Well, I think the researchers themselves took it seriously enough - at any rate, sufficiently to ensure their methodology was as beyond reproach as any research can be. I suppose their interest arose from a seemingly widely-held belief that survivors of great tragedies and trauma live longer than the rest of us. I've read such things. I have also been tempted to believe them myself as (from my personal experience at any rate) the WW2 fighters seem a remarkably spry and long-lived lot. But I guess it's nonsense. One notices those all still with us, twinkling away and reminiscing, but forgets all those who have died. Walter Lord (TNLO) commented on the youthfulness of survivors, but it was probably just their genes after all. I think the BMJ research was interesting - thanks.