Lost Sense of Smell Is a Strong Predictor of Death Within 5 Years 139
HughPickens.com writes: Mo Costandi reports at The Guardian that a new study shows losing one's sense of smell strongly predicts death within five years, suggesting that smell may serve as a bellwether for the overall state of the body, or as a marker for exposure to environmental toxins. "Olfactory dysfunction was an independent risk factor for death, stronger than several common causes of death, such as heart failure, lung disease and cancer," the researchers concluded, "indicating that this evolutionarily ancient special sense may signal a key mechanism that affects human longevity." In the study, researchers tested a group of volunteers for their ability to correctly identify various scents. Five years later, they retested as many of the volunteers as they could find.
During the five-year gap between the two tests, 430 of the original participants (or 12.5% of the total number) had died. Of these, 39% who had failed the first smell test died before the second test, compared to 19% of those who had moderate smell loss on the first test, and just 10% of those with a healthy sense of smell. Despite taking issues such as age, nutrition, smoking habits, poverty and overall health into account, researchers found those with the poorest sense of smell were still at greatest risk. The tip of the olfactory nerve, which contains the smell receptors, is the only part of the human nervous system that is continuously regenerated by stem cells. The production of new smell cells declines with age, and this is associated with a gradual reduction in our ability to detect and discriminate odors. Loss of smell may indicate that the body is entering a state of disrepair, and is no longer capable of repairing itself.
During the five-year gap between the two tests, 430 of the original participants (or 12.5% of the total number) had died. Of these, 39% who had failed the first smell test died before the second test, compared to 19% of those who had moderate smell loss on the first test, and just 10% of those with a healthy sense of smell. Despite taking issues such as age, nutrition, smoking habits, poverty and overall health into account, researchers found those with the poorest sense of smell were still at greatest risk. The tip of the olfactory nerve, which contains the smell receptors, is the only part of the human nervous system that is continuously regenerated by stem cells. The production of new smell cells declines with age, and this is associated with a gradual reduction in our ability to detect and discriminate odors. Loss of smell may indicate that the body is entering a state of disrepair, and is no longer capable of repairing itself.
Nose smell recepters regenerated by stem cells? (Score:2)
1. Harvest nose stem cells from homeless people
2. ???
3. Profit!
Re:Nose smell recepters regenerated by stem cells? (Score:5, Funny)
1. Harvest nose stem cells from homeless people
2. ???
3. Profit!
So you've obviously lost your sense of taste. How long do you suppose you've got to live? :-)
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Or maybe the sense of smell... (Score:5, Interesting)
is what so often keeps you out of trouble such as knowing when food has gone bad or you need to wash. From working in a nursing home, I think it is the lack of smell that kills a lot of people. I'm sure the lack of stem cell regeneration hurts, but not knowing when to was your hands or not knowing if food is bad can be a killer for someone with a weak immune system.
Re:Or maybe the sense of smell... (Score:4, Insightful)
If you wait until you stink to wash, you already have issues.
Re:Or maybe the sense of smell... (Score:4, Interesting)
Dementia can wreak havoc on someone's ability to do stuff. Cues like "smell" would certainly help someone who isn't too far down the dementia path.
Re:Or maybe the sense of smell... (Score:5, Informative)
If you wash religiously, you won't stink.
If you don't wash, you won't stink.
If you wash periodically, you will stink.
Human beings aren't supposed to stink. We're supposed to have bacterial cultures on our skin that prevent it. Washing kills those cultures.
Here's some evidence:
http://www.nytimes.com/2014/05... [nytimes.com]
Long story short, we use too much soap.
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Yes, and for people whose bodies work 100% to specification, that's true. Don't be surprised if you find out that not everyone's born with a body that's in perfect working order.
Second, many people don't want dirt and grime on them. Soap makes it easier to get rid of. Therefore, most take the acceptable loss of a regular cleaning regimen in return for having clean-looking skin without much scrubbing.
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It has nothing to do with your body being in working order or not. They're a bacterial colony that grows on your skin. Like grass growing on a field. The earth does not extrude the grass, and your body doesn't produce the bacteria.
Soap is unnecessary to get dirt off your body. You can scrub yourself with sand, you can rinse yourself in clear water and rub yourself with a scrubber.
If you do this, you'll have healthier skin and it will look nicer and feel softer.
