Among US South Asian adults aged 44 to 84, type 2 diabetes prevalence is 23%, compared with 6% in white adults, 18% in African American adults, 17% in Latino adults, and 13% in Chinese American adults [1]. That difference is real, measured, and partly unexplained. It is not a personal forecast, not a fate, and not something you cannot act on. This page walks what the data actually show, where the numbers come from, and what sits in your control.

What does the MASALA and MESA data show?

The MASALA study is a longitudinal research project on heart disease risk factors among US South Asians, coordinated by the University of California San Francisco Department of Medicine, and it describes itself as the first of its kind in this population [2]. Kanaya and colleagues analyzed MASALA and MESA participants aged 44 to 84 without diabetes at baseline and found an age-adjusted type 2 diabetes prevalence of 23% among South Asian adults [1]. The comparison groups in the same analysis, all aged 44 to 84, showed 6% among white adults, 18% among African American adults, 17% among Latino adults, and 13% among Chinese American adults [1].

That 23% sits at the top of the table. It means that among South Asian adults in that age band, roughly one in four had type 2 diabetes when the data were collected. The prevalence in white adults was one in 17. The gap is not small, and it is not explained by any single factor measured so far.

Why is the risk higher if body composition does not explain it?

Flowers and colleagues added body composition measures to the MASALA and MESA analyses and concluded they did not identify strong evidence that accounting for body composition explains differences in the risk for type 2 diabetes [3]. That finding matters because it means the elevated prevalence is not simply a story about weight distribution or muscle mass. The mechanism is not fully understood. That uncertainty is honest, and it is also the reason screening matters more than waiting for a complete explanation.

What are the screening thresholds for South Asian adults?

The American Diabetes Association recommends testing for type 2 diabetes in adults with overweight or obesity, meaning a BMI of 25 or higher, or 23 or higher in individuals of Asian ancestry, who have one or more additional risk factors [4]. Those risk factors include a first-degree relative with diabetes, high-risk race, ethnicity and ancestry, a history of cardiovascular disease, hypertension, abnormal cholesterol or triglyceride levels, polycystic ovary syndrome, and physical inactivity [4].

A BMI of 23.0 was identified by a WHO expert consultation as a potential public health action point for Asian populations, and the consultation noted that the proportion of Asian people at high risk of type 2 diabetes and cardiovascular disease is substantial at BMI values lower than the existing WHO cut-off point for overweight of 25 or higher [5].

Here is how the screening thresholds compare:

Group BMI threshold for testing Additional risk factors required
General adult population 25 or higher Yes, one or more [4]
Asian ancestry, including South Asian 23 or higher Yes, one or more [4]
WHO action point for Asian populations 23.0 Identified as potential threshold [5]

What does an A1C result actually mean?

The A1C test measures the amount of hemoglobin with attached glucose and reflects your average blood glucose levels over the past 3 months [6]. Below 5.7% is normal. An A1C of 5.7% to 6.4% is prediabetes [6]. An A1C of 6.5% or higher is diabetes [6].

Prediabetes usually has no symptoms. Most people who have it do not know. People with prediabetes have a high chance of developing type 2 diabetes within 5 to 10 years [6]. That timeline is not inevitable. The Diabetes Prevention Program found that losing 5% to 7% of body weight lowered the chance of developing type 2 diabetes [6].

What risk factors can actually change?

Some risk factors sit outside your control. Age and family history you cannot change. But knowing your family history matters because it tells you whether screening is urgent. And knowing the threshold matters because it tells you whether to ask for the test.

The ones you do control are weight, physical activity, and diet. These are the factors that appear in every screening guideline because they are the ones that respond to action. A first-degree relative with diabetes is a reason to screen earlier, not a reason to wait.

What does elevated group risk actually mean for you?

Group risk is measured, and it is never a personal forecast. The 23% figure describes a population, not a person. It means that among South Asian adults in that age band, roughly one in four had diabetes when measured. It does not mean you will. It does not mean your risk is fixed. It does not mean you cannot act.

The mechanism is not fully explained. Body composition did not account for the difference. That means the reason for the higher prevalence is not yet known. That uncertainty is real, and it is also why screening is the concrete step: you do not need to understand the mechanism to know whether your own A1C is 5.7% or 6.5%.

What to do next

  1. Ask your clinician whether you meet the screening criteria: a BMI of 23 or higher plus one or more additional risk factors [4].
  2. If you do, request an A1C test or a fasting glucose test at your next visit. Write down your result and what it means: normal, prediabetes, or diabetes [6].
  3. If your result is prediabetes, ask about the Diabetes Prevention Program or another evidence-based lifestyle program in your area.
  4. If you have a first-degree relative with type 2 diabetes, tell your clinician, because family history is a risk factor that lowers the screening threshold [4].
  5. Read the screening threshold for South Asians to understand why the BMI cutoff is different.
  6. Learn which risk factors can actually change and which ones cannot.
  7. Visit the Sehat guides for more on screening, prediabetes, and what the numbers mean.

Sources

  1. Kanaya and colleagues, MASALA and MESA diabetes prevalence, age-adjusted prevalence among US adults aged 44 to 84, PubMed, accessed 2026-08-06, https://pubmed.ncbi.nlm.nih.gov/24705613/
  2. MASALA study, study design and population, accessed 2026-08-06, https://www.masalastudy.org/
  3. Flowers and colleagues, body composition and diabetes risk in South Asians, MASALA and MESA analysis, PubMed, accessed 2026-08-06, https://pubmed.ncbi.nlm.nih.gov/30796111/
  4. American Diabetes Association, Diagnosis and Classification of Diabetes, Standards of Care in Diabetes 2026, screening thresholds and risk factors, accessed 2026-08-06, https://diabetesjournals.org/care/article/49/Supplement_1/S27/163926/2-Diagnosis-and-Classification-of-Diabetes
  5. WHO expert consultation, appropriate body-mass index for Asian populations, Lancet 2004, action points and risk thresholds, PubMed, accessed 2026-08-06, https://pubmed.ncbi.nlm.nih.gov/14726171/
  6. NIDDK, insulin resistance and prediabetes, risk factors and progression timeline, accessed 2026-08-06, https://www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes/prediabetes-insulin-resistance