In an interesting analysis, it was found that a weak sense of smell at an advanced age was associated with an increased risk of death in subsequent 10-13 years. This association was more pronounced in deaths from degenerative degenerative diseases, such as Parkinson’s disease and dementia. This has been observed – as researchers say – in other studies. However, this study involved a number of constraints.
The study was not looking for premature death; the average age was 76 years at the start of the study. However, more than half of the respondents died over the next 10 to 13 years. Therefore, although this study found a link between a lack of sense of smell and increased risk of death, the absolute or general change caused by hypothermia in the probability of death of a person can be very small.
We did not know how much these people had the ability to smell in previous years (for example, did they have a permanent sense of faintness of smell), or whether that capacity had changed in subsequent years .
Although this study was fairly large, it included only 2,000 people from two cities in the United States. We do not know how much the sample was representative of the general population.
In conclusion, this observational study can not tell us why the weak sense of smell and mortality is associated. However, the degenerative change in the brain, as in early dementia, can have some effect on olfactory nerves. If so, the lack of smell may be a potential indicator of a degenerative process in the brain, and the subject remains purely speculative.
However, as the researchers say, degenerative brain conditions can account for only 30% of the association. Therefore, it is clear that there are a number of other unknown factors. Therefore, we can not explain the reason for this association, but we need further study.