Of course, you'd know all this if you read
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It has nothing to do with your body being in working order or not. They're a bacterial colony that grows on your skin. Like grass growing on a field. The earth does not extrude the grass, and your body doesn't produce the bacteria.
Yes, it does. For the same reason some people are lactose intolerant and some aren't - the body supports the colony. If the body isn't the right environment, the colony will not grow correctly.
You can scrub yourself with sand
My skin's not quite that thick. I don't have standard-issue skin.
Of course, you'd know all this if you read the fucking article.
I read it (skimmed it - wordy garbage). I do not see how that makes every human body genetically uniform.
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Sounds like you have some underlying religious assumptions.
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You're a fucking idiot.
If I said "Human beings aren't supposed to have 6 legs and snakes growing out of their head", would you make the same ridiculous comment?
Go soak your head till the bubbles stop.
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You're a fucking idiot.
If I said "Human beings aren't supposed to have 6 legs and snakes growing out of their head", would you make the same ridiculous comment?
Go soak your head till the bubbles stop.
Man, you religious nuts can't take a joke.
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Human beings aren't supposed to stink. We're supposed to have bacterial cultures on our skin that prevent it. Washing kills those cultures.
It's still washing if you don't use soap.
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If you don't wash, you won't stink.
Yep, tell that to the homeless guy on the subway the next time you see him. Better yet, tell yourself that while you're in the same car. And then tell your friends and coworkers afterwards that the smell coming off of you wasn't from getting skunked.
Sorry dude, you will stink. Eventually. Some people faster than others. But it will happen. Just because you can't smell it anymore doesn't mean it doesn't happen.
Other than that, you certainly will stink after bathing. Especially if you bathe in hot water. Cold
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Perhaps, but skin irritation from too much washing is unlikely to be amongst them, and since you won't stink, it's not like anyone can tell. So what does it matter?
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My grandfather didn't have a sense of smell. So one day a skunk sprayed under his house and he never noticed, although he was getting nauseous but didn't know why. Then my grandmother came home and started shouting about how awful the smell was and he figured it out.
Yay science (Score:2)
OMG, lol (Score:1)
"Olfactory dysfunction was an independent risk factor for death, stronger than several common causes of death, such as heart failure, lung disease and cancer," the researchers concluded, "indicating that this evolutionarily ancient special sense may signal a key mechanism that affects human longevity."
I doubt the "loss" of smell is the cause of much at all but rather can be a symptom of a problem. Sounds like just another Corn-Flake theory...Most people who were involved in accidents or became sick had som
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The "Corn Flake" issue does not apply here. If that were true than people who could smell and had cancer would die at about the same rate as those who could not smell and never have had cancer.
A big issue is the small study size with limited data.
So, it more points to promising lines of research than proving anything.
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A big issue is the small study size with limited data.
So, it more points to promising lines of research than proving anything.
I agree that the sample size is too small and the result could be the one hit wonder. If they keep researching and allow publishing of any result (both support and against), I am quite certain that the outcome is much lower.
However, it is a common sense that humans would face more danger if their olfactory becomes malfunction (if you think about it). Why? What are the purposes of smell? One is to help you identify what is good and what is bad. Even though it is more subjective, it is a very common tool f
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The study was done on Americans between 57 and 85, so we can strike most of your objections. I don't think many died from gas leaks or rancid food.
The researches did consider the link between smell, apatite, and caloric intake and where able to account for that. So strike that.
A hint is that the study was inspired for the search for neurological diseases such as Alzheimer’s and Parkinson’s. Being able to smell depends on stem cells rejuvenating the bits of the nose that we smell with. If those
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It didn't say "cause", it was noted as a correlation. Two different things.
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It didn't say "cause", it was noted as a correlation. Two different things.
Different but related things. If you see a correlation, there is some cause for the correlation. "A correlated with B" doesn't mean "A causes B" or "B causes A", but it does imply that there is at least one causal chain that includes both A and B.
You almost certainly understand this, but I often see people taking the position that "correlation != causation" to mean that they are completely unrelated.
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According to TFA, the researchers stated clearly that the loss of the sense of smell is most likely a symptom of a condition that leads to death rather than being a direct cause. However, they cannot rule out the latter based on the research.
