LONDON—Nine modifiable risk factors may account for about a third of dementia cases, according to an estimate by the Lancet International Commission on Dementia Prevention, Intervention, and Care. The estimate is part of a commission report that was presented at the 2017 Alzheimer’s Association International Conference and published in Lancet.
The report reviews the evidence for pharmacologic, psychologic, environmental, and social interventions for patients with dementia. It includes algorithms for the management of psychosis, agitation, and depression. And it emphasizes the importance of assessing risks to patients (eg, abuse and nutritional deficiencies), caring for family caregivers, and future planning.
“There has been a great deal of focus on developing medicines to prevent dementia,” said Lon S. Schneider, MD, Professor of Psychiatry and Behavioral Sciences at the Keck School of Medicine of University of Southern California in Los Angeles and one of the report’s authors. “But we cannot lose sight of the … advances we have already made in treating dementia, including preventive approaches.”
Nine Risk Factors
The authors reviewed the literature on dementia risk factors and estimated the potential percentage reduction in new cases of dementia if a risk factor were eliminated (ie, the population attributable fraction). The results suggest that approximately 35% of cases of dementia are attributable to a combination of low education level in childhood, hearing loss, hypertension, obesity, smoking, depression, physical inactivity, social isolation, and diabetes. In comparison, eliminating risk from the ApoE ε4 allele would be expected to reduce the incidence of dementia by 7%.
The model assumes a causal association between a risk factor and dementia. Although randomized controlled trials to establish causality are not possible for many dementia risk factors, causal relations are plausible, the authors said. Potential mechanisms include effects on cognitive reserve, brain damage, and brain inflammation. Other potentially modifiable risk factors that were not included in the analysis due to insufficient data include diet, visual impairment, sleep disorders, and particulate air pollution.
“While public health interventions will not delay, prevent, or cure all potentially modifiable dementia, the management of metabolic, mental health, hearing, and cerebrovascular risk factors might push back the onset of many cases for some years,” the report says.
Patients with Alzheimer’s disease or dementia with Lewy bodies should be offered cholinesterase inhibitors at all stages of disease, or memantine for severe dementia, the commission recommends. Because effects on cognition and function are small, clinicians often cannot determine treatment response in individual patients. Side effects of cholinesterase inhibitors (eg, nausea, vomiting, diarrhea, vivid dreams, and cramps) often influence treatment decisions.
Evidence indicates that nonpharmacologic interventions are superior to antipsychotic medications for the treatment of dementia-related agitation and aggression. Antipsychotic drugs increase the risk of death, cardiovascular adverse events, infection, and excessive sedation and should only be used when symptoms cause distress or increase risk, the report says. Physicians should discuss with the patient, his or her family, and care staff whether the possible benefits of treatment with an antipsychotic drug are likely to outweigh the risks, and they should document the discussion.
“The most effective psychosocial treatments are usually multimodal, individualized care, and train carers in skills, including optimizing communication, coping, and environmental adaptations,” according to the commission report.
Livingston G, Sommerlad A, Orgeta V, et al. Dementia prevention, intervention, and care. Lancet. 2017 Jul 19 [Epub ahead of print].