Autism in Norway: The 7-fold increase in Autism linked to Maternal Migration

 

The Olso to Bergen line is one of Europe’s most beautiful railways

 

I did have another sense of déjà vu, when I read about the big spike in autism in one city in Norway.  Norway is a very expensive country, but well worth a visit.  We enjoyed it.  One of Monty’s former 1:1 assistants emigrated to Norway to work in their excellently funded special needs therapy system.  

A decade ago, there was a peak in media interest in Somali autism clusters in Sweden, Minneapolis and San Diego. Refugees had been taken to live in far away lands, with very different environmental conditions.  They soon started to produce children with a very high incidence of autism. This was a surprise to all the academics and a shock to the parents.   The Somali-Swedes even started calling it the Swedish disease, because they had never encountered such children before in Somalia.

 

Swedish study dissects autism risk in immigrants

Swedish migration: Only specific groups of immigrants — those from low-income countries and those who migrated near or during pregnancy — have an increased risk of autism, suggests a new study.

 

The Swedish Disease (Link to the old blog post)

 

A few hundred posts later after my one on the “Swedish disease”, it really is absolutely no surprise that the Norwegians have experienced the same phenomenon. 

 

Risk of autism seven times higher in Norwegian children with immigrant mothers

A study was conducted after health professionals started noticing a concerning pattern.

Researchers concluded in a recent Norwegian study that children of foreign-born mothers have a far higher risk of being diagnosed with autism. The study included 142 children aged 2-6 years old with an autism diagnosis in Sør-Trøndelag in mid-Norway.

The risk of autism in these children was just over seven times higher if the children were born of immigrant mothers.

The over-representation of this population indicates that the mothers' immigrant backgrounds may impact the development of autism, the researchers behind the study write in an article in Tidsskriftet, the journal of the Norwegian Medical Association. 

 

The actual research paper:

 

Autism spectrum disorder in preschool children in Sør-Trøndelag 2016–19

BACKGROUND

Autism spectrum disorder (ASD) is an umbrella term covering a range of conditions characterised by challenges with social interaction, restricted interests and repetitive behaviours. The prevalence of ASD has increased significantly in recent years, and there is a clinical impression of a preponderance of cases among young children whose mothers were not born in Norway.

MATERIAL AND METHOD

The study included 142 children aged 2 to 6 years who were diagnosed with autism in the county of Sør-Trøndelag, Norway in the period 2016–2019. The following information was collected: age at onset of symptoms and diagnosis, primary diagnosis, ADOS-2 (Autism Diagnostic Observation Schedule) scores, whether the child was born in Norway and the mother's country of birth.

RESULTS

Children of mothers born outside of Norway had a 7.7 times higher risk of being diagnosed with autism than children of Norwegian-born mothers, with an annual incidence of 0.74 % and 0.10 % respectively. These children were diagnosed earlier, at an average age (standard deviation) of 41.9 (11.8) and 51.8 (18.1) months respectively (95 % CI 4.7 to 15.2); a p-value of <0.001 for the difference. They also had a higher ADOS score, with an average (standard deviation) of 19.0 (6.2) and 15.3 (7.1) respectively.

INTERPRETATION

The preponderance of autism diagnoses may be an indication that the mothers' country of origin has an impact on the development of the condition. This has implications for adaptions to the assessment and follow-up of this patient group.

MAIN FINDINGS

The incidence of autism spectrum disorder was higher among children of migrant mothers than children of Norwegian-born mothers.

Children of migrant mothers were younger at the time of diagnosis and had more severe symptoms than children of Norwegian-born mothers. 

Clinical impressions suggest an overrepresentation of autism spectrum disorder (ASD) among young children of migrant mothers and that the severity of ASD is greater in this group. This impression is supported by an official Norwegian report from 2020, where data from the Norwegian Patient Registry suggests an increased risk of autism in young children with a minority background (1).

 

 

Age at symptoms onset in preschool children with autism spectrum disorder in Sør-Trøndelag 2016–19 divided into six-month intervals (n = 133). The difference in reported symptom onset between the two groups is not statistically significant.

 

Country of origin for mothers of preschool children diagnosed with ASD in Sør-Trøndelag 2016–19 (N = 142).

