South Asian adults in the United States face significantly higher rates of prediabetes, diabetes and hypertension by midlife compared with several other racial and ethnic groups, even though many report healthier diets and lower alcohol use.
The study, led by researchers at Northwestern University Feinberg School of Medicine and published in the Journal of the American Heart Association, followed 2,700 adults ages 45 to 55 for a decade. Researchers combined data from two long-running cohort studies, MASALA, which focuses on South Asian adults, and MESA, which includes white, Black, Hispanic and Chinese adults.
By age 45, 31% of South Asian men had prediabetes, compared with 4% of white men, 10% of Black men, 10% of Hispanic men and 13% of Chinese men. About 25% of South Asian men had hypertension at age 45, higher than white, Hispanic and Chinese men in the study. South Asian women showed a similar pattern. Nearly 18% had prediabetes by age 45, roughly twice the rate seen among women in the other groups studied.
By age 55, South Asian men and women were at least twice as likely to develop diabetes as white adults.
“The mismatch between healthier lifestyle behaviors and clinical risk was surprising,” said senior author Dr. Namratha Kandula, professor of general internal medicine and epidemiology at Northwestern University. “This paradox tells us we’re missing something fundamental to what is driving this elevated risk among South Asians.”
Participants of South Asian heritage reported healthier diets, lower alcohol use, comparable physical activity and lower average BMI than most other groups. The findings suggest that traditional risk markers such as BMI and self-reported diet quality may not fully capture cardiometabolic risk in this population.
Researchers point to several possible contributors. Previous MASALA data show that South Asians tend to carry more visceral fat around internal organs even at lower BMI levels, a pattern associated with higher risk for diabetes and heart disease. Kandula said early life nutrition, environment and stressors may also shape risk long before midlife.
“We’ve now identified a critical window in the 40s when risk is already high, but disease is still preventable,” she said.
The study was observational and relied in part on self-reported diet and lifestyle data. It does not suggest that healthy eating or exercise are ineffective. Instead, the findings reinforce that cardiometabolic risk can vary significantly across populations and may require earlier or more targeted screening.
For adults of South Asian background, clinicians recommend checking blood pressure, fasting glucose or A1c, cholesterol and lipoprotein(a) before middle age. Early detection and management of elevated blood sugar and blood pressure can reduce long-term cardiovascular risk.
More broadly, the study highlights a key message in nutrition science: metabolic health is influenced by diet and lifestyle, but also by body fat distribution, early life factors and genetic background. A normal BMI does not always mean low cardiometabolic risk.
The MASALA and MESA cohort studies were supported by the National Institutes of Health through multiple federal research grants.