I am not a proper researcher but if I were investigating this the first thing I would do is compare to data-sets from elderly people in Japan. They get a massive amount of Omega-3's in their diet without even trying. This comes up in other studies related to Omega-3's but I do not have any links handy. It should be easy to find this data.

There was also a video including Dr. Rhonda Patrick and another scientist talking about the effects of Japan's high Omega-3 diets and its countering effects on smoking but I can't remember the other scientists name. This is going to bug me because it was a really interesting video. I think it was several years back. It's related because of some of the protective effects on cells.