Olfactory tests can help doctors identify older people who are at greater risk of developing dementia, researchers say.
The sense of smell is known to deteriorate with age. However, researchers have previously found that, perhaps, also hinted at problems with health: the elderly, who are trying to identify the smells, are more likely to die in the near future, no matter how old they are.
Other studies have found elderly people who have difficulty in identifying and memorizing odors are more likely to have characteristics associated with a greater risk of developing Alzheimer's disease even if there is no current sign of cognitive decline.
It is believed, smell with & # 39 is one of the first departments who suffered from certain neurodegenerative diseases.
Now experts say that they investigated further, in and of themselves, these diseases do not explain why a bad smell may be a bad omen.
"My suspicion [the] The process of smell in older people is likely to have a much wider potential implications for health than what we already know about, "said Professor Honglei Chen, co-author of the study from the University of Michigan. It is speculated that this may be due to the conditions of the immune system and even mental disorders.
Writing in the Annals of Internal Medicine, researchers in the US and Sweden reported as more than 2,200 people aged 71 to 82 held a smell identification tests at the turn of the millennium, which then go to more than 13 years. Test participation 12 participants fragrant variety of common odors, so the smell of strawberries and a selection of the identity of each of the four possible answers.
The team then grouped the participants into "good", "moderate" or "bad" smell, depending on how many correct answers they gave. They also examined the causes of death among participants who died during the study period. If the team took into account factors such as age, sex, race, smoking and general health at the outset, they found that a bad smell was associated with a 46% higher risk of dying within 10 years compared with those assessed as a a good sense of smell.
The researchers concluded that this trend is carried out regardless of gender or race participants, but the relationship was present only among those who have been in very good health at the start of the study.
The researchers say that this may be due to those who are in poor health were a lot of factors that can affect the duration of their lives, the vast no effect associated with a poor sense of smell. "On the other hand, a bad smell in older people with excellent to good health may be an early sign of the insidious adverse health conditions that eventually lead to death," the authors write.
They found a bad smell was associated with the death of dementia and Parkinson's disease with some features that have not smell also can be linked to death from cardiovascular diseases. There was no connection between the bad smell and deaths from cancer or respiratory diseases.
Further analysis showed 22% of the increased risk of death among people with poorer sense of smell was to neurodegenerative diseases, from 6% to weight loss.
The team says the rest of the association with mortality, probably until the health status that have not yet been identified as being associated with smell. After it was unpicked, said Chen, it may be necessary to add the smell test for general health screening.
However, others pointed out that it was unclear when the results conducted among young people, while the sense of smell has been tested only once. Moreover, visible communication between sense and mortality can be up to factors that affect both, but have been omitted.
Professor Jayant Pinto of the University of Chicago, who conducted preliminary research in this area, welcomed the study. "While we still need to understand what a bad smell signaling in terms of specific mechanisms that lead to increased risk of death, it seems clear that the violation of the sense of smell with the & # 39 is an early sign of both diseases, such as Alzheimer's disease and Parkinson's disease, as well as heart disease, "he said.
"I am a supporter of a broader application of the odor testing in general practice because it can signal the suras & # 39; serious health problems in the future," he added, "Even if we do not yet have treatments. [Alzheimer’s or Parkinson’s disease] , It is better to study these patients may help us to take care of them and plans for the future for patients and their seven & # 39; ads ".