Impact of the Dynamic Change of Metabolic Health Status on the Incident Type 2 Diabetes: A Nationwide Population-Based Cohort Study

The prevalence of metabolically healthy obesity and its transition into the unhealthy state: A 5-year follow-up study

People with metabolically healthy obesity (MHO) are at risk of developing cardiometabolic diseases. We investigated the prevalence of MHO and factors influencing its transition into a metabolically unhealthy state (MUS). This study was conducted as part of the Kerman Coronary Artery Disease Risk Factor Study (KERCADRS). From 2014 to 2018, 9997 people were evaluated. The obesity and metabolic status of the MHO participants were re-examined after 5 years of their initial participation in the study. Out of 347 MHO, 238 individuals were accessed at follow-up. Twenty-nine (12.2%) had metabolic unhealthy normal weight (MUNW), 169 (71.0%) had metabolic unhealthy obesity (MUO), and the others had healthy metabolic state. Among age, total cholesterol, diastolic blood pressure and triglyceride (TG) variables, the baseline serum TG level was associated with a significant increase in the risk of developing MUS during 5 years (p <.05). The TG level optimal cut-off point for predicting the development into MUS was 107 mg/dL with 62.1% sensitivity and 77.5% specificity (AUC = 0.734, p <.001). A high percentage of MHO people transit into MUS during 5 years. A TG level higher than 107 mg/dL can help to identify people at a higher risk of developing into MUS.

Dynamic Changes in Metabolic Status Are Associated With Risk of Ocular Motor Cranial Nerve Palsies

BACKGROUND

To investigate whether recovery from or development of metabolic syndrome (MetS) in a population is associated with an altered risk for ocular motor cranial nerve palsy (CNP).

METHODS

This cohort study included 4,233,273 adults without a history of ocular motor cranial nerve palsy (ocular motor CNP) who underwent 2 consecutive biennial health screenings provided by the Korean National Health Insurance System between 2009 and 2011. They were followed up until December 31, 2018. Participants were categorized into a MetS-free, MetS-developed, MetS-recovered, or MetS-chronic group. A multivariable Cox proportional hazard regression model was used. Model 3 was adjusted for age, sex, smoking status, alcohol consumption, and physical activity.

RESULTS

Compared with the MetS-free group, the MetS-chronic group had the highest risk of ocular motor CNP (hazard ratio [HR]: 1.424; 95% confidential interval [CI]: 1.294-1.567, Model 3), followed by the MetS-developed group (HR: 1.198, 95% CI: 1.069-1.343), and the MetS-recovered group (HR: 1.168, 95% CI: 1.026-1.311) after adjusting for potential confounders. The hazard ratio of ocular motor CNP in men with chronic MetS was 1.566 (95% CI, 1.394-1.761) while that of women with chronic MetS was 1.191 (95% CI, 1.005-1.411). Among age groups, those in their 30s and 40s showed the highest association between dynamic MetS status and ocular motor CNP.

CONCLUSIONS

In our study, recovering from MetS was associated with a reduced risk of ocular motor CNP compared with chronic MetS, suggesting that ocular motor CNP risk could be managed by changing MetS status.

Metabolically healthy obese individuals are still at high risk for diabetes: Application of the marginal structural model

AIM

To assess the effect of obesity phenotype on the incidence of diabetes, considering phenotype as a time-varying exposure.

METHODS

We used community-based cohort data from the Korean Genome and Epidemiology Study, with a 16-year follow-up period. Obesity phenotype was determined using body mass index and metabolic syndrome criteria. The influence of obesity phenotype on the occurrence of diabetes was evaluated using a Cox proportional hazard model and a marginal structural model (MSM).

RESULTS

Obesity phenotypes were defined in 6265 individuals, with diabetes identified in 903 (14.4%) during the follow-up period. Individuals with metabolically healthy obesity (MHO) exhibited a higher risk of diabetes compared to those with metabolically healthy normal weight (MHNW), with a hazard ratio (HR) of 1.48 (95% confidence interval [CI] 1.15-1.90). This association remained significant after applying the MSM (HR 1.49, 95% CI 1.01-2.20). Moreover, various sensitivity analyses consistently demonstrated a higher risk of diabetes in individuals with MHO compared to those with MHNW.

