Prevalence of dementia in over 65s has declined by a third, study finds

Women are more likely to develop dementia than men

The prevalence of dementia in people aged 65 and over in the US is declining, a new study suggests.

Researchers at RAND corporation, a US-based think tank, analysed data on more than 21,000 people over the age of 65 between 2000 and 2016.

They also looked at the results of a survey which tested the cognitive ability of 97,000 people, some of whom also underwent clinical assessment for dementia.

They found the prevalence of dementia in people aged 65 and over decreased by 3.7 per cent in the 16-year period – from 12.2 per cent in 2000 to 8.5 per cent in 2016.

“The reasons for the decline in the prevalence of dementia are not certain, but this trend is good news for older Americans and the systems that support them,” said Péter Hudomiet, an economist and lead author of the study.

“This decline may help reduce the expected strain on families, nursing homes and other support systems as the American population ages.”

There are around 6.2 million people living with dementia in the US. In the UK, around 900,000 have dementia, and it is the leading cause of death. Women are more likely to develop dementia in their lifetimes.

While the prevalence of dementia was higher among women than men across the entire period, the difference declined.

In men, cases of dementia fell by 3.2 per cent from 10.2 per cent in 2000 to 7 per cent in 2016. The decrease was larger in women – down 3.9 per cent from 13.6 per cent to 9.7 per cent.

As old age is the strongest risk factor for developing dementia, it has long been thought that increasing life expectancies will increase the prevalence of the disease. However, the research suggests that age-adjusted dementia is declining.

Experts said this could be a result of increased education, a reduction in smoking and greater awareness of cardiovascular risk factors, like high blood pressure.

Despite the overall decrease, dementia tended to be more prevalent among men and women from ethnic minority backgrounds

Hudomiet commented: “Closing the education gap across racial and ethnic groups may be a powerful tool to reduce health inequalities in general and dementia inequalities in particular, an important public health policy goal.”