[HN Gopher] Rates of Parkinson's disease are exploding. A common...
       ___________________________________________________________________
        
       Rates of Parkinson's disease are exploding. A common chemical may
       be to blame
        
       Author : bookofjoe
       Score  : 212 points
       Date   : 2021-04-08 15:56 UTC (7 hours ago)
        
 (HTM) web link (www.theguardian.com)
 (TXT) w3m dump (www.theguardian.com)
        
       | sbradford26 wrote:
       | So IBM had/has a serious issue with TCE in Endicott, NY. IBM has
       | mostly left Endicott but they are still paying to clean up the
       | area.
       | 
       | News article about it: https://wbng.com/2019/11/21/40-years-
       | after-spill-former-ibm-...
       | 
       | EPA Website with status on the cleanup:
       | https://www.epa.gov/hwcorrectiveactionsites/hazardous-waste-...
        
       | lucb1e wrote:
       | For those wondering if the "exploding" from the headline is
       | clickbait or a misread statistic: not exactly, it sounds true
       | (enough) based on what Wikipedia says:
       | 
       | > In 2016 PD resulted in about 211,000 deaths globally, an
       | increase of 161% since 1990. The death rate increased by 19% to
       | 1.81 per 100,000 people during that time.
        
       | throwaway78124 wrote:
       | I live ~1000ft from a super fund site that is cleaning up
       | TCE/DCE, and there are a few more within 5-10 miles of here.
       | 
       | I smell weird things in the mornings sometimes, and also after
       | rainstorms. We lived pretty close to another super fund site when
       | I was growing up, and my father has Parkinson's. So I assume that
       | I get to die early.
        
         | adammunich wrote:
         | You should move
        
       | dcolkitt wrote:
       | Just speculating here. Could be due to declining smoking rates.
       | Especially among the cohort that's aging into age into prime
       | diagnosis years. Nicotine is highly effective at preventing
       | Parkinson's.
       | 
       | https://actaneurocomms.biomedcentral.com/articles/10.1186/s4...
        
         | fab1an wrote:
         | This is a very plausible explanation.
        
           | tubularhells wrote:
           | How would you know?
        
             | nabla9 wrote:
             | What does plausible mean?
             | 
             | My understanding:
             | 
             | plausible: it is possible to make reasonable case for that
             | argument.
             | 
             | possible: is capable of becoming true, though it's not
             | always reasonable.
             | 
             | The logic of possible nicotine link seems completely clear
             | on the basis of current nt knowledge. That does not mean it
             | exists or is important. Somebody has to look into it.
        
               | mrow84 wrote:
               | "Very plausible" carries different connotations to
               | "plausible". The former suggests (to me) that it _really
               | might be the right explanation_ , whereas the latter just
               | sounds like it is an explanation that fits currently
               | known facts.
        
               | samatman wrote:
               | Nicotine is in fact _highly protective against
               | Parkinsons_. The effect is not small!
               | 
               | Smoking has declined by at least half in the last fifty
               | years in the United States. Also not a small effect!
               | 
               | "Very plausible" here means "someone should really do a
               | study where they correlate for lower levels of nicotine
               | use and see if there's anything left to explain".
               | 
               | I can't imagine anyone would see "very plausible" and
               | think the explanation should be accepted without
               | investigation. That's just not what that phrase means.
        
               | mrow84 wrote:
               | > Nicotine is ...
               | 
               | > Smoking has ...
               | 
               | Neither I, nor anyone in this thread, has contested the
               | existence of evidence to support this claim.
               | 
               | > "Very plausible" here means ...
               | 
               | Why does "plausible" not suffice?
               | 
               | > I can't imagine anyone would see "very plausible" and
               | think the explanation should be accepted without
               | investigation. That's just not what that phrase means.
               | 
               | I didn't suggest otherwise.
        
