Keen sense of smell halves dementia risk
BeinG able to smell roses, onions and lemons in old age means you are half as likely to develop dementia, a study has shown.
scientists followed nearly 1,800 pensioners in their 70s over ten years and found losing a sense of smell was a key early warning sign for memory loss.
Overall 328 participants began to suffer from dementia – with rates of the disease twice as high among those with a poor sense of smell.
The university of san Francisco (uCsF) researchers tested sense of smell by asking the pensioners to identify scents such as roses, lemons, onions, turpentine and paint thinner.
More than one in four of those with a poor sense of smell developed dementia, compared with just 12 per cent of those with a good sense of smell.
The study also examined the link between other senses and dementia, finding that a decline in hearing, touch or sight was also linked to the condition, but less so. The risk of dementia increased by 19 per cent if sense of smell was lost, compared with a 3 per cent increase for declines in the other senses.
The researchers found that participants who remained dementia-free tended to have higher brain function at the beginning of the study and no sight, hearing or smell loss.
They said that the loss of senses may accelerate brain decline, or the same underlying conditions may cause both dementia and smell loss.
Dr Willa Brenowitz, author of the study published in Alzheimer’s And Dementia: The Journal Of The Alzheimer’s Association, said: ‘it’s thought that smell may be a pre-clinical indicator of dementia, while hearing and vision may have more of a role in promoting dementia.’
uCsF’s Professor Kristine Yaffe said: ‘even mild or moderate sensory impairments were associated with an increased risk of dementia, indicating that people with poor multi-sensory function are a high-risk population that could be targeted prior to dementia onset for intervention.’
Participants who retained good use of their senses were likely to be healthier than those with poor sensory function, suggesting some lifestyle habits may help to reduce the risk of developing dementia.