Higher incidence of dementia in former rugby players?

The New York times recently reported on a study that suggested a much higher incidence of dementia among former NFL players (similar to Rugby Union) than among the general population - up to 19 times more than the normal rate for males aged 30 to 49. I have not yet seen the actual research and this should obviously be interpreted with caution. I know of no similar statistics for Rugby Union, as played in South Africa. Given, however, the high incidence of concussion in the local game and the cavalier attitude sometimes towards incidents of concussion, it is certainly something that bears looking into.