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Anecdotical counter-evidence: my uncle lost his sense of smell back in '94, arguably because he was smoking too much. He quit smoking in '95 and is still alive and well, 19 years later. He's born in 1942, if anyone cares to know.
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Anecdotical counter-evidence: my uncle lost his sense of smell back in '94, arguably because he was smoking too much. He quit smoking in '95 and is still alive and well, 19 years later. He's born in 1942, if anyone cares to know.
Back in high school (Jurassic Period) my girlfriend Holly had absolutely no sense of smell. She said that she just stopped smelling things when she was very young, perhaps 5 or 6 for no apparent reason. Otherwise, she was completely healthy. She was a top scholar, a "triple threat" on the stage, beautiful, talented, creative, curvy, great kisser, the whole package. The fact that she couldn't smell anything was just a wonderful gift from the lord, as far as I was concerned. . High school was a great time
If they can't smell their own urine ... (Score:2)
OK, OK correlation != causation. (Score:3)
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Too much nose picking?
Naw I can still smell just fine.
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The matter is likely very complex with multiple contributing factors causal and otherwise. Here I've listed a few factors which may have an impact and I'm sure you can find others.
Causal:
1) Smell is very important for our psychological well-being. Simple things like enjoying food and sexual attraction. Suicide is surprisingly common with severe loss of the sense. Even in the absence of suicide, people tend not to live very long if they don't particularly want to.
2) A poor sense of smell may result in eating
Olfactory genes may be a canary-in-coalmine (Score:2)
Olfactory genes have a higher rate of mutation than most other genes because the DNA they are in gets packed more tightly and gets replicated later than other genes. As a result, they often show up as false positive in cancer gene searches. Read more here:
http://www.nature.com/nature/journal/v499/n7457/full/nature12213.html
This might mean that they're a canary-in-the-coal-mine: If someone's DNA replication is starting to suffer in general, olfactory genes might be where the breakdown shows up first an
Loss of smell... (Score:1)
"...may indicate that the body is entering a state of disrepair, and is no longer capable of repairing itself."
Yeah. There's a name for that. It's called "getting old".
Farting on your brother is doing him a favor. (Score:5, Funny)
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Dead people neither smell well, nor do they smell good.
Are you both happy now?
No kidding, Sherlock?! (Score:2)
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So I gather your father did not lose his sense of smell due to deterioration from age, unless of course he was 100 years plus when he died of throat cancer. So the study was particularly focused on loss of the sense of smell due to age deterioration and not other causes.
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My dad lost his sense of smell in the final days of WWII. He was the belly turret gunner on a B-17. It belly flopped on landing, propelling him up into the burning wreckage,where he inhaled burning fuel through his nose. He barely survived, but never had a sense of smell from then on, he was 19 at the time, he lived to be 77.
We built race cars together.
Your post made me smile remembering my father, thanks. (:
Cancer_patient (Score:5, Interesting)
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Interesting, I had a head injury ~14ish years ago which increased the frequency, duration, and pain of regular headaches, but also increased the frequency of migraines. I've lost close to 90% of my sense of smell, and occasionally get "weird tastes" in terms of what something should taste like. My favorite these days is mint(which I can lightly taste) tastes more like oranges. On the upside with the loss of smell, I can tell when I'm going to have a migraine attack, since I'll smell things that don't act
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I doubt there's much for you to worry about this. The research only noted the correlation, not that the loss of smell was itself the cause or contributing factor. Your sense of taste may have been more directly damaged by the treatments, instead of being an indicator that your body is failing. Even if it was, the fact that it recovered over time is further evidence that your damaged metabolic processes have returned.
OTOH, IANAD. HTH. HAND.
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Smell is the shittiest sense we have - there are no "good" smells except those that seem to overpower the most shitty smells and/or the utter lack of smell.
I take it you are unfamiliar with concepts like "bacon", "flowers" and "coffee" then?
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Any reason you left out napalm?
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Any reason you left out napalm?
Indeed there was. Check the header:
by arth1 (260657) on Friday October 03, 2014 @03:29PM
I should be dead (Score:5, Funny)
Re:I should be dead (Score:5, Funny)
It's a good thing someone leaned over your corpse and hit the submit button. We are thankful they got your message out.
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No his head collapsed on the mouse button that was over the Submit button. ;)
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Wow, I lost most of my sense of smell over 10 years ago after what my doctors suspect was a virus. I still feel pretty good. I'm in good health with low cholesterol and normal blood pressure. Overall, I feel pretty good for a dea
Dead man walking!
