[strictnein]

If I had to bet, it would be on HPV causing a majority of the rise in colorectal cancer. It is a major cause of throat cancer in men[0] and causes almost 100% of cervical cancer in women[1]. We have had a significant increase in anal sex over the past 10+ years[2] and are now seeing an increase in colorectal cancer.

"Britain has found that the proportion of 16- to 24-year-olds engaging in heterosexual anal intercourse has risen from 12.5% to 28.5% over recent decades. Similarly, in the US 30% to 45% of both sexes have experienced it."

Still needs to be studied more as there don't seem to be any large studies yet.

"We found that colorectal tissues from 28 (51%) of 55 patients with colorectal cancer were positive for HPV DNA." [3]

[0] https://www.ucihealth.org/blog/2025/04/hpv-related-oropharyn...

[1] https://pmc.ncbi.nlm.nih.gov/articles/PMC7062568/

[2] https://www.theguardian.com/society/2022/aug/11/rise-in-popu...

[3] https://pmc.ncbi.nlm.nih.gov/articles/PMC1479314/

[jampekka]

My bet is on obesity.

"Overweight and obesity significantly increase colorectal cancer risk: a meta-analysis of 66 studies revealing a 25–57% elevation in risk" https://pmc.ncbi.nlm.nih.gov/articles/PMC12181496/

[red-iron-pine]

yeah HPV is definitely an angle, but there are easy fixes -- HPV vaccines work, as do condoms.

obesity is still a big driver and is a much harder fix. GLP-1s work but it's not one-and-done like a vaccine

[jampekka]

Saying condoms are an easy fix to STDs is a bit like saying eating less is an easy fix for obesity though.

[casey2]

Contrary to what you say there have been large studies [1], they just disagree with your article from 2005(!).

[1] https://www.sciencedirect.com/science/article/abs/pii/S09598...

[strictnein]

"Conclusions

HPV may be associated with a subset of colorectal cancers. Future large-scale multicenter case–control studies with data on risk factors such as lifestyle and sexual behaviour are needed."

Is this the disagreement? How does it disagree with a study showing there might be a link, but that it needs more research - "HPV infection may play a role in colorectal carcinogenesis"?

I'm honestly really confused here. Because the study you linked _agrees_ with the one I linked.

Did you also notice that your link is from 2014 and looked at data from 22 March, 2013(!!) or earlier? Or does the age not matter in this instance, but does matter in the link I provided?

In 2019 (since dates are really important, I guess), the KFF directly stated that the vaccine is targeted to the "...9 strains of HPV associated with most cervical cancer, anal cancer, and throat cancer".

https://www.kff.org/womens-health-policy/the-hpv-vaccine-acc...

[port11]

Wouldn’t that mean that the gay community would have very high colorectal cancer numbers?

[red-iron-pine]

they probably do. probably.

however they have lower screening rates than the straights, e.g.

https://www.thelancet.com/journals/langas/article/PIIS2468-1...

[lenerdenator]

Kinda surprised at the idea that HPV is the cause; at least in the US, there was a fairly large push about 15 years ago to get more people (particularly teenage girls and young women) vaccinated against HPV. Would we not see a corresponding dip in deaths related to HPV-associated cancers by now?

[strictnein]

Two things, I think.

1. The original guidance did not call for boys to get the vaccine. It does now.

2. We're talking about two different age groups. The article talks about those under 50. The group who got the HPV vaccine as part of their normal schedule are now just hitting their early 20s.

There's also still a huge number of people in the US who have HPV. It's really, really common.

"Approximately 42.5 million Americans are infected with HPV and there are at least 13 million new infections annually" [0]

Interestingly, the article calls out HPV directly as a cause of an increase in anal cancers.

"While HPV-related cervical and vaginal cancer rates have decreased since 1999, rates for oropharyngeal and anal HPV-related cancers have increased."

[0] https://www.kff.org/womens-health-policy/the-hpv-vaccine-acc...

[UncleOxidant]

Any idea what the percentage of teenagers who are getting the HPV vaccine is? I'm going to guess it's fairly low at this point given that there tend to be religious objections and also given the growing antivaxx sentiments.

[strictnein]

Slightly paraphrased: "As of 2024, 62.9% of adolescents ages 13-17 with up-to-date HPV vaccine series"

Scroll down to the see the per state numbers.

https://www.kff.org/womens-health-policy/the-hpv-vaccine-acc...

[buescher]

True, but “normal schedule” is hiding a bit of subtlety there: the hpv vaccine was recommended for women up to 26 at the time, so the oldest women who got it then would be pushing 50 now.

[strictnein]

Not sure if there's something more recent than this, but it was about 15.5% of adults aged 27-45.

It also notes this:

"Human Papillomavirus (HPV) is the leading sexually transmitted infection in the United States, and 85% of sexually active individuals will be infected at some point in their lifetime"

So, if you're not vaccinated and have had multiple sexual partners, it is rather likely you have or have had HPV.

https://www.tandfonline.com/doi/full/10.1080/21645515.2024.2...

[loeg]

There are many strains, though, and the vaccine provides coverage against a few of the most harmful, so it's still probably worth getting even if you may have been exposed to a subset of strains.

[loeg]

> The group who got the HPV vaccine as part of their normal schedule are now just hitting their early 20s.

Uh, their 30s.

[elric]

Several things at play here:

1. As others have mentioned, males were excluded from vaccination until relatively recently. This seems like such a stupid decision in hindsight. When I (male) got my vaccines, I was told that it wasn't routinely done in boys "because of availability issues", which I took to mean "because it's expensive".

2. Initial vaccines offered protection against 4 strains of HPV, newer vaccines protect against 9. People who got the older vaccines remain susceptible to the other 5 strains.

3. It can take years for an HPV infection to become dangerous or cancerous.

4. This last one is speculative, but I assume that when a woman tests positive for HPV or cervical cancer, their partner is also looked at. With the rates of symptoms and cancers going down in woman, their partners might fall through the gaps: there are no routine tests for males.

[picofarad]

The test for males used to be putting acetic acid on the genitalia and looking for spots under a blacklight, right? So what is it now? Blood test for the DNA?

[m463]

what I don't understand is why hpv vaccination isn't given to older people?

[loeg]

Cost and the statistical property that older people have fewer sexual partners on average. There's also a sort of fatalist assumption that you've already been maximally exposed. If the vaccine was zero cost, you'd give it to everyone.

[mancerayder]

How do you define cost here? The medical cost of the vaccine and nurse time? Or the risk to health? I'd pay for it out-of-pocket, even as an old. But I wouldn't know where.

[loeg]

The cost of the vaccine and nurse time, yes.

If you want to pay for it out of pocket, you totally can. Just ask your PCP.