  

The study included 142 children in Sør-Trøndelag diagnosed with ASD in the period 2016–19 (Table 1). Parents of 80 of the children (56 %) reported their first concern about symptoms between 12–24 months of age (Figure 1). The difference in age at symptom onset between children of migrant mothers and children of Norwegian-born mothers was not statistically significant.

 Our findings suggest that the mother's migration background is associated with an increased risk of ASD in preschool children, as well as more severe symptoms and a younger age at diagnosis. The findings suggest that the mother's migration background may influence the development of ASD.

Previous studies support our findings of an increased risk for ASD in children of migrant mothers (9–11, 22).

We found a higher mean ADOS score in children of migrant mothers compared with children of Norwegian-born mothers. This group was also younger at the time of diagnosis. A plausible explanation could be that these children were identified and examined at an earlier age because they had more severe symptoms. An Australian study (12) found that children of mothers who migrated from low-income countries were younger at the time of diagnosis and had an increased risk of intellectual disability. Our findings may indicate greater severity of the disorder in children of migrant mothers. The association between higher ADOS scores and early age of diagnosis was shown in both groups. This indicates that young children with clear signs of developmental disorder are identified and evaluated early, regardless of the mother's country of origin. 

A Swedish study (10) found that the mother's migration background increased the risk for ASD independent of the migration background of the father. A Finnish study (11) found no increased risk of ASD among children where only the father had a migrant background.

CONCLUSION AND IMPLICATIONS

This study supports the clinical impression that ASD is overrepresented among children of migrant mothers. The incidence of ASD was 7.7 times higher in children of migrant mothers than children of Norwegian-born mothers. Our findings also suggest that children with ASD of migrant mothers are younger at the time of diagnosis and have more severe symptoms.

   

It’s the Immune system, forget Vitamin D

One explanation for those Somali autism clusters a decade ago was vitamin D; researchers thought that the pregnant mothers in Sweden were short of sunshine.   But what about the big Somali autism cluster in very sunny San Diego? 

The immune system adapts very slowly to its environment and gets used to living along side a wide family of bacteria from the environment.

Adults will struggle to adapt to changes in their bacterial environment.  Consider a Western backpacker travelling around India on the cheap, he is going to get sick, or just lose a lot of weight.  I chose the latter when I did this.  If you want to lose weight, take a budget trip to India.  Visit Scandinavia and you will not get sick, but it will lighten your wallet. 

For the fetus created in Somalia, it is the lack of exposure to the expected bacteria in Sweden or Norway that upsets the immune system. It ends up over-reacting and damaging itself.  

  

Conclusion 

Migration from very poor countries to very rich ones, while pregnant, risks seriously disrupting development of the immune system of the fetus and its vital calibration process.  The result may be autism or other neurological conditions.  In Norway a 7-fold increase in autism has been found; they did not measure the impact on related, but less troubling disorders like ADHD and dyslexia.

Not only is there 7x more autism, but it is more severe autism, with a higher score on the ADOS scale.

Clearly many people do not get advance knowledge of when they might become a refugee.  Very poor countries have very high birth rates and so young females are quite likely to be pregnant at any given time.

We know that any kind of severe stress also increases the incidence of autism.  Examples in the research include extreme weather events like hurricanes. Wars, fleeing from home, journeying overland in harsh conditions will be very stressful.

We can use this data to further the wider understanding of how the immune system is a factor in the increase in autism prevalence worldwide. We can then consider modifying the immune system to protect the future fetus from autism and indeed pure auto-immune conditions (asthma, eczema, IBS etc).  The simple way to do this is to add back exposure to bacteria that your grand parents and great grand parents would have been exposed to.  In particular, this means exposure to domesticated animals, even just cats and dogs.

We were recently in Pelion, Greece and over there you cannot avoid contact with animals.  Cats and dogs are roaming freely in cafes and restaurants, mainly outside but not exclusively.  Several times a day you will brush up against some four-legged new friend.  Are auto-immune diseases less prevalent in Greece?  What do you think?

Ideally you would be exposed to cows, horses, sheep, goats etc.  Take a hike through the countryside or visit a farm.  Don’t try and sterilize your shoes afterwards.

This kind of animal contact is nowadays uncomfortable to many people, but over tens of thousands of years your immune system has been trained to expect it.

Another take home message is that nobody is reading all this autism research and putting the pieces together; you have to do it for yourself.