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an increased level of stink usually works, too (Score:2)
if nobody will go into the room to check on the patient because the door is melting, that's also a solid indication that first one in can turn off the IV drip.
A Telomere Canary (Score:2)
This sounds like a Telomere Canary. That is, an outward sign that cells are no longer able to replicate accurately.
You know who you are (Score:1)
Well, my sense of smell is intact. I excercised it thoroughly but accidentally by going to a hobby store two Saturdays ago. and passing the gaming tables.
Erroneous Summary (Score:5, Informative)
First off, the original article is open access at PLOS ONE here: http://www.plosone.org/article... [plosone.org]
The summary statement, "The tip of the olfactory nerve, which contains the smell receptors, is the only part of the human nervous system that is continuously regenerated by stem cells", implies several things that are misleading and/or totally untrue.
The tip of the olfactory nerve is the olfactory epithelium, where the olfactory sensory receptor cells are located. The olfactory nerve travels through the cribriform plate, a porous area of skull, where it then synapses with the olfactory bulb. The olfactory bulb has several cell types, and only one of these, inhibitory granule cells, is continually regenerated via neuroblasts migrating along the rostral migratory stream from the sides of the lateral ventricles. These cells are thought to play a role in associative learning and coding of new olfactory cues. The olfactory nerve does not have a capacity for self-renewal, nor do any of the olfactory receptor cells.
Furthermore, there is more than one area where neurons undergo continual self-renewal. The dentate gyrus of the hippocampus also fosters a neurogenic niche, and these new cells have important implications for learning, memory, stress, and emotion that we are just beginning to understand.
Thirdly, we don't really know if neurogenesis in the olfactory bulb has anything at all to do with the observed results because this was not measured in the study, but it is a plausible hypothesis for future study.
As a side note, one of the very intriguing aspects of neurogenesis is that after cortical injuries such as trauma or stroke, neuroblasts from the ventricles migrate toward the lesion, rather than toward the olfactory bulb. These cells are capable of forming electrochemically active synapses at the lesion site and appear to aid in recovery. Unfortunately, astrocytic scarring and inflammation limit the regenerative capacity of these cells - but this is an area of intense research in the field of neurotrauma. My current (undergraduate) research is focused on analyzing the effects of post-injury recovery environment (for rats) on subventricular and hippocampal neurogenesis.
For a good summary on neurogenesis:
http://chuang01.web.wesleyan.e... [wesleyan.edu]
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great comment! Thank you!
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Everything in your comment is true, except "The olfactory nerve does not have a capacity for self-renewal, nor do any of the olfactory receptor cells.". The olfactory receptor cells are not considered part of the central nervous system, and the usual rules of "no regeneration in the CNS" do not apply. In fact, olfactory receptor cells die all the time, and the turnover time is about 40 days. Through axon guidance cues, the new ones usually find the same targets as the old ones, resulting in a sense of sm
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Makes sense. (Score:5, Interesting)
Our sense of smell is the sense running at the lowest level. It's wired straight into the brain in the shortest path of any sense.
This is why the peanut butter smell test [ufl.edu] can help diagnose Alzheimer's disease. I would expect nontraumatic loss of smell to highly positively correlate with damage to the structures of the temporal lobe (amygdala, basal ganglia, etc). This is where memory lives (in all its forms).
Smell is a pretty raw sense, as opposed to say, vision, which is highly processed by many different cortical systems and areas. I would therefore expect it to yield the best raw cerebral status metadata.
Oh my god, I would have been dead at 5-10 yo (Score:3)
I either NEVER had a sense of smell, or at least not since I was 5 years old. So I should have died over 25 years ago.
It is a minor inconvenience... I have to be careful about gas leaks and such.
As for food, I have a good enough sense of taste to distinguish most foods so it's not like I feel like I'm eating sawdust like some people assume.
A for the rest, just minor stuff:
Visually check to make sure I didn't step in dog poo
Don't use any fragrance or cologne... I'll never get it right
Make sure I'm always clean, and have deoderant on
etc
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I either NEVER had a sense of smell, or at least not since I was 5 years old. So I should have died over 25 years ago.
