Dr Ray O’Connor takes a look at the latest clinical studies on dementia, including its diagnosis and management
Diagnosis, Management, Environment and Lifestyle factors
Dementia is a clinical syndrome marked by changes in memory, language, problem-solving and other cognitive skills – resulting in functional impairment.
A study has shown that the number of Canadians living with dementia is predicted to double by 2030. Alzheimer’s disease (AD), the most common and most studied cause of dementia, is a chronic, progressive neurodegenerative disease.
This was a retrospective observational study1 using de-identified primary care data from electronic medical records (EMR) data in Canada from August 2011 to August 2021. Individuals ≥50 years old with dementia or AD were identified using AD and dementia-related diagnostic codes, medications, and in the EMR chart notes. The objective of the study was to understand the real-world clinical practice patterns and variation in AD diagnostic and screening tool utilization by primary care physicians (PCPs), including tools used for assessing dementia/AD severity and subsequent treatment patterns.
Dr Ray O’Connor
The study cohort included 417 individuals with all-cause dementia (mean age: 78.86 years), and 71 individuals with AD (mean age: 76.13). The most-used scale was the Montreal Cognitive Assessment (MoCA; dementia: 53.2%, AD: 84.5%).
Severity scores, often unspecified, suggested various stages of cognitive impairment. Among the medications examined, cholinesterase inhibitors were prescribed in 27.8% and 57.8% of people with dementia and AD, respectively. Antidepressants were the most frequently prescribed medication examined (dementia: 49.6%; AD: 71.8%). The authors’ conclusion was that PCPs play an important role in the early detection and management of dementia/AD. As new biomarkers and therapies emerge for early AD, there is a need for connected health system data to guide PCPs through the early diagnostic process.
The authors of this umbrella review and meta-analysis2 sought to synthesize the literature on environmental risk factors for dementia and mild cognitive impairment. As a secondary objective, the authors examined risk factors for two common phenotypes of dementia: AD dementia and vascular dementia.
A total of 19 reviews containing 37 meta-analyses were included. The authors found nine factors where exposure was associated with higher risks of all-cause dementia. These were: fine particulate matter, particulate matter, nitrogen dioxide, nitrogen oxides, carbon monoxide, shift work, night shift work, chronic noise, and extremely-low frequency magnetic fields.
Neighbourhood greenness was associated with a lower risk of all-cause dementia. In a narrative review, it was found that exposure to sulphur dioxide, proximity to roadways, ionizing radiation, aluminium, solvents, pesticides, and environmental tobacco smoke were also associated with dementia.
Particulate matter and chronic noise were related to vascular dementia. No systematic review reported on mild cognitive impairment. The authors concluded that achieving stronger air quality targets has the potential to reduce population-level dementia risk. Also, neighbourhood (i.e., greenness and chronic noise) and occupational (i.e., shift work) characteristics are associated with dementia and are viable public health intervention points.
The Mediterranean diet—characterized by high consumption of fruits, vegetables, whole grains, fish, and olive oil—has been widely recognized for its cardiovascular benefits and may also reduce the risk of cognitive decline and dementia. To investigate the protective effects of the Mediterranean diet on cognitive health, the authors conducted a systematic literature review,3 focusing on studies published between 2000 and 2024.
The studies included in the meta-analysis examined the adherence to the Mediterranean diet and the incidence of dementia and AD. The findings were that the combined Hazard Ratio (HR) for cognitive impairment among those adhering to the Mediterranean diet was 0.82 (95% CI 0.75–0.89); for dementia, the HR was 0.89 (95% CI 0.83–0.95); and for AD, the HR was 0.70 (95% CI 0.60–0.82), indicating substantial protective effects.
Significant heterogeneity was observed across studies, The authors’ conclusion was that adherence to the Mediterranean diet is associated with an 11–30% reduction in the risk of age-related cognitive disorders, including cognitive impairment, dementia, and AD. They suggest that their findings underscore the Mediterranean diet’s potential as a central element in neuroprotective public health strategies to mitigate the global impact of cognitive decline and dementia and to promote healthier cognitive ageing.
The aim of this next study was to determine the effectiveness of music interventions on depressive symptoms among care home residents with dementia in Australia, Germany, the Netherlands, Norway, Turkey, and the UK. Music Interventions for Dementia and Depression in Elderly care was a large, multinational, cluster randomised controlled trial4 with a 2×2 factorial design to examine the effects of group music therapy, recreational choir singing, or both compared with standard care.
The trial was done in 86 care home units. Participants were required to be aged 65 years or older; a fulltime resident in a participating care home unit; have dementia as indicated by a Clinical Dementia Rating score of 0⋅5–3 and a Mini-Mental State Examination score of 26 or less; have mild depressive symptoms as indicated by a Montgomery–Åsberg Depression Rating Scale (MADRS) score of at least 8.
Unfortunately, the findings were that internationally, active group music interventions as conducted in this study do not reduce depressive symptoms more than standard care in the long term. Country was the strongest predictor for differences in effects, underlining the importance of cultural and systemic differences. The authors recommend that future multi-site trials should focus on more narrowly defined target groups or contexts to reduce the risk of heterogeneity overshadowing potential effects of interventions. (Even old people don’t like muzak? – Ed?)
What about the role of sleep? Sleep disorders, particularly insomnia and obstructive sleep apnoea, are increasingly implicated as significant contributors to cognitive decline, dementia, and neurodegenerative diseases such as AD and vascular cognitive impairment and dementia (VCID).
This meta-analysis5 evaluated the impact of common sleep disorders on the risk of developing dementia and cognitive decline. Thirty nine cohort studies were included, with subgroup analyses showing significant associations between all-cause dementia and obstructive sleep apnoea (HR 1.33), insomnia (HR 1.36), and other sleep disorders (HR 1.33).
Obstructive sleep apnoea increased the risk for AD (HR 1.45), though its association with vascular dementia did not reach statistical significance. The authors’ conclusion was that Insomnia was significantly associated with increased risk for both vascular dementia and AD. This emphasises the need for early detection and management of sleep disturbances. Targeted interventions could play a pivotal role in reducing dementia risk, particularly among high-risk populations.
References:
Ismail Z et al. Diagnosis and Management of Alzheimer’s Disease in Primary Care: A Real-World Study in Ontario, Canada. Journal of Primary Care & Community Health Volume 16: 1–10. DOI: 10.1177/21501319251363156.
Jones A et al. Environmental risk factors for all-cause dementia, Alzheimer’s disease dementia, vascular dementia, and mild cognitive impairment: An umbrella review and meta-analysis. Environmental Research 270 (2025) 121007. https://doi.org/10.1016/j.envres.2025.121007.
Fekete M et al. The role of the Mediterranean diet in reducing the risk of cognitive impairment, dementia, and Alzheimer’s disease: a meta‑GeroScience (2025) 47:3111–3130. https://doi.org/10.1007/s11357-024-01488-3.
Sveinsdott V et al. Clinical effectiveness of music interventions for dementia and depression in older people (MIDDEL): a multinational, cluster-randomised controlled trial. Lancet Healthy Longev 2025; 6: 100783. Published Online December 8, 2025. https://doi.org/10.1016/j.lanhl.2025.100783.
Ungvari Z et al. Sleep disorders increase the risk of dementia, Alzheimer’s disease, and cognitive decline: a meta‑ GeroScience (2025) 47:4899–4920. https://doi.org/10.1007/s11357-025-01637-2.