Cognitive decline

Overview

Cognitive decline refers to a reduction in cognitive abilities such as memory, attention, executive function, processing speed, and learning. It is a clinical and research term used across the spectrum from normal aging-related change to mild cognitive impairment and dementia. In biomedical research, cognitive decline is often studied as a shared outcome of neurodegenerative disease, vascular injury, metabolic dysfunction, inflammation, sleep disorders, environmental exposures, and psychosocial factors.

The recent literature highlights cognitive decline as a multifactorial process rather than a single disease entity. Studies in aging cohorts and disease-specific populations have linked it to Alzheimer disease biomarkers such as plasma p-tau217, tau-related markers, amyloidopathy, insulin resistance, neuroinflammation, oxidative stress, white matter damage, loneliness, and vascular pathology. It is also a major public health concern because it affects independence, medication adherence, caregiver burden, and healthcare utilization in older adults and in people living with dementia.

Focus of Latest Publications

Recent studies have examined cognitive decline as both an outcome and a target for prevention, diagnosis, and symptom management. In population-based work, long-term anthropometric measures were evaluated in relation to late-life plasma p-tau217 and dementia, reflecting interest in whether central and general adiposity contribute to Alzheimer disease biomarker profiles and later cognitive deterioration. Another population study used omics approaches to identify signatures associated with new-onset mild cognitive impairment and dementia, underscoring the use of molecular profiling to detect early transitions along the cognitive decline continuum.

Several studies focused on biological mechanisms that may drive decline. insulin resistance was associated with more severe cognitive impairment in the Alzheimer disease continuum, suggesting effects that may be partly independent of core Alzheimer pathology. Related work linked methionine, homocysteine, and methylation status to cognitive decline in Alzheimer disease, consistent with a role for one-carbon metabolism and blood DNA methylation. Other studies implicated neuroinflammation, mitochondrial dysfunction, ferroptosis, and synaptic loss; for example, LRP1 activation was reported to attenuate lipopolysaccharide-induced cognitive deficits through metabolic reprogramming and Mrc1 expression, while ajugol was reported to mitigate amyloid pathology, synaptic dysfunction, and cognitive decline in 5×FAD mice by enhancing BNIP3-mediated mitophagy. A separate study identified the ATP11B-YAP axis as a potential route to repair mitochondrial function and inhibit neuronal ferroptosis in age-related cognitive decline.

Vascular, metabolic, and systemic factors were also prominent. Race and ethnicity differences in dementia incidence and pathology were examined in relation to hypertension and neuroimaging markers of brain aging, with the authors noting multifactorial mechanisms underlying disparities. White matter arteriolosclerosis and VCING scoring were associated with dementia status and white matter damage in an unselected aging brain cohort, reinforcing the contribution of small-vessel disease. In another study, lower lymphocyte counts and higher systemic immune-inflammation index values were associated with increased risk of cognitive impairment, and serum cotinine levels were examined as a modifiable exposure in older adults. Fine particulate matter (PM2.5) exposure was also reported to impair cognitive function and alter DNA methylation signatures of circadian rhythm genes, linking environmental exposure to cognitive decline through epigenetic mechanisms.

Lifestyle and psychosocial factors were repeatedly investigated. Loneliness and social isolation were described as important risk factors for cognitive decline and dementia, and trajectories of cognitive decline before and after new-onset loneliness were analyzed in a longitudinal aging cohort. Intermittent fasting attenuated cognitive decline in D-galactose-induced aging rats, and exercise-related interventions were reported to improve cognitive impairment in preclinical models, including exercise serum and irisin-mediated effects. Nutritional and supplement-related studies examined calcium supplementation, Folate and vitamin B12 status, homocysteine, lutein-zeaxanthin extract, magnesium salts, quercetin, ginseng, and SGLT2/DPP-4 inhibitor repurposing, all in the context of cognitive function or mild cognitive impairment.

Clinical and care-oriented studies emphasized the consequences of cognitive decline for diagnosis, treatment, and daily living. Early diagnosis of dementia was described as critical for timely treatment and management, and help-seeking after case finding of early cognitive impairment was studied to understand barriers to follow-up and access to care. In primary care, prescribing patterns for anti-dementia medications were evaluated, while other studies addressed medication adherence, self-medication management systems, and the burden on spouse carers and family caregivers. A mixed-methods protocol in Sweden examined how home care services are organized for people living with dementia, and a peer-tutored “Good Life with Dementia” course was studied as a post-diagnostic support approach. Together, these studies frame cognitive decline as a condition requiring integrated biomedical, behavioral, and social responses.

Key Publications

• Jun Associations of Anthropometry Measures Across 35 Years With Late-Life Plasma P-tau217 and Dementia: The HUNT Study. (Neurology, 2026, PMID 42228892): "Central and general adiposity have been linked to dementia risk, but their relation to blood-based Alzheimer disease (AD) biomarkers is unclear."
• Jun Omics signature of new-onset mild cognitive impairment and dementia in a population-based study. (Scientific reports, 2026, PMID 42303781): "...associations with baseline prevalent MCI and dementia."
• Jun Aging in Place - A mixed methods study protocol of how care providers in Sweden organise and adapt granted home care services to the preferences and needs of people living with dementia. (PloS one, 2026, PMID 42302009): "The project focuses on: 1) what specific social care services older persons living at home with dementia are granted; if a dementia diagnosis is needed for some services; and the differences between municipalities;"
• Jun A fully automated immunoassay for plasma kallikrein-8: Development and evaluation in mild cognitive impairment. (Brain research, 2026, PMID 41819517): "Early diagnosis of dementia is critical for timely treatment and management before the disease progresses to a severe stage."
• Jun Baseline Dementia Prevalence and Subtypes in Older Adults Hospitalized With Acute Coronary Syndrome: A Multicenter Study From a Large Integrated Health Care Delivery System. (The Permanente journal, 2026, PMID 41804553): "Dementia is increasingly common among older adults (≥ 65 years) and is associated with poor outcomes."
• Jun Race and Ethnicity, Hypertension, and Neuroimaging Markers of Brain Aging: A Causal Mediation Analysis in the HABS-HD Study. (Neurology, 2026, PMID 42284535): "The mechanisms underlying racial/ethnic differences in dementia incidence and pathology are multifactorial..."
• Jun The Good Life with Dementia approach: A realist-informed qualitative study of a peer-tutored course, co-produced with and for people living with dementia. (PloS one, 2026, PMID 42284370): "People with dementia often report a lack of post-diagnostic support, and much of the current dementia training available is for staff or carers, not for the person diagnosed."
• Jun Prescribing of anti-dementia medications in primary care: A retrospective cohort study in 1489 English General Practices. (PloS one, 2026, PMID 42224406): "Existing studies often included all-cause dementia, not just the specific subtypes in which medication is indicated."
• Jun Evaluating the Impact of Blood-Brain Barrier-Penetrant ACE Inhibitors on HIV-Associated Neurocognitive Disorders. (Journal of acquired immune deficiency syndromes (1999), 2026, PMID 41677167): "we identified an association between blood-brain barrier (BBB)-penetrant angiotensin-converting enzyme inhibitors (ACEi) and reduced risk of dementia in PWH."
• Jun VCING Scoring and White Matter Arteriolosclerosis Show Relationships to Dementia Status and White Matter Damage in an Unselected Ageing Brain Cohort. (Neuropathology and applied neurobiology, 2026, PMID 42187146): "Vascular disease is associated with late-life dementia and other morbidities during life and commonly coexists with neurodegenerative pathologies."