Association between erythrocyte omega-3 polyunsaturated fatty acid levels and fatty liver index in older people is sex dependent

Background/Objectives: Non-alcoholic fatty liver disease (NAFLD) is highly prevalent in older people but currently no specific drugs are available for its treatment. Omega-3 polyunsaturated fatty acids (n-3PUFA), known for their lipid-lowering, anti-inflammatory and anti-hypertensive properties, may have therapeutic potential for the management of NAFLD. The aim of this study was to determine whether n-3PUFA levels are associated with the prevalence of NAFLD in older adults. Methods: A cross-sectional sample of older adults aged 65–95 years (n = 620) from the Retirement Health and Lifestyle Study (RHLS) was analysed. Fatty Liver Index (FLI) scores, used as an indicator of NAFLD risk, were calculated using a validated algorithm that incorporates body mass index, waist circumference, plasma triglycerides and γ-glutamyl transferase. Omega-3 index scores (O3I, %eicosapentaenoic acid plus %docosahexaenoic acid) were determined by analysing the fatty acid composition of erythrocyte membranes by gas chromatography. Results: Following application of exclusion criteria, 475 participants were included in the analysis (age 77.9 ± 7.0 years; 60.4% females). Of these, 216 participants had FLI scores (≥60) suggestive of NAFLD (age 77.0 ± 6.6 years; 49.1% females). O3I was significantly lower in participants with NAFLD compared to those without NAFLD (p < 0.01). A significant inverse relationship was found between O3I and FLI (r = −0.165; p < 0.001). This relationship was gender specific with women, but not men, showing a significant association (r = −0.206; p < 0.001). Conclusions: The current study demonstrated a sex-dependent inverse relationship between erythrocyte n-3PUFA concentrations and NAFLD in older adults. The finding supports the proposal for sex-stratified n-3PUFA intervention trials in this high-risk age group.