Prevalence of diabetes and pre-diabetes in rural Tehri Garhwal, India: influence of diagnostic method

Burden of Type 2 Diabetes and Associated Cardiometabolic Traits and Their Heritability Estimates in Endogamous Ethnic Groups of India: Findings From the INDIGENIUS Consortium

To assess the burden of type 2 diabetes (T2D) and its genetic profile in endogamous populations of India given the paucity of data, we aimed to determine the prevalence of T2D and estimate its heritability using family-based cohorts from three distinct Endogamous Ethnic Groups (EEGs) representing Northern (Rajasthan [Agarwals: AG]) and Southern (Tamil Nadu [Chettiars: CH] and Andhra Pradesh [Reddys: RE]) states of India. For comparison, family-based data collected previously from another North Indian Punjabi Sikh (SI) EEG was used. In addition, we examined various T2D-related cardiometabolic traits and determined their heritabilities. These studies were conducted as part of the Indian Diabetes Genetic Studies in collaboration with US (INDIGENIUS) Consortium. The pedigree, demographic, phenotypic, covariate data and samples were collected from the CH, AG, and RE EEGs. The status of T2D was defined by ADA guidelines (fasting glucose ≥ 126 mg/dl or HbA1c ≥ 6.5% and/or use of diabetes medication/history). The prevalence of T2D in CH (N = 517, families = 21, mean age = 47y, mean BMI = 27), AG (N = 530, Families = 25, mean age = 43y, mean BMI = 27), and RE (N = 500, Families = 22, mean age = 46y, mean BMI = 27) was found to be 33%, 37%, and 36%, respectively, Also, the study participants from these EEGs were found to be at increased cardiometabolic risk (e.g., obesity and prediabetes). Similar characteristics for the SI EEG (N = 1,260, Families = 324, Age = 51y, BMI = 27, T2D = 75%) were obtained previously. We used the variance components approach to carry out genetic analyses after adjusting for covariate effects. The heritability (h²) estimates of T2D in the CH, RE, SI, and AG were found to be 30%, 46%, 54%, and 82% respectively, and statistically significant (P ≤ 0.05). Other T2D related traits (e.g., BMI, lipids, blood pressure) in AG, CH, and RE EEGs exhibited strong additive genetic influences (h² range: 17% [triglycerides/AG and hs-CRP/RE] - 86% [glucose/non-T2D/AG]). Our findings highlight the high burden of T2D in Indian EEGs with significant and differential additive genetic influences on T2D and related traits.

Epidemiology of Ischemic Heart Disease and Diabetes in South Asia: An Overview of the Twin Epidemic

BACKGROUND & OBJECTIVES

Ischemic heart disease (IHD) is one of the most important causes of death and disability in the world and diabetes is an important risk factor. This review was performed to describe the mortality and morbidity burden from this twin epidemic in South Asian countries.

METHODS

Country-level data on the epidemiology of IHD and diabetes were obtained from the Global Burden of Disease (GBD) study. Sub-national data were available only for India. We also retrieved epidemiological studies from published reviews on IHD and diabetes in India. These were supplemented with MEDLINE search.

RESULTS

GBD study and regional epidemiological studies have reported that there are significant regional variations in IHD mortality and disease burden within South Asian countries. IHD burden has increased significantly from 2000 to 2017. Prospective Urban Rural Epidemiology study has reported that diabetes is an important IHD risk factor in the South Asian region. GBD Study and International Diabetes Federation have reported increasing diabetes-related mortality and disease burden in South Asian countries, especially India. There are regional variations in diabetes-related mortality, disease burden, and prevalence in South Asia. At the macrolevel, rapid food and nutrition transition along with increasing physical inactivity is responsible for this twin epidemic.

CONCLUSION

Increasing trends in IHD and diabetes-related mortality and disease burden with regional variations are observed in South Asian countries.