CONCLUSIONS

Even when obesity phenotype was treated as a time-varying exposure, individuals with MHO were still at higher risk for developing diabetes than those with MHNW. Consequently, such individuals should aim to avoid transitioning to a metabolically unfavourable state and strive to reduce their body weight to a normal range.

From Metabolic Syndrome to Type 2 Diabetes in Youth

In the frame of metabolic syndrome, type 2 diabetes emerges along a continuum of the risk from the clustering of all its components, namely visceral obesity, high blood pressure and lipids, and impaired glucose homeostasis. Insulin resistance is the hallmark common to all the components and, in theory, is a reversible condition. Nevertheless, the load that this condition can exert on the β-cell function at the pubertal transition is such as to determine its rapid and irreversible deterioration leading to plain diabetes. The aim of this review is to highlight, in the context of metabolic syndrome, age-specific risk factors that lead to type 2 diabetes onset in youth; resume age specific screening and diagnostic criteria; and anticipate potential for treatment. Visceral obesity and altered lipid metabolism are robust grounds for the development of the disease. Genetic differences in susceptibility to hampered β-cell function in the setting of obesity and insulin resistance largely explain why some adolescents with obesity do develop diabetes at a young age and some others do not. Lifestyle intervention with a healthy diet and physical activity remains the pillar of the type 2 diabetes treatment in youth. As to the pharmacological management, metformin and insulin have failed to rescue β-cell function and to ensure long-lasting glycemic control in youth. A new era might start with the approval for use in pediatric age of drugs largely prescribed in adults, such as dipeptidyl peptidase-4 and sodium-dependent glucose transport inhibitors, and of new weight-lowering drugs in the pipeline such as single and multiple agonists of the glucagon-like peptide 1 receptor. The latter drugs can have tremendous impact on the natural history of the disease. By treating diabetes, they will reduce the burden of all the metabolic abnormalities belonging to the syndrome while causing a tremendous weight loss hitherto never seen before.

Association of anthropometric parameters as a risk factor for development of diabetic retinopathy in patients with diabetes mellitus

OBJECTIVE

To study the relationship of body fat distribution in patients with diabetes mellitus (DM), and its long-term complications like diabetic retinopathy (DR), in Indian population.

METHODS

This was a prospective, cross-sectional observational study involving 1773 subjects diagnosed with DM and 1778 age and gender-matched individuals. The patients with DM were assessed for the presence and severity of DR. Severe non-proliferative DR and proliferative DR were categorised as sight threatening DR (STDR). Anthropometric parameters, i.e., neck circumference (NC); mid-upper arm circumference (MAC); waist circumference (WC); hip circumference (HC); mid-thigh circumference (MTC) and body mass index (BMI) were measured using standardised technique.

RESULTS

The mean age was 59.33 ± 9.32 for DM group, and 66.03 ± 11.04 for non-DM group. DM group showed significantly greater NC, WC, and MTC and significantly reduced MAC and weight. HC and BMI were comparable between the groups. There was a significant positive correlation of MAC and WC (with any level of DR) and MAC, WC, and weight (for STDR); and a significant negative correlation of HC and MTC (with any level of DR) and NC, HC, MTC, and BMI (for STDR). Multiple logistic regression analysis confirmed that WC was the single most important predictor for any level of DR and STDR.

CONCLUSIONS

Association of body fat distribution with DM and DR appears multifactorial. However, central obesity signified by waist circumference appears to be the significant risk related to the development of DR and STDR in Indian population.

Obesity Metabolic Phenotype, Changes in Time and Risk of Diabetes Mellitus in an Observational Prospective Study on General Population

Objectives: To evaluate the distribution and changes in different obesity metabolic phenotypes, as well as their impact on the incidence of type 2 diabetes mellitus (T2DM) in a northwest Chinese population sample.

Methods: Data comes from prospective cohort study (n = 1,393, mean follow up = 9.46 years). Participants were classified into four groups through a combination of the Chinese Diabetes Society (CDS) diagnostic criteria for metabolic syndrome with anthropometric measurements: metabolically healthy normal weight (MHNW), metabolically healthy overweight/obese (MHO), metabolically unhealthy normal weight (MUNW), and metabolically unhealthy overweight/obese (MUO). Cox regression models with time-dependent covariates were used to evaluate changes in obesity metabolic phenotypes and risk of T2DM.

