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.