Paul Vallely: Blame it all on our ancestors

Ever since I moved out of London to live in Manchester I have been mildly disquieted by the fact that, as surveys show, the health of people in the north is noticeably worse than in the south.

Ever since I moved out of London to live in Manchester I have been mildly disquieted by the fact that, as surveys show, the health of people in the north is noticeably worse than in the south. Conventional wisdom says that rich Southerners have a better diet and healthier life-style. But now there are two new theories.

First, however, I have to declare a bias. Three months ago I developed vague chest pains, which turned out to be unstable angina and saw me carted off to hospital with blue lights flashing and subjected to emergency angioplasty. This is an amazing business in which you are fully conscious throughout the procedure, during which they stick a tube into your leg and push it round the arteries till it gets to your heart. In my case it revealed that I had one coronary artery narrowed in four places, which the docs cleared by inflating a balloon in the artery and propping it open with a tiny wire cage which goes in like a ship in a bottle. You see all this on three TV screens – on which your heart appears from many angles, courtesy of an array of X-ray cameras – above the operating table. The viewing, it has to be said, is more compelling than anything you can hire from Blockbuster.

Anyway, since then, when I'm not flaunting my new-found fitness in the gym, on the bike, in the pool, on the canal towpath, in the yoga class (or at the osteopath, but that's a different and altogether more painful story), I pass the odd spare moments flicking through back copies of the British Heart Foundation's newsletter. Which is where I found out about the Vikings.

An item reported that researchers at the Family Heart Survey in Leeds have discovered that the parts of the UK where heart disease is highest are exactly the areas where the Norsemen invaded – the tip of East Anglia, in the North-East, down the West side of Scotland, and in Northern Ireland. People in those places have almost twice the chance of having a heart attack as the rest of the population.

This was not what I wanted to hear. My ancestors came from Armagh (bad) and settled in Middlesbrough (very bad), where I was born. Middlesbrough – along with Easington – has the worst rate of deaths from coronary heart disease in the north of England. Only Scotland is worse again, with Glasgow as the heart attack capital of Europe. The legendary local diet of chips, bacon butties and deep-fried Mars bars only partly explains why.

Genetics may be up to half of the reason why heart disease occurs, according to Professor Alistair Hall, who heads the Leeds research team. The Viking settlers, when they intermarried with the locals, passed their naturally high rates of cholesterol on to their descendants.

"What was a good gene for energy and warmth when everyone died at 40 from some horrendous infection or got murdered looks rather different in the days of better diet, antibiotics and central heating," said another of the Leeds cardiologists, Dr Richard Lawrance. "So the good news is that people who have coronary heart disease needn't feel it's their fault if they go on to have a heart attack."

Very reassuring, I told him, with ill- disguised sarcasm, especially since all of the usual warnings about smoking, low-fat diet, exercise, blood pressure and so on still apply if you want to avoid the non-genetic 50 per cent of the risk. But there is a comforting aspect to the news, he said: "If we can use the results of the Human Genome Project to work out which gene is responsible, then we might find a way to counter it too." But first he is looking for another 1,200 volunteers to sign up to take part in his research. "We need 2,500 people who have got heart disease and who have a brother or sister so that we can compare their genes. So far we've got about 1,300 but we need volunteers [Freephone 0800 052 7154] because the Data Protection Act prevents us from asking hospitals and GPs to trawl their databases. You'd be eligible if you'd like to ..." he said, handing me a form to fill in.

I took it home. But it seems a bit tame, a research project. Now I know I've got the genes for it I thought I might indulge in a bit of looting and pillaging. It's nature, not nurture, you know.

Here's a bit of bad news. Red wine may not be good for your heart after all. While I was in the Cardiovascular Research centre in Leeds I was given an elementary lesson in statistical manipulation. "All kinds of weird things can be 'proved' by surveys," said Dr Richard Lawrance. "If you have enough baseline data – height, weight, hair colour, place people live, etc. – you can keep re-analysing your results until you get what looks like a significant result. Some common factors will be there by coincidence. There's a one in 20 chance of that. So if you keep breaking your survey down into sub-groups you'll probably end up concluding that the highest risk factor for a heart attack is, let's say, driving a red BMW." Theories like the one that people who live in areas where the water is naturally soft (the North) are less healthy than those who live with hard water (the South) mostly fall into this category, he said. But not, I hastily inquired, the notion that red wine is good for you. "That's spurious too, in all probability. It's just perpetuated by the wine trade and by drinkers who want to believe it." I decided to leave before I heard anything even more disturbing.

Perhaps I should have ignored Leeds and gone to Blackburn. There's a doctor there with an altogether different theory. Heart disease – along with cancers, multiple sclerosis and loads of other things – are worse in the North because of the weather. There's just not enough sunshine, says Dr David Grimes, a consultant at the town's infirmary and medical director of the Blackburn and Ribble Valley NHS Trust. And, since the body is stimulated to produce Vitamin D when the sun's ultra- violet light hits the skin, Northerners don't get enough of the vital chemical.

"It's not a Mediterranean diet that we need, it's Mediterranean sunshine," says Dr Grimes. He has tested blood samples from 36,000 patients and found much higher cholesterol levels in winter than in summer, even though their diets remained the same. A substance in the skin called squalene is converted to vitamin D in the sunlight – but in the absence of sunlight, it is converted into cholesterol.

"All World Health organisation statistics show that the closer you live to the equator, the lower the rate of heart attacks," Dr Grimes says. "The reason that statistics vary between rich and poor parts of town is because the poor do not have gardens and can't afford foreign holidays." But then again, not many of them drive red BMWs.