Ethnic differences in prediabetes incidence among immigrants to Canada: a population-based cohort study

Natural History of Type 2 Diabetes in Indians: Time to Progression

OBJECTIVE

To describe the natural history of diabetes in Indians.

RESEARCH DESIGN AND METHODS

Data are from participants older than 20 years in the Centre for Cardiometabolic Risk Reduction in South Asia longitudinal study. Glycemic states were defined per American Diabetes Association criteria. Markov models were used to estimate annual transition probabilities and sojourn time through states.

RESULTS

Among 2,714 diabetes-free participants, 641 had isolated impaired fasting glucose (iIFG), and 341 had impaired glucose tolerance (IGT). The annual transition to diabetes for those with IGT was 13.9% (95% CI 12.0, 15.9) versus 8.6% (7.3, 9.8) for iIFG. In the normoglycemia ↔ iIFG → diabetes model, mean sojourn time in normoglycemia was 40.3 (34.6, 48.2) years, and sojourn time in iIFG was 9.7 (8.4, 11.4) years. For the normoglycemia ↔ IGT → diabetes model, mean sojourn time in normoglycemia was 34.5 (29.5, 40.8) years, and sojourn time in IGT was 6.1 (5.3, 7.1) years.

CONCLUSIONS

Individuals reside in normoglycemia for 35-40 years; however, progression from prediabetes to diabetes is rapid.

Beyond the Body: Using Photovoice to Explore Social Determinants of Diabetes With South Asian Adolescents in the Peel Region of Ontario, Canada

OBJECTIVES

The higher prevalence of diabetes in the South Asian (SA) population living in Canada spans across generations and is often associated with individual risk factors while undermining the social determinants of health (SDOH). There is a scarcity of studies on the perspectives of SA adolescents with a family history of type 2 diabetes mellitus (T2DM). Learning directly from these adolescents can fill a major gap by providing insight on how the SDOH contribute to disproportionate rates of T2DM in SA immigrant communities.

METHODS

In this study, we used Photovoice, which is a community-based participatory research (CBPR) method that involves the use of photography to visually capture the challenges of diabetes prevention from the perspective of those with lived experiences. A group of 15 SA youth were recruited from an adolescent diabetes education program in the Peel Region of Ontario. The youth discussed their images and accompanied written narratives during focus groups.

RESULTS

Four themes emerged from the thematic analysis of the photographs and participant narratives that influence the manifestation of T2DM in SA communities: 1) immigration and resettlement stressors; 2) food insecurity; 3) unhealthy school environments; and 4) academic pressures.

CONCLUSIONS

Findings suggest the need to address T2DM as a response to unjust conditions and environments rather than as an epidemic entrenched in genetic predisposition, culture, and poor lifestyle choices.

Evaluation of ethnic differences in cardiometabolic risk in children

PURPOSE

In adults, cardiometabolic conditions manifest differently by ethnicity with South Asians particularly predisposed. Whether these differences arise in childhood remains narrowly explored. To address this evidence gap, we examined whether children of different ethnicities display differences in cardiometabolic risk (CMR).

METHODS

A cross-sectional analysis was conducted among 5557 children (3-11 years). Multivariable linear regression models adjusted for age, sex, z-body mass index, and demographic factors were used to estimate differences in CMR outcomes between children with parents that self-reported European ancestry (reference group) and one of 13 other ethnicities (African, Arab, East Asian, Latin American, South Asian, Southeast Asian, Mixed Ethnicities, and Other). The primary outcome was a CMR score, calculated as the sum of age- and sex-standardized waist circumference, systolic blood pressure (SBP), glucose, log-triglycerides, and inverse high-density lipoprotein cholesterol (HDL-C), divided by √5.

RESULTS

Lower mean CMR scores were observed among children with African (β = -0.62, 95% CI: -0.92; -0.32) and East Asian (β = -0.41, 95% CI: -0.68, -0.15) ancestry compared to children with European ancestry. Children with South Asian ancestry had higher SBP (β = 2.25, 95% CI: 1.27, 3.22) and non-HDL-C (β = 0.17, 95% CI: 0.07, 0.26) than children with European ancestry.

CONCLUSIONS

Ethnic differences in CMR were observed in early and middle childhood.

