(PTFS21-05-24) Impact of Changing Eicosapentaenoic Acid and Docosahexaenoic Acid Levels on Hematologic Biomarkers

Objectives: Risk biomarkers for disease and mortality include blood eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) fractions, neutrophil-lymphocyte ratio (NLR), and red blood cell (RBC) distribution width (RDW). Cross-sectional studies have reported inverse associations between both NLR and RDW values with the omega-3 index (O3I, RBC EPA+DHA). We aimed to determine if changes in EPA+DHA levels are associated with changes in NLR and RDW values by studying baseline and post-treatment values measured in randomized, controlled trials (RCTs).

Methods: Data were combined from two fish oil supplementation RCTs (1. n=115 participants; 0, 300, 600, 900 or 1800 mg EPA+DHA/d; 5mo; 2. N=184; 0 or 2500 mg EPA+DHA/d; 6mo). Pre- and post-treatment levels of EPA and DHA were measured by gas chromatography from RBCs (1) or plasma (2) and expressed as % of total fatty acids whereas NLR and RDW were obtained from routine hematology. We examined whether pre- to post changes (Δ) in O3I were associated with ΔNLR or ΔRDW using regression models adjusting for age, sex, BMI, study, pre-O3I, and either pre-NLR or pre-RDW, with parallel analyses using fish oil dose instead of ΔO3I.

Results: The pooled sample was 41% male with Mean±SD of 41±18y, BMI=25.5±4.3. NLR=1.75±0.71 and RDW=13.08±0.64 at baseline. O3I increased in supplemented individuals (300, 600, 900, 1800 & 2500) from 4.76±1.03% (pre) to 8.22±1.89% (p < 0.0001). Pre- and post-O3I for controls were 4.81±0.90% and 4.33±0.71% (p < 0.0001), respectively. We found a statistically significant association between ΔEPA+DHA and ΔNLR [adjusted correlation (r) -0.11 (95% CI: -0.01, -0.22; p=0.04)], but not between ΔEPA+DHA and ΔRDW [adjusted r 0.07 (95% CI: -0.05, 0.18; p=0.25)]. These results mirrored those found in models looking at dose-response effects of the interventions [ΔNLR (p=0.03) and ΔRDW (p=0.79)].

Conclusions: In this pooled sample of healthy individuals (normal NLR/RDW), we identified an association between both fish oil supplementation and the ΔEPA+DHA with ΔNLR, but not with ΔRDW. Further exploration is needed to contextualize the clinical impact of this preliminary finding.

Funding Sources: There was no specific financial support for this project.