Six months after a leading academic in New Zealand claimed rugby was more dangerous to play than American football, more than 100 former England rugby internationals will take part in a study to examine the long-term effects of the game on the brain.

The NFL, the governing body of American football, has settled a £660m class action brought by a number of former players who had repeated concussions during their careers after three who suffered depression and took their own lives donated their brains for research. It was found they all suffered from chronic traumatic encephalopathy, a type of dementia related to repeated blows to the head that can be established only after death.

The Rugby Football Union, which has commissioned the research by the London School of Hygiene & Tropical Medicine, the Institute of Occupational Medicine and the universities of Oxford and Queen Mary in London, would potentially be at risk of legal action if the study found a causal link between playing rugby and permanent brain damage but believes there is a pressing need for greater scientific knowledge to help the game and its players going forward.

The former internationals are all over the age of 50 and played in the amateur era when concussion resulted less from collisions and tackles and more from punches. A recent study of retired French rugby players reported a “significantly greater number of concussions and recurrent concussions than other retired sportsmen”. It also found retired rugby players with recurrent concussions were more likely to suffer from major depressive disorders.

The Drake Foundation, which has linked up with Saracens in a three-year concussion study that involves players wearing impact sensors and having blood, saliva and urine tests before and after match, is providing more than £450,000 to fund the research. Three high-profile players, Mike Brown, George North and the England captain, Dylan Hartley, have had long lay-offs in the last two seasons because of repeated concussions with Hartley saying he would consider retiring if he suffered one more.

The project aims to provide a greater amount of information on the potential medium and long-term neurocognitive risks of playing rugby than is currently available from other studies. Ninety former Oxford and Cambridge Blues will also take part in the study which will gather data on the retired players’ quality of life and social circumstances, with an extensive set of tests capturing physical and cognitive capabilities and a neurological clinical examination.

There will also be face-to-face assessments as well as blood and urine samples taken for future analysis. The same tests and procedures will be used in a separate ongoing 1946 Birth Cohort Study which will provide a general population comparison and provide evidence of the potential increased risks of neurodegenerative diseases, including dementia and cte, for rugby players. The RFU’s chief medical officer Simon Kemp said: “The RFU has worked extremely hard to increase the education of those involved in the game about concussion and to improve the management of the risk of the injury based on the evidence available. The next step for us a union and as a sport is progress beyond delivering ‘recognise, remove, recover and return’ and try to understand more about the possible longer-term effects on the health of the brain.”

Recent studies in New Zealand have shown a high rate of dementia among two teams of players who played in the 1960s and last year Doug King, a sports injury epidemiologist at the Auckland University of Technology, said: There are a number of people who say rugby is a totally different game to American football, but my findings show the risks may actually be higher in rugby.”