Addressing the rise of diabetes and heart disease in South Asia - Global Health Research feature

As rates of diabetes and heart disease rapidly rise among South Asian populations, NIHR-funded researchers are developing unique resources and novel approaches to understand and prevent their key risk factors.

Low and middle income countries (LMICs) have seen a sharp rise in rates of type 2 diabetes in recent years and it now represents one of their biggest public health problems. Once considered a disease of affluence, diabetes is increasingly common among poorer populations experiencing economic changes, and especially so in South Asia where nearly 1 in 10 adults live with diabetes and many more remain undiagnosed. 

South Asian populations are three times more likely to be diagnosed with diabetes than Europeans, and at an earlier age and lower body weight, putting them at increased risk for many other health conditions, especially cardiovascular disease (CVD). Significant lifestyle changes in the region over recent years, such as unhealthier diets and reduced exercise, are thought to play a role but the risk remains high for people of South Asian background living across the world. 

In the UK, people of South Asian descent represent less than 10% of the population but account for nearly one-fifth of the total population living with diabetes. Genetics are an important factor in the development of diabetes, but their interaction with lifestyle behaviours is not fully understood and more needs to be done to reduce the health and economic burden of diabetes and CVD in this population globally. 

The NIHR Global Health Research Unit on Diabetes and Cardiovascular Disease in South Asians was launched in 2017 with a £7 million grant to understand those risks and promote better health in the region. Based at Imperial College London and directed by John Chambers, Professor of Cardiovascular Epidemiology, the Unit works alongside leading universities and healthcare organisations in its partner countries of India, Bangladesh, Sri Lanka and Pakistan, supporting their development of unique data resources and evidence-based interventions. 

Working across the four countries, the team’s surveillance study established more than 200 health observatories to record around 1,500 men and women’s health-related measurements. These unique records contributed to the development of the South Asia Biobank - funded by Wellcome and overseen by NIHR, Imperial College London and the Medical Research Council. This is the first comprehensive repository of South Asian health data that enables researchers to analyse their risk factors and interactions contributing to diabetes and CVD.

“Our completed and ongoing research will improve understanding of diabetes and heart disease in South Asian populations, including underlying mechanisms, optimal approaches to identification of high-risk individuals, and scalable approaches for personalised and community wide preventative strategies. This will contribute to helping reverse the current epidemic of these major diseases in this key global population.”

Professor John Chambers, Director of the NIHR Global Health Research Unit and Network for Diabetes and Cardiovascular Disease in South Asia (expanded Unit launched in 2021)

Poor diet and obesity are strongly associated with the development of type 2 diabetes but the relationship between food environments and diet in LMICs is poorly understood. A study carried out by the Unit, and published in PLOS Medicine, examined whether the availability of unhealthy food outlets near a person’s home affected their likelihood of developing diabetes. Using data for over 12,000 adults in Bangladesh and Sri Lanka, the team found that a higher proportion of fast-food retailers and restaurants within 300m of a participant’s home was associated with higher blood glucose levels and an increased risk of diabetes. 

The study found that women and higher earners were the most likely to have diabetes. Given that South Asian women are more likely to have diabetes than white women, and are at greater risk of CVD and diabetes-related complications, the results suggested that interventions within food environments may be particularly important for women in these countries. 

The team also suggested that interventions involving healthy food subsidies and fast-food taxes, including nutrition labels in fast-food outlets and improving communities’ understanding of good nutrition, had the potential to promote better diets among South Asians at greatest risk of developing diabetes around the world. The results showed that interventions targeting the environment may be effective in preventing diabetes but must be specific and targeted to reach those most at risk. Policy actions are also required to improve the quality of food environments in South Asian countries. More details about this study can be readin our news story: Living near fast food restaurants in South Asia may increase risk of type 2 diabetes.

Digital interventions delivered by smartphone apps offer a highly accessible form of health promotion, with India alone accounting for 20% of global smartphone ownership. Before developing their own apps, the team reviewed existing tools to identify those best suited for health promotion in South Asia. Following successful pilot studies of their new and existing apps to assess their acceptability among the target population, the team now plan to carry out a clinical trial to evaluate their effectiveness for diabetes prevention. 

