Major Lancet study says 40% of dementia cases are preventable

Four in 10 dementia cases could be prevented or delayed with lifestyle changes, a major study has shown, with hearing loss found to be the biggest risk.

Guidance about avoiding dementia has been out for some time, but now a study by University College London, published in the Lancet, reinforces what we know, adds a little more, and posits that it’s the responsibility of individuals and policy makers to make a sure life styles are adjusted.

People with hearing loss account for 8% of dementia cases, which scientists now think may trigger brain damage as well as being socially isolating. This is said to be the biggest ‘modifiable risk factor’.

Poor education in early years is also linked to 7% of cases, and smoking to 5%. Altogether, there are said to be 12 preventable factors that play a role in the onset of dementia.

Those we know already are depression, physical inactivity, social isolation, diabetes, cardiac conditions and high blood pressure. Emphasized in the report are hearing loss, air pollution, high alcohol consumption and low educational attainment. “Culture, poverty, and inequality are key drivers of the need for change.”

The report’s lead author, UCL’s Professor Gill Livingston, said that policy-makers and individuals have the power to prevent and delay a significant proportion of dementia, to make an impact on each stage of a person’s life.

It’s a bulky report with interesting detail, for example, a Cochrane review found that statins given to older people at risk of vascular disease do not prevent cognitive decline or dementia, and that a study of 19.114 healthy older adults age 65-plus did not reduce dementia, death, physical disability, or cardiovascular disease over a period of almost five years.

It also found that ‘intellectual activity as adults’ particularly problem-solving, is associated with ‘cognitive ability acquisition’, and a 12-year-old study of 1,658 people found that retiring later was associated with lower dementia rates. Another study found a two-fold increase in ‘episodic memory loss’ in retired people, compared to non-retirees, adjusting for health, age, sex, and wealth.

The report begins with an encouraging, if confusing, note; the incidence of dementia – that is the number of new cases in the ’age-specific’ population – has fallen in many countries, because of improvements in life in general. This has been confirmed by other studies, including one by the Harvard T.H.Chan School of Public Health that says that dementia rates have fallen by 15% per decade over the last 30 years due to life-style changes. At the same time the number of older people living with dementia is rising - as more people reach the age of 80, where the risk increases.

You can find our resources, here: ‘Dementia: Pathways to Hope‘ which gives practical ways of preventing dementia, and caring for care-givers.