It is estimated that around 45 million people in the world suffer from dementia, most of them over 60 years old. With increases in life expectancy, this incidence is projected to double every 20 years . In fact, dementia affects 13.9% of persons aged 71 years and older and 37.4% of those over 90 . Alzheimer’s disease (AD) is the most common neurodegenerative disease and it is one of the greatest health-care challenges of the 21st century. AD inevitably leads to death, although patients frequently die of the complications of other chronic illnesses such as cardiovascular disease, cancer, respiratory disease, and diabetes [1, 3]. Interestingly, the prevalence of dementia in the United States among those aged 65 or older decreased significantly between 2000 and 2012. Increased levels of educational attainment have been linked to this decline in dementia prevalence, but the full set of social, behavioral, and medical factors that contributed to the decline remains unclear . These days we are aware that the greatest risk factor for the development of AD is old age, but this in itself is not enough to cause the disease. Other major risk factors include the presence of one or more apolipoprotein gene E4 alleles, low educational and occupational attainment, family history of AD, moderate or severe traumatic brain injuries, and cardiovascular risk factors [5, 6]. Despite decades of study, there is to date no disease-modifying therapy against AD in particular or dementia in general. However, around a third of AD cases worldwide could be attributable to potentially modifiable risk factors [7, 8]. Interventions that postpone dementia onset by even two years would cut projected dementia prevalence in 2047 by 22% .
Normal cognitive aging (NCA) may be influenced not only by our genes but also by our lifestyle. Healthy aging, which incorporates stimulation of the mind, means revitalizing the brain and replacing unhealthy habits with healthy habits. Patients with AD have reduced activity levels (physical and mental) in mid-life compared with healthy control-group subjects . Educational and occupational attainment have been found to protect against the development of the disease in a ‘‘use it or lose it’’ scenario, but participation in activities has received little attention . According to various scientific indications, playing chess frequently delays NCA . Neuroplasticity tells us about the importance of practice (repetitive engagement in activities that enhance brain health) if one wants to markedly improve brain function. Animal studies have found that a little daily stress may enhance neuronal and synaptic function, promote neurogenesis in the hippocampus, and improve cognitive performance in certain tasks .
Here there are twelve reasons to support the use of chess in the primary prevention of dementia:
- Chess is universal.
- Chess is cheap.
- Chess is a very complete activity: game, sport, art, and science. It provides very interesting connections between art and science .
- Chess has been documented for more than 15 centuries.
- Chess develops intelligence at any age, and particularly with children .
- Chess delays NCA [12, 16]. It also produces small amounts of stress which improves neuroplasticity.
- Chess has been shown to be very useful in various problem social contexts: in prisons, with drug addicts, the unprivileged, people who have panic attacks, and with hyperactive or autistic children [17, 18].
- Chess produces fascinating personalities. For instance, the world chess champion and genius Bobby Fisher.
- Chess is the only sport that can be played on the Internet. You can also meet people across the world because of chess and put into practice your social skills. There are many consolidated platforms such as Chess24, Chessbase, Lichess, iChess, etc.
- Chess has many variants that can be a great way to mix things up and apply your chess skills in different and exciting ways. The Encyclopedia of Chess Variants estimates that there are well over 2,000 different variants.
- Chess can be played on some platforms that are universally accessible. Chess can be concurrently played by people with different abilities and preferences, including people with disabilities (e.g., people with hand-motor or visual impairment or who are blind).
- Chess bestows a good image on those who play and sponsor it.
Finally, work has recently been published indicating that “speed of processing training” resulted in an almost 30% reduction in the risk of developing dementia . This is the first study to show that any intervention (behavioral or pharmacological) can lower the risk of dementia, supporting the notion that playing chess should be part of this brain booster training.
 Scheltens P, Blennow K, Breteler MM, de Strooper B, Frisoni GB, Salloway S, Van der Flier WM (2016) Alzheimer's disease. Lancet 388, 505-517.
 Plassman BL, Langa KM, Fisher GG, Heeringa SG, Weir DR, Ofstedal MB, Burke JR, Hurd MD, Potter GG, Rodgers WL, Steffens DC, Willis RJ, Wallace RB (2007) Prevalence of dementia in the United States: the aging, demographics, and memory study. Neuroepidemiology 29, 125-132.
 Sarkar A, Irwin M, Singh A, Riccetti M, Singh A (2016) Alzheimer's disease: the silver tsunami of the 21(st) century. Neural Regen Res 11, 693-697.
 Langa KM, Larson EB, Crimmins EM, Faul JD, Levine DA, Kabeto MU, Weir DR (2017) A comparison of the prevalence of dementia in the United States in 2000 and 2012. JAMA Intern Med 177, 51-58.
 Apostolova LG, Risacher SL, Duran T, Stage EC, Goukasian N, West JD, Do TM, Grotts J, Wilhalme H, Nho K, Phillips M, Elashoff D, Saykin AJ, Alzheimer's Disease Neuroimaging Initiative (2018) Associations of the top 20 Alzheimer disease risk variants with brain amyloidosis. JAMA Neurol 75, 328-341.
 Apostolova LG (2016) Alzheimer disease. Continuum (Minneap Minn) 22, 419-434.
 Norton S, Matthews FE, Barnes DE, Yaffe K, Brayne C (2014) Potential for primary prevention of Alzheimer's disease: an analysis of population-based data. Lancet Neurol 13, 788-794.
 Sanchez-Mut JV, Graff J (2015) Epigenetic alterations in Alzheimer's disease. Front Behav Neurosci 9, 347.
 Brookmeyer R, Johnson E, Ziegler-Graham K, Arrighi HM (2007) Forecasting the global burden of Alzheimer's disease. Alzheimers Dement 3, 186-191.
 Edwards JD, Xu H, Clark DO, Guey LT, Ross LA, Unverzagt FW (2017) Speed of processing training results in lower risk of dementia. Alzheimers Dement (N Y) 3, 603-611.
 Friedland RP, Fritsch T, Smyth KA, Koss E, Lerner AJ, Chen CH, Petot GJ, Debanne SM (2001) Patients with Alzheimer's disease have reduced activities in midlife compared with healthy control-group members. Proc Natl Acad Sci U S A 98, 3440-3445.
 Desai AK (2011) Revitalizing the aged brain. Med Clin North Am 95, 463-475, ix.
 Lyons DM, Buckmaster PS, Lee AG, Wu C, Mitra R, Duffey LM, Buckmaster CL, Her S, Patel PD, Schatzberg AF (2010) Stress coping stimulates hippocampal neurogenesis in adult monkeys. Proc Natl Acad Sci U S A 107, 14823-14827.
 Sala G, Foley JP, Gobet F (2017) The effects of chess instruction on pupils' cognitive and academic skills: state of the art and theoretical challenges. Front Psychol 8, 238.
 Aciego R, Garcia L, Betancort M (2012) The benefits of chess for the intellectual and social-emotional enrichment in schoolchildren. Span J Psychol 15, 551-559.
 Dowd SB, Davidhizar R (2003) Can mental and physical activities such as chess and gardening help in the prevention and treatment of Alzheimer's? Healthy aging through stimulation of the mind. J Pract Nurs 53, 11-13.
 Barzegar K, Barzegar S (2017) Chess therapy: A new approach to curing panic attack. Asian J Psychiatr 30, 118-119.
 Pakenham-Walsh R (1949) Chess as a form of recreational therapy. J Ment Sci 95, 203.