HbA1c-defined prediabetes and progression to type 2 diabetes in Denmark: A population-based study based on routine clinical care laboratory data

AIMS

To estimate the prevalence, incidence, mortality, and risk of progression to type 2 diabetes for individuals with HbA1c-defined prediabetes based on Danish nationwide population-based laboratory databases.

METHODS

We included all HbA1c measurements from general practice and hospitals during 2012 to 2018. We estimated the cumulative incidence of having at least one HbA1c measurement. The prevalence and incidence rates of prediabetes (HbA1c 42-47 mmol/mol) were examined in the adult Danish population. The 5-year cumulative incidence of progression to type 2 diabetes was estimated with death as competing event.

RESULTS

Among 4,979,590 adult Danes, 70.8% (95% CI 70.8-70.9) had at least one HbA1c measurement during 2012 to 2018. The prevalence of prediabetes was 7.1% (95% CI 7.1-7.1) in 2018. The incidence rate was 14.2 (95% CI 14.1-14.3) per 1,000 person-years, with median age 66.9 years (IQR 56.7-75.7) and median HbA1c 43 mmol/mol (IQR 42-44) at prediabetes diagnosis. Within five years, 17.5% (95% CI 17.3-17.7) died and the 5-year cumulative incidence of type 2 diabetes was 21.3% (95% CI 21.1-21.5).

CONCLUSIONS

Out of 100 Danish adults, 1.4 develop prediabetes each year and they can be identified at an early stage in laboratory databases. Within five years, one in five individuals with prediabetes progresses to diabetes and one in six dies.

Macrovascular and renal microvascular complications in West Africans with intermediate hyperglycemia living in West Africa and Europe: The RODAM study

Background

Metabolic conditions, including intermediate hyperglycemia (IH), affect migrants to a greater extent than the populations of origin. Evidence suggests that IH increases the risk of vascular complications, but it is unclear whether the differences in IH between the non-migrant and migrant populations translate to differences in vascular complications between the two populations. We compared the prevalence of macrovascular and renal microvascular complications among West Africans with IH living in West Africa and their migrant compatriots in Europe.

Methods

Data from the multicenter Research on Obesity and Diabetes among African Migrants(RODAM) study were analyzed. Ghanaians with IH(524 non-migrant and 1439 migrants) were included. Logistic regression analyses were used to determine the associations between migrant status and macrovascular [coronary artery disease(CAD) and peripheral artery disease(PAD)] and renal microvascular[nephropathy] complications with adjustment for age, sex, socioeconomic status, smoking, systolic blood pressure, BMI, total cholesterol, HbA1c, C-reactive protein, and serum uric acid.

Findings

The prevalence of microvascular/macrovascular complications was higher in non-migrants than in migrants(nephropathy 15.3vs.9.7%; PAD 3.1%vs.1.3%; and CAD 15.8% vs. 5.0%). The differences persisted in the fully adjusted model: nephropathy [odds ratio, 2.12; 95% CI(1.46-3.08); PAD, 4.44(1.87-10.51); CAD 2.35(1.64-3.37)]. Non-migrant females had higher odds of nephropathy[2.14(1.34-3.43)], PAD[7.47(2.38-23.40)] and CAD [2.10(1.34-3.27)] compared to migrant females. Non-migrant males had higher odds of nephropathy[2.54(1.30-4.97)] and CAD[2.85(1.48-5.50)], but not PAD[1.81(0.32-10.29)],than their migrant peers.

Interpretation

Macrovascular and renal microvascular complications were more prevalent in non-migrants than in migrant West Africans with IH. Further studies are needed to identify factors that increase the risk to aid preventive/treatment strategies.

