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Comment by hinkley | Hacker News Reader

> Australia has among the highest incidence of Crohn’s disease in the world

We really need to look at supply chain and environmental factors.

IBDs like Crohn's and Ulcerative Colitis have increased in incidence (controlling for better diagnosis) as countries develop[1] [2]. People in developing countries have a lower rate of incidence, and if they move to developed countries, the incidence remains low. However, their children, born in developed countries, experience the higher rate of incidence. Something about being a child in a developed country increases your chance of developing an IBD

Several theories have been proposed, including hygiene hypothesis, lack of fiber in the diet, and pollution, but finding causality has been hard. Worse yet, nobody knows what causes these illnesses.

It's also interesting to note many food allergies have increased in prevalence in the last 30 years - although the causes for that might be different, they are both GI related auto-immune conditions.

[1] https://www.gastrojournal.org/article/S0016-5085%2811%290016...

[2] https://www.thelancet.com/cms/attachment/1bc07ee3-782c-4670-...

[3] https://pubmed.ncbi.nlm.nih.gov/19917585/

It's all about the gut microbiome

Yeah. And I suspect diet. There has been some speculation that the "safe" levels of herbicide are not actually safe for beneficial gut flora.

> And I suspect diet

Of course, your diet influences your gut health

I should have phrased that better. I meant "the safety of food in one's diet" rather than "the tips of food constituting one's diet".

Probably not eating enough dirt early on.

I know this is contentious, but one factor here that lines up with the timeline you've presented is: vaccines.

Children are given far more of them than adults. People moving from developing countries to developed countries won't receive as many. But if they have kids in a developed country, their kids will get a ton.

> It's also interesting to note many food allergies have increased in prevalence in the last 30 years

Wonder how much of this is due to the relatively recent trend of having dual incomes with both parents working?

Cause and effect might be hard to tease out but it’s looking like there are some drastic differences in babies that were born early in the pandemic:

> only about 5% of the lockdown babies had developed a food allergy at age one, compared to 22.8% in the pre-COVID group.

> Of the lockdown babies only 17% needed an antibiotic by the age of one. In the pre-pandemic group, 80% of infants had taken antibiotics by 12 months

Can’t find a link to the original study at the moment but here’s a secondary source:

https://news.sky.com/story/covid-19-pandemic-babies-develope...

Breast milk? Or maybe literal live breast feeding? Mouth on mother's skin and all that.

I think nicotine can also suppress UC, so smoking rates might also be a factor.

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