Not if you read the article - it says the that the olfactory nerves are continually regenerated, so if your body stops being able to regenerate itself you will lose your sense of smell first. It doesn't say anything about losing your sense of smell because of other reasons.
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I either NEVER had a sense of smell, or at least not since I was 5 years old. So I should have died over 25 years ago.
Same story for a high school girlfriend who was exceptional in every way. She said she lost her sense of smell at around 5 or 6 years of age and for no apparent reason .
;-)
Nothing else unusual, except for a nose missing from her face (... just kidding
Sense of Smell (Score:2)
I always joked that I had no sense of smell. It was there, but something had to really stink to get up my nose. Considering that I also couldn't breathe through one of my nostrils, this made sense to me. Finally, after much testing and worried about sleep apnea, we found the cause of my blocked airways. A structure in my nose was trying to grow a third airway. Doing this pushed my septum over and made my one nostril's airway extremely narrow. I had surgery a few months ago to remove this structure and
Playing on Netflix now... (Score:1)
... we are all gonna die! (Score:2)
I should be dead (Score:2)
My dog has no nose. (Score:1)
My dog has no nose.
How does he smell?
Terrible.
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I prefer the antihumor version:
My dog has no nose.
How does he smell?
He can't, he doesn't have a nose!
Prodromal Indicator for Pancreatic troubles... (Score:5, Informative)
Four years ago, I lost my sense of smell. No other physical manifestations. After a month without any smell (quite disconcerting - couldn't smell coffee, food, or anything, Took much of the color out of life), Kaiser hospital did a cat scan of my head and reported a very minor nasal obstruction, probably mucus.
Over the next few months, a weird constellation of symptoms showed up: severe anxiety. Sudden, severe depression. Occasional double vision. Absolute insomnia for four days. Bizarre - in my life, I'd never felt anything like this. (I don't do drugs, alcohol, or have any history of mental troubles)
Then my pee turned black. My wife took me to the hospital...
After sonograms & catscans, the radiologist found a walnut sized tumor on my pancreas.
The doctor looks at me and asks if I have any kids. "Sure, two of 'em," I replied.
"Then you'd better get to an attorney and make your will. Don't waste any time."
Less than 5% of pancreatic cancer patients live for 5 years. After making my will, I had a Whipple operation (don't ask), the surgeon removed the tumor (along with a gall bladder, and god knows what else). I'm still alive today, almost 4 years later, writing Python code and shell scripts. Within my field, I'm moderately well known, so I'm posting this anonymously.
Here's the important part: Pancreatic and other cancers often show strange pro-dromal symtoms, months before the obvious manifestations occur. Things like sudden onset, severe anxiety. depression, and emotional distress. And the sudden loss of smell. Sure, laugh at the postings here. But take it seriously if this happens to you or someone you know.
Loss of smell might just be from a common cold. But it may be a prodromal indicator of something serious.
Hypothesis by researchers (Score:2)
Contrary to all the speculative guesses in the comments, the researchers do have a hypothesis for this.
From the linked PLOS article [plosone.org]:
Hmm .... (Score:2)
What's this stuff in the back of the fridge? It doesn't smell bad. I think I'll reheat it for lunch.
I just told my wife ... (Score:2)
... the reason I poot a so much because I'm just checking on her health and stuff.
So why am i still alive? (Score:2)
I lost my sense of smell over 15 years ago.
+1 to smoking, and for making this report complete bullcrap!
There are lies, damned lies, and statistics. (Score:1)
This is useless without more information/data.
Old people are more likely to lose their sense of smell.
Old people are more likely to die within 5 years.
Therefore, people who lose their sense of smell are more likely to die within 5 years.
This is the whole "ice cream causes drownings" all over again.
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Didn't you RTFS?
You're trotting out Disraeli's line. That's normally a sign of someone who doesn't actually know how to read and analyse statistics. That's your failure, not a failure of statistics.
This Story Really Stinks (Score:2, Offtopic)
There's too much coke and too much smoke
Look what's going on inside you
Ooooh that smell
Can't you smell that smell
Ooooh that smell
The smell of death surrounds you
Re:This Story Really Stinks (Score:4, Informative)
Happy Friday, sir! Say hello to your family from myself, and from Mrs Fuckwit, too, of course!
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Hey now, he's a complete fuckwit with good taste in music - props where they're due.
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You sort of are an insincere bastard, with very weak troll-magic.