I always advise caution when former players ask me if I think they should participate in this study or that, and I usually say, “NO.” The reason for that is that most of the studies I’ve been asked about were either sponsored or funded by NFL and/or NFLPA. I think of this similar to a Miranda violation with no warning where your data will most likely be manipulated and used against you and others.
That said, there are a few reputable studies that I’d encourage participation in. I have great regard and admiration for the work that Boston University and Concussion Legacy Foundation have done in advancing our knowledge of CTE, and how it relates to football exposure. Two new studies are getting underway; one by BU and the other by Johns Hopkins, endorsed by Concussion Legacy Foundation.