       | athoun wrote:
       | To add a data point, I recently had a grandparent who died with
       | Parkinson's disease.
       | 
       | After doing research, it turns out their home was located very
       | close to a Superfund cleanup site from a dry cleaner that
       | operated in the 60's and contaminated the groundwater with TCE
       | and PCE. The chemicals leach into the groundwater and can spread
       | hundreds of feet per year. Buildings located over these plumes
       | are exposed to vapors which accumulate indoors over time and
       | expose the occupants.
       | 
       | According to Wikipedia, the PCE solvent which is used at nearly
       | every dry cleaner across the country has been known as a x10 risk
       | factor for Parkinson's [1].
       | 
       | For California residents, you can find out about these
       | groundwater plumes on the waterboards website. They are located
       | all over Silicon Valley and former dry-cleaners around the
       | country [2].
       | 
       | [1]: https://en.wikipedia.org/wiki/Tetrachloroethylene
       | 
       | [2]: https://geotracker.waterboards.ca.gov/
        
         | Wohlf wrote:
         | Similarly, my uncle has rapidly progressing Parkinson's caused
         | by exposure to Agent Orange as a Seabee in Vietnam, his VA
         | doctors have confirmed this as the cause.
        
       | franklyt wrote:
       | There are measurable links between use of ADD/ADHD medication and
       | Parkinson's, which makes sense given that the former modulates
       | dopamine and the latter has to do with dopamine modulation.
       | 
       | I view this direct connection as more compelling an explanation.
        
         | dsego wrote:
         | Wait till you see what anti-psychotics can do.
        
           | franklyt wrote:
           | Errr... I was more implying that ADD/ADHD medications are in
           | very common usage, making it a notable data point. Perhaps I
           | should have make that explicit.
        
         | challengly wrote:
         | And medicating kids for acting like kids is already dubious,
         | even if a Parkinson's link proves to not hold.
        
         | Wohlf wrote:
         | This may be true in the future but seems unlikely today,
         | Parkinson's rarely occurs before 60 and the rise in ADHD
         | diagnoses started in the 90s.
        
           | franklyt wrote:
           | Yeah, we'd need more data. Because PD is such a low-incidence
           | disease generally, any kind of uptick, even in the pre-60
           | cohort, would push the dial substantially. Are pre-60 cases,
           | which I just found out trivially are at 4%, increasing
           | substantially? Is 4% inclusive of a much older dataset? I'd
           | venture that the answer is yes, but I have no idea.
        
       | xxpor wrote:
       | Looking at the wiki entry for trichloroethylene:
       | 
       | https://en.wikipedia.org/wiki/Trichloroethylene
       | 
       | I guess I'm a little skeptical of the explaination that it could
       | be the source of the explosion of Parkinson's over the past
       | decade. Trichloroethylene has known to be a problem since at
       | least the 50s. For example, its use in bulk in dry cleaning was
       | replaced in the 50s with tetrachloroethylene, and it was used for
       | spot cleaning only up until 2000.
       | 
       | The only seemingly recent increase in uses are:
       | 
       | "The demand for TCE as a degreaser began to decline in the 1950s
       | in favor of the less toxic 1,1,1-trichloroethane. However,
       | 1,1,1-trichloroethane production has been phased out in most of
       | the world under the terms of the Montreal Protocol, and as a
       | result trichloroethylene has experienced some resurgence in use
       | as a degreaser."
       | 
       | I don't think most people are exposed to industrial degreaser in
       | their line of work, let alone in domestic settings.
       | 
       | "TCE is also used in the manufacture of a range of fluorocarbon
       | refrigerants[13] such as 1,1,1,2-tetrafluoroethane more commonly
       | known as HFC 134a"
       | 
       | Now this seems somewhat plausible. R134a started to be used in
       | the early to mid 90s, so the timeline would make sense. However,
       | it says it's only used in the manufacture of it. Perhaps there's
       | some residual left in the final R134a product, and that's how
       | people would be exposed to it? Plenty of ACs and fridges in
       | people's lives.
        
