The health of British Asians is to be investigated on an unprecedented scale in a study now being planned at the University of Oxford.
The British Asian Health Study will follow the health of 250,000 people in the UK aged between 18 and 74 from backgrounds in India, Pakistan and Bangladesh. It is hoped that the study will lead to a better understanding of the effects that people’s diets and lifestyles have on their risk of common diseases including cancer, heart disease, diabetes and stroke. Previous studies have been much smaller, involving only around 10,000 people of South Asian origin.
There is already evidence that British Asians have higher rates of diabetes and heart disease than British white people. On the other hand, many types of cancer are less common among British Asians.
Disease patterns are changing over time, with cancer incidence among second generation British Asians becoming similar to British whites. Differences in diet and lifestyle may partly account for these patterns, with British Asians increasingly adopting a lifestyle similar to the white population.
To identify reliably the factors causing these rapid changes in disease occurrence, a large study that will follow the health of hundreds of thousands of people over a long period of time is needed. This is what the British Asian Health Study will do. Its findings could be important for disease prevention and treatment – not just in Britain, but also among the 1.5 billion people in India, Pakistan and Bangladesh where people’s lifestyles are becoming increasingly ‘Westernised’.
‘What’s certain is that we need more information about the reasons for these differences in incidence of common diseases like cancer,’ says Dr Raghib Ali, director of the INDOX Cancer Research Network at the University of Oxford, who will lead the study. ‘We’re particularly interested in factors, such as diet, smoking, exercise, obesity and alcohol that could explain the differences in outcome for British Asians. Genetic factors are unlikely to explain the different disease risks between first and second generation British Asians.’
‘We need to know the importance of these different factors in causing cancer, chronic respiratory diseases, heart disease, and diabetes. Most people will eventually get one of these diseases and three-quarters will die from one of them.
‘If we understand what factors trigger these diseases, we can do something about them – whether that’s identifying something that’s leading to diabetes or something that’s protective for bowel cancer.’
The researchers will use mobile clinics across the UK to reach British Asians who want to participate in the study – using the same approach and equipment as the existing UK Biobank study, which successfully recruited 500,000 people of all backgrounds. NHS records of heart disease, cancer and other conditions will allow the health of participants to be followed over time.
The researchers are now seeking funding for a pilot study to ensure that all the procedures work, and held an event last night in London to raise awareness of the study. The pilot study will take two years to complete and will cost £250,000. The full scale study will cost £2.5 million.
‘A large and comprehensive study of British South Asians is long overdue,’ says Professor Dame Valerie Beral, Director of Cancer Epidemiology Unit at the University of Oxford, who is also involved in the study. ‘Most existing follow-up studies of this type have been done in Western or East Asian populations.’
‘The UK is ideally suited for such a study. It is home to one of the largest populations of people of South Asian origin (outside South Asia) and NHS records facilitate study participants to be followed over time for the occurrence of cancer, heart disease and other conditions.’
‘Diet, smoking and alcohol intakes vary more widely in South Asians than in Western European populations, making it easier to find clear links between these factors and the risk of common diseases.’
Dr Ali gives an example of the sorts of questions that could be addressed by the study: ‘We know that rates of bowel cancer among first-generation South Asians coming to live in the UK are lower than among whites. But this difference has vanished by the second generation.
‘As we don’t know much about what causes bowel cancer, this is a really important clue. It’s possible that the generational differences could be down to diet, with those in the first generation largely sticking to typical Asian foods. It is thought that spices – curcumin for example, but probably spices more generally – include a compound similar to aspirin which may reduce the risk of bowel cancer.
‘Such a connection is hard to prove and it needs a study like ours to establish a link. But if it is true, it could offer a way of preventing bowel cancer.’
Dr Ali is clear: ‘This study needs to happen now. The first generation of British Asians arrived in Britain in the 1950s and 1960s, and they are ageing. If we don’t start this research now, we’ll lose the opportunity of involving this important first generation. By the next generation, there appear to be fewer differences in health with white Britons and the opportunity to learn from this experience will be lost.’