Results: Participants in MUO state had the highest risk of developing T2DM, the incidence density was 12.10/1,000 person-year. The MHO and MUO groups showed an increased risk of incident diabetes based on body mass index (BMI) (HR, 1.29; 95% CI, 1.03–1.61; p = 0.026 and HR, 1.20; 95% CI, 1.02–1.40; p = 0.024 respectively.) Besides, the MHO group had an increased risk of incident diabetes based on waist circumference (WC) (HR, 1.41; 95% CI, 1.10–1.80; p = 0.006).

Conclusion: Diabetes is more frequent in the MHO and MUO groups and co-occurrence of obesity and metabolic abnormalities (MA) contributes to the development of T2DM.

Metabolically obese phenotype and its dynamic change are associated with increased carotid intima-media thickness: Results from a cohort study

BACKGROUND AND AIMS

To examine associations between metabolically obese phenotypes or their changes and increased carotid intima-media thickness (CIMT).

METHODS AND RESULTS

This prospective cohort included 13,681 Chinese adults aged 20-80 years who completed follow-up health examination with carotid ultrasound and were divided according to metabolic and weight status: metabolically healthy and normal weight (MHNW); metabolically obese but normal weight (MONW); metabolically healthy but obese (MHO); metabolically abnormal and obese (MAO). Cox and logistic regression were used to evaluate the associations of the phenotypes or their changes with increased CIMT. During a mean follow-up of 33 months, 1927 participants developed increased CIMT. After adjusting for age, sex and potential biochemical confounders, MAO was significantly associated with increased CIMT (HR 1.22, 95% CI [1.07, 1.4]); the association remained significant in those 40 years or older. Compared with stable MHNW, increased CIMT risk was higher for stable MAO (OR 1.35 [1.16, 1.57]), transitional MAO from MONW (OR 1.44 [1.04, 1.97]), and transitional MHO from MHNW (OR 1.59 [1.10, 2.26]) in demographic adjusted models; only stable MAO remained significant in the multivariate adjusted model (OR 1.23 [1.05, 1.45]).

CONCLUSION

MAO significantly elevated the risk of increased CIMT. Stable MAO and obese transitions also promoted CIMT progression.

Metabolically healthy obesity: Is it really healthy for type 2 diabetes mellitus?

Metabolically healthy obese (MHO) individuals are reported to have a lower risk of developing cardiovascular diseases in comparison with individuals with metabolic syndrome. However, the association between MHO and type 2 diabetes (T2DM) is still controversial. Some studies indicated that MHO is a favorable phenotype for T2DM, but more studies showed that MHO individuals have an increased risk of developing T2DM compared with metabolically healthy normal-weight individuals, especially among those who would acquire metabolically unhealthy obesity. This has been supported by finding insulin resistance and low-grade inflammatory responses in MHO individuals with a tendency for impaired beta-cell dysfunction. Studies also showed that liver fat accumulation increased the risk of incidence of T2DM in MHO. Here, we reviewed current literature on the relationship between MHO and T2DM, discussed the determinants for the development of diabetes in MHO, and summarized the measures for the prevention of T2DM in MHO.

New metabolic health definition might not be a reliable predictor for diabetes in the nonobese Chinese population

AIM

To investigate the predictive values of the new metabolic health (MH) definition for future diabetes in a nonobese Chinese population, compared with the MH definition from metabolic syndrome (MetS).

METHODS

The data were collected in 1992 and then again in 2007 from the same group of 653 participants. The risk assessment of the new MH definition and the MH definition from MetS for future diabetes was performed by Cox regression analysis with overlap weighting as the primary analysis.

RESULTS

During the follow-up, 62 participants were diagnosed with diabetes. In the primary analysis with overlap weighting, there was no significant association between new MH and diabetes (HR: 1.12; 95% CI: 0.45-2.78, p = 0.803); conversely, based on the MH definition from MetS, the participants with MH were less likely to have had diabetes than the participants with MUHs (HR: 0.41; 95% CI: 0.22-0.78, p = 0.007). Furthermore, other analysis methods also confirmed the reproducibility of abovementioned results. In addition, sensitivity analysis excluding participants with prediabetes also demonstrated similar results with the primary analysis.

