Abstract
BACKGROUND: Obesity and excessive body fat lead to metabolic and inflammatory disturbances. The fat mass index (FMI) has recently been recognized as a more sensitive measure of obesity than body mass index (BMI). Therefore, we investigated the relationship between higher FMI and alterations in platelet phospholipid fatty acid (FA) composition, oxidative stress, and inflammation. METHODS: Cross-sectional study of adults aged 18-49 years attended an outpatient clinic National Osteoporosis Center from May 2023 till June 2024, who agreed to participate in the study. EXCLUSIONS: major chronic diseases, active cancer, pregnancy, weight-affecting medications, thyroid/adrenal disorders, and diabetes. The total body composition was assessed via DXA; FMI (kg/m²) was categorized as fat deficit, normal, excess fat, or obesity. Fasting blood was analysed for glucose, total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, CRP, and insulin; serum malondialdehyde (MDA) by HPLC; platelet phospholipid FA profile by GC/MS. FMI group differences were tested with Kruskal-Wallis and Mann-Whitney. The Spearman coefficient was used to evaluate the associations. RESULTS: The study included 169 participants (36.3 ± 6.25 years; 64.5% female). Across ascending FMI groups (fat-deficit to obesity), adverse metabolic shifts were observed: HDL-cholesterol declined from 1.8 to 1.3 mmol/L (p < 0.001), whereas triglycerides rose from 0.7 to 1.4 mmol/L (p < 0.001) and CRP from 0.3 to 2.4 mg/L (p < 0.001). In platelet phospholipid membrane, the proportion of polyunsaturated FAs increased with FMI (from 2.5% to 4.8%; p = 0.002), including ω3 (from 1.1% to 2.0%; p = 0.003) and ω6 (from 7.5% to 11.4%; p = 0.016). The ω6/ω3 ratio showed a weak positive association with LDL-cholesterol (ρ = 0.166; p = 0.040). Serum MDA increased across FMI groups (from 95.5 to 104.3 µg/L; p = 0.019) and correlated with the polyunsaturated FAs (ρ = 0.178, p = 0.027). CONCLUSIONS: An elevated FMI is associated with altered platelet FA composition and increased OS. These changes may be early markers for metabolic and inflammatory dysregulations that underlie the pathogenesis of cardiometabolic risk. Moreover, platelet FA profiling could provide additional value for risk stratification in overweight individuals.