If I may, the paper is very detailed. It has a number of symptoms and quite a rigorous medical evaluation of these people who were deployed. Again, I've done some medical research. I practised medicine for 20 years. I have to admit, that's the first time I've ever heard the phrase regarding scientific studies that “large doesn't make good”. One of the problems with scientific studies is that the smaller your studies, the more difficult it is to basically ascribe significance to them.
On May 13th, 2019. See this statement in context.