         | nitrogen wrote:
         | There are groundwater plumes of TCE around air force bases
         | because they used to just dump extra TCE into open pits
         | thinking it would evaporate. Maybe those plumes reached enough
         | city wells to cause problems over the last few decades.
        
           | downrightmike wrote:
           | Example:
           | https://www.library.pima.gov/blogs/post/trichlorethylene-
           | tce... Hughes is now Raytheon Trichlorethylene (TCE), an
           | industrial solvent, was routinely dumped in areas of South
           | Tucson during the 1950s. The Tucsonans who lived in these
           | areas have had various cancers as a result of this pollution.
           | 
           | The boundary of the area contaminated by TCE is roughly south
           | of 22nd street, north of Los Reales Road, east of Interstate
           | 19 and west of Del Moral Boulevard.
           | 
           | Hughes Aircraft and the city of Tucson were accused of
           | dumping TCE in the water table for 29 years, beginning in
           | 1952. A lawsuit against the city was settled in 1981 for $31
           | million, and in 1991 a suit against Hughes Aircraft was
           | settled for $84.5 million. In 1981 the Environmental
           | Protection Agency (EPA) tested water wells on the south side
           | of Tucson and found TCE levels were beyond the EPA limits.
           | 
           | In 1983, the EPA set a large southside area of Tucson on its
           | Superfund cleanup list. In March 2000, a $35 million plan was
           | secured for cleanup of the contaminated areas. Other
           | government supervised cleanups started about 20 years ago.
           | The last settlements involving TCE lawsuits occurred in June
           | 2006.
        
           | chriselles wrote:
           | I recall this making headlines in the 90's in proximity to
           | airbases in Pennsylvania.
           | 
           | Specifically issues around drinking water for residential
           | housing with wells in proximity to the airbases.
        
         | mauvehaus wrote:
         | If your fridge or AC is exposing you to trace amounts of TCE
         | left over from the process of making the R134a it's primarily
         | charged with, it also isn't keeping your food cold.
         | 
         | A common AC charge for a car is around 500g +/- 25g It doesn't
         | take much of that leaking out before it doesn't blow cold air.
         | Even if there was a bunch of residual TCE, you're unlikely to
         | be subject to a long term exposure because you'd notice your AC
         | or fridge not working long before the full charge leaked out to
         | expose you.
         | 
         | In spite of the efforts of the world's accountants, fridges and
         | air conditioners still routinely last a decade or more. That's
         | because the charge of R134a is largely staying put.
        
         | pomian wrote:
         | There is also the interesting process of chemical Oxidation,
         | which occurs naturally, and with environmental clean up. (
         | Various treatment processes: ozonation, peroxide injection,
         | etc.) The break down by products of complex chemicals, are
         | often more toxic (long term hazard to organisms, including
         | humans.) For example, Tetra fluoroethylene, may easily
         | breakdown down to Tri fluoroethylene. There are even more toxic
         | by products, further down the break down chain. Soil chemistry
         | is very complicated, and interesting. EPA has very good
         | articles following these processes across hundreds of superfund
         | sites, across the USA.
        
         | criddell wrote:
         | My dad is suffering from Lewy Body Dementia which is related to
         | Parkinson's. He was an auto mechanic his entire adult life
         | (from around 1960 - 2010). I wonder if he was exposed to TCE?
         | 
         | I did a 23 and Me test and never unlocked the health results.
         | I'm a little terrified of finding out that dementia is in my
         | future as well.
        
           | throwawayboise wrote:
           | If he used a lot of brake cleaner or carburator cleaner then
           | likely yes. Either TCE or a similar chlorinated solvents.
        
           | londons_explore wrote:
           | Degreaser is a common part of a car mechanics life.
           | Especially so 30+ years ago where it was more common to clean
           | and replace parts than now when it's more usual to just
           | replace any removed part.
        
             | athenot wrote:
             | This is counter-intuitive but I guess there are cases where
             | throwing away the part and replacing with a new one is
             | _MORE_ environmentally friendly that reusing the part--when
             | it involves not-so-nice solvents. I hadn 't considered this
             | before.
        
