Change in pancreatic B-cell function (HOMA-B) varies in different populations with similar genetic backgrounds but different environments

Cardiometabolic Profile and Outcomes in Migrant Populations: A Review of Comparative Evidence from Migrants in Europe in Relation to Their Country of Origin

BACKGROUND

The potential effect of migration on increasing cardiometabolic risk factors remains partially understood. We aim to synthesize the evidence comparing the burden of diabetes and adiposity of migrating populations in Europe, with that of their country of origin.

METHODS

We conducted a scoping literature review. We searched PubMed for studies investigating the effect of migration on diabetes or adiposity outcomes among migrants in countries from the European Union or the United Kingdom compared to the population in the country of origin. Studies were qualitatively synthesized in evidence tables and the demographic characteristics, study design, risk factors investigated, and outcomes were quantitatively summarized using measures of central tendency.

FINDINGS

Of 1175 abstracts retrieved, 28 studies were eligible. Most of the studies included migrating populations residing in Western (50%), Northern (39%), and Southern Europe (11%) originating from countries in Africa (46%), Asia (29%), or European overseas (25%) regions of which 85% were classified as low-middle-income countries. Most of the studies (93%) had a cross-sectional design. The median number of individuals in the country of origin was greater [917; IQR: 231-1378] than in the receiving country [249; 150-883]. Thirty-five percent of the studies investigated migration as an independent risk factor, whereas 28% contextualized migration into lifestyle changes. The majority of the studies (57%) reported both diabetes and adiposity outcomes. Within the limited evidence available, controversial results were found as some studies showed poorer outcomes for the migrating populations, while others showed the opposite.

CONCLUSION

Studies assessing the impact of migration by comparing migrating populations and the population of origin on diabetes and adiposity outcomes have gained interest. So far, the available evidence is highly heterogeneous to inform public health strategies in the receiving countries. We recommend further research including a more robust methodology and in-depth characterization of the migrant populations.

Increase in glycemic set point, alongside a decrease in waist circumference, in the non-diabetic population during the Japanese National Intervention Program for metabolic syndrome: A single-center, large-scale, matched-pair analysis

Background

In 2008, the Japanese government implemented a National Intervention Program for metabolic syndrome. Low-risk individuals were not direct targets of this intervention. Nevertheless, they were indirectly enlightened by this massive campaign. Documentation of the metabolic shifts in low-risk individuals following the program launch may inform public health policy regarding approaches to metabolic risks in the general population.

Methods

We conducted a cross-sectional analysis of data from non-diabetic participants who underwent general health check-ups at the Physical Check-up Center of Sumitomo Hospital. Participants during 2007–2008 were pair-matched with those during 2015–2016 with respect to sex, age, smoking status, hemoglobin level, and red blood cell (RBC) count. Each participant was included only once in the study.

Results

Totals of 3,140 men and 2,048 women were pair-matched. The non-diabetic participants showed lower waist circumference, blood pressure, heart rate, and serum lipid concentrations during the second study period. In contrast, the entire distributions of fasting plasma glucose (FPG) concentration in both sexes and glycated hemoglobin (HbA_1c) in women were shifted upwards. In men, Δ FPG was +1.6 mg/dL (P < 0.001) and Δ HbA_1c was ±0% (P = 0.6). In women, Δ FPG was +3.0 mg/dL (P < 0.001), and Δ HbA_1c was +0.1% (P < 0.001). Δ Homeostasis model assessment of β-cell function was −6.6 in men (P < 0.001) and −10.3 in women (P < 0.001). The homeostasis model assessment of insulin resistance did not change significantly.

Conclusions

The “glycemic set point” has increased in non-diabetic people in Japan during recent years. Lifestyle or environmental changes may have caused this metabolic shift through obesity-independent pathways, possibly through effects on pancreatic β-cell function. The underlying mechanism awaits further investigation.

β-cell mass in people with type 2 diabetes

The early occurrence of β‐cell dysfunction has been broadly recognized as a critical determinant of the development and progression of type 2 diabetes. β‐cell dysfunction might be induced by insufficient β‐cell mass, by a dysfunction of the β‐cells, or both. Whether or not β‐cell dysfunction constitutes a cause of reduced β‐cells or vice‐versa currently remains unclear. The results of some studies have measured the loss of β‐cells in type 2 diabetic patients at between 22 and 63% by planimetric measurements. Because β‐cell hypertrophy has been noted in type 2 diabetic patients, the loss of β‐cell number should prove more profound than what has thus far been reported. Furthermore, β‐cell volumes are reduced even in patients with impaired fasting glucose. Such defects in β‐cell mass are associated with increased apoptosis rather than insufficient replication or neogenesis of β‐cells. With these results, although they still require clarification, the peak β‐cell mass might be determined at quite an early stage of life, and then might decline progressively over time as the result of exposure to harmful environmental influences over one’s lifetime. In this review, we have summarized the relevant studies regarding β‐cell mass in patients with type 2 diabetes, and then presented a review of the various causes of β‐cell loss in adults. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2010.00072.x, 2010)

Homeostatic model assessment indices in evaluation of insulin resistance and secretion in hemodialysis patients

Background

Some previous observations suggest that insulin resistance and glucose metabolism disturbances are frequent complications of chronic kidney disease. However, there are no conclusive studies on other indices of the effectiveness of insulin action in end-stage renal disease (ESRD) patients, including chronically hemodialysed (HD) ones.

Material/Methods

The groups comprised 33 non-diabetic ESRD hemodialysed patients and 33 healthy controls matched for age, sex, and body mass index (BMI). In both groups, HOMA-%B, HOMA-%S, HOMA-IR indices, and DI were calculated using HOMA1 and HOMA2 as measures of insulin resistance. The indices were also assessed in subgroups divided according to BMI.

Results

Mean fasting plasma glucose concentrations were lower in ESRD patients than in healthy persons (82.4±10.4 vs. 93.9±11.6, p=0.001). Fasting serum insulin concentrations were similar in both groups (median 6.8 vs. 6.0 mU/l, p=0.698). HOMA1-%B values were higher in ESRD patients than controls (median 137.1 vs. 81.6, p=0.002). HOMA1-%S (median 75.6 vs. 71.5) and HOMA1-IR (median 1.3 vs. 1.4) values were not significantly different (p=0.264 and p=0.189, respectively). DI1 levels were higher for HD patients than for healthy subjects (median 1.16 vs. 0.53, p<0.001). In subgroup analysis, all statistically significant differences were restricted mainly to persons with BMI <25 kg/m². Similar results as for the HOMA1 model were obtained for HOMA2.

Conclusions

1. HOMA beta-cell function is strongly correlated with HOMA insulin resistance in HD patients. 2. In non-diabetic ESRD hemodialysed patients, the HOMA indices and DI may be useful and important models in interpretation of glucose metabolism disturbances.

Beta-cell apoptosis in type 2 diabetes: quantitative and functional consequences

Type 2 diabetes, the most common form of diabetes in humans, is characterized by impaired insulin secretion paralleled by a progressive decline in beta-cell function and chronic insulin resistance. Several authors have showed that in type 2 diabetes there is a reduction of islet and/or insulin-containing cell mass or volume. Regulation of the beta-cell mass appears to involve a balance of beta-cell replication and apoptosis but, at the molecular level, pancreatic beta-cell loss by apoptosis appears to play an important role in the development of insulin deficiency and the onset and/or progression of the disease. The mechanisms favoring apoptosis in type 2 diabetic pancreatic islets and new potential therapeutic approaches to prevent beta-cell death and maintain beta-cell mass are discussed.