The number of older people, including those living with dementia, is rising, as younger age mortality declines. However, the age-specific incidence of dementia has fallen in many countries, probably because of improvements in education, nutrition, health care, and lifestyle changes.
Overall, a growing body of evidence supports the nine potentially modifiable risk factors for dementia modelled by the 2017 Lancet Commission on dementia prevention, intervention, and care: less education, hypertension, hearing impairment, smoking, obesity, depression, physical inactivity, diabetes, and low social contact.
We now add three more risk factors for dementia with newer, convincing evidence. These factors are excessive alcohol consumption, traumatic brain injury, and air pollution. We have completed new reviews and meta-analyses and incorporated these into an updated 12 risk factor life-course model of dementia prevention. Together the 12 modifiable risk factors account for around 40% of worldwide dementias, which consequently could theoretically be prevented or delayed.
The potential for prevention is high and might be higher in low-income and middle-income countries (LMIC) where more dementias occur. Our new life-course model and evidence synthesis has paramount worldwide policy implications. It is never too early and never too late in the life course for dementia prevention. Early-life (younger than 45 years) risks, such as less education, affect cognitive reserve; midlife (45–65 years), and later-life (older than 65 years) risk factors influence reserve and triggering of neuropathological developments.
Culture, poverty, and inequality are key drivers of the need for change. Individuals who are most deprived need these changes the most and will derive the highest benefit.
Lancet’s 2017 Metanalysis mentions 9 Dementia risk factors. The 2020 Paper adds 3 additional factors. TRAUMATIC BRAIN INJURY, ALCOHOLISM, and AIR POLLUTION.
The inclusion of Trauma, with a 3% weighting, may be due to the increased awareness of TBE stemming from football injuries. The preventable 12 Factors are still in the minority. 60% of the factors are not preventable, since they are Genetically determined.
LESS EDUCATION, HEARING LOSS and SOCIAL ISOLATION, 3 of the original 9 factors,all lead to less brain stimulation, and can be unified under the idea of COGNITIVE RESERVE. If a person starts with less Cognition, it is reasonable to think he would be Demented sooner.
Together, less education, hearing loss, and social isolation account for almost Half of the correctable conditions. SMOKING is one of those things which impact almost every human disorder. It is amazing that cigarettes are still manufactured. In fact, their use is actually Increasing,especially the Far East, where they probably account for much of the escalating problem with Dementia in that region.
Our favorite causes, Sleep, Diet, and Exercise, apparently play only a minor role in Dementia. Sleep is completely dismissed in this report. The fact that both Sleeping less than the Ideal 7-8 hours, and more than that amount is thought to correlate with health problems is probably the main reason for the omission.
My own opinion is that people who are in poor health may need more sleep, and therefore sleep longer. My own sleep is interrupted 3-5 times per night, so it is not surprising that I need an hour extra to feel rested. Any less than 9-10 hours, and I need a nap, which in my opinion is a sign of insufficient nighttime sleep. Poor sleep may be a factor in metabolic syndrome, often leading to DIABETES, OBESITY, and HYPERTENSION, which are factors in Dementia, mentioned in the article as bit players.
PHYSICAL INACTIVITY is mentioned as a minor factor in Dementia, but exercise, studied as a treatment of dementia, was found to improve only strength. Diet is not mentioned, but does contribute to OBESITY, which is a minor factor. Dementia is a great emotional and economic burden, afflicting many otherwise happy families with misfortune.
The Lancet metanalysis is admirable. But don’t forget the healthy lifestyle emphasizing Sleep Diet and Exercise; and exercise includes cognitive exercise. Anything we can do to avoid dementia is worthwhile. –