Dr Ranjit Mohan Anjana, Vice President at the Madras Diabetes Research Foundation, leads the digital health project in India. She said: “Through these new interventions, we hope to be able to implement successful digital health care for non-communicable diseases to all four South Asian countries”.

Primary healthcare teams play a critical role in the prevention and management of diabetes and CVD. The Unit investigated ways to strengthen these teams through culturally appropriate training programmes for community health workers meeting with local populations. Alongside local stakeholders and its network of health observatories, it also developed digital care tools to assist with health data collection and clinical decisions by health workers. A pilot study evaluation of the tool assessed 2,000 participants in Bangladesh and identified 800 people with diabetes or CVD and referred them for diagnosis and treatment, resulting in improved health behaviours and uptake of medical treatment. 

Dr Malay Mridha, Professor of the James P Grant School of Public Health at BRAC University and the Unit’s principal investigator in Bangladesh, said: “We have been involved with the training of primary health care providers on the national guidelines for the management of patients with hypertension and diabetes. After the training we carried out supportive supervision to further enhance the behavioural and clinical management skills of the trainees”.

In addition to healthcare training, one of the Unit’s priorities was to develop a sustainable programme of research through which its partner countries’ researchers could develop the necessary knowledge and skills to lead future projects. During the award period, more than 1,000 professionals across the four countries were trained in public health, health economics and research management. The Unit has supported partner organisations to become national centres of excellence for non-communicable disease research, which led to the development of local clinical research networks. They have also collaborated with other research programmes at the University of Melbourne, Australia and Lee Kong Chain School of Medicine, Singapore. 

Learning from people living with diabetes and CVD helps ensure that any interventions are relevant to areas where action is most needed. Much of the Unit’s work has therefore centred around the inclusion of diverse and vulnerable groups in South Asia, ensuring they are represented not only in the planning but also through participation in the research. 

One of their approaches was to describe their research in region- and language-specific videos to improve communication with local communities, using feedback from locally-based focus groups to adapt their methods. In Pakistan, engaging women in research can be challenging but, working alongside local primary healthcare teams, the offer of dedicated sessions for women and use of mobile health units helped engage those who were unable to travel to more central meetings. Researchers in India regularly met with community leaders, including leaders of local mosques and Hindu temples, to reach participants. 

The high level of public engagement achieved by the Unit’s researchers across South Asia assisted their successful recruitment and surveillance of the 150,000 people whose data contributed to the biobank. The Unit’s surveillance study data has also been used in UN global monitoring reports to estimate the prevalence of diabetes and CVD, and to assist in the allocation of healthcare resources in the region. 

During the Covid-19 pandemic, the Unit adapted its research to conduct telephone interviews with more than 30,000 existing participants of the surveillance programme about their behaviour during lockdown. The results of this work, published in the journal SSM – Population Health, showed a low uptake of recommended prevention behaviours and the high socioeconomic impact of national lockdown measures in South Asia. 

Through its research programme the Unit has strengthened existing approaches for monitoring diabetes and CVD in South Asia, helping to assess the needs of the population, healthcare system performance and identify priorities for action. In 2021, the Unit received a new 5-year NIHR grant of £7 million  to continue and extend its work as the NIHR Global Health Research Unit and Network for Diabetes and Cardiovascular Disease in South Asia. It continues to focus on understanding the risk factors for diabetes and CVD and influencing health promotion strategies for prevention and control of these health conditions. 

The expanded Unit is now following up the 150,000 surveillance study participants in the biobank to identify those newly diagnosed with diabetes and CVD. Their aim is to understand which lifestyle, environmental and genetic factors influence diabetes and CVD among South Asians populations around the world, including in the UK. The Unit also plans to improve assessments of people’s diabetes risk and facilitate earlier diagnosis of the condition, leading to better prevention and control of diabetes and CVD.

“Our research has the potential for considerable impact - even a conservative 10% reduction in the incidence will prevent around 6 million people developing diabetes and approximately 4 million people dying from CVD in South Asia over the next 10 years. Our research will therefore directly contribute to improving health and welfare, and reducing inequality, instability and poverty in South Asia.”

Professor Anuradhani Kasturiratne, Specialist in Community Medicine at the University of Kelaniya and Principal Investigator in Sri Lanka for the NIHR Global Health Research Unit and Network for Diabetes and Cardiovascular Disease in South Asia