BACKGROUND:
Dementia is a neurodegenerative condition with no known cure, so far. In 2021, 57 million people were living with dementia worldwide, with almost 10 million new cases recorded every year. In 2019, dementia’s global economic burden reached US$1.3 trillion. Given this, addressing the modifiable risk factors remains one of the critical aspects of dementia prevention. This umbrella review examines the psychosocial and behavioural factors associated with increased risk or protective effects for dementia and cognitive impairment.
METHODS:
The study adhered to the Preferred Reporting Items of Systematic Review and Meta-Analysis (PRISMA) guidelines. Search was performed in PubMed, on 11 November 2024, from 01 September 2020, right after the publication of the 2020 update Lancet Commission on dementia prevention. Abstracts and full-texts were screened based on inclusion-exclusion criteria and 90 systematic reviews were retained.
RESULTS:
Psychosocial risk factors include hearing loss, depression, social isolation, low levels of education, vision impairment, poor sleep quality, psychotic disorders, childhood adversity and neuroticism. On the other hand, engagement in social activities, treatment of vision impairment, higher cognitive reserve and participation in cognitively stimulating activities, a strong sense of meaning, purpose in life, and overall psychological well-being along with leisure activities and visual art therapy, optimism and positive affect have also been linked to protective effects. Evidence remains inconclusive regarding anxiety, stress and PTSD. Behavioural risk factors include physical inactivity, alcohol use disorder, impaired mastication and playing professional football/soccer, involving head trauma. Protective factors encompass regular physical activity, moderate alcohol consumption, smoking cessation, adherence to a Mediterranean diet, use of nutritional supplements for vitamin B and iron, tea consumption, moderate coffee intake, and participation in multidomain non-pharmacological interventions. Evidence remains inconclusive about the effects of milk/dairy consumption, the caffeine component of tea/coffee and sleep duration. There is insufficient evidence about the impact of dental prostheses, gum chewing, Vitamin C and protein supplements, bilingualism, musical abilities and traditional board game playing.
CONCLUSION:
Interventions to mitigate risk factors and promoting protective factors would help reducing the incidence of dementia/cognitive decline. More studies are required to enhance the understanding of the factors that have inconclusive or insufficient evidence.