New research to be presented at the Annual Meeting of the European Association for the Study of Diabetes (EASD) in Milan, Italy (Sept 28 – Oct 2) and published in The Lancet Diabetes & Endocrinology shows that the small island nation of Mauritius is the first country in the world to prove it is reversing the type 2 diabetes epidemic using the objective gold standard testing method of the 2-hour oral glucose tolerance test (2 hour OGTT). The authors – who include Professor Jaakko Tuomilehto, Department of Public Health, University of Helsinki, Finland – say the achievement offers hope to all countries worldwide battling the huge human and economic cost of type 2 diabetes.
The prevalence of type 2 diabetes has been increasing globally for decades. Estimates are primarily based on population surveys conducted in some countries and routine administrative data sources, while no survey data are available for most countries. Only a few countries have conducted repeated, longitudinal diabetes surveys over many years. Moreover, survey methodologies have varied across countries, and most studies have not followed the standards recommended by WHO – the 2-hour OGTT. In studies that have not relied on OGTTs, prevalence estimates of diabetes and intermediate hyperglycaemia (also called prediabetes) have likely been biased and underestimated. Today, including in many high-income countries, type 2 diabetes is tested for, at least in the first instance, by testing for fasting plasma glucose or glycated haemoglobin (HbA1c) in the blood – but these tests have been shown to miss many asymptomatic cases that can be detected by 2-hour OGTT.
In the OGTT, fasting is required - not eating or drinking anything except water for at least 8 to 10 hours before the test. A healthcare professional will then take a blood sample to test your fasting blood sugar level. The person then drinks a sweet liquid that contains a specific amount of glucose, usually 75 grams for adults, and additional blood samples are taken, typically at one hour and two hours after finishing the drink. It is necessary to remain sedentary, avoid any eating and drinking, smoking, and exercising before blood sampling after two hours.
The island nation of Mauritius, located in the Indian Ocean east of Madagascar and with a population of 1.2 million has recently undergone a profound socioeconomic transition, changing living conditions and lifestyles, leading to a shift in its disease burden from infectious to chronic non-communicable diseases (NCDs), including type 2 diabetes. In this, Mauritius is similar to many other island nations, including those in the Pacific Ocean, that have seen obesity and type 2 diabetes surge since the 1980s.
However, unlike other nations, Mauritius has monitored this transition and diabetes prevalence through seven cross-sectional surveys conducted since 1987. Prof. Paul Zimmet (currently Professor of Diabetes, Monash University, Melbourne, Australia), initiated the surveys, which were conducted by staff of the Ministry of Health and Wellness. Teams led by Prof. Zimmet, Prof. Tuomilehto, and Prof. Sir George Alberti from the UK supported the surveys, and more recently Prof. Stefan Söderberg from Umeå, Sweden. In each survey, type 2 diabetes and intermediate hyperglycaemia have been assessed using the OGTT. Mauritius is the only country in the world that has systematically used the OGTT to monitor type 2 diabetes and intermediate hyperglycaemia over time. In this study, the authors investigated long-term changes in the prevalence of type 2 diabetes and intermediate hyperglycaemia using population-based data from OGTTs. The results for each year were as follows (and see table 1 full paper)
- 1987 – overall 14.7% ; women 14.0%, men 15.3%
- 1992 – overall 17.3% ; women 16.6%, men 18.0%
- 1998 – overall 20.2%; women 19.3%, men 21.1%
- 2004 – overall 18.6%; women 18.3%, men 18.7%
- 2009 – overall 23.3%; women 22.0%, men 24.7%
- 2015 – overall 23.1%; women 23.7%; men 22.6%
- 2021 – overall 19.9%; women 18.1%; men 21.7%
Type 2 diabetes prevalence increased between 1987 and 2009 by 61% in men and by 56% in women. Between 2009 and 2021, prevalence decreased, by 11% in men and 16% in women.
The authors analyse several possible reasons for Mauritius's success. They say the results highlight the potential effect of initiatives to prevent and manage type 2 diabetes in Mauritius. Examples of these multisectoral approaches include: (1) Prevention: creating an action plan; policy (including advocacy and legislation); NCD risk factor screening (including mobile clinics); and community engagement and participation (including national action plans for nutrition, physical activity, and tobacco control). (2) A national integrated NCD action plan: a roadmap to improve health and wellbeing across the life-course. (3) A national service framework for NCDs: a policy set to define standards of care for NCDs within a service protocol with appropriate quality standards. And public sector health services are free of charge, including essential medicines.
The authors conclude: "Mauritius is the first country to show a sustained decrease in the prevalence of type 2 diabetes and prediabetes, based on long-term data using the WHO-recommended gold standard oral glucose tolerance test-based diagnostic criteria. It is encouraging to learn that the continuous increase in type 2 diabetes occurring in almost all countries all around the world could be halted and even reversed. Previous experiences with other major public health problems, such as cardiovascular diseases and lung cancer, have shown that it is possible to tackle chronic NCD epidemics."
