Estimation and predictors of the Omega-3 Index in the UK Biobank

Abstract

Information on the Omega-3 Index (O3I) in the United Kingdom (UK) are scarce. The UK-Biobank (UKBB) contains data on total plasma omega-3 polyunsaturated fatty acids (n3-PUFA%) and DHA% measured by NMR. The aim of our study was to create an equation to estimate the O3I (eO3I) from these data. We first performed an interlaboratory experiment with 250 random blood samples in which the O3I was measured in erythrocytes by gas chromatography, and total n3% and DHA% were measured in plasma by NMR. The best predictor of eO3I included both DHA% and a derived metric, the total n3%-DHA%. Together these explained 65% of the variability (r=0.832, p<0.0001). We then estimated the O3I in 117,108 UKBB subjects and correlated it with demographic and lifestyle variables in multivariable adjusted models. The mean (SD) eO3I was 5.58% (2.35%) this UKBB cohort. Several predictors were significantly correlated with eO3I (all p<0.0001). In general order of impact and with directionality (- = inverse, + = direct): oily-fish consumption (+), fish oil supplement use (+), female sex (+), older age (+), alcohol use (+), smoking (-), higher waist circumference and BMI (-), lower socioeconomic status and less education (-). Only 20.5% of eO3I variability could be explained by predictors investigated, and oily-fish consumption accounted for 7.0% of that. With the availability of the eO3I in the UKBB cohort we will be in a position to link risk for a variety of diseases with this commonly-used and well-documented marker of n3-PUFA biostatus.

Lower Omega-3 Status Associated with Higher Erythrocyte Distribution Width and Neutrophil-Lymphocyte Ratio in UK Biobank Cohort

“…In this study examining the UK Biobank cohort, we confirm previously reported inverse associations of long chain omega-3 fatty acid concentrations with RDW [22] (Figure 2) and NLR [23] (Figure 3). The average estimated O3I of 5.59% in the UK Biobank cohort [27] is similar to that (~5.0%) reported in healthy individuals globally [28,29]. The average RDW in the UK Biobank cohort (13.5%) is similar to values (12.6-12.9%) reported in adults living in the US [30], including those free of cardiovascular disease (NHANES 1994(NHANES -2004 [31] and without clinical evidence of anemia or inflammation [22].…”

“…Thirty-one percent of participants reported using fish oil supplements, and fatty fish were consumed by 56% of the cohort, factors contributing to a mean Omega3% of 4.42% (Table 3) and O3I = 5.59% [27]. In this cohort of 109,191 individuals, the correlation between Omega3% and DHA% was r=0.88.…”

“…Within the cohort, 117,351 adults ≥18y had data available for Omega3% and DHA%, and 109,191 also had complete data on RDW, neutrophil count, lymphocyte count, NLR, age, sex, body mass index (BMI), highsensitivity C-reactive protein (CRP), and hemoglobin (Hb) (Figure 1). Since O3I was not measured in the UK Biobank, the O3I was calculated from Omega3% using the method of Schuchardt et al [27]. UK Biobank has ethical approval (Ref.…”

Association between blood N-3 fatty acid levels and the risk of coronavirus disease 2019 in the UK Biobank

“… 3 Based on Schuchardt et al. ( 20 ) . 4 An index of 0 means “average deprivation” in the United Kingdom; a negative value means less deprived than average, and a positive means more deprived than average.…”

“…To estimate the O3I values associated with these DHA levels, we used an equation described by Schuchardt et al. [ 20 ], which found a correlation between the observed O3I and estimated O3I (eO3I) of 0.83.…”