabetes and whether industrial TFA and ruminant TFA exert the same effect on health.
Research Design and Methods:
To investigate the relation of seven ruminant and industrial TFA, including two conjugated linoleic acids (CLA), plasma phospholipids TFA were measured in a case-cohort study nested within the European Prospective Investigation Into Cancer and Nutrition (EPIC)-Potsdam cohort. The analytical sample was a random subsample (n=1,248) and incident cases of type 2 diabetes (n=801) over a median follow-up of 6.5 years. Using multivariable Cox regression models, we examined associations of TFA with incident type 2 diabetes.
The TFA subtypes were intercorrelated with each other, with other fatty acids, and to different food sources. After controlling for other TFA, the industrial TFA (18:1n-6t, 18:1n-9t, 18:2n-6,9t) were not associated with diabetes risk. Some ruminant TFA subtypes were inversely associated with diabetes risk: vaccenic acid (18:1n-7t, HR per SD 0.72; 95% CI 0.58-0.89) and t10c12-CLA (0.81; 0.70-0.94), while c9t11-CLA was positively associated (1.39; 1.19-1.62). Trans-palmitoleic acid (16:1n-7t) was not associated with diabetes risk when adjusting for the other TFA (1.08; 0.88-1.31).
The TFA conformation plays an essential role in their relationship to diabetes risk. Ruminant TFA subtypes may have opposing relations to diabetes risk. Previous observations for reduced diabetes risk with higher circulating trans-palmitoleic acid are likely due to confounding.