           | maxerickson wrote:
           | Both Parkinson's and Dementia with Lewy Bodies mostly occur
           | without family history, so the test may not say much anyway.
           | 
           | In my mom's case I wonder about a viral infection she had in
           | her eye. It was quite severe.
        
             | criddell wrote:
             | > mostly occur without family history
             | 
             | Does that suggest it's environmental rather than genetic?
        
               | maxerickson wrote:
               | I don't know really.
               | 
               | I think the cutting edge opinion is that it isn't known
               | why they occur.
        
               | inglor_cz wrote:
               | Even genetic diseases sometimes need environmental
               | influences to develop.
               | 
               | For example, some people are prone to alcoholism in a
               | hereditary way. But if they live in a society that has
               | zero alcohol, they won't ever become alcoholic. Upon
               | moving to a society where alcohol is sold freely and
               | frequently, they may sink into alcoholism without having
               | any obviously alcoholic ancestor.
        
               | DoreenMichele wrote:
               | Not necessarily. A homozygous recessive disorder often
               | occurs without prior family history.
               | 
               | Two carriers have a child together, the child has the
               | disorder, this is how they learn they are carriers.
        
           | okprod wrote:
           | _I did a 23 and Me test and never unlocked the health
           | results. I 'm a little terrified of finding out that dementia
           | is in my future as well._
           | 
           | I was in almost the identical boat but I pulled the trigger
           | on looking at the test results, ended up fine. Better to know
           | and try to manage it I think.
        
             | criddell wrote:
             | Intellectually, I know you're right.
             | 
             | There's also the angle that if I want to buy life insurance
             | I may be better off not knowing.
             | 
             | After seeing how it's affecting my dad, I know how I'd
             | "manage" it. It really is awful and decades of mental
             | decline coupled with terrifying hallucinations is not
             | something I'm willing to endure.
        
               | evanmoran wrote:
               | The life insurance angle is real, but the solution isn't
               | to wait, it's to get into the plan before you find out.
               | You can always stop the plan if you think your risks
               | aren't as high later when you know more!
        
               | prepend wrote:
               | > buy life insurance I may be better off not knowing.
               | 
               | I think it's moot because life insurance will check your
               | genes as part of underwriting.
               | 
               | In the US genes can't be used to discriminate for
               | employment or healthcare [0], but can for everything
               | else.
               | 
               | I got a quote for term insurance in 2008 and they tested
               | for lots of genetic conditions.
               | 
               | You can probably get by if you have unique, rare
               | mutations that aren't commonly studied. But anything
               | basic enough to be found in a 23andme profile is likely
               | to be checked by your insurance.
               | 
               | [0] https://en.wikipedia.org/wiki/Genetic_discrimination
        
           | jxramos wrote:
           | I bought some brake cleaner not too long ago and saw all the
           | labeling about the new formulation. I just looked up what the
           | old formulations used to look like, check it out.
           | 
           | > Chlorinated brake cleaners (often sold as non-flammable)
           | use organochlorides like tetrachloroethylene and
           | Dichloromethane.
           | 
           | https://en.wikipedia.org/wiki/Brake_cleaner#Composition
           | 
           | Compared to the new formulation
           | 
           | https://www.crcindustries.com/products/brakleen-174-pro-
           | seri...
           | 
           | so called 50 state compliant.
           | https://www.crcindustries.com/products/brakleen-174-pro-
           | seri...
        
             | tristor wrote:
             | Well shit, I always preferred the old fully chlorinated
             | stuff because it works better. When you say "chlorinated" I
             | assume that means it contains chlorine, which isn't great,
             | but is more an issue for chemical burns than anything, so
             | you wear gloves and eye pro and don't worry about it. I
             | never looked into it. I've probably inadvertently exposed
             | myself to a /ton/ of TCE working on cars and other
             | mechanical things. I buy brake cleaner by the case...
        
