Comment by Retric
4 years ago
More likely the underlying causes are genetic.
Identical twins have 70% chance to share same allergic diseases vs 40% for non identical twins, and both of which is vastly more common than their prevalence in the general population. Though this also demonstrates environmental factors play a significant role.
That said, the human immune system includes significant randomness so environment may be even less important than generally assumed.
But why would it have apparently increased so much in the relatively recent past if the cause was genetics?
Changing rates of testing combined with false positives are presumably part of it. Apparently 10% of people think they are allergic to Penicillin but only 1% test positive and under 0.1% have a significant reaction.
That said, environment is a factor. People in the developing world test positive for fewer though by no means zero allergies compared to their relatives in the developed world.
There's also changes to breeds and varieties in common use. For example, modern wheat has like 20x the histamine response vs older varieties. These kinds of things will also affect different people differently.
_Has_ sesame allergy increased? Like, it’s _rare_; it’s just extremely nasty (it kills people).
It could be sampling bias or increased availability, but it does seem as if allergies in general are increasing: https://www.npr.org/sections/thesalt/2019/08/02/747545877/se...
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How do you compare non identical twins to the general population? Aren’t twins, even non identical likely to share the same diet, the same environmental factors and maybe even the same viruses etc - all could be contributing factors?
Non identical twins are still siblings so they share a lot of DNA while also growing up in similar environments.
The huge difference between identical and non identical twins is suggestive of a very strong genetic component.