Blood lipids as accessible biomarkers for early dementia risk screening: Bridging diagnostic gaps in resource-limited settings

BACKGROUND: Dementia prevalence is rising globally, with the greatest increase occurring in low- and middle-income countries where access to advanced diagnostic tools remains limited. Circulating lipid parameters have been increasingly investigated as accessible biomarkers for dementia risk and cognitive decline. OBJECTIVE: To systematically review and synthesize existing evidence on the relationship between circulating lipid parameters and dementia risk, Alzheimer's disease, and cognitive decline, with particular consideration of their potential utility in resource-limited settings. METHODS: A systematic literature review was conducted in accordance with PRISMA guidelines. Studies published between 2000 and May 2025 evaluating associations between lipid profiles and cognitive outcomes, dementia, or neurodegenerative disease were included and narratively synthesized. RESULTS: Evidence across studies suggests that lipid dysregulation is associated with dementia-related outcomes, although findings remain heterogeneous. Elevated total cholesterol, low-density lipoprotein cholesterol, and triglycerides were frequently associated with increased risk of dementia, Alzheimer's disease, or cognitive decline, whereas high-density lipoprotein cholesterol generally showed protective associations. Several studies also identified prognostic value in composite lipid ratios and lipid variability measures. However, the strength and direction of associations varied according to age, sex, timing of lipid assessment, and study population. CONCLUSIONS: Circulating lipid parameters alone are insufficient as definitive diagnostic biomarkers. However, when interpreted in a population-specific and life-course context, they may contribute to early risk stratification and complement neuropsychological screening, particularly in resource-limited settings where access to advanced neuroimaging and cerebrospinal fluid testing is restricted.