           | sjg007 wrote:
           | I'm sorry to hear that.
           | 
           | TCE is a degreaser which is used to clean car parts so most
           | likely.
        
       | elzbardico wrote:
       | Just another justification for my hatred of carpets.
        
       | jedimastert wrote:
       | The headline is /r/savedyoaclick bait.
       | 
       | It's trichloroethylene, but only maybe?
        
         | yourmom2 wrote:
         | great comment bro thanks
        
       | gabaix wrote:
       | Little known fact: high concentration of TCE permeates the Bay
       | Area in cites like Palo Alto and Mountain View. The concentration
       | is so bad that these superfund sites are regularly monitored by
       | the federal government.[1]
       | 
       | I lived next to the superfund site of Palo Alto, which was right
       | under Mayfield Soccer Complex. Little had been done to monitor
       | the risks for the children [2]. Reading this article linking TCE
       | to Parkinson's disease, I hope there will be more awareness about
       | Silicon Valley toxic undergrounds.
       | 
       | [1] https://www.nytimes.com/2018/03/26/lens/the-superfund-
       | sites-... [2] http://www.aarongreenspan.com/writing/20130404/in-
       | search-of-...
        
         | gnicholas wrote:
         | There's even a TCE site where Facebook used to be headquartered
         | (between California Ave and Page Mill Road), where Stanford now
         | has a faculty housing development. The university has stated
         | that they built the homes with protection against TCE
         | leakage/accumulation, but I've read that TCE can easily
         | permeate PVC pipes that are often used for water distribution.
         | 
         | My family decided not to live in this development (or in the
         | nearby neighborhood) because of the risks of TCE contamination.
         | But who knows what risks there are in the area we decided to
         | live, which is right next to SLAC!
        
         | ericbarrett wrote:
         | Jogging through the hills of Stanford and Palo Alto in the 90s,
         | you would occasionally smell something sweet, reminiscent of
         | baking bread, even though there were no bakeries or homes
         | nearby. I was told by an old-timer (worked in SV in the 60s and
         | 70s) that's the smell of the outgassing TCE. Not sure if it's
         | true, but it definitely made the smell less appealing.
        
       | sbehlasp wrote:
       | Surprise to see that we are pointing and blaming one chemical
       | only here. PFAS, a class of more than 4,000 different chemicals,
       | is everywhere [https://on.natgeo.com/2Q2UtMS] food, water we
       | drink and even in our blood. We don't even know when and how we
       | are consuming it directly or indirectly. Do we have any kind of
       | full proof study about all 4000 chemicals, that how these
       | chemicals would be affecting our health! I think nature has
       | already been polluted/damaged to an extent which is kind-a
       | irreversible. Hoping for the better world.
        
         | sjg007 wrote:
         | PFAS is on furniture, clothes, cooking ware, food containers,
         | firefighting foam and so forth. The firefighting foam gets it
         | into the water table as do badly managed dumps.
         | 
         | It's been detected in milk, eggs, water..
        
         | ed25519FUUU wrote:
         | I sometimes think back about our attitudes towards lead,
         | mercury, and even radium[1], and I truly wonder how we survived
         | as a specifies!
         | 
         | I am grateful that collectively things seem to be improving.
         | We're learning more about diseases, their causes, and their
         | treatments.
         | 
         | 1. https://www.thevintagenews.com/2017/01/24/an-energy-drink-
         | th...
        
           | outworlder wrote:
           | Frankly, this could be the Great Filter.
        
             | jschwartzi wrote:
             | This kind of thing is what eventually kills off Brewer's
             | Yeast. The individual yeast cells keep making sugar into
             | alcohol until the alcohol concentration is so great that
             | they kill each other off.
        
