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

Characterization of metabolic alterations in the lean metabolically unhealthy alpha defensin transgenic mice

Inflammation is consistently linked to dysmetabolism. In transgenic mice (Def+/+) model the neutrophilic peptide, alpha defensin, proved atherogenic. This phenotype occurred despite favorable cholesterol and glucose levels, and lower body weight and blood pressure. In this study, integration of metabolic&behavioral phenotyping system, endocrine, biochemical and mitochondrial assessment, pathological and immunohistochemical tests, and multiple challenge tests was established to explore the metabolic impact of alpha defensin. Compared to the control group, Def+/+ mice exhibited lower total energy expenditure and carbohydrate utilization, and higher fat oxidation. Their ACTH-cortisol and thyroid profiles were intact. Intriguingly, they had low levels of glucagon, with high ammonia, uric acid, triglyceride, and lactate. Mitochondrial evaluations were normal. Overall, defensin-induced hypoglucagonemia is associated with lipolysis, restricted glucose oxidation, and enhanced wasting. Def+/+ mice may be a useful model for studying the category of lean, apparently metabolically healthy, and atherosclerotic phenotype, with insight into a potential inflammatory-metabolic link.

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.

Metabolically healthy obesity is associated with higher risk of both hyperfiltration and mildly reduced estimated glomerular filtration rate: the role of serum uric acid in a cross-sectional study

BACKGROUND

The impact of metabolically healthy obesity (MHO) on kidney dysfunction remains debatable. Moreover, few studies have focused on the early stages of kidney dysfunction indicated by hyperfiltration and mildly reduced eGFR. Thus, we aimed to investigate the association between the MHO and early kidney dysfunction, which is represented by hyperfiltration and mildly reduced estimated glomerular filtration rate (eGFR), and to further explore whether serum uric acid affects this association.

METHODS

This cross-sectional study enrolled 1188 residents aged ≥ 40 years old from Yonghong Communities. Metabolically healthy phenotypes were categorized based on Adult Treatment Panel III criteria. Obesity was defined as body mass index (BMI) ≥ 25 kg/m². Mildly reduced eGFR was defined as being in the range 60 < eGFR ≤ 90 ml/min/1.73m². Hyperfiltration was defined as eGFR > 95th percentile after adjusting for sex, age, weight, and height.

RESULTS

Overall, MHO accounted for 12.8% of total participants and 24.6% of obese participants. Compared to metabolically healthy non-obesity (MHNO), MHO was significantly associated with an increased risk of mildly reduced eGFR (odds ratio [OR] = 1.85, 95% confidence interval [CI]  1.13-3.01) and hyperfiltration (OR = 2.28, 95% CI 1.03-5.09). However, upon further adjusting for uric acid, the association between the MHO phenotype and mildly reduced eGFR was reduced to null. Compared with MHNO/non-hyperuricemia, MHO/non-hyperuricemia was associated with an increased risk of mildly reduced eGFR (OR = 2.04, 95% CI  1.17-3.58), whereas MHO/hyperuricemia was associated with an observably increased risk (OR = 3.07, 95% CI  1.34-7.01).

CONCLUSIONS

MHO was associated with an increased risk of early kidney dysfunction, and the serum uric acid partially mediated this association. Further prospective studies are warranted to clarify the causality.

Association between metabolic obesity phenotype, transition of metabolic phenotypes and the risk of hyperuricemia in Chinese adults: A cohort study