Heterogeneity of Diabetes: β-Cells, Phenotypes, and Precision Medicine: Proceedings of an International Symposium of the Canadian Institutes of Health Research's Institute of Nutrition, Metabolism and Diabetes and the U.S. National Institutes of Health's National Institute of Diabetes and Digestive and Kidney Diseases

One hundred years have passed since the discovery of insulin-an achievement that transformed diabetes from a fatal illness into a manageable chronic condition. The decades since that momentous achievement have brought ever more rapid innovation and advancement in diabetes research and clinical care. To celebrate the important work of the past century and help to chart a course for its continuation into the next, the Canadian Institutes of Health Research's Institute of Nutrition, Metabolism and Diabetes and the U.S. National Institutes of Health's National Institute of Diabetes and Digestive and Kidney Diseases recently held a joint international symposium, bringing together a cohort of researchers with diverse interests and backgrounds from both countries and beyond to discuss their collective quest to better understand the heterogeneity of diabetes and thus gain insights to inform new directions in diabetes treatment and prevention. This article summarizes the proceedings of that symposium, which spanned cutting-edge research into various aspects of islet biology, the heterogeneity of diabetic phenotypes, and the current state of and future prospects for precision medicine in diabetes.

Heterogeneity of Diabetes: β-Cells, Phenotypes, and Precision Medicine: Proceedings of an International Symposium of the Canadian Institutes of Health Research's Institute of Nutrition, Metabolism and Diabetes and the U.S. National Institutes of Health's National Institute of Diabetes and Digestive and Kidney Diseases

One hundred years have passed since the discovery of insulin-an achievement that transformed diabetes from a fatal illness into a manageable chronic condition. The decades since that momentous achievement have brought ever more rapid innovation and advancement in diabetes research and clinical care. To celebrate the important work of the past century and help to chart a course for its continuation into the next, the Canadian Institutes of Health Research's Institute of Nutrition, Metabolism and Diabetes and the U.S. National Institutes of Health's National Institute of Diabetes and Digestive and Kidney Diseases recently held a joint international symposium, bringing together a cohort of researchers with diverse interests and backgrounds from both countries and beyond to discuss their collective quest to better understand the heterogeneity of diabetes and thus gain insights to inform new directions in diabetes treatment and prevention. This article summarizes the proceedings of that symposium, which spanned cutting-edge research into various aspects of islet biology, the heterogeneity of diabetic phenotypes, and the current state of and future prospects for precision medicine in diabetes.

Heterogeneity of Diabetes: β-Cells, Phenotypes, and Precision Medicine: Proceedings of an International Symposium of the Canadian Institutes of Health Research's Institute of Nutrition, Metabolism and Diabetes and the U.S. National Institutes of Health's National Institute of Diabetes and Digestive and Kidney Diseases

One hundred years have passed since the discovery of insulin-an achievement that transformed diabetes from a fatal illness into a manageable chronic condition. The decades since that momentous achievement have brought ever more rapid innovation and advancement in diabetes research and clinical care. To celebrate the important work of the past century and help to chart a course for its continuation into the next, the Canadian Institutes of Health Research's Institute of Nutrition, Metabolism and Diabetes and the U.S. National Institutes of Health's National Institute of Diabetes and Digestive and Kidney Diseases recently held a joint international symposium, bringing together a cohort of researchers with diverse interests and backgrounds from both countries and beyond to discuss their collective quest to better understand the heterogeneity of diabetes and thus gain insights to inform new directions in diabetes treatment and prevention. This article summarizes the proceedings of that symposium, which spanned cutting-edge research into various aspects of islet biology, the heterogeneity of diabetic phenotypes, and the current state of and future prospects for precision medicine in diabetes.

Metabolic risk factors among prediabetic individuals and the trajectory toward the diabetes incidence

BACKGROUND

This study investigates the trajectory of the risk factors of prediabetes progression to overt diabetes.

METHODS

The study retrospectively investigated 1610 prediabetic individuals. The trajectory of metabolic indicators was investigated using the generalized estimated equation method with autoregressive working correlation structure through a linear model with the identity link function.

RESULTS

During 15 years of follow-up, the trajectories of metabolic risk factors changed from 3 years before diabetes occurrence for fasting plasma glucose (FPG) and 2-hour plasma glucose (2hPG), 6 years for waist circumference (WC), 9 years for high-density lipoprotein cholesterol (HDL-C), and earlier for body mass index, triglyceride (TG), and TG:HDL ratio. It was shown that the differences in the trajectory of WC and HDL were stable after adjustment for other metabolic risk factors. The trajectories of FPG and 2hPG remained stable after considering multiple insulin resistance markers.

