(PTFS04-06-25) Associations of Serum Omega-6 Polyunsaturated Fatty Acids with Biomarkers of Glucose Homeostasis

Objectives: Observational evidence supports an association between higher intakes of omega-6 (n-6) polyunsaturated fatty acids (PUFA) and reduced risk of incident type 2 diabetes mellitus. It is known that serum levels of total n-6 PUFA and linoleic acid (LA), the predominant dietary n-6 PUFA, correlate with dietary LA intake. The purpose of this cross-sectional analysis using baseline data from the Aegis cohort was to examine associations of serum LA and total n-6 PUFA levels with body mass index (BMI) and biomarkers of glucose homeostasis.

Methods: Height, weight, and fasting serum levels of glucose and insulin were assessed. Homeostasis model assessment for insulin resistance (HOMA-IR) was calculated from fasting glucose and insulin levels. Univariate Pearson or Spearman correlation coefficients were calculated, and multivariate linear models were used to assess biomarker levels across quintile categories of serum fatty acids (FA) with BMI, age, and sex as covariates.

Results: Analyses included 1894 participants for whom relevant biomarker data were available (65% female, mean age: 50 y, mean BMI: 29.0 kg/m², 62% Non-Hispanic White, 11% Black/African American, 7% Hispanic/Latino, 10% Asian, 10% mixed/other). LA and n-6 PUFA levels, expressed as the % of circulating FA, were inversely correlated (all P < 0.001) with BMI (r = -0.25 and -0.28, respectively), glucose (r = -0.25 and -0.28, respectively), insulin (r = -0.17 and -0.22, respectively), and HOMA-IR (r = -0.20 and -0.26, respectively). The 20^th and 80^th percentiles for LA were 31.3% and 36.4%, respectively, and for total n-6 PUFA were 38.5% and 42.8%, respectively. Least squares geometric means (95% CI) for quintile (Q)1 and Q5 of serum LA for BMI were 30.4 (29.7, 31.0) kg/m² and 26.9 (26.4, 27.5) kg/m², respectively (P < 0.001); for glucose were 109 (107, 112) mg/dL and 100 (97.9, 102) mg/dL, respectively (P < 0.001); for insulin were 9.95 (9.22, 10.7) mU/L and 8.79 (8.14, 9.49) mU/L, respectively (P = 0.016); and for HOMA-IR were 2.69 (2.47, 2.92) and 2.17 (2.00, 2.36), respectively (P < 0.001). Results were similar for total n-6 PUFA.

Conclusions: Higher serum levels of LA and total n-6 PUFA were associated with more favorable levels of BMI and biomarkers of glucose homeostasis.

Funding Sources: The Indiana University Foundation funded this research.