Racial/ethnic differences in the burden of type 2 diabetes over the life course: a focus on the USA and India

Abstract

Type 2 diabetes is a common disease worldwide, but its prevalence varies widely by geographical region and by race/ethnicity. This review summarises differences in the frequencies of type 2 diabetes according to race, ethnicity, socioeconomic position, area of residence and environmental toxins. Type 2 diabetes susceptibility often begins early in life, starting with genetic susceptibility at conception and continuing in later life, via in utero, childhood and adult exposures. Early-life factors may lead to overt type 2 diabetes in childhood or in later life, supporting the concept of developmental origins of health and disease. The causes of the racial/ethnic differences in incidence of type 2 diabetes are not well understood. Specifically, the relative contributions of genetic and environmental factors to such differences are largely unknown. With a few exceptions in isolated populations, there is little evidence that differences in frequencies of known type 2 diabetes susceptibility genetic alleles account for racial/ethnic differences, although the search for genetic susceptibility has not been uniform among the world's racial/ethnic groups. In the USA, race/ethnicity is associated with many other risk factors for type 2 diabetes, including being overweight/ obese, diet and socioeconomic status. Some studies suggest that some of these factors may account for the race/ethnic differences in prevalence of type 2 diabetes, although there is inadequate research in this area. A better understanding of the impact of these factors on type 2 diabetes risk should lead to more effective prevention and treatment of this disease. This has not yet been achieved but should be a goal for future research.

Risk of type 2 diabetes in metabolically healthy people in different categories of body mass index: an updated network meta-analysis of prospective cohort studies

“…Recently Indian people with T2DM reported to have lower beta cell function compared with Europeans which is originates during intrauterine development, and not only diet; this fact support the ‘thrifty phenotype’ hypothesis. 60 Diet may also play a fundamental role in intergenerational vulnerability to T2DM. Maternal vitamin B12 deficiency and hyperhomocysteinemia are related to IR and adiposity in childhood.…”

The association between hypertension and other cardiovascular risk factors among non-diabetic Saudis adults–A cross sectional study

“…Studies on mentioned associations did not include people from the Arab world. Genetic factors, and hence ethnicity play an important role in susceptibility to disease [ 34 , 35 ], In an earlier study, conducted in Jeddah, Saudi Arabia, [ 36 ], we reported an association between above than normal weight with dysglycemia, and hypertension, which was gender specific. Moreover, in another survey, conducted in the same city at a later date, high LDL-C was found to be associated with an increased probability of pre-diabetes (Al amri et al 2019), which points to the clustering of the three CVD risk factors, excess weight increased blood pressure and dysglycemia in the Saudi population, as noted in studies from other countries [ 12 – 17 ].…”

Ethnic differences in adiposity and diabetes risk – insights from genetic studies

“…Type 2 diabetes is a common disease worldwide, but its prevalence varies widely across different ethnic groups. The prevalence of diabetes in the USA, according to self‐reported ethnicity and self‐reported physician‐diagnosed diabetes, ranges from 17.7% in white European individuals to 22.5% in Asians, 30.6% in Hispanics and Africans, and 45.2% in American Indians/Alaska Natives in adults ≥ 75 years of age [1]. This diversity is even evident in ethnic subgroups, where Indians have the highest risk of disease (38.8%) amongst Asians, and Mexicans have the highest prevalence (33.4%) amongst Hispanics [2].…”