CONCLUSIONS

Deterioration of metabolic risk factor status can be a predictor of diabetes many years before its occurrence, but the abrupt change in plasma glucose is evident 3 years before diabetes mellitus onset. It seems that the HDL-C and WC trajectories are two independent predictors for diabetes incidence. It was also found that when the rising trend in plasma glucose starts, preventive strategies to lessen insulin resistance might not be efficient.

Fracture prediction from FRAX for Canadian ethnic groups: a registry-based cohort study

We identified large between-ethnicity calibration differences in the Canadian FRAX® tool which substantially overestimated the major osteoporotic fracture (MOF) risk in Asian women and Black women, and overestimated hip fracture risk in Asian women.

PURPOSE

FRAX® is calibrated using population-specific fracture and mortality data. The need for FRAX to accommodate ethnic diversity within a country is uncertain. We addressed this question using the population-based Manitoba Bone Mineral Density (BMD) Program registry and self-reported ethnicity.

METHODS

The study population was women aged 40 years or older with baseline FRAX assessments (Canadian and other ethnic calculators), fracture outcomes, and self-reported ethnicity (White N = 68,907 [referent], Asian N = 1910, Black N = 356). Adjusted hazard ratios (HR) with 95% confidence intervals (CI) for time to MOF and hip fracture were estimated. We examined candidate variables from DXA that might contribute to ethnic differences including skeletal size, hip axis length (HAL), trabecular bone score (TBS), and estimated body composition.

RESULTS

Adjusted for baseline risk using the Canadian FRAX tool with BMD, Asian women compared with White women were at much lower risk for MOF (HR 0.46, 95% CI 0.35-0.59) and hip fracture (0.16, 95% CI 0.08-0.34). Black women were also at lower MOF risk (HR 0.58, 95% CI 0.32-1.00); there were no hip fractures. The US ethnic-specific FRAX calculators accounted for most of the between-ethnicity differences in MOF risk (86% for Asian, 92% for Black) but only partially accounted for lower hip fracture risk in Asian women (40%). The candidate variables explained only a minority of the effect of ethnicity. Gradient of risk in analyses was similar (p-interactions ethnicity*FRAX non-significant).

CONCLUSIONS

We identified significant ethnic differences in performance of the Canadian FRAX tool with fracture probability overestimated among Asian and Black women. The US ethnic calculators helped to address this discrepancy for MOF risk assessment, but not for hip fracture risk among Asian women.

Ethnic variation in the conversion of prediabetes to diabetes among immigrant populations relative to Canadian-born residents: a population-based cohort study

OBJECTIVE

The aim of this study was to compare absolute and relative rates of conversion from prediabetes to diabetes among non-European immigrants to Europeans and Canadian-born residents, overall, and by age and level of glycemia.

RESEARCH DESIGN AND METHODS

We conducted a retrospective cohort population-based study using administrative health databases from Ontario, Canada, to identify immigrants (n=23 465) and Canadian born (n=1 11 085) aged ≥20 years with prediabetes based on laboratory tests conducted between 2002 and 2011. Individuals were followed until 31 December 2013 for the development of diabetes using a validated algorithm. Immigration data was used to assign ethnicity based on country of origin, mother tongue, and surname. Fine and Gray's survival models were used to compare diabetes incidence across ethnic groups overall and by age and glucose category.

RESULTS

Over a median follow-up of 5.2 years, 8186 immigrants and 39 722 Canadian-born residents developed diabetes (7.1 vs 6.1 per 100 person-years, respectively). High-risk immigrant populations such as South Asians (HR: 1.72, 95% CI 1.55 to 1.99) and Southeast Asians (HR: 1.65, 95% CI 1.46 to 1.86) had highest risk of converting to diabetes compared with Western Europeans (referent). Among immigrants aged 20-34 years, the adjusted cumulative incidence ranged from 18.4% among Eastern Europeans to 52.3% among Southeast Asians. Conversion rates increased with age in all groups but were consistently high among South Asians, Southeast Asians and Sub-Saharan African/Caribbeans after the age of 35 years. On average, South Asians converted to diabetes 3.1-4.6 years earlier than Western Europeans and at an equivalent rate of conversion to Western Europeans who had a 0.5 mmol/L higher baseline fasting glucose value.

CONCLUSIONS

High-risk ethnic groups converted to diabetes more rapidly, at younger ages, and at lower fasting glucose values than European populations, leading to a shorter window for diabetes prevention.