Prospective evidence on the association of obesity and metabolic health status and its transition over time with the risk of hyperuricemia in the Chinese population is limited. This study aims to investigate the phenotypic transition characteristics of metabolic obesity in Chinese adults and its association with hyperuricemia. Using the China Health and Retirement Longitudinal Survey (CHARLS) survey data in 2011 and 2015, 6059 adults aged ≥ 18 years were selected as the research people. The participants' general information, living habits, blood sample testing, and blood uric acid testing data during follow-up were extracted. According to body weight and metabolic health status, obesity phenotypes were divided into: metabolically normal weight group (MHNW), metabolically normal overweight/obesity group (MHOWO); metabolically abnormal normal weight group (MUNW); metabolically abnormal overweight/obese group (MUHOWO). Multiple linear regression was used to evaluate the correlation between metabolic obesity phenotype and serum uric acid level, and logistic regression model was used to analyze the association of metabolic obesity phenotype and transition with the risk of hyperuricemia. The average age of all subjects was (58.62 ± 8.93) years old, and 42.1% were male. The MHOWO phenotype was present in 19.2% of the general population and 48.6% of the baseline who were overweight or obese population. During the 4-year follow-up period, only 10.7% of participants with MHNW at baseline converted to MHOWO. Among MHOWO participants, 21.2% converted to MUHOWO. MHOWO also increased the risk of hyperuricemia (OR, 1.57; 95% CI 1.15-2.13; P = .004), both in obese and normal-weight individuals, even when metabolic status changed from unhealthy to healthy. Risk of hyperuricemia was high among those who remained metabolically unhealthy but of normal weight (OR, 3.09; 95% CI 1.51-6.30; P = .001). MHOWO also increases the risk of hyperuricemia, and MHOWO remains stable or changes to MUHOWO, which increases the risk of hyperuricemia. Therefore, close attention should be paid to the transition of metabolic health status over time, and individualized prevention strategies should be focused on metabolically unhealthy and obese individuals.

Abdominal obesity phenotypes are associated with the risk of developing non-alcoholic fatty liver disease: insights from the general population

Background

The diversity of obesity-related metabolic characteristics generates different obesity phenotypes and corresponding metabolic diseases. This study aims to explore the correlation of different abdominal obesity phenotypes with non-alcoholic fatty liver disease (NAFLD).

Methods

The current study included 14,251 subjects, 7411 males and 6840 females. Abdominal obesity was defined as waist circumference ≥ 85 cm in males and ≥ 80 cm in females; according to the diagnostic criteria for metabolic syndrome recommended by the National Cholesterol Education Program Adult Treatment Panel III, having more than one metabolic abnormality (except waist circumference criteria) was defined as metabolically unhealthy. All subjects were divided into 4 abdominal obesity phenotypes based on the presence ( +) or absence (− ) of metabolically healthy/unhealthy (MH) and abdominal obesity (AO) at baseline: metabolically healthy + non-abdominal obesity (MH⁻AO⁻); metabolically healthy + abdominal obesity (MH⁻AO⁺); metabolically unhealthy + non-abdominal obesity (MH⁺AO⁻); metabolically unhealthy + abdominal obesity (MH⁺AO⁺). The relationship between each phenotype and NAFLD was analyzed using multivariate logistic regression.

Results

A total of 2507 (17.59%) subjects in this study were diagnosed with NAFLD. The prevalence rates of NAFLD in female subjects with MH⁻AO⁻, MH⁻AO⁺, MH⁺AO⁻, and MH⁺AO⁺ phenotypes were 1.73%, 24.42%, 7.60%, and 59.35%, respectively. Among male subjects with MH⁻AO⁻, MH⁻AO⁺, MH⁺AO⁻, and MH⁺AO⁺ phenotypes, the prevalence rates were 9.93%, 50.54%, 25.49%, and 73.22%, respectively. After fully adjusting for confounding factors, with the MH⁻AO⁻ phenotype as the reference phenotype, male MH⁻AO⁺ and MH⁺AO⁺ phenotypes increased the risk of NAFLD by 42% and 47%, respectively (MH⁻AO⁺: OR 1.42, 95%CI 1.13,1.78; MH⁺AO⁺: OR 1.47, 95%CI 1.08,2.01); the corresponding risks of MH⁻AO⁺ and MH⁺AO⁺ in females increased by 113% and 134%, respectively (MH⁻AO⁺: OR 2.13, 95%CI 1.47,3.09; MH⁺AO⁺: OR 2.34, 95%CI 1.32,4.17); by contrast, there was no significant increase in the risk of NAFLD in the MH⁺AO⁻ phenotype in both sexes.

Conclusions

This first report on the relationship of abdominal obesity phenotypes with NAFLD showed that both MH⁻AO⁺ and MH⁺AO⁺ phenotypes were associated with a higher risk of NAFLD, especially in the female population. These data provided a new reference for the screening and prevention of NAFLD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02393-9.