Trans-fatty acids in New Zealand patients with coronary artery disease.

Background: Dietary surveys indicate that New Zealanders have a low intake of trans-fatty acids (TFA) with little derived from industrial sources. This observational cross-sectional study in New Zealand patients with surgical coronary artery disease assesses the plasma levels of TFA and the association of TFA levels with clinical markers of vascular disease.

Methods: 390 patients with severe coronary artery had fasting blood tests taken. Plasma levels of four TFA derived from hydrogenated vegetable oils and ruminant animal products were measured by gas chromatography. Relations between plasma TFA levels and the recent occurrence of myocardial infarction, the presence of polyvascular disease, and serum levels of C-reactive protein (CRP) were assessed.

Results: The median TFA level was 0.85% by weight of total fatty acids (IQR 0.59-1.79%), with skewed distribution to the right. For the lowest (<0.74%), middle (0.74-1.07%), and highest (>1.07%) thirds of total TFA, respectively, the proportion of patients with polyvascular disease was 10%, 16%, and 27% (p = 0.0004). Plasma CRP also increased by tertile of TFA (median 2.0, 2.9, 3.2 mg/l, p = 0.007). The association with polyvascular diseases and CRP remained significant after adjustment for risk factors. Significant associations were present between plasma TFA from both ruminant and hydrogenated vegetable oil sources and these markers of cardiovascular risk.

Conclusions: There is an association between relatively low plasma levels of total TFA, mostly derived from ruminant sources, and an increased risk of polyvascular disease and increased CRP in patients with severe coronary artery disease. These high-risk patients may benefit from a targeted approach to minimize all sources of TFA in the diet.