> The increasing rates of Autism now are most likely the result of increasingly advanced maternal age for pregnancies

Wiki seems to say it's either even split between parents, or leans paternal:

> It is not known whether mutations that arise spontaneously in autism and other neuropsychiatric disorders come mainly from the mother or the father, or whether the mutations are associated with parental age.[74] However, recent studies have identified advancing paternal age as a significant indicator for ASD.

There's also the other factors:

https://en.wikipedia.org/wiki/Epidemiology_of_autism#Causing...

But as another mentioned, the increased awareness and access to medical professionals could also explain an upward trend in diagnosis.

> the increased awareness and access to medical professionals could also explain an upward trend in diagnosis.

I don't see how any other hypothesis can even be considered until this is controlled for. How many people diagnosed as autistic today would have, had they lived in the past, been considered as having mental illness or intellectual disability? Would those who are high-functioning even be diagnosed as having anything at all, or just thought of as eccentric or a little touched?

What bothers me more is that people on this forum, which is most likely over-represented by the broad autism phenotype, and so quick to 'other' autism. Might not even have dawned on them that they might be talking a little about themselves.

Fair point.

Maybe... but anecdotally we had an autistic son born when my wife was 26. But we later had 4 more children (including 2 more boys) who were born throughout her 30s and none of them are autistic. I think there is more going on than simple advanced maternal age.

Oh for sure there's more to it than advanced maternal age. These things are also probabilistic to some degree (X chances of having a child with X disease). I know many women who gave birth in their 40s to healthy children.

Was that a difficult conversation with your wife about whether to keep trying for kids knowing your first was autistic?

I don't know about this person but I have an acquaintance who is a autistic and has three children, all on the spectrum, and they love them all. It never occurred to them that they should not have more children.

I know a couple that underwent sterilization because they did not want a younger sibling to be burdened with the care of an autistic older brother. They were also concerned that they would not be able to adequately raise another child while also caring their autistic firstborn.

I don't judge, it's a very personal decision and there's so much that goes into raising any child. Our two anecdotes illustrate how easy it is to find people at either end of this continuum. This stuff is very difficult for people to talk about.

I find this a strange thing to ask.

An autist is defined as such by having the following distinct characteristics that make them unique (I have customized each criterion based on myself and my children): - difficulty in social interactions (with neurotypicals) - repetitive behaviors, superior memory and highly focused interests resulting in expert level knowledge - greater sensitivities, physically and emotionally (when compared to neurotypicals.

If I had had a neurotypical child, I'd be worried that I wouldn't know how to relate to them and that they'd have to try much harder to succeed.

No, we never had any sort of conversation of that sort.

It’s the Back to Sleep campaign that started in the 90s.

https://advances.sciencemag.org/content/5/1/eaav5188/tab-art...

Basically, sleeping is important to brain development in new borns and infants and forced back sleeping is hugely disruptive. Hence the increase in autism rates for kids born in 90s and later.

It seems like a large leap from “voles develop social bonding problems when their sleep is disrupted in early life” to “making babies sleep on their backs increases the rate of autism”. Is there any other data that would indicate a correlation between back sleeping in infants and autism rates?

That’s actually not what made the connection for me. I noticed my son developed much more quickly than his peers and we stomach slept him. Also my friends got much worse sleep than we did, which surely meant so did their babies. My son hated back sleeping. He’d sleep 3 hours at a time versus through the night. So I looked up when forced back sleeping became a thing and it was strongly correlated to when autism exploded. I think there may be a Euro study. Then I read this recently https://advances.sciencemag.org/content/6/38/eaba0398

And I emailed the authors about my theory and they sent me the voles study. They can’t do a human study for ethical reasons. Maybe they can find a natural study ala Israel and peanut butter puffs but forced back sleeping is prevalent worldwide as it reduces SIDS. We were comfortable stomach sleeping my son with good air circulation because of this study: https://jamanetwork.com/journals/jamapediatrics/fullarticle/...

Back sleeping may have adverse side effects beyond low sleep quality for baby and parents. Frankly, it’s well established that sleep matters a lot for all brains. It’s not hard to make the leap that reduced sleep quality during important stages of life might matter a lot.

That certainly doesn't explain an awful lot of cases. Two of the most fit women I knew had autistic kids in their early 20s. And "blame the mother" has a really bad history for autism.

> That certainly doesn't explain an awful lot of cases.

Doesn't need to explain all of the cases, or even a large minority of them. If it's a significant factor - but a minor one - it will add to the total.

(Sources in another comment I posted)

Surely increased emphasis on actually diagnosing it has to be one of the bigger drivers.

I once read a theory that it was caused by different prenatal nutrition and lack of Vitamin D, which of course involves the mother but I wouldn't call blaming her since, as they say, it takes a village.

Not sure if people currently believe this or not.

> I once read a theory that it was caused by

One thing that is almost certainly true: ASD doesn't have a single cause. Any theory to explain ASD is, at the very best, only going to explain a minority of cases, and even in those cases quite possibly only partially.

