Cardiff University found this month that a healthy lifestyle can reduce the likelihood of dementia by 60 per cent.

The research, which involved following 2,235 people since 1979, found that regular exercise, eating plenty of fruit and veg, staying slim, drinking moderately and not smoking reduced the chance of getting dementia.

It also found that if 50 per cent of men followed those five principles there would be 13 per cent less dementia generally.

My father and my grandmother (his mother) both developed dementia.

Given genetic trends dementia developments are of more than passing interest to my brother and me.

But my dad really did follow the five criteria. He exercised every day, going for regular walks and swimming before he got too old.

He ate a balanced diet. He drank only lightly and gave up smoking about 30 years before he died - before which he was a moderate pipe smoker.

So the latest research doesn't throw much light on dementia among the Donovans. The idea that it is down to a genetic cause still seems to apply.

So the research simply underlines the need for more research. There are over 800,000 dementia sufferers in Britain and Northern Ireland, with the number predicted to increase.

Critics attack the low level of funding for dementia research compared with, say, cancer, which receives four times more money.

As the research was published David Cameron was about to host a G8 summit on dementia - or, as it was more dramatically called, "the 21st century plague."

Such international prioritising should be welcomed, but it raises questions of its own.

If Cardiff's research is accepted, we must conclude that environmental factors are conducive or otherwise to developing dementia.

But this leads us to look at the evolution of human societies in the 21st century.

The lifestyle of many people is becoming more and more sedentary. Economic progress is being driven increasingly by internet technology.

Young and old alike spend growing amounts of time locked in to laptops or mobiles, seemingly cut off from the natural world.

It always amazes me when travelling by train to see people plugged into these devices and totally missing the fantastic, rolling countryside beyond the window.

This sedentary existence is further promoted by the loss of playing fields across the country. Computer games are replacing physically active games as much because they are easier to access than anything else.

Obesity is increasing to endemic proportions, particularly among the young, as a result of these huge changes in our ways of living and working.

There's also a growing ignorance regarding food - an explosion of fast food on the back of a culture that no longer creates the space for proper meals shared by families.

Then there are other lifestyle issues. The prevalence of insecure work increases stress and prevents a healthy work-life balance.

If you work long hours for low pay in a call centre, your work is not conducive to following the five elements set out for healthy living.

You don't have time for exercise and the stress may push you towards drinking and smoking as a means of relaxation.

If you have children to care for the problems only multiply.

As someone who endured the pain of watching my dad descend into dementia until he did not recognise any of the family, I welcome any advance in averting or treating the disease.

But if we're to take the medical research seriously we need to look at the sort of society we are creating.

Low wages and insecure work are anathema to healthy living. Of course individuals can take responsibility for the way they live but we need to take a look at how social patterns affect this.

The ultimate conclusion is that the whole direction of modern capitalist society makes conditions such as dementia more, not less, likely to develop.

If we are to follow the five principles that apparently help avoid it, the whole way our society is organised needs re-evaluation.

It is only by taking a truly holistic approach that we can really overcome "the 21st century plague."

Paul Donovan blogs at www.paulfdonovan.blogspot.com