Insulin Resistance and β-Cell Function of Lean versus Overweight or Obese Filipino Patients with Newly Diagnosed Type 2 Diabetes Mellitus

Comparison of β-Cell Function and Insulin Sensitivity Between Normal-Weight and Obese Chinese With Young-Onset Type 2 Diabetes

Normal-weight individuals with usual-onset type 2 diabetes have reduced β-cell function and greater insulin sensitivity compared with their obese counterparts. The relative contribution of β-cell dysfunction and insulin resistance to young-onset type 2 diabetes (YOD) among normal-weight individuals is not well established. In 44 individuals with YOD (24 with normal weight and 20 with obesity) and 24 healthy control individuals with normoglycemia (12 with normal weight and 12 with obesity), we conducted 2-h 12 mmol/L hyperglycemic clamps to measure acute (0-10 min) and steady-state (100-120 min) insulin and C-peptide responses, as well as insulin sensitivity index. Normal-weight individuals with YOD had lower acute insulin response, steady-state insulin and C-peptide responses, and a higher insulin sensitivity index compared with their obese counterparts with YOD. Compared with BMI-matched healthy control individuals, normal-weight individuals with YOD had lower acute and steady-state insulin and C-peptide responses but a similar insulin sensitivity index. The impairment of steady-state β-cell response relative to healthy control individuals was more pronounced in normal-weight versus obese individuals with YOD. In conclusion, normal-weight Chinese with YOD exhibited worse β-cell function but preserved insulin sensitivity relative to obese individuals with YOD and BMI-matched healthy individuals with normoglycemia. The selection of glucose-lowering therapy should account for pathophysiological differences underlying YOD between normal-weight and obese individuals.

ARTICLE HIGHLIGHTS

Mean age and body mass index at type 2 diabetes diagnosis: Pooled analysis of 56 health surveys across income groups and world regions

BACKGROUND

Screening for type 2 diabetes mellitus (T2DM) targets people aged 35+ years and those with overweight/obesity. With mounting evidence on young-onset T2DM and T2DM patients with lean phenotypes, it is worth revising the screening criteria to include younger and leaner adults. We quantified the mean age and body mass index (BMI; kg/m2 ) at T2DM diagnosis in 56 countries.

METHODS

Descriptive cross-sectional analysis of WHO STEPS surveys. We analysed adults (25-69 years) with new T2DM diagnosis (not necessarily T2DM onset) as per fasting plasma glucose ≥126 mg/dL measured during the survey. For people with new T2DM diagnosis, we summarized the mean age and the proportion of each five-year age group; also, we summarized the mean BMI and the proportion of mutually exclusive BMI categories.

RESULTS

There were 8695 new T2DM patients. Overall, the mean age at T2DM diagnosis was 45.1 years in men and 45.0 years in women; and the mean BMI at T2DM diagnosis was 25.2 in men and 26.9 in women. Overall, in men, 10.3% were 25-29 years and 8.5% were 30-34 years old; in women, 8.6% and 12.5% were 25-29 years and 30-34 years old, respectively. 48.5% of men and 37.3% of women were in the normal BMI category.

CONCLUSIONS

A non-negligible proportion of new T2DM patients were younger than 35 years. Many new T2DM patients were in the normal weight range. Guidelines for T2DM screening may consider revising the age and BMI criteria to incorporate young and lean adults.

Trajectories of fasting glucose and glycated haemoglobin in obese and non-obese incident diabetes: Results from two large cohort studies

AIMS

Diabetes development mechanisms vary by weight status. We aimed to compare cardiometabolic risk and characterize fasting plasma glucose (FPG) and glycated haemoglobin (HbA1c) trajectories before diagnosing type 2 diabetes in individuals with/without obesity.

METHODS

Data from the China Health and Retirement Longitudinal Study (CHARLS) and English Longitudinal Study of Ageing (ELSA) were analysed. Participants without diabetes and with a body mass index of 18.5-40 kg/m2 at baseline were included. Incident diabetes was ascertained by self-reported physician diagnosis and/or antidiabetic drug use, FPG ≥126 mg/dl and/or HbA1c ≥6.5%. The difference in the FPG/HbA1c trajectory before the diabetes diagnosis in participants with/without obesity was examined using mixed-effects models.

RESULTS

Among 11 925 eligible participants, 1361 incident diabetes cases (mean age: 61.4 years; male: 46.2%) were identified within 15 years of follow-up. Obese diabetes showed higher levels of diastolic blood pressure and C-reactive protein at diagnosis than non-obese diabetes. Mixed-effects models indicated the difference in the FPG trajectory before diagnosis by weight status was non-significant with a slope difference of 0.149 mg/dl (SE = 0.642, p = .816, CHARLS) and 0.013 mg/dl (SE = 0.013, p = .337, ELSA). However, obese diabetes showed a steep increase in HbA1c before diagnosis with a slope difference of 0.036% (SE = 0.016, p = .021) in the CHARLS and 0.032% (SE = 0.014, p = .027) in the ELSA, respectively. Sex-stratified analyses showed that the difference in HbA1c trajectory before the diabetes diagnosis by weight status was only significant in males.

