The unknowns surrounding the mysterious rise of cancer in young adults | Hacker News Reader

The unknowns surrounding the mysterious rise of cancer in young adults

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> The BMJ Oncology study concludes that “dietary risk factors, alcohol consumption, and tobacco use were the main risk factors for major early-onset cancers.” But it adds that “prospective lifetime cohort studies are needed to explore the etiologies [causes] of early-onset cancers.”

> In the UK, specialists have specifically flagged up the risks of processed foods, which includes ready-made meals and pizzas, which young people tend to consume more of.

Food seems to be the main culprit..

Dietary fiber is well established to reduce the risk of Colorectal cancer [1]. If there's one thing that's seriously missing from an ultra-processed diet it's fiber.

Almost certainly multifactorial though.

1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3926973/

there is also an extraordinary amount of plastic and chemicals getting absorbed by nearly all food, as per a study last week:

https://edition.cnn.com/2024/09/16/health/food-packaging-che...

> [.. &] alcohol consumption, and tobacco use were the main risk factors for major early-onset cancers

This would be a good explanation for any decline in early onset cancer given that a 40 year old could not have been binge drinking and smoking at their height in 1970s UK.

As a small data set, my mother and grandparents all smoked like there was no tomorrow and drank plenty, but never had any cancer issues. Though my mother and grandfather both had COPD, my mother in particular spent the last few years of her too-short life (late 60s) basically drowning because she couldn't expel the CO2.

Prepared and ultra-processed foods, gut feel, seem to be a huge problem in many ways. A buddy of mine, his girlfriend is a big health nut and her rule of thumb is: Don't eat anything that has more than 4 ingredients or comes in a bag, and that seems like a good idea to me.

Here is some general advice about how to translate between “your life” and statistics.

Imagine that some new product gets released that increases your chance of chancer by 10x, so something extremely bad and very noticeable in studies. Now let’s say 2/10000 typically get this type of cancer normally and that it’s an extremely popular product so 50% of the world population use it. Start consuming it straight away.

That leads us to having 2/10000 cases before the product and 7/10000 afterwards, and you’ll have 4994/5000 of people who use the OBVIUSLY bad product stating confidently that there can’t be any issue, because they aren’t effected. Imagine they all have 2 kids who have two kids and suddenly the common sense attitude that “this can’t be dangerous because my grand parents…” is the overwhelming majority opinion.

You don’t have “a small dataset” you only have a bias, nothing more, nothing less. You can’t translate between data and your personal life how you’d expect to, it’s just not possible.

Also regarding your buddies girlfriend’s advice she’s completely wrong. It’s actually anything with less than 3 ingredients or more than 5 but less than 7 you shouldn’t eat. Everything else is safe. You can trust me because “I’m a huge health nut”.

Disclaimer: numbers might be slightly off, corrections are appreciated, but the point stands.

> Also regarding your buddies girlfriend’s advice she’s completely wrong. It’s actually anything with less than 3 ingredients or more than 5 but less than 7 you shouldn’t eat. Everything else is safe. You can trust me because “I’m a huge health nut”.

Wtf?

I think he's making fun of the arbitrary number that was originally given. Obviously healthy foods can have far more than four ingredients, such as dozens of spices (or really anything). I think many people want to be able to follow some sort of broad guideline in life and it frequently causes those to arrive at meaningless conclusions.

Gotcha, thanks. I was utterly confused by this.

> I think many people want to be able to follow some sort of broad guideline in life and it frequently causes those to arrive at meaningless conclusions.

But it's just that, a broad guideline.

I think that only few people would not intuitively understand that seven types of fresh vegetables in a box is not the same as some meaty goo made from seven unpronouncable industrial ingredients with E-numbers attached.

HN types seem to like to nitpick a broader point by conjuring up edge cases.

I think the response is misunderstanding thd difference between a guideline and a rule. "Nothing from a bag or box, nothing with more than 4 ingredients" allows for bags of frozen veggies, allows for 5+ simple ingredients, but a good way to quickly rule out ultraprocessed foods. Saying "avoid ultraprocessed foods" would likely not be actionable to a great many people: look at a set of ingredients and is it ultraprocessed, processed, or just fancy names for everyday things (should I avoid sodium chlorite and dihydrogen monoxide?).

Tangentially related question: one cause of cancer would be lack of physical activity (https://www.who.int/news-room/fact-sheets/detail/cancer).

