Triathlon Deaths—At What Point Does A Trend Emerge?

According to this article, there have been at least eight triathletes who died in competition this year. All eight deaths occurred during the swim portion of the competition. Something like this raises the question: At what point do a series of deaths go beyond coincidence and become a trend that must be investigated as such?

"Precise cause of death remains elusive in many cases" ... although several theories are fleshed out within the piece. I always find it interesting to look at what point we move beyond a statistical blip and move into territory where it is helpful to researchers to investigate happenings as some sort of cluster. There are some similarities in these cases, but many of them are weak, things like the dead being men with experience with triathlons. Well, how many of the total racers were men who had experience with triathlons? Probably a pretty big amount, statistically speaking.