Association between plasma trans‐fatty acid concentrations and diabetes in a nationally representative sample of <scp>US</scp> adults

Abstract Background A diet high in trans‐fatty acids (TFA) induces insulin resistance in rodent models and primates. However, previous epidemiological studies on the association between TFAs, based primarily on self‐reported intake from the diet, and diabetes in humans have yielded conflicting results. Herein we examined the associations of objectively measured plasma TFA concentrations with diabetes in a large population‐based study among US adults. Methods We included 3801 participants aged ≥20 years from the National Health and Nutrition Examination Survey 1999–2000 and 2009–10. Four major TFAs, namely palmitelaidic acid (C16:1 n‐7t), elaidic acid (C18:1 n‐9t), vaccenic acid (C18:1 n‐7t), and linolelaidic acid (C18:2 n‐6t, 9t), were measured in fasting plasma using gas chromatography–mass spectrometry. Diabetes was defined by self‐reported physician diagnosis, plasma fasting glucose ≥126 mg/dL, or HbA1c ≥6.5%. Results After adjustment for other major risk factors, the odds ratios (95% confidence intervals) of diabetes comparing the highest with lowest quintile of plasma TFAs was 2.19 (1.27–3.79) for total TFAs ( P trend = 0.01), 2.34 (1.48–3.72) for elaidic acid ( P trend = 0.0004), 1.33 (0.82–2.15) for linolelaidic acid ( P trend = 0.18), 1.58 (0.97–2.58) for palmitelaidic acid ( P trend = 0.02), and 1.64 (0.95–2.84) for vaccenic acid ( P trend = 0.08). In addition, total TFAs, elaidic acid, palmitelaidic acid, and vaccenic acid were significantly associated with fasting glucose, fasting insulin, the insulin resistance index, and HbA1c. Conclusions In a nationally representative population, plasma TFAs, in particular elaidic acid, were positively associated with diabetes and biomarkers of glucose metabolism.