         | Nasrudith wrote:
         | We don't even know how all of our bodily chemicals affect our
         | health. It is because nature is inherently a messy and complex
         | process. Unknowns are the default state and a fact of life.
         | 
         | Now consuming them may not be ideal but the fear of the unknown
         | is overemphasized. We already know from pharmacology that
         | higher effectiveness needs fewer data instances to prove from
         | the strength of the effect. The more powerful something's
         | effect not noticing it becomes increasingly improbable as
         | patterns should become increasingly obvious in large numbers.
         | Try not to notice plutonium toxicity.
         | 
         | The fact we aren't seeing more immediate effects from higher
         | level of exposure suggests it is not catastrophic - may not be
         | good but it is an implicit upper bound on harm based upon what
         | we see cannot be possible. To give an absurd example we know
         | PFAS does not cause people's heads to explode at current levels
         | of exposure because there have been zero reports of people's
         | heads exploding without a known cause.
        
           | whatshisface wrote:
           | > _there have been zero reports of people 's heads exploding
           | without a known cause._
           | 
           | There is a long list of common and unexplained medical
           | problems like fibromyalgia awaiting an explanation like "that
           | water you've been drinking is toxic." There is no shortage of
           | illnesses that could potentially be caused by a problem like
           | that.
        
         | yabones wrote:
         | PFAS is going to be the asbestos of our generation, except it
         | won't be so easy to get rid of this time around. It's more like
         | the asbestos of every future generation until we find a way to
         | reliably break it down.
        
           | Layke1123 wrote:
           | That or it will be a natural form of selection for old age,
           | increasing human longevity at the expense of temporary
           | population reduction. Let's hope artificial gene therapy is
           | within our lifetimes or hope we drew the golden ticket.
        
       | WrtCdEvrydy wrote:
       | Is the chemical "clickbaitium"?
        
         | yourmom2 wrote:
         | uh oh... we got one of those sharp hackers over here
        
       | feralimal wrote:
       | Perhaps this is a water filter advert: "Using activated carbon
       | filtration devices (like Brita filters) can help reduce TCE in
       | drinking water"
       | 
       | But really, how could they possibly narrow it down to that? How
       | can they ignore all the metals that we are injected and sprayed
       | with as possible alternative causes?
        
       | odyssey7 wrote:
       | If this product weren't already on the market, and this link was
       | suspected, would it be easy for it to come to market in our
       | regulatory environment?
       | 
       | Now that it's on the market, and the link is suspected, how hard
       | is it going to be to get it out of use?
        
       | [deleted]
        
       | dralley wrote:
       | >Those near National Priorities List Superfund sites (sites known
       | to be contaminated with hazardous substances such as TCE) are at
       | especially high risk of exposure. Santa Clara county, California,
       | for example, is home not only to Silicon Valley, but 23 superfund
       | sites - the highest concentration in the country. Google Quad
       | Campus sits atop one such site; for several months in 2012 and
       | 2013, the Environmental Protection Agency (EPA) found employees
       | of the company were inhaling unsafe levels of TCE in the form of
       | toxic vapor rising up from the ground beneath their offices.
        
         | ptudan wrote:
         | I used to play basketball on this campus all the time! Sheesh
        
           | jeffbee wrote:
           | It's not like this is Google-specific. Santa Clara County is
           | just toxic. All of this junk, for example, is built on a
           | plume of TCE. https://www.google.com/maps/@37.3823386,-121.98
           | 41579,458m/da...
        
             | outworlder wrote:
             | Just curious, what specifically are you pointing at? Is
             | there any manufacturing going on? I'd think these are
             | mostly office buildings.
        
               | jeffbee wrote:
               | It was semiconductor manufacturing before, then it was an
               | empty lot, now its offices and parking. This would have
               | been an orchard, 50 years ago.
        