ASD is caused by a complex interaction of dozens of poorly understood factors, and the mix of causes differs widely from individual to individual

It is a very complex phenomenon, and all simplistic explanations in terms of a single cause are doomed to fail

> lack of vitamin D

Wouldn't that mean we would see more autistic kids further away from the equator and born from April to June?

autism does correlate with birth month https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3296777/?report... and does seem to be more prevalent in particular latitudes, though that may be an effect of social/industrial/economic conditions.

Somali children in Sweden are 3-4x more likely to be Autistic than Swedish children:

https://www.researchgate.net/publication/23221308_Prevalence...

73% of pregnant Somali women in Sweden are Vitamin D deficient vs 5% of pregnant Swedish women:

https://www.alliedacademies.org/articles/vitamin-dbinding-pr...

This is a very good example of how difficult can be the biology sometimes.

Different social strata.

Parents working in different jobs, maybe more prone to go in contact with dangerous substances or living in more contaminated areas.

Different diets, maybe relying more in very cheap food choices.

Different country, with different resources and laws that could lead this women to not be fully aware of the local opportunities available in their pregnancy, or how to ask for their rights.

Recent campaigns of hate against immigrants in Swedden, that could lead to a worse treatment in hospitals by one or a few racist members of the staff.

Not able to pay for a premium healthcare while giving birth.

And immigrants live in countries with poor environmental laws and endure a dangerous travel that can damage their health. Dangerous levels of heavy metals were found in workers that had to burn hardware and recycle computers in a third world country to pay for their travel to Europe, for example. Somali people also eat a lot of migrant fish (aka: mercury with fins).

Vitamin D is just one in a thousand of possible explanations

Lets call a spade a spade.

There are evolutionary adaptations to the local environment of Northern Europe that Africans lack: light skin, light hair, light eyes.

There are cultural aspects such as the wearing of veils for women.

This has a significant impact on Vitamin D generation from the available sunlight.

https://sunburnmap.com/ - March 2021, a central European city will give saturation-level Vitamin D generation (before redness appears from preliminary sunburn) to a person with light features in 22 minutes, or someone with the darkest features in 1h40 minutes.

Just as Northern Europeans are evolutionarily and culturally poorly adapted to central Africa, so are Africans to Northern Europe.

This is nothing and easily compensated by changing your diet even if you don’t go outside more often. There’s no valid results from genetics unless you remember diet and environment come after it. So if there’s a problem I’d say it’s because we’re not giving them supplements.

e.g. the last time I went to Hawaii I got sunburned so bad I couldn't go outside for a week.

But it's not true to say I'm racially inferior for Hawaii living or that I'm not suited for going on vacation. What I should've done is wear more sunscreen.

> 73% of pregnant Somali women in Sweden are Vitamin D deficient vs 5% of pregnant Swedish women

You have to be careful with those claims; I believe "Vitamin D deficiency" is one of the medical metrics that isn't race-normed. But there's no reason to expect Somalis to have the same natural level of Vitamin D that Swedes do.

Given the terrible health consequences of deficiency, I think assuming racial difference in healthy vitamin D levels is a more dangerous claim that requires a burden of proof.

Melanin absorbs the UV light our bodies use to produce vitamin D.

It is an important public health issue for people with darker skin living in temperate or polar areas to get enough vitamin D.

Lack of vitamin D for people with darker skin is the inverse of paler people being at risk of burns in sunny areas.

I thought a complaint that Somalis in Minnesota had was that autism in their kids was disproportionately (not sure about exact meaning of this term) "low-functioning"

Low/high functioning isn't really a specific medical term, but basically it just means if you can live on your own or not.

If you're not only high functioning but gifted* then you're "twice exceptional".

* school term that supposedly means exceptionally intelligent, sometimes gets you to a different school/class for smart kids, but actually it's like special education for kids too fast/nerdy to be in regular classes without going nuts

Really interesting, ty. Agree with the sibling comments, needs normalization of course, but if that doesn't warrant funding I'm not sure what does. If I can throw a few bucks at it, please let me know how!

Right, I remembered this because I know an autistic Swedish person whose mother was an Iranian immigrant, just not what the evidence was.

Thanks! That was the perfect paper.

Only if you assume everyone has the same diet, biology, and tendency to stay inside as each other and as previous generations, which isn't true.

There would definitely be an effect but you'd have to do things like blood tests, I don't think you can easily predict which people are deficient.

People have linked Vitamin D deficiency to so many diseases that I think it shows more of the statistocal-slopyness disease than anything else.

So, this is to be taken with a grain of salt:

A nurse once told me about this. I guess in the 90's(?) or so, there were a lot of children that were cognitively deficient to the extent that they required specialized care and such, but didn't necessarily fall into a category that would allot the parents funding. Lo and behold, autism becomes one of those categories, and the medical industrial complex has no qualms helping families to find funding. Autism is a perfect dragnet, lots of features to latch on to.

Something like that. So maybe a lot of the autism diagnoses fall into the category of "we can't define this, but this family is fucked without the funds, so that's autism."

But I never validated his claims, just food for thought. Good luck in the rabbit hole.

Source?

The OBGYN director taught me this during a lecture at my hospital (I'm a medical student). He's also a PhD. It was casual conversation, so I don't have the sources.