Google Ngram Viewer is a research tool based on Google Books, that charts frequencies of any word or short sentence using yearly count of n-grams found in the sources printed between 1800 and 2000 in American English, British English, French, German, Spanish, Russian, Hebrew, and Chinese. Our aim was to determine the utility of Google Ngram Viewer for finding an association between prevalence of aeroallergen and food allergen citations in published books between year 1920 and 2000, and the allergy epidemic.
Google Ngram Viewer (books.google.com/ngrams) was searched for common aeroallergens and food allergens, for example, “dust mite allergy”, “cat allergy”, “peanut allergy”, etc. Data was compared with the reported prevalence of such allergies in the scientific literature.
Allergic reactions were virtually unknown prior to 1870 and this is reflected by the book citations in Google Ngram Viewer. Aeroallergens started to appear widely in published books in 1930s with a steady increase over the years. There was a large early peak in “mold allergy” citations with maximum signal in 1948 and it continued to dominate book publications until 1995 when it was overtaken by “dust mite allergy”. Mold allergy is still the third most mentioned allergy after dust mite and ragweed.
Food allergens first appeared widely in book citations in 1920 and had a bimodal peak, a smaller one in 1940s, and a bigger one 1990s, with continued increase. Milk allergy continues to dominate book citations but with lower prevalence after 1980.
Aeroallergen and food allergen citations in published books between year 1920 and 2000 showed an association with the allergy epidemic reported in scientific literature. Some findings were surprising including the dominance of “mold allergy” and “milk allergy” citations over the last 80 years. Further exploration is warranted of this rich resource, in conjunction another research tool, Google Trends, which indexes online information, to determine if future trends can be predicted.
Comparison to Google Trends:
Info: Google Ngram Viewer http://buff.ly/1CDeGLS
The allergy epidemics: 1870-2010 - Journal of Allergy and Clinical Immunology http://buff.ly/1CDeA76
Geographical variation in the prevalence of positive skin tests to environmental aeroallergens in the European Community Respiratory Health Survey I. Allergy, 2007.
The prevalence of allergic skin test reactivity to eight common aeroallergens in the U.S. population: Results from the second National Health and Nutrition Examination Survey. JACI, 1987.
Prevalences of positive skin test responses to 10 common allergens in the US population: Results from the Third National Health and Nutrition Examination Survey, JACI, 2005.