       | nanis wrote:
       | There is always the problem of over time people not dying of
       | other causes so that more get to live to the ages where they can
       | get diseases that used to be rarer. Also, AFAIK, improvements
       | have been made in the diagnosis of Parkinson's.
       | 
       | > in the US, the number of people with Parkinson's has increased
       | 35% the last 10 years
       | 
       | 10 years ago, the oldest U.S. baby boomers were reaching 65. Now,
       | they are reaching 75[1].
       | 
       | Given the fact that birth rate went from 19/1000 to 27/1000
       | between 1935 and 1946 and the fact that people born in 1946 faced
       | a much friendlier environment to grow up in, the numbers are not
       | surprising.
       | 
       | The fact is, industry also grew at the same time, so it will
       | always be possible to find positive correlations between
       | prevalence of some disease and some industrial chemical.
       | 
       | It is not impossible that a causal relationship exists, but that
       | needs to be established using something other than simple
       | correlations.
       | 
       | [1]:
       | https://en.wikipedia.org/wiki/Mid-20th_century_baby_boom#Nor...
        
         | mrow84 wrote:
         | "A 2008 peer-reviewed study in the Annals of Neurology, for
         | example, found that TCE is "a risk factor for parkinsonism."
         | And a 2011 study echoed those results, finding "a six-fold
         | increase in the risk of developing Parkinson's in individuals
         | exposed in the workplace to trichloroethylene (TCE).""
         | 
         | It doesn't strike me as fair to dismiss studies like the ones
         | quoted (from the article) as simple correlations.
        
           | nanis wrote:
           | > It doesn't strike me as fair to dismiss studies like the
           | ones quoted (from the article) as simple correlations.
           | 
           | I didn't see the particular studies and I am not dismissing
           | them out of hand, but I've seen a lot of studies, lost a lot
           | of battles against all sorts of unsound statistical analysis.
           | When I taught Intro Stats, I had no trouble finding examples
           | of what not to do to illustrate in class: Just look at the
           | front page of the campus newspaper which seemed intent on
           | filling pages with bogus "studies".
           | 
           | Again, I am not calling this one[1] bogus, but I am going to
           | point out that study seems to consist solely of finding
           | people who have Parkinson's and have worked around the
           | chemical.
           | 
           | Causality requires (not p) => (not q).
           | 
           | [1]: https://hero.epa.gov/hero/index.cfm/reference/details/re
           | fere...
        
         | gnramires wrote:
         | This can be done by 'Controlling for age' in statistics. If
         | your cohort gets older, you get more prevalence of old age
         | diseases of course. But by isolating by sufficiently small age
         | groups (assuming the age distribution is approximately
         | constant, or flat, within a group[1]), we can tell if the rate
         | per given age is increasing or not. In this case simple
         | multivariate statistics to judge if the changes are
         | significant.
         | 
         | [1] The variation in distribution among age groups can be
         | controlled by more sophisticated methods, but it may be
         | sufficient to make the groups small and multivariate analysis
         | (although results might be weakened by assumptions of
         | independent errors if groups are too small).
        
         | chemeng wrote:
         | While this is always something to consider, generally, 6-fold
         | increase in risk due to exposure is likely not just a
         | population demographic artifact.
         | 
         | TCE and its relation to Parkinson's has been studied for at
         | least the last 15 years. Though I haven't come across anything
         | definitive on the mechanism of action, there seems to be
         | indication that a combination of TCE or its analogues combined
         | with other risk factors (assumed to be genetic) generates
         | substantial progressive dopaminergic neuron loss, a hallmark of
         | Parkinson's disease progression.
        
           | nanis wrote:
           | > 6-fold increase in risk due to exposure
           | 
           | Interestingly, the Guardian article does not cite a source
           | for that claim, so it is impossible to evaluate it soundly.
           | 
           | However, just above, it states:
           | 
           | >> the number of people with Parkinson's has increased 35%
           | the last 10 years
           | 
           | which is completely in line with the increase in at risk
           | population + improved probability of diagnosis.
           | 
           | That doesn't mean there is no link.
        
         | hutzlibu wrote:
         | This is a very important, often overlooked point.
         | 
         | Also food malnutrition is way less common, than it was before.
         | 
         | But we also are exposed to many new chemicals, not occuring in
         | nature, so we could not adopt to them.
         | 
         | So ... I guess there is no definite, simple answer.
        
