What did the coroner say?

The South Staffordshire Coroner Andrew Haigh ruled at an inquest at Burton-on-Trent that Astle died as a result of "industrial disease."

He said that Astle had suffered a degenerative brain disease likely to have been caused by "repeated small traumas to the brain" related to heading a heavy leather football.

Why would heading put the brain at risk?

The tissues of the brain are highly delicate. The skull provides a high level of protection, but head impact can cause the brain to bash against the skull, leading to bruising and possible tissue damage over time.

Some experts believe the problem is exacerbated when the subject is dehydrated, as this may reduce the cushioning effect provided by the fluid within which the brain floats inside the skull.

The old-style leather footballs used during Astle's professional career were much heavier than today's hi-tech version, and therefore more likely to inflict damage.

Why would this damage lead to a degenerative condition?

Studies on animal have shown that when brain cells are damaged they release a protein called amyloid, which is toxic to other cells.

The formation of amyloid plaques is strongly associated with the development of Alzheimer's disease.

Is this the first time that heading a football has been linked to brain injuries?

No. There is a growing body of evidence documenting subtle brain injury among people who have played football for many years.

Cases have been reported of accelerated tissue death, and of changes to the electrical activity in the brains of footballers.

Some players have also experienced problems with loss of memory, concentration and alertness.

Tests carried out in the US found that amateur footballer players performed significantly worse in test of memory and planning than other sportspeople.

Is heading necessarily to blame?

Some research suggests heading is most likely to blame for these problems.

However, other experts believe that the more violent trauma associated with a clash of heads, or with a player's head hitting the ground during a fall could be a factor.

Why should heading in particular cause a problem?

There is a lot of evidence to suggest that over time the brain is more vulnerable to the cumulative effect of repeated mild blows, than to a single more substantial impact.

Should people continue to play football?

Yes. The risk of brain injury is far outweighed by the positive effect on general health.