As early as 2017, the respected science journal Nature pointed out that it is not a sudden change in the genetics of humanity that could be held responsible for the increasing cases of allergies.
The cause is not in genetics but in the environment.
In 2016, a pioneering study appeared in the New England Journal of Medicine , which provided potential clues to the connections. Scientists had studied the children of US Amish and Hutterite communities, both close-knit Protestant denominations, on the incidence of allergic diseases .
The Amish had an incidence of asthma of 5.2% and the Hutterites - 21.3%. In atopy (atopic dermatitis, etc.), the incidence rate was 7.2% among the children of the Amish and 33.3% among the Hutterites. The difference is that the Amish have a very traditional agriculture, the Hutterites, however, a highly engineered agriculture.
Other studies have also shown that children that grew up in farms and rural areas are less likely to have allergic diseases than city children. Probable cause, although not proven causally by these epidemiological studies, is contact with potential allergens or germs during the last trimester of pregnancy, from the first months of life to the end of the first year of life.