CONCLUSIONS

Obese and non-obese diabetes developments may share a similar FPG but distinct HbA1c trajectory. Obese diabetes interventions require more attention to cardiometabolic risks. Moreover, studies addressing weight/sex-related differences in diabetes aetiologies and treatments are warranted.

Current Knowledge on the Pathophysiology of Lean/Normal-Weight Type 2 Diabetes

Since early times, being overweight and obesity have been associated with impaired glucose metabolism and type 2 diabetes (T2D). Similarly, a less frequent adult-onset diabetes in low body mass index (BMI) people has been known for many decades. This form is mainly found in developing countries, whereby the largest increase in diabetes incidence is expected in coming years. The number of non-obese patients with T2D is also on the rise among non-white ethnic minorities living in high-income Western countries due to growing migratory flows. A great deal of energy has been spent on understanding the mechanisms that bind obesity to T2D. Conversely, the pathophysiologic features and factors driving the risk of T2D development in non-obese people are still much debated. To reduce the global burden of diabetes, we need to understand why not all obese people develop T2D and not all those with T2D are obese. Moreover, through both an effective prevention and the implementation of an individualized clinical management in all people with diabetes, it is hoped that this will help to reduce this global burden. The purpose of this review is to take stock of current knowledge about the pathophysiology of diabetes not associated to obesity and to highlight which aspects are worthy of future studies.

Dietary protein and the glycemic index handle insulin resistance within a nutritional program for avoiding weight regain after energy-restricted induced weight loss

Background and aim

The role of dietary protein and glycemic index on insulin resistance (based on TyG index) within a nutritional program for weight loss and weight maintenance was examined.

Methods

This study analyzed 744 adults with overweight/obesity within the DIOGenes project. Patients who lost at least 8% of their initial weight (0–8 weeks) after a low-calorie diet (LCD) were randomly assigned to one of five ad libitum diets designed for weight maintenance (8–34 weeks): high/low protein (HP/LP) and high/low glycemic index (HGI/LGI), plus a control. The complete nutritional program (0–34 weeks) included both LCD plus the randomized diets intervention. The TyG index was tested as marker of body mass composition and insulin resistance.

Results

In comparison with the LP/HGI diet, the HP/LGI diet induced a greater BMI loss (p < 0.05). ∆TyG was positively associated with resistance to BMI loss (β = 0.343, p = 0.042) during the weight maintenance stage. In patients who followed the HP/LGI diet, TyG (after LCD) correlated with greater BMI loss in the 8–34 weeks period (r = −0.256; p < 0.05) and during the 0–34 weeks intervention (r = −0.222, p < 0.05) periods. ΔTyG₁ value was associated with ΔBMI₂ (β = 0.932; p = 0.045) concerning the HP/LGI diet.

Conclusions

A HP/LGI diet is beneficial not only for weight maintenance after a LCD, but is also related to IR amelioration as assessed by TyG index changes. Registration Clinical Trials NCT00390637.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12986-022-00707-y.

The protective effect of hydrogen-rich water on rats with type 2 diabetes mellitus

The hydrogen-rich water (HW) has been reported to possess a beneficial role in patients with diabetes. However, a systemic evaluation with an appropriate animal model is necessary to reveal its mechanisms and efficacy. Herein, the protective effects of drinking HW on lipid and glucose metabolism, oxidative stress, and inflammation in type 2 diabetes mellitus (T2DM) rats were investigated. The well-modeled T2DM rats (induced by high-fat diet combined with low-dose streptozotocin (STZ) injection) were divided into two groups (n ≥ 15 of each): fed a high-fat diet and drinking distilled water or HW at a constant concentration above 1.0 ppm; normal rats were used as control group (n ≥ 10): fed a regular diet and drinking distilled water. Several biomarkers of lipid and glucose metabolism, oxidative stress ,and inflammation were evaluated after drinking distilled water or HW for 3 weeks. The effect of HW on liver, kidney, and spleen of T2DM rats was also analyzed by HE and Oil Red O staining. The results showed that drinking HW suppressed the increase in glucose, total cholesterol, oxidative stress, and inflammation. Moreover, HW also ameliorates hyperglycemia-induced liver, kidney, and spleen dysfunction. Overall, this study indicates that patients with T2DM may be able to improve their condition by supplementing HW as daily drinking water.