What's the mechanism of this? Cancer is caused by bad-luck random cell division creating a bad cell, I can see how chemicals influence this process, but how does physical activity?

> What's the mechanism of this?

It doesn’t necessarily have an easy to understand soundbite explanation. Biology is like spagetti code. Everything depends on everything in difficult to comprehend ways.

Cancer is caused by bad-luck random cell division creating a bad cell

That is only the first necessary step towards cancer. Our bodies have various mechanisms to kill suspicious cells before they start being a systemic problem. Apoptosis, or the immune system attacking them if they can be recognized. These mechanisms are pretty efficient; in the animal world, animals with really strong immune systems, like bats, very rarely get cancer. And most of our current progress against cancer involves ... very careful stimulation of the immune system against targets specific for that particular patient's tumor.

Physical activity can probably influence these anti-cancer mechanisms, as does aging etc.

The simplest explanation is that physical activity increases blood circulation and lung ventilation, which (as long as one is not exercising in a polluted environment) helps the liver and kidneys process and excrete various toxins at a greater rate. It also reduces body fat, which can store fat-soluble toxins.

There's also a high likelihood that people who get regular exercise are also eating healthier food that hasn't been highly processed and loaded up with pesticide residue, biocides that slow fungal and bacterial growth, animal growth hormones, etc.

The fundamental equation is something like:

(body load of toxins) = (ingestion rate) - (excretion rate)

A significant risk factor for some cancers is chronic inflammation. Physical activity can help with that directly, but also indirectly as it can help reduce weight (diet is more important there). Reducing/eliminating chronic inflammation is generally a good thing anyways for other health concerns besides just cancer.

A cutting edge theory is that exercise can interfere's with cancer's metabolism (Warburg Effect) and helps to regulate lactate levels which chronically dis-regulated will promote cancer.

"Specifically, we posit that in carcinogenesis aberrant cell signaling due to exaggerated and continually high lactate levels yields an (inappropriate) positive feedback loop"

[1] https://academic.oup.com/carcin/article/38/2/119/2709442

Here’s a meta-study on the mechanisms for the benefits of moderate exercise, and it includes a sizeable list of different chemical changes in the body that exercise promotes: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9923435/

Recent science suggests that the body adjusts to burn approximately the same amount of calories per day, given a consistent amount of activity, regardless of how much activity there actually is. So, a person with an active lifestyle will burn approximately the average 2,000 calories, but a person at rest will also burn about the same number.

I'm oversimplifying massively, but essentially, the theory is that if you don't give your body an outlet to burn with, it will burn the calories on things that aren't good for you. Eg, increasing inflammation.

It wouldn't surprise me if some of these effects are contributing factors.

Source: https://youtu.be/vSSkDos2hzo?si=CrPh2_vLRqHG0Z3i

Exercise induces stress which triggers a systemic hormetic response. That response makes cells more resistant to random errors. Additionally, that stress can trigger apoptosis in senescent or unhealthy cells.

I never found a reason BUT my personal opinion is:

Probably putting some "stress" on the cells is beneficial, is like forcing them to work a little once in a while instead of letting them function in the "just survive" mode.

Maybe blood circulation? It may clean toxins from where the blood may flow slower?

That's my headcanon

Hearing the evolutionary anthropologist Herman Pontzer talk about this was really eye-opening for me:

https://www.msnbc.com/msnbc-podcast/examining-energy-evoluti...

"[Y]ou can think about all these processes as competing for calories over the course of the day. And normally, low priority things like having a really high inflammation response or having a high stress response, those get tamped down in a highly active population like we've all evolved in. But now, you move to these weird zoos that we've built ourselves, where you don't have to be active, food's available all over the place, energy supply is really easy. And now, these low priority activities which used to probably only happen very occasionally in the past, in the deep past, now are happening all the time, chronically, at these super high levels, and it's actually really bad for you."

That's a good read. But one of the processes competing for calories is the immune system.

> If you take somebody who is really sedentary and you get them exercising, what happens? Things like inflammation, which is your immune system being overactive, goes down. [Also cortisol level when under stress, and reproductive hormone levels, go down.]

So that puts a small hole in the "exercise helps the immune system clear up cancer" theory. Maybe it in fact stops the immune system causing cancer. Or maybe it does both things, since biology is messy and the immune system might have multiple energy budgets for all I know.

Oh wow, super useful link.

So in a way my simplified assumption was more or less right, my ego grew a little bit and i think that's a bad thing

Whatever science I read on this seems to indicate that the exercise induces a high amount of oxidative molecule release in your cells. That should be bad for the body because that results in oxidative damage.

