We measured the RBC fatty acid composition of cases admitted to the hospital for depression (n=150) and compared it to that of controls (n=161).
Cases and controls had similar ages, gender proportions, and body mass index (BMI) distributions, but there was a significant difference in racial/ethnic composition due to differences in recruitment sites. The unadjusted odds ratio for case status was 0.72 (95%CI; 0.55-0.95) for a 1%absolute increase in the omega-3 index. A multivariable logistic regression model was used to determine which fatty acids were useful in classifying cases and controls; BMI, age, gender, and race/ethnicity were forced into the model. Seven fatty acids were selected (DHA, myristic, stearic, oleic, trans linoleic, trans palmitoleic, and alpha-linolenic acids) to optimize the model fit to the data. In the adjusted model, the odds ratio was 0.67 (95%CI; 0.49-0.93) for a 1 SD increase in DHA. Adding the seven fatty acid profile to the basic model increased the area under the ROC curve by 12.6%(7.5%-17.6%).
These findings support the hypothesis that adolescent depression is associated with a perturbed RBC fatty acid pattern which includes a reduced omega-3 index. Intervention studies with EPA and DHA should be conducted in this vulnerable population for which few, safe therapeutic options currently exist.