Multimillion-pound studies of heart disease in Europe are institutionally racist and fail to address the condition within ethnic minority groups, a leading epidemiologist has told The Herald Society.

Professor Raj Bhopal, professor of public health at the University of Edinburgh, claims that new studies must be undertaken urgently so that we can begin to explain why some minority groups are more likely to die early from the disease.

His comments come after he conducted a review of 72 major heart disease studies in Europe and North America and found that not one major study conducted in Europe produced information that could be used to investigate the causes of the disease among the black and minority ethnic community (BME). Until such studies are conducted, Bhopal claims, race will dictate the quality of treatment received for heart disease in Britain.

Frontline health workers dealing directly with the BME community in Scotland echo Bhopal's demands. They say the current lack of research leads to health inequalities, with one doctor describing treatment of minority groups for heart disease as "a shot in the dark". However, an expert with more than 30 years experience researching heart disease questions whether such a piece of research is even feasible.

South Asians - Indians, Pakistanis and Bangladeshis - living in the UK are 50per cent more likely to die early from heart disease than the white population. Meanwhile other groups - those of Chinese origin and African-Caribbeans, for instance - have lower rates of heart disease.

These variations, Bhopal says, can't be explained away by genetics. They must occur, he claims, because of differences in lifestyle: "Culture has a massive effect on the way people behave and therefore on their health. Sikhs for instance hardly smoke because it is a holy taboo. In Bangladeshi culture if you are a man you smoke and if you are a woman you are likely to chew tobacco."

Pinpointing exactly what makes south Asians more prone to heart disease would affect treatment, he adds. "If you don't know the cause how do you implement the right preventative measures? You have to have a sound understanding of what is causing it."

There are various theories. Some believe that the lower birth weight of south Asians increases their susceptibility to heart disease. Others say it's the higher rate of diabetes, a tendency to do less exercise or a tendency among south Asians resident in the UK to carry more fat even while appearing slim. However, nothing is certain because the phenomenon has never been thoroughly investigated.

In his review of major heart disease studies published this month, Bhopal, along with Meghna Ranganathan of The Robert Wood Johnson Foundation in the US, found only 15 looked at ethnic minority groups, all of which were conducted in the US. No European study had data on ethnic minorities.

"One of the most important ways of investigating mysteries such as these variations in the rate of heart disease is the cohort study which studies the pattern of disease in the population, " says Bhopal. "This means you take people in a particular population and follow them up over time examining the risk factors - the food they eat, whether they smoke and other things you think might explain the mystery. You follow them for five years, 10 years, 15 years and you see what kind of people get the disease."

Cohort studies have been responsible for advancing our understanding of the relationship between risk factors - smoking, high cholesterol, lack of exercise - and cardiovascular disease in the white population. These risk factors also apply to ethnic minority groups - if an Indian has high cholesterol he is more likely to suffer heart disease - but they fail to tell the full story.

Bhopal says: "Indians for example are less likely to smoke than the population as a whole, their Body Mass Index is no greater than the population as a whole, their levels of exercise are a bit lower, their blood pressure is slightly lower and their cholesterol is slightly lower yet they are more likely to die early of heart disease - why?"

Failing to make any attempt to unravel this puzzle, Bhopal claims, amounts to unwitting prejudice: "We have so much information on the European origin population and so little on the minority population. Our failure to investigate, I don't believe is racism on a personal level - researchers aren't saying: 'We must not study ethnic minority populations.' But I do believe that this gap amounts to institutional racism."

A large-scale cohort study focussing on ethnic minority groups must be conducted in Europe, he says, allowing researchers to test potential explanations. "For the past 25 years the major theory we have been working with as an explanation of the higher rate of heart disease among south Asians is higher insulin resistance and higher rates of diabetes, " he says. "Now even Paul McKeigue, the main proponent of this theory, is beginning to think that maybe it isn't the full story. Without a large-scale cohort study it is very difficult to prove these hypotheses."

McKeigue, professor of genetic epidemiology at the University College Dublin, agrees that more work is needed in the area. Worryingly, he remains the UK's foremost authority on the cause of heart disease in south Asians in spite of changing to a new research area some eight years ago.

"It has been a disappointment to me that there has not been the type of largescale study that Bhopal is proposing and that nobody has really taken up where I left off, " says McKeigue. "If you were starting now with the methods and technologies of 2006 you could go much further."

Dr Heinrich Volmink, who works with the BME community in Govanhill, Glasgow, also backs Bhopal. More comprehensive studies, he says, would help doctors deliver sound advice. "As the BME community represents a rapidly growing part of our population an extensive understanding of their health needs is critical, " he says. "A major study into heart disease could, for instance, affect the priorities of NHS boards nationwide, resulting in an intervention policy in an attempt to cut rates of heart disease. Just now treatment amounts to a shot in the dark."

But would such research be possible to carry out? How do you, for instance, define someone's ethnicity? Are south Asians one group or many different ones?

Professor Hugh TunstallPedoe, from Dundee University, first proved in the early 1970s that higher levels of heart disease existed among south Asians living in Britain. He has been researching heart disease ever since, and though he agrees that more research would be useful, he just can't fathom how it could be done: "You would need hundreds if not thousands of people in each ethnic group followed for many years to get definitive results.

"Populations are increasingly unstable and mobile, particularly ethnic minority groups. Asians I know are frequently popping backwards and forwards, holidaying, and even retiring to Asia, which would make follow-up difficult.

"We do need more research. But to make the argument for a new study based on ethnic minorities you would have to make a very strong case that it is feasible and cost effective."

However, Bhopal believes there would be long-term benefits: "These are expensive studies and there is no doubt that this is the underlying reason why one has not been carried out looking at ethnic minority groups. But in 10 to 20 years time we might find something else that prevents their heart disease. That would be of benefit to the entire population."

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