As an observer and participant in modern biomedical research, and a lover of deep history, I tend to focus not on the immediate or last few years, but look for trends of accumulating risk over longer periods of time. Seeking an answer to the question of “when”, I used Pubmed to estimate, per yer, the number of studies and papers discussing diseases and conditions of unknown origin. I search for the term “unknown causes”, and also for the term “journal” to get some idea of the percentage of studies, papers and editorials discussing disease of unknown causes. I had no idea what to expect.
Looking at a trend of topics per year, one has to correct for some estimate of the total number of articles published, because a mere count would, in part, reflect the overall trend in the explosion of total articles published. I chose as my control term the word “journal”, because many titles of publications include that term (e.g., “Journal of Nephrology). Here is the control result, which is not surprising, and completely expected:
Again, this merely reflects the trend in the increase in publications in Pubmed, and so using it would provide a relative control for that trend.
Next I searched for “Unknown Causes”, and calculated the number of articles citing unknown causes per 10,000 articles (again, relative denominator term).
What I found is shocking. Here is a graph of the number of articles per 10,000 discussing “unknown causes” (Y = #articles mentioning “unknown causes” / #articles mentioning “journal”, as in the title of journals).
Because the studies in Pubmed include all sorts of journals studying all sorts of things, the actual number is not as important as the trend. The signature is undeniable. Something changed dramatically in 1976. To the skeptic: the increase is greater if one does not correct for total publications.
What changed was national mass vaccination against influenza….