But of course we've evolved mechanisms to compensate. For that, there's a corresponding release of antioxidants and cellular repair to deal with the oxidation events of exercise.

Exercise in general raises your immune system as well. Your immune system cleans up a lot of rogue mutation cells. It may also be the physical activity increases massive amounts of blood flow through your entire system and helps at a macro level with this cleanup of deviant cells.

But I'm not an oncologist nor am I a physiological biologist.

Higher fitness -> higher chance the immune system will kill the rogue cells on its own.

I'd expect the opposite: higher fitness -> immune system more busy with repairing wear&tear. Lower fitness -> immune system bored and more reactive to any suspicious cellular activity.

The repair of the wear and tear seems to provide more opportunities for the body to reject cancers. Also, aerobic activity may encourage selection for oxidative metabolism which is very suppressed in most cancers. It's counterintuitive but the epidemiology is very clear that exercise is protective. It doesn't wear you out faster but rather helps you rebuild and maintain yourself more rapidly (without which, you wear out).

That might be true in the extreme ends, say for Ironman athletes, but a bit misleading as a summary since we already have lots of data that moderate exercise correllates with reduced risks of everything from getting a cold to heart disease. If we’re comparing to people who don’t exercise, the alternative should be moderate exercise, not high intensity training. Also a bored and over-reactive immune system can be a pretty bad thing.

When it comes to dealing with any biological systems always look for outcomes over mechanisms. There is plenty of evidence showing exercise improves almost all markets of health

What's the mechanism behind that? Being "more fit" is not exactly one single thing.

is it obvious that good fitness is related to good immune function?

It seems obvious when you see your own body aging and slowly loose both.

well there’s the obvious pathway that people who exercise regularly tend to have fewer number of cells than those who don’t

e: okay, not the pathway - but we do know that additional weight increases cancer risk

Cancer mortality in elephants is estimated at less than 5%. In sharks I believe it's even lower.

Elephants are an outlier in terms of animal species, they have something genetic that prevents cancers. For most animals, the mass of the animal does correlate with cancer rates: “having a greater number of body cells, and a higher number of cell divisions, usually increases the chance of accumulating the mutations that can lead to cancer” https://www.livescience.com/52432-elephants-cancer-resistanc...

They ate a lot of fiber at least

i would be curious if larger elephants were more likely to develop cancer than smaller elephants, less so in the between species comparison

Except that adipose cells don't undergo mitosis. When is the last time you heard someone dying of "fat cancer"?

Believe it or not, professional researchers probably tried to think of "obvious pathways" too.

Lipomas can turn into cancer. That's literally fat cancer.

Liposarcoma is a comparatively rare type of cancer.

If the parent's hypothesis is:

"less exercises == higher weight == more cells == (more mitosis / mutagenic potential) == more cancer"

Which tissue type is accounting for most of the weight difference (in equal height people) who do and don't exercise?

You could even reverse this and look at body builders with greater muscularity than average. The number of cells itself is clearly not the cause of increased cancer risk, because neither fat nor muscle cells cause the most common cancers.

i wasn’t claiming professional researchers didn’t know something, so not sure where you are pulling that from.

i guess the mechanism correlating weight and cancer is more complex than “more cells more cancer”, but the correlation is still well measured and i assume a reason why physical exercise would anti-correlate as well

e: also my understanding was non-adipose cell count was also correlated as weight

Of course there is a correlation. You were proposing an "obvious" explanation for it based on relative cell counts, which "obviously" is not correct if you consider the nature of the tissues involved.

Oh definitely. It wasn’t clear from my above comment, but I acknowledge that bit was definitely wrong and will eat crow for that.

I guess the main thing I was trying to say was that we know obesity is correlated with cancer and I thought we had some understanding of the mechanism behind that, so my guess is that physical exercise is just the inverse of that mechanism?

Whatever we're consuming is most likely the culprit (or whatever is being sprayed on/injected into/fed to what we're consuming).

All the studies say glyphosate is safe. But, glyphosate use really ramped up in the 90s with "round up ready" GMOs being created in 1996. It is even sprayed pre-harvest to uniformly dry grains for harvest.