CONCLUSION

In contrast to the previous MH definition from MetS, the new MH definition was not a reliable predictor for future diabetes in the nonobese Chinese population.

Implications of metabolic health status and obesity on the risk of kidney cancer: A nationwide population-based cohort study

PURPOSE

This study evaluated the association between metabolic health status and incident kidney cancer among obese participants.

MATERIALS AND METHODS

A total of 514,866 individuals were included from the Korean National Health Insurance Service-National Health Screening Cohort. Changes in metabolic health status and obesity from the baseline examination in 2009-2010 to the next biannual examination in 2011-2012 were determined. Based on the status change, obese participants were divided into four groups: stable metabolically healthy obesity, metabolically healthy obesity to metabolically unhealthy obesity, metabolically unhealthy obesity to metabolically healthy obesity, and stable metabolically unhealthy obesity.

RESULTS

The stable metabolically healthy obesity phenotype did not confer an increased risk of incident kidney cancer, compared to the stable metabolically healthy non-obese group. In contrast, the metabolically healthy obesity to metabolically unhealthy obesity group had a significantly higher risk of incident kidney cancer than the stable metabolically healthy non-obese group. Among patients with metabolically unhealthy obesity at baseline, those who transitioned to the metabolically healthy obese group had no increased risk of kidney cancer, whereas those who remained in metabolically unhealthy obesity status had a higher risk of incident kidney cancer than the stable metabolically healthy non-obese group. The transition or maintenance of metabolic health was a decisive factor for kidney cancer in obese patients.

CONCLUSIONS

Maintaining or restoring metabolic health should be stressed upon in obese patients to reduce the risk of kidney cancer.

The risk of Alzheimer's disease according to dynamic changes in metabolic health and obesity: a nationwide population-based cohort study

We evaluated the association of metabolic health and obesity phenotypes with the risk of Alzheimer's disease (AD). This study enrolled 136,847 elderly participants aged 60 or above from the Korean National Health Insurance System. At baseline examinations in 2009 and 2010, subjects were categorized into four groups: the metabolically healthy non-obese (MHNO), metabolically healthy obese (MHO), metabolically unhealthy non-obese (MUNO), and metabolically unhealthy obese (MUO) groups. Based on the phenotypic transition after 2 years, the subjects were further categorized into 16 subgroups. They were followed from 2009 to 2015 to monitor for AD development. The MHO phenotype protected subjects from AD, relative to the MHNO phenotype (HR, 0.73; 95% CI, 0.65-0.81). Among subjects initially classified as MHO, 41.8% remained MHO, with a significantly lower risk of AD compared with the stable MHNO group (HR, 0.62; 95% CI, 0.50-0.77). Among MUO subjects at baseline, those who changed phenotype to MUNO were at higher risk of AD (HR, 1.47; 95% CI, 1.28-1.70), and the transition to the MHO phenotype protected subjects from AD (HR, 0.62; 95% CI, 0.50-0.78). The MHO phenotype conferred a decreased risk of AD. Maintenance or recovery of metabolic health might mitigate AD risk among obese individuals.

Excessive Intake of High-Fructose Corn Syrup Drinks Induces Impaired Glucose Tolerance

The number of patients with diabetes was approximately 463 million worldwide in 2019, with almost 57.6% of this population concentrated in Asia. Asians often develop type 2 diabetes (T2D), even if they are underweight and consume a smaller amount of food. Soft drinks contain large amounts of sweeteners, such as high-fructose corn syrup (HFCS). Excessive intake of HFCS drinks is considered to be one of the causes of T2D. In the present study, we investigated the effect of excessive consumption of HFCS-water on glucose tolerance and obesity under conditions of controlled caloric intake using a mouse model. Three-week-old male ICR mice were divided into two groups and given free access to 10% HFCS-water or deionized water. The caloric intake was adjusted to be the same in both groups using a standard rodent diet. The excess HFCS-water intake did not lead to obesity, but led to impaired glucose tolerance (IGT) due to insulin-secretion defect. It affected glucose and fructose metabolism; for example, it decreased the expression of glucokinases, ketohexokinase, and glucose transporter 2 in the pancreas. These results suggest that excessive consumption of HFCS drinks, such as soft drinks, without a proper diet, induces nonobese IGT due to insulin-secretion defect.

