Red blood cell fatty acids are associated with depression in a case-control study of adolescents.
Level 4 - case-series / case-control
Case-control study
PubMed 22464051 · doi:10.1016/j.plefa.2012.03.002
What was done
The authors compared red blood cell (RBC) fatty acid profiles, including the omega-3 index (EPA + DHA), between adolescents hospitalized for depression (n=150) and non-depressed controls (n=161). Multivariable logistic regression models adjusted for age, gender, body mass index (BMI), and race/ethnicity evaluated associations between fatty acid levels and case status, and assessed the classification improvement via the area under the ROC curve.
What was found
Cases and controls had similar age, gender, and BMI distributions, but differed in racial/ethnic composition due to different recruitment sites. - Unadjusted odds ratio (OR) for depression was 0.72 (95% CI: 0.55–0.95) for a 1% absolute increase in the omega-3 index. - In the adjusted model, the OR was 0.67 (95% CI: 0.49–0.93) for a 1 SD increase in DHA. - Adding a selected profile of seven fatty acids (DHA, myristic, stearic, oleic, trans linoleic, trans palmitoleic, and alpha-linolenic acids) to the baseline demographic model increased the area under the ROC curve by 12.6% (95% CI: 7.5%–17.6%).
Why it matters
This study extends previous adult findings to adolescents, showing that reduced red blood cell omega-3 levels and perturbed fatty acid profiles are associated with severe adolescent depression. It provides observational justification for clinical trials evaluating EPA and DHA supplementation in this population.
Limits
The case-control design cannot determine causality or temporality, as depressed states may alter dietary intake. Cases were recruited exclusively from hospital admissions, potentially limiting applicability to milder community-managed depression. Differences in recruitment sites introduced significant baseline racial/ethnic disparities between groups.
Cited by
- supports A lower omega-3 index is associated with an increased risk of depression.