Who knows if glyphosate is causing cancer. I think there is strong evidence that it is the cause of the rise of celiac disease cases.

i am not convinced the rise of celiac is not due to some combination of better testing/new thresholds and more awareness to get testing

Gluten compositon might have changed:

https://www.sciencedaily.com/releases/2020/08/200811120112.h...

if you actually read the article it's basically a negative result

I actually did and it said: "While the proportion of critically viewed gliadins fell by around 18 percent, the proportion of glutenins rose by around 25 percent."

Sure, you can say one thing is a little bit lower and another thing is a little bit higher, so it is the same. But as I always said: Units! Units! Units!

Maybe the glutenins are underrated?

and also that any drift over time is swamped by weather effects

What's your background?

professional critical thinker

Actual lol. Thank you :)

Isn't tobacco and alcohol at a high time low in the younger generations?

AIUI gen z is slightly more health focused and has lower alcohol usage. Millennials and gen x make up for it.

Not to mention that they’ve cut out alcohol but added vapes and what seems to be a healthy amount of marijuana. I don’t think that makes them healthier overall.

cutting out smoking and alcohol and subbing in vapes and marijuana is almost certainly a net win healthwise

Unless it isn’t. Frankly we don’t know what the long term effects of vaping and marijuana usage are because we’ve not really dug into them.

there are a fair number of long term studies in marijuana.

it’s clear that for normal usage patterns compared to normal tobacco usage patterns, the cancer risk is much lower.

How about compared to alcohol? Various kinds of alcohol? The claim was that vaping and marijuana were both lower risk than smoking and alcohol. I think jury is still out.

Marijuana consumption is well-studied to be less bad than alcohol. Vaping we have strong reasons to think is less bad, but it is not well studied.

What is a healthy amount of marijuana?

This leads to obesity and terrible diets as a rise.. If this study is worth anything.

> tobacco use

What's the worst part of a cigarette, the fact that it has tobacco, or the fact that it has like 100 different cancer causing toxins?

My dad is 98. Started smoking when he was 9. At one point he was smoking 70 a day. He worked as a fireman on steam trains when he was in his 20s. He lived in London during the 1950s when the smog was so bad you could walk into a lamp post when the lamp above was lit. People warned their houses with coal, powered the city with coal, burnt their trash in the back garden and smoked a lot. Sure, the average lifespan was low. But he only quit smoking in the 1980s. I'm not saying that smoking isn't bad, but if there is a sudden rise in cancer among young people, it's not that simple. The number of smokers today is tiny. In the UK, smoking rates among young adults (aged 18-24) have significantly declined over the last few decades. In 2011, about 25.7% of this age group smoked, but by 2021, that number had fallen to 13.2%. I don't have stats from the 50s but according to my father he didn't know anyone who didn't smoke.

Self-explanatory:

https://en.wikipedia.org/wiki/Lung_cancer#/media/File:Lung_C...

Vapes are at all time high though.

I'm still trying to find the memo I missed that made it socially acceptable for folks to vape indoors. Come into my house and vape around my kids? Really?

Who is walking in to your house and letting off clouds? Generally you ask, or if your host is a vaper wait to see if they do first.

For all other public indoor settings its already illegal.

I've had to tell off at least 2 people who were vaping in the climbing gym in London.

people think it is more surreptitious than it is

Sugar

I see people say this but what's the mechanism?

Exercise/fitness/activity would be primary suspicion, which is also diet. You need a very high level of activity in order to properly exist in today's high carbohydrate corn syrup food base

Permoplastics might have a roll but you figure that would have showed up by now a lot earlier.

It could also be binge drinking. The culture of binge drinking has been steadily compounding itself over several generations of college students. But that may be an American phenomenon. This is a global one and it may not apply.

The study cited is "Global trends in incidence, death, burden and risk factors of early-onset cancer from 1990 to 2019". BMJ Oncology. 2023.

Important context lacking here is that a scientist called Jianhui Zhao, has been caught cheating previously in a 2018 article about cancer. Results didn't matched the experiments.

https://pubmed.ncbi.nlm.nih.gov/33901310/

"certain of the Transwell cell migration and invasion assay data shown in Fig. 3B were strikingly similar to data appearing in different form in a pair of other articles written by different authors at different research institutes, one of which had already been published elsewhere prior to the submission of this paper to International Journal of Molecular Medicine"

--If-- this author from the Second Affiliated Hospital on Zhejiang (China) is the same person that worked previously on the Hospital of Jilin University (China), we should take the results claimed here with a healthy dose of caution.