         | bjornjajayaja wrote:
         | Honestly what good comes out of any "industrial scale"
         | chemical? I think people are screwed because this is _one_
         | chemical; what about all of the synthetic materials in peoples
         | houses these days (the carpet itself)?
         | 
         | We need to go back to basics here instead of trying to over-
         | science things. Bust out that bottle of vinegar and keep things
         | simple in my opinion.
        
           | allannienhuis wrote:
           | The whole world runs on industrial scale chemicals. Virtually
           | everything in our modern society relies on them. They are
           | base inputs to almost every chain of goods from foodstuffs to
           | textiles to manufactured items of every sort. Even your
           | vinegar example is primarily produced as an industrial scale
           | chemical.
        
         | ddeck wrote:
         | _> > in the US, the number of people with Parkinson's has
         | increased 35% the last 10 years_
         | 
         |  _> 10 years ago, the oldest U.S. baby boomers were reaching
         | 65. Now, they are reaching 75[1]._
         | 
         | The numbers do match up rather well. The US population over the
         | age of 65 has grown around 33% in the last 10 years.
         | 
         | I see conflicting information regarding the average/median age
         | at diagnosis, but it seems to be around there.
         | 
         | https://fred.stlouisfed.org/series/POPTOTUSA647NWDB
         | 
         | https://fred.stlouisfed.org/series/SPPOP65UPTOZSUSA
        
           | alcover wrote:
           | > population over the age of 65 has grown around 33% in the
           | last 10 years
           | 
           | Which strikingly echoes GP's _" birth rate went from 19/1000
           | to 27/1000 between 1935 and 1946"_.
           | 
           | But 10 years too late ? I'm confused maybe.
        
             | ddeck wrote:
             | The data was intended to back up the GP's point, pointing
             | out the growth in the underlying population of those
             | diagnosed very closely mirrors the growth in number
             | diagnosed.
        
               | alcover wrote:
               | I know. I meant the echoing wavefront seems 10y late :
               | 1935+65 = 2000
        
               | nanis wrote:
               | > I know. I meant the echoing wavefront seems 10y late :
               | 1935+65 = 2000
               | 
               | Good point. I believe I was thinking about 75. 65 crept
               | in because I was also going to mention that at the
               | beginning of the US Social Security program (1935), the
               | assumption was no one lived much beyond 65.
               | 
               | Here is a table that might cast light on the diagnosis of
               | Parkinson's by age: https://academic.oup.com/view-
               | large/1251178
               | 
               | Note population pyramids for 2000[1], 2010[2], and
               | 2020[3].
               | 
               | [1]: https://www.populationpyramid.net/united-states-of-
               | america/2... [2]:
               | https://www.populationpyramid.net/united-states-of-
               | america/2... [3]:
               | https://www.populationpyramid.net/united-states-of-
               | america/2...
        
         | robocat wrote:
         | A comparison can still be made between the same age cohorts
         | i.e. compare rates of Alzheimer's for the cohort 60 to 65 year
         | olds. There is always a potential for confounding factors, but
         | if the rates are up 35% for all cohorts then that says
         | something.
         | 
         | Also the beautiful flow graph
         | https://images2.minutemediacdn.com/image/upload/c_fit,f_auto...
         | (graph for US Women I think) does show that after about 70
         | "mental" starts being a significant percentage of deaths,
         | although Parkinson's is only one component of that I think.
         | 
         | Source for graph is: https://flowingdata.com/2016/01/05/causes-
         | of-death/
        
         | nabla9 wrote:
         | A six-fold increase in the risk in individuals exposed in the
         | workplace to trichloroethylene is more like a natural
         | experiment than "simple correlation".
        
           | bobthepanda wrote:
           | It's not the only thing they were exposed to though in the
           | natural experiment, so it's entirely possible that third
           | factor C is what's driving it.
           | 
           | There are more studies according to the article that make the
           | solid case, but one instance of correlation is not
           | necessarily a smoking gun.
        
       ___________________________________________________________________
       (page generated 2021-04-08 23:01 UTC)