COMMENTARY

Why Diabetes Management May Need to Change for South Asians

Moneeza Siddiqui, PhD

Disclosures

September 19, 2019

This transcript has been edited for clarity

I'm Dr Moneeza Siddiqui from the University of Dundee, and I'm here at the European Association for the Study of Diabetes (EASD) 2019 Annual Meeting presenting some results we have from the India-Scotland Partnership for Precision Medicine in Diabetes (INSPIRED).

These are first results from INSPIRED. Our aim was to understand how clinical features at the time of diagnosis of type 2 diabetes differed between Asian Indians and White Europeans. These are results from a cross-sectional study of 100,000 individuals from South India and the United Kingdom.

What were your findings?

Essentially what we found were that what are well known to be traditional risk factors for the age of onset of type 2 diabetes, do not appear to predict risk for onset as well in South Asians as they do in white Europeans. Primarily features like obesity, calculated by body mass index, or waist circumference, while strongly associated with the age of onset in white Europeans, very obese white Europeans could develop diabetes quite young, whereas those developing diabetes at the age of 60, or 70, or later, tend to be quite slim.

This effect was completely absent in South Asians who were generally a lot slimmer than white Europeans when they developed diabetes and never really showed a strong association of increased obesity with early age of onset.

The other very striking result we had was with regards to blood pressure. It's well known that the metabolic syndrome, which is how diabetes is generally described in white Europeans is associated with not only obesity, but also hypertension. And we definitely see that in our white European population where young onset diabetes is associated with quite high systolic and diastolic hypertension. But this effect was again completely absent in Asian Indians, who in comparison had very normal systolic and diastolic blood pressure - 120/80 being the norm for those diagnosed under the age of 40, which was also quite puzzling.

But finally, the area in which we did see a big difference was in beta cell function. Beta cells are obviously a marker of insulin secretion. And we could see quite clearly that in those diagnosed young in South Asians, there was a lower beta-cell function that was not evident in white Europeans who were diagnosed at similar ages, suggesting that that's really where the answer lies for Asian Indians.

What other differences did you find?

Actually, what's really striking in our results was that it's pretty well known that South Asians develop diabetes much younger than white Europeans. But in this particular study, in this particular population, we're looking at a 15 year difference in the age of onset on average.

Part of the population level effect that's occurring here is that, aside from the ethnically driven risk, is that Asian Indians in this study are from a private clinic system for the management of type 2 diabetes. So it is possible that we're looking at a slightly more extreme group of people with type 2 diabetes. But it's not uncommon in India, if you have a chronic health condition to seek management in a private specialist facility. What's particularly of note here is that if we are looking at a slightly more extreme kind of, a more aggressive type of type 2 diabetes, what’s even more striking is that in spite of that there is lower adiposity and hypertension compared to white Europeans, which is really of note. We did undertake additional analyses, comparing our Asian Indian cohort with a population-level dataset from the same region in India, and noticed an increased BMI and waist circumference in our cohort (who had type 2 diabetes) compared to the local population. This does suggest there is an increase in adiposity in Asian Indians with diabetes, it is just to a much lesser degree than in white Europeans. Our results also suggest that increased adiposity in Asian Indians does predict who will develop diabetes, but not when.

What's the message from your research for primary care?

Obviously, before these findings become incorporated into routine care, there would need to be plenty of clinical trials done to understand first of all, what drugs would best work in South Asians, because clearly what we are starting to see here is that the pathogenesis of the disease is very different. And so I think the same therapies may not work to the same efficacy in these two ethnically different populations.

Based on our findings, there are two main unknows in Asian Indians:

  1. What specifically is causing the beta-cell failure?

  2. Could we improve our understanding of adiposity in this ethnic group?

We're seeing this across the EASD. Several talks this year have focused on perhaps a different standard of screening for South Asians, whereby they’re screened younger perhaps, should be screened more frequently. Because this is noted both in our study, which is looking at indigenous South Asians, as well as some studies that I have been to today, that have discussed South Asians living in the UK, for example, who, when they are diagnosed with type 2 diabetes, seem to have very high HbA1Cs, which perhaps suggests that they aren’t seeking health care as routinely as white Europeans are or perhaps they aren't being compelled to be screened as often as they should be, given that we already know they are at an increased risk.

So I think the main message for primary care, primary care physicians,would be essentially to just be a little bit more aware that the disease comes on that much sooner in in South Asians, and that early-onset may not necessarily come bundled together with our idea of metabolic syndrome, as in those people may not be quite as obese or as hypertensive as you might think they would be to have risk at that young age. Essentially, what we're looking at is a beta cell issue, so perhaps tailoring medications for that might be the future of primary healthcare for diabetes in South Asians.

Editor's Note: This article was updated after publication to include additional informsation from Moneeza Siddiqui.

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