Anyone aware of the possible correlation between this and forever chemicals found in humans increasing? I don’t see it mentioned in the article

If I had to guess I'd think microplastics[1] because we actively consume them and they're found in our tissues and they didn't really exist before the 50s/60s.

But I haven't seen any research showing correlations in real human beings yet.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10340669/

PFAS are big in media right now but likely not the main cause.

> people born in 1990 [have] a significantly higher rate of developing colorectal cancer compared to people born in 1950

Wow. As someone born in 1990 +/- 2 years that's a statistic that will fester in ny mind.

That's the kind which scares me the most given how quickly it can grow and spread without any symptoms. Feel really fortunate to live in a country where screening starts at thirty years. Back home I would have to be well into my fifties.

The article seems to skip over the pandemic, which has changed behaviours significantly. Also, the Coronavirus itself is suspected to promote cancer [1].

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10202899/

There is some correlation between COVID exhausting certain white blood cells that fight cancer:

https://www.nature.com/articles/s41423-021-00750-4

It’s almost certainly much too early to have any data on the relationship between the pandemic and cancer. Cancer causing factors may take decades to turn into detectable cancers, and even if the data were available, publishing them can take a couple of years on top.

The study in question looks at data from before the pandemic: "Global trends in incidence, death, burden and risk factors of early-onset cancer from 1990 to 2019"

yes and then there is the elephant in the room nobody talks about: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10184721/

The pseudouridine in the current generation of mRNA vaccines has also been demonstrated to promote cancer growth: https://www.sciencedirect.com/science/article/abs/pii/S01418...

Ok, since many comments chip in subjective suggestions of who the culprit might be, here are my unsubstantiated reasons for rising cancer rates in young adults:

china [1] higher education [2]

[1] having spent time in China and seen how there is simply no remorse selling toxic waste as food, toys or skin care products I can’t see how western households, which are overproliferated with cheap goods made in China (i’d say 95% of everything a Westerner owns is made in PRC), aren’t affected by it. Put differently, why would China wait for its demographic Overton window to close and let its empire buildup be hampered by health concerns, let alone those of foreigners?

[2] inflationary amounts of degree holders create more toxicity in the womb: Eggs are older and the mothers under a lot more stress (both parents need to work, societal pressure to not just excel in classic female fields, but also classic male domains, specifically academia)

One more possibility to throw on the pile.. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5860074/

I think it’s from dysautonomia impairing the immune system. Pretty much anything that affects the autonomic nervous system, which is a huge number of very different things, can trigger dysautonomia. The rational for my reasoning is that the propensity for cancer appears to occur at roughly the same rate as the propensity for dysautonomia regardless of the cause of dysautonomia.

Covid and the Covid Vaccine are both triggers for dysautonomia, I presume because both use the spike protein. The vaccine triggered mine but I have a strong genetic propensity for it anyway with multiple inherited anxiety disorders.

<in a snarly medical tyranny voice> NIE, you will have zeh vackzine!

Jokes aside though, how is it that hard for people to connect the dots of what happened after "covid"? I guess because there are many other causes for cancer that have also increased since 2019 (poorer sleep quality, worse diets, depression, social isolation). But then again, forcibly injecting something with known carcinogens, into your blood that has since caused athletes and children to immediately collapse and die (or later on from myocarditis) should be overwhelming evidence of something akin to genocide.

There’s been another hypothesis around the wider spread use of emulsifiers, specifically in lower fat foods. Lots of people are eating “healthy” almost whole food sources that contain them.

You should at least post a link to some source when spreading these rumors.

https://pubmed.ncbi.nlm.nih.gov/38349899/

Not a rumour.

From when to when? What is badly needed is statistics before Covid hit and after Covid hit.

And statistics by countries and depending on who got which vaccine and compared to people who didn't get the vaccine.

P.S: FWIW I got the mRNA one from Pfizer/BioNTech and had I know what I know today I'd never have taken it.

All the crap drinks they are promoting to young kids like Prime or redbull so prevailent in social media could be a factor

The vaccine?

Obviously. It is the only recent nationwide (worldwide actually) environmental change. Might also ask about the plethora of athletes dropping dead or falling extremely ill on the playing field.

I sure hope that the continuing sharply elevated rates of excess mortality [1,2] will be objectively and responsibly investigated so we can find the root cause.

[1] https://www.bmj.com/company/newsroom/high-excess-death-rates... [2] https://www.swissre.com/press-release/Covid-19-may-lead-to-l...

Climate change strikes again. It has no end of unexpected consequences.

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