Cumulative Exposure to Metabolic Syndrome Components and the Risk of Dementia: A Nationwide Population-Based Study

BACKGROUND

Metabolic disturbances are modifiable risk factors for dementia. Because the status of metabolic syndrome (MetS) and its components changes over time, we aimed to investigate the association of the cumulative exposure to MetS and its components with the risk of dementia.

METHODS

Adults (n=1,492,776; ≥45-years-old) who received health examinations for 4 consecutive years were identified from a nationwide population-based cohort in Korea. Two exposure-weighted scores were calculated: cumulative number of MetS diagnoses (MetS exposure score, range of 0 to 4) and the composite of its five components (MetS component exposure score, range of 0 to 20). Hazard ratio (HR) and 95% confidence interval (CI) values for dementia were analyzed using the multivariable Cox proportional-hazards model.

RESULTS

Overall, 47.1% of subjects were diagnosed with MetS at least once, and 11.5% had persistent MetS. During the mean 5.2 years of follow-up, there were 7,341 cases (0.5%) of incident dementia. There was a stepwise increase in the risk of all-cause dementia, Alzheimer's disease, and vascular dementia with increasing MetS exposure score and MetS component exposure score (each P for trend <0.0001). The HR of all-cause dementia was 2.62 (95% CI, 1.87 to 3.68) in subjects with a MetS component exposure score of 20 compared with those with a score of 0. People fulfilling only one MetS component out of 20 already had an approximately 40% increased risk of all-cause dementia and Alzheimer's disease.

CONCLUSION

More cumulative exposure to metabolic disturbances was associated with a higher risk of dementia. Of note, even minimal exposure to MetS components had a significant effect on the risk of dementia.

Metabolic health is a determining factor for incident colorectal cancer in the obese population: A nationwide population-based cohort study

Background

The association of the risk of colorectal cancer (CRC) with obesity or obesity‐induced metabolic disturbances remains controversial. We assessed the association of metabolic health status with incident CRC among subjects with obesity.

Methods

This study included 319,397 subjects from the Korean National Health Insurance Service‐National Health Screening Cohort. Transitions in metabolic health status and obesity were examined during 2009–2010 and 2011–2012. We categorized subjects with obesity into four separate groups according to their dynamic metabolic health status: metabolically healthy obesity (MHO), MHO to metabolically unhealthy obesity (MUO), MUO to MHO, and stable MUO. Subjects were followed up from 2009 to 2015 for incident CRC.

Results

The stable MHO group showed no increased risk of incident CRC (hazard ratio [HR], 0.97; 95% confidence interval [CI], 0.83–1.14). However, the MHO to MUO group had a higher risk of incident CRC than the stable metabolically healthy nonobese (MHNO) group (HR, 1.34; 95% CI, 1.15–1.57). Among patients with MUO at baseline, those in the subgroup who transitioned to MHO group were not at increased risk of CRC (HR, 1.06; 95% CI, 0.91–1.25), whereas those who remained in the stable MUO group had a higher risk of incident CRC than those in the stable MHNO group (HR, 1.29; 95% CI, 1.19–1.41).

Conclusions

The transition of metabolic health was a determining factor for CRC among subjects with obesity. Hence, maintenance or recovery of metabolic health should be addressed to prevent CRC in individuals with obesity.

