A Prospective Study of <i>Trans</i> Fatty Acids in Erythrocytes and Risk of Coronary Heart Disease

Background— High consumption of trans fat has been linked to the risk of coronary heart disease (CHD). We assessed the hypothesis that higher trans fatty acid contents in erythrocytes were associated with an elevated risk of CHD in a nested case-control study among US women. Methods and Results— Blood samples were collected from 32 826 participants of the Nurses’ Health Study from 1989 to 1990. During 6 years of follow-up, 166 incident cases of CHD were ascertained and matched with 327 controls. Total trans fatty acid content in erythrocytes was significantly correlated with dietary intake of trans fat (correlation coefficient=0.44, P &lt;0.01) and was associated with increased plasma low-density lipoprotein cholesterol ( P for trend =0.06), decreased plasma high-density lipoprotein cholesterol concentrations ( P for trend &lt;0.01), and increased plasma low-density lipoprotein to high-density lipoprotein ratio ( P for trend &lt;0.01). After adjustment for age, smoking status, and other dietary and lifestyle cardiovascular risk factors, higher total trans fatty acid content in erythrocytes was associated with an elevated risk of CHD. The multivariable relative risks (95% confidence intervals) of CHD from the lowest to highest quartiles of total trans fatty acid content in erythrocytes were 1.0 (reference), 1.6 (0.7 to 3.6), 1.6 (0.7 to 3.4), and 3.3 (1.5 to 7.2) ( P for trend &lt;0.01). The corresponding relative risks were 1.0, 1.1, 1.3, and 3.1 ( P for trend &lt;0.01) for a total of 18:1 trans isomers and 1.0, 1.5, 2.5, and 2.8 ( P for trend &lt;0.01) for a total of 18:2 trans isomers. Conclusions— These biomarker data provide further evidence that high trans fat consumption remains a significant risk factor for CHD after adjustment for covariates.