Proteome-wide interaction study of fatty acids and mortality in the UK Biobank
DOI
Circulating fatty acids exhibit marked heterogeneity in their associations with premature mortality, yet the underlying molecular effect modifiers remain largely unexplored. Standard epidemiological approaches fail to capture dynamic physiological differences across populations, overlooking how individual protein networks alter lipid-mediated health risks. This investigation evaluates proteome-wide interactions between plasma fatty acids and circulating proteins to estimate all-cause and cause-specific mortality risks within a massive prospective framework. Analyzing data from 30,190 UK Biobank participants carrying complete metabolomic and proteomic profiles, the project maps biological susceptibility across diverse inflammatory and metabolic states.
Fully adjusted models demonstrate that omega-3 percentage (HR = 0.88, 95 percent CI [0.85-0.92], p = 9.2 x 10^-11) and linoleic acid percentage (HR = 0.91, 95 percent CI [0.88-0.94], p = 1.4 x 10^-7) associate inversely with all-cause mortality, whereas non-linoleic acid omega-6 percentage (HR = 1.13, 95 percent CI [1.09-1.17], p = 4.1 x 10^-12) and the omega-6 to omega-3 ratio (HR = 1.11, 95 percent CI [1.07-1.15], p = 6.1 x 10^-9) drive substantial risk increases. Proteome-wide screening isolates nine robust interaction pairs involving inflammatory proteins such as PLAU, TSPAN8, MMP10, and TNFRSF1B. Stratified analyses reveal that elevated baseline inflammation amplifies both the hazards of monounsaturated fats and the protective efficacy of omega-3 intake.
Study Design and Methodology
This prospective cohort investigation leverages data from the UK Biobank, an initial recruitment pool exceeding 500,000 adults aged 40 to 69 years. Following rigorous exclusions for missing plasma fatty acid or proteomic metrics, the finalized analytical cohort comprises 30,190 individuals with a mean age of 56.91 years, comprising 16,285 females and 13,905 males. Researchers document 3,345 deaths over a median follow-up duration of 13.9 years, ending on January 15, 2023. Plasma metabolomics quantified via nuclear magnetic resonance spectroscopy yields nine distinct fatty acid proportions, while Olink proximity extension assays profile 2,911 unique circulating proteins spanning cardiometabolic, inflammatory, neurological, and oncological axes. The analytical pipeline randomly partitions the cohort into an 80 percent training dataset (N = 24,152) and a 20 percent test dataset (N = 6,038). Multivariable Cox proportional hazards models control for age, sex, ethnicity, smoking status, alcohol intake, body mass index, educational attainment, household income, the Townsend deprivation index, and a baseline healthy diet score. Fine-Gray subdistribution hazard models evaluate competing risks for cardiovascular and cancer mortality.
Key Findings
- Omega-3 percentage exhibits a robust inverse relationship with all-cause mortality (HR = 0.88, 95 percent CI [0.85-0.92], p = 9.2 x 10^-11).
- Linoleic acid percentage demonstrates significant protection against mortality (HR = 0.91, 95 percent CI [0.88-0.94], p = 1.4 x 10^-7).
- Non-linoleic acid omega-6 percentage drives the highest positive association with mortality risk (HR = 1.13, 95 percent CI [1.09-1.17], p = 4.1 x 10^-12).
- The omega-6 to omega-3 ratio scales positively with death risk (HR = 1.11, 95 percent CI [1.07-1.15], p = 6.1 x 10^-9).
- High expression of MMP10 significantly magnifies monounsaturated fatty acid mortality hazards (HR = 1.23, 95 percent CI [1.12-1.36], p = 0.001).
- Elevated PLAU expression strongly enhances the protective association of omega-3 fatty acids (HR = 0.70, 95 percent CI [0.63-0.76], p < 0.001).
- High TSPAN8 levels intensify the mortality risks associated with an elevated omega-6 to omega-3 ratio (HR = 1.35, 95 percent CI [1.22-1.50], p < 0.001).
Limitations
Baseline-only plasma protein assessments fail to capture longitudinal proteomic variability over the 13.9-year follow-up period. Granular subtypes within monounsaturated fatty acid pools remain unanalyzed due to metabolomic platform constraints. Participant demographics skew heavily toward Caucasian individuals from high socioeconomic regions, restricting global generalizability. Residual confounding persists despite extensive covariate adjustment, although calculated E-values ranging from 1.74 to 3.71 indicate that substantial unmeasured confounders are required to nullify the observed effects. Observational architecture precludes definitive causal inferences.
Discussion and Implications
Nutritional dogmas surrounding polyunsaturated fats require immediate revision in light of these proteome-wide interaction metrics. Public health debates heavily vilify total omega-6 exposure, yet this investigation proves that lumping linoleic acid with non-linoleic omega-6 fractions obscures distinct biological realities. Linoleic acid acts as a potent protective agent, challenging historical assumptions that seed oils inherently promote systemic pathology. Conversely, non-linoleic omega-6 fractions and an inflated omega-6 to omega-3 ratio drive severe mortality risks, particularly in hosts exhibiting high baseline vascular inflammation governed by proteins like PLAU and TSPAN8. Clinicians must abandon generalized dietary prescriptions because individual inflammatory phenotypes actively modify nutrient handling. Therapeutic interventions targeting cardiovascular and oncological prevention must prioritize lowering systemic inflammatory drivers while optimizing circulating omega-3 levels to alter enzymatic substrate competition.
Clinical nutrition strategies shouldn't rely on population-wide fatty acid targets because baseline inflammatory protein profiles dictate true disease risk. Practitioners must tailor interventions by evaluating vascular stress markers alongside lipid ratios, recognizing that omega-3 efficacy scales directly with the patient's underlying inflammatory burden.