Huge Number of Dementia Cases Could Be Prevented with Lifestyle Changes

It is never too early or late to change one's lifestyles in order to prevent dementia, according to experts who have identified three new risk factors for the condition.

Drinking more 21 units or more per week, air pollution, and traumatic brain injuries have been added to a list of nine modifiable risk factors highlighted in a 2017 report of The Lancet commission on dementia prevention. Those were being less educated, high blood pressure, hearing problems, smoking, obesity, depression, physical inactivity, diabetes and low levels of social contact.

The international team of 28 leading dementia experts behind the commission carried out the report by reviewing existing studies on dementia.

"Together the 12 modifiable risk factors account for around 40 percent of worldwide dementias, which consequently could theoretically be prevented or delayed," the authors wrote in The Lancet. The percentages are broken down in a chart at the bottom of this article.

"It is never too early and never too late in the life course for dementia prevention," they wrote.

"Although behaviour change is difficult and some associations might not be purely causal, individuals have a huge potential to reduce their dementia risk," the team said.

The team categorized the risk factors by age, with education found to be a means of prevention in early life, or for those 45-years-old and younger; blood pressure, obesity, hearing loss, brain injuries, and alcohol misuse related to mid-life for the 45 to 65s, and the remainder associated with later life in those older than 65.

As more people get older, the number of people living with dementia is rising. An estimated 50 million people worldwide live with the condition, of which Alzheimer's disease is the most common form. This is forecast to hit 152 million by 2050, with low and middle-income countries likely to be hard particularly hit, the group said.

However, the incidence of dementia related to age has in fact fallen in many countries likely due to improvements with education, diet, health care, and lifestyle changes, wrote the authors.

Experts not involved in the research welcomed the report. Professor Tara Spires-Jones of the U.K. Dementia Research Institute at the University of Edinburgh said in a statement the "well-conducted" report was "important as it highlights practical ways we can all try to reduce our risk of dementia."

Spires-Jones said: "However, it is important to note that this type of association data does not prove causation leaving a lot of "chicken and egg" questions." It is, for example, not clear if depression contributes to depression or is a symptom of it.

"This report estimates that 40 percent of dementias might be preventable with lifestyle changes which means that the remaining 60 percent are to the best of our knowledge caused by things people cannot control like their genes—so I hope that this report will not lead to people feeling like having dementia is their 'fault.'"

Professor Huw Williams, a clinical neuropsychologist at the University of Exeter and an expert on traumatic brain injury, said the team's report was robust. "This analysis shows how the two big neuro-health conditions—Traumatic Brain Injury and dementia—are intricately linked."

Dr Rosa Sancho, head of research at the charity Alzheimer's Research U.K., said the report is the "the most comprehensive overview into dementia risk to date."

Professor Bart De Strooper, director of the U.K. Dementia Research Institute, said: "These interventions may lead to healthier aging, which is great, but it is only one part of the picture.

"The genetic make-up of an individual is at least as great a risk factor for Alzheimer's disease as lifestyle, for example. "

Risk factorPercentage of dementia cases which could be prevented or delayed by targeting risk factor
Less education (early life)7.1%
Hearing loss (middle life)8.2%
Traumatic brain injury (middle life)3.4%
High blood pressure (middle life)1.9%
Alcohol use >21 units per week (middle life)0.8%
Obesity (BMI 30 or above) (middle life)0.7%
Smoking (later life)5.2%
Depression (later life)3.9%
Social Isolation (later life)3.5%
Physical Inactivity (later life)1.6%
Diabetes (later life)1.1%
Air pollution (later life)2.3%
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A stock image shows an older person holding a photo. A report has highlighted 12 risk factors for preventing dementia. Getty