Prepregnancy smoking and the risk of gestational diabetes requiring insulin therapy

The relationship between maternal smoking and gestational diabetes mellitus (GDM) is inconclusive. We investigated whether prepregnancy smoking is a risk factor for insulin-requiring GDM in Korean women. Using the National Health Insurance Service database, 325,297 women who delivered between 2011 and 2015 and who received a health examination within 52 weeks before pregnancy were included. Insulin-requiring GDM was defined as no claims for diabetes mellitus and a fasting blood glucose level of < 126 mg/dL before pregnancy, and initiation of insulin treatment during pregnancy. Smoking status was identified in a self-reported questionnaire completed during the health examination. There were 2,114 women (0.65%) with GDM who required insulin therapy. Compared with nonsmokers, the fully adjusted odd ratios (ORs) of former smokers and current smokers for insulin-requiring GDM were 1.55 (95% confidence interval [CI] 1.27–1.90) and 1.73 (1.42–2.09), respectively. The ORs (95% CIs) of insulin-requiring GDM among women who reported ≤ 2, 2–≤ 4, 4–≤ 6, 6–≤ 8, 8–≤ 10, and > 10 pack-years of smoking were 1.50 (1.22–1.84), 1.71 (1.31–2.22), 1.60 (1.13–2.26), 1.97 (1.14–3.40), 2.34 (1.22–4.51), and 2.29 (1.25–4.22), respectively, compared with nonsmokers (P for trend < 0.001). This association was similar in women with or without obesity and abdominal obesity. In conclusions, women who smoke have a significantly higher risk of GDM requiring insulin therapy, which may be proportional to the cumulative exposure to smoking. Cessation of smoking should be emphasized in women of childbearing age for the prevention of GDM.

Exploring Therapeutic Targets to Reverse or Prevent the Transition from Metabolically Healthy to Unhealthy Obesity

The prevalence of obesity and obesity-related metabolic comorbidities are rapidly increasing worldwide, placing a huge economic burden on health systems. Excessive nutrient supply combined with reduced physical exercise results in positive energy balance that promotes adipose tissue expansion. However, the metabolic response and pattern of fat accumulation is variable, depending on the individual’s genetic and acquired susceptibility factors. Some develop metabolically healthy obesity (MHO) and are resistant to obesity-associated metabolic diseases for some time, whereas others readily develop metabolically unhealthy obesity (MUO). An unhealthy response to excess fat accumulation could be due to susceptibility intrinsic factors (e.g., increased likelihood of dedifferentiation and/or inflammation), or by pathogenic drivers extrinsic to the adipose tissue (e.g., hyperinsulinemia), or a combination of both. This review outlines the major transcriptional factors and genes associated with adipogenesis and regulation of adipose tissue homeostasis and describes which of these are disrupted in MUO compared to MHO individuals. It also examines the potential role of pathogenic insulin hypersecretion as an extrinsic factor capable of driving the changes in adipose tissue which cause transition from MHO to MUO. On this basis, therapeutic approaches currently available and emerging to prevent and reverse the transition from MHO to MUO transition are reviewed.

Physiological and Lifestyle Traits of Metabolic Dysfunction in the Absence of Obesity

PURPOSE OF REVIEW

Individuals with metabolically unhealthy normal weight (MUNW) have an adverse cardiometabolic risk factor profile in the absence of excess body weight, and increased risk for diabetes and heart disease. We critically review some physiological traits and lifestyle characteristics of the MUNW phenotype.

RECENT FINDINGS

The prevalence of MUNW varies considerably around the world and among ethnicities, partly because of different definitions; on average, this phenotype affects about ~ 30% of normal weight persons globally. Most studies have recruited MUNW subjects who, although within the normal weight range, are significantly "more obese" than their metabolically healthy lean peers (greater body mass index or total body fat); hence one cannot ascertain whether observed differences are true traits of the MUNW phenotype of simply secondary to greater relative adiposity within the normal range. Carefully matched studies have indicated that MUNW can exist in the absence of excess total body fat. These subjects have a preferential accumulation of fat in the upper body (abdominal subcutaneous and visceral adipose tissues) and the liver, but not skeletal muscle; perhaps surprisingly, this predominantly "android" fat distribution does not translate into increased waist circumference. The MUNW phenotype is associated with lower aerobic fitness and muscle mass and strength, but whether this is simply due to inadequate regular physical activity is not entirely clear. Likewise, no consistent associations have been found between any dietary factors and the development of MUNW phenotype, but diet-induced modest weight loss facilitates its resolution. Delineating the mechanisms leading to metabolic dysfunction in the absence of increased body weight and body fat will likely reveal important targets for improving metabolic health and eventually for reducing the burden of cardiometabolic disease, not only in individuals with normal body weight but also in people with obesity.