In the past few years there have been a number of players who have died while playing football. Most recently, Ivorian star Cheick Tiote slumped and died during training.

A study analysis suggests that 26 of the 64 players who have died in the last 10 years are from African countries. That is nearly 40%.

While Africans make up 17% of the world's footballers they account for nearly 40% of the known deaths.

The biggest cause of death of footballers on the pitch was sudden cardiac death and this was particularly true for African players, as 25 of the 26 died from this cause.

Could African players really be more susceptible to sudden cardiac death?

Professor of cardiology Sanjay Sharma told the BBC that evidence from the US shows that sudden cardiac death amongst black basketball players is around three times more common than for white players.

"There is data from the National Collegiate Athletic Association in the US that shows that the overall risk of sudden cardiac death during sport is around one in 48,000.

"But when someone actually examines this more closely that risk is considerably higher in black athletes; one in 18,000 in black males."

Professor Sharma said that in the UK the Football Association has done research on young players. The death rate for white footballers in that sample is one in 25,000 but it is one in 4,000 for black players.

In other words, a black player is about six times more likely to die than a white player, though the chances are still very small.

"The precise reasons aren't clear," said Prof Sharma. But he thinks that the evidence he looked at suggests black sports players are more likely to suffer from cardiac arrest because the wall of the left side of the heart seems to thicken more than players of other ethnicities.

"Which may be a situation that causes abnormal electrical disturbances that can cause a sudden death."

Professor Sharma said this can be made worse by higher blood pressure during exercise.