Targeted approaches for T2D prevention, treatment needed for different Asian ethnic groups

Asians of different ethnicities have different risk factors for type 2 diabetes (T2D), according to a study, highlighting the potential value of tailored prevention and treatment strategies.

In a Singapore multi-ethnic cohort of 7,427 adults, ethnic Malays (odds ratio [OR], 2.08, 95 percent confidence interval [CI], 1.69–2.56) and Indians (OR, 2.22, 95 percent CI, 1.80–2.74) had approximately twofold higher risk of T2D compared with ethnic Chinese. [BMJ Open Diabetes Res Care 2023;11:e003385]

A large part of the excess T2D risk in Malays and Indians versus the Chinese appeared to be mediated by body mass index (BMI; mediation effect: 68.8 percent for Malays and 47.9 percent for Indians) and high-density lipoprotein (HDL)-cholesterol levels (mediation effect: 33.6 percent for Malays and 51.9 percent for Indians), as the investigators pointed out.

Additionally, the higher insulin resistance, C-reactive protein (CRP), and waist circumference seen in Indians explained 23.8 percent, 13.1 percent, and 10.4 percent of the difference in T2D risk between this ethnic group and the Chinese, respectively.

“In contrast, we observed a negative mediation effect for adiponectin for the T2D risk in Indians (−21.3 percent) and Malays (−37.4 percent) compared with Chinese participants. These negative mediation estimates suggest that higher adiponectin levels in Indians and Malays resulted in a smaller excess T2D risk compared with Chinese,” the investigators said.

“Despite [their] lower diabetes risk, ethnic Chinese had the lowest adiponectin levels among the three ethnic groups,” they added.

Unique biological risk factor profiles

Malays had a higher BMI than the Chinese, and this largely explained the higher T2D risk in Malays. However, Malays also had a more favourable abdominal fat distribution and adipocyte function for a given BMI.

Indeed, results from the mediation analysis show that the excess T2D risk in Malays than in Chinese would have been larger if Malays did not have better adiponectin levels and fat distribution, according to the investigators.

“In contrast, higher adiposity could not fully explain the higher T2D risk in Indians than in Chinese,” they noted.

What’s clear is that the levels of several T2D risk factors were worse in Indians than in Chinese, including markers of general adiposity, abdominal fat, insulin resistance, beta-cell function, inflammation, and dyslipidemia.

“Inflammation may promote diabetes development by inducing insulin resistance and pancreatic beta-cell death, and higher CRP levels have been consistently associated with a higher risk of T2D,” the investigators explained. [Eur Cardiol 2019;14:50-59; Diabetes Care 2013;36:166-175]

“Taken together, these findings indicate that both higher insulin resistance and lower insulin secretion capacity may underpin the higher T2D risk in Indians, with body composition, dyslipidaemia, and inflammation contributing to these conditions,” they added.

Looking at the overall data, the investigators believe that interventions to prevent excess adiposity may be an important step to reduce ethnic disparities in T2D risk between Chinese, Malays, and Indians.

“However, our results also highlight that different Asian ethnic groups have unique biological risk factor profiles related to T2D that may warrant targeted approaches for prevention and treatment,” they said.

The study population comprised 3,662 ethnic Chinese (49.3 percent), 1,945 ethnic Malay (26.2 percent), and 1,819 ethnic Indian participants (24.5 percent). Their mean age was 43.6 years. A total of 595 cases of incident diabetes were recorded during an average follow-up of 7.2 years.

The Chinese were more likely to have higher education and income levels, be more physically active, have a lower BMI, and were less likely to be current smokers than Malays or Indians. Fasting plasma glucose and HbA1c were highest in Indians, intermediate in Malays, and lowest in Chinese.