Prevalence and cardiometabolic risks of normal weight obesity in Chinese population: A nationwide study

Association between normal weight obesity and comorbidities and events of cardiovascular diseases among adults in South China

BACKGROUND

The increased risks for cardiovascular comorbidities and cardiovascular diseases (CVD) in populations with normal weight obesity (NWO) have not been well-identified. We aimed to study their associations in an adult population in South China.

METHODS

Based on the CVD prevalence of 4% in Shenzhen and a calculated sample size of 6,000, a cross-sectional study with a multi-stage stratified cluster sampling method was conducted in Shenzhen City. The cardiovascular comorbidities being studied were abdominal obesity (AO), diabetes, hypertension, dyslipidemia, metabolic syndrome, and chronic kidney disease, while the CVD events were occurrences of myocardial infarction and strokes. Questionnaire surveys, physical examinations, and laboratory tests were performed. NWO was defined as a condition with the highest tertile of body fat percentage (BF%) among the normal body mass index (BMI) range (18.5-23.9 kg/m2). Continuous data were reported as mean [standard deviation (SD)] and categorical data as percentages (%). CVD comorbidities and CVD events and their detection rates in different groups were compared using ANONA analysis and Chi-squared test. Spearman's correlation coefficients between BF% and cardiometabolic abnormalities were calculated by partial correlation analysis. Multivariate logistic regression models were used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) for BF%, CVD comorbidities, and CVD events, adjusted for multiple confounders.

RESULTS

Among the total 6,240 subjects who completed the study and had BMI and BF% data available, 3,086 had normal BMI. The prevalence of NWO was 16.36%, with 13.15% for men and 19.54% for women. With confounders adjusted, the risks of AO (OR = 6.05, 95%CI = 3.40-10.75), essential hypertension (OR = 1.56, 95%CI = 1.09-2.22), dyslipidemia (OR = 1.85, 95%CI = 1.49-2.29), and metabolic syndrome (OR = 4.61, 95%CI = 2.32-9.18) were significantly increased in the populations with NWO compared with the population without NWO (P < 0.05). BF% was not significantly associated with the risk of CVD events in the total (OR = 1.56, 95%CI = 0.83-2.93), male (OR = 1.00, 95%CI = 0.44-2.30), and female populations (OR = 2.53, 95%CI = 0.91-7.06).

CONCLUSION

NWO was found to be positively associated with CVD comorbidities but not with CVD events. The current study provides a ground to conduct further studies on whether body fat affects the risk of occurrence of CVD events and the underlying mechanisms in the future.

Normal Weight Central Obesity and its Impact on Type 2 Diabetes Mellitus

PURPOSE OF REVIEW

The aim of this review is to provide an updated commentary on the current literature examining the impact of normal weight obesity (NWO) and normal weight central obesity (NWCO) on type 2 diabetes mellitus in adults.

RECENT FINDINGS

Total 14 studies were included, comprising 9 cross-sectional and 5 cohort studies with 334,438 subjects. The quality of evidence was mixed. The pooled prevalence of NWO was 16.1% (95% CI: 12.7-19.4) and NWCO was 21.1% (95% CI: 12.2-30.1). The prevalence of NWO and NWCO higher in females and non-Asians. This review also showed that type 2 diabetes was significantly associated with NWO and NWCO (pooled OR: 1.82 [1.62, 2.04], p < 0.01, I2 = 64%). Subgroup analyses revealed consistent relationships between type 2 diabetes and NWO/NWCO across sex, region and definition approach. There was a relative high prevalence of NWO and NWCO, particularly in females and non-Asian populations. There was a consistent association of NWO/NWCO with type 2 diabetes. Implications for future research to guide intervention optimization in clinical practice and public health promotion are provided.

Biomarkers of intestinal permeability are associated with inflammation in metabolically healthy obesity but not normal-weight obesity

Systemic inflammation is reported in normal-weight obesity (NWO) and metabolically healthy obesity (MHO), which may be linked to their increased cardiovascular disease (CVD) risk. Yet, drivers of this inflammation remain unclear. We characterized factors known to influence inflammatory status (i.e., intestinal permeability, adipose tissue, diet quality, microbiota), and their relationships with measured inflammation, in NWO and MHO, healthy control subjects (CON), and metabolically unhealthy obesity (MUO; N = 80; n = 20/group). Serum indicators of intestinal permeability and inflammation were assessed by ELISA and/or multiplex. Total, visceral, and percent body fat were measured with dual-energy X-ray absorptiometry (DXA). Fecal microbiota composition was assessed via 16S rRNA sequencing (n = 9-10/group). For C-reactive protein (CRP), MUO > NWO > CON (P < 0.0001). In MHO, CRP was intermediate and similar to both MUO and NWO. Lipopolysaccharide binding protein (LBP) and the ratio of LBP to soluble CD14 (sCD14) were higher in MHO and MUO vs. CON/NWO (P < 0.0001). Across correlation and regression analyses, LBP consistently displayed the strongest relationships with CRP in the entire sample (r = 0.78; β = 0.57; P < 0.0001) and in MHO (r = 0.74; P < 0.01) but not NWO (r = 0.37; P = 0.11). Shannon index was higher in CON compared with MUO (P < 0.05) and inversely correlated with CRP in the full sample (r = -0.37; P < 0.05). These data are consistent with the notion that intestinal permeability is associated with low-grade inflammation in MHO, which could be implicated in this population's reported CVD risk.NEW & NOTEWORTHY This is the first study to our knowledge to examine biomarkers of intestinal permeability in normal-weight obesity and one of few assessing microbiota compositions in this population. Additionally, we report that individuals with metabolically healthy obesity and metabolically unhealthy obesity displayed similar evidence of intestinal permeability, which was more strongly associated with systemic inflammation than total and visceral adipose tissue mass.

Lipidomic perturbations of normal-weight adiposity phenotypes and their mediations on diet-adiposity associations

BACKGROUND & AIMS

Normal-weight obesity (NWO) and normal-weight central obesity (NWCO) have been linked to higher cardiometabolic risks, but their etiological bases and attributable dietary factors remain unclear. In this study we therefore aimed to identify lipidomic signatures and dietary factors related to NWO and NWCO and to explore the mediation associations of lipids in diet-adiposity associations.

METHODS

Using a high-coverage targeted lipidomic approach, we quantified 1245 serum lipids in participants with NWO (n = 150), NWCO (n = 150), or propensity-score-matched normal-weight controls (n = 150) based on the Regional Ethnic Cohort Study in Northwest China. Consumption frequency of 28 major food items was recorded using a food frequency questionnaire.

RESULTS

Profound lipidomic perturbations of NWCO relative to NWO were observed, and 249 (dominantly glycerolipids) as well as 48 (dominantly glycerophospholipids) lipids were exclusively associated with NWCO or NWO. Based on strong lipidomic signatures identified by a LASSO model, phospholipid biosynthesis was the top enriched pathway of NWCO, and sphingolipid metabolism was the top pathway of NWO. Remarkably, sphingolipids were positively associated with NWO and NWCO, but lyso-phosphatidylcholines were negatively associated with them. Rice, fruit juice, and carbonated drink intakes were positively associated with the risk of NWCO. Both global and individual lipidomic signatures, including SE(28:1_22:6) and HexCer(d18:1/20:1), mediated these diet-NWCO associations (mediation proportion: 15.92%-26.10%).

CONCLUSIONS

Differential lipidomic signatures were identified for overall and abdominal adiposity accumulation in normal-weight individuals, underlining their core mediation roles in dietary contributions to adiposity deposition.

The Normal Weight Obesity (NWO) Problem-Prevalence and Time Changes in Children and Adolescents From Kraków (Poland)

OBJECTIVES

Normal weight obesity can be associated with an increased risk of metabolic abnormalities, systemic inflammation and mortality. The main aim of the study was to analyze the changes in the prevalence of normal weight obesity in 8-18-year-olds from Kraków (Poland) between 2010 and 2020.

METHODS

The study was based on two sets of cross-sectional, school-based data obtained in 2010 and 2020. Body height, weight, and fat percentage were obtained. Body mass index was calculated, and only normal-weight individuals were included. Normal weight obesity was defined as normal BMI with adiposity >85 percentile for age and sex.

RESULTS

The prevalence of normal weight obesity among Polish children and adolescents has been alarming for at least the last 10 years. Depending on the sex and age, normal weight obesity was present in more than 10% up to even more than 20% of the examined population.

CONCLUSIONS

Alarming numbers of Polish children and adolescents suffer from NWO and this problem seems to be present for at least the last decade. A need for a maximally universal definition and cut-offs to diagnose normal weight obesity should also be stressed, as it will be helpful in providing the best prophylaxis and help to persons already suffering from normal weight obesity.

Association of combined body mass index and central obesity with cardiovascular disease in middle-aged and older adults: a population-based prospective cohort study

BACKGROUND

Cardiovascular diseases (CVDs) pose a significant threat to public health. Evidence indicates that the combination of central obesity and normal body mass index (BMI) is associated with an increased risk of cardiovascular disease and mortality. However, limited evidences exists in middle aged and elderly adults in China.

METHODS

This was a prospective cohort study that utilized a nationally representative sample of 6,494 adults aged 45 years and above. These individuals participated in the China Health and Retirement Longitudinal Study spanning from 2011 to 2018. Height, weight and waist circumference (WC) were measured, and BMI was calculated by height and weight. Other variables were obtained through self-reported questionnaires. Association analysis was conducted using Cox proportional hazard regression models.

RESULTS

A total of 10,186 participants were investigated, with 57,185 person-years of follow-up. During this period, 1,571 CVDs occurred, including 1,173 heart diseases and 527 strokes. After adjusting for various factors including age, gender, education, marital status, smoking status, alcohol intake, social activity, hypertension, dyslipidemia, diabetes, cancer, chronic lung diseases, liver disease, kidney disease, digestive disease, ENP(emotional, nervous, or psychiatric problems), memory related disease, arthritis or rheumatism, asthma, self-rated health and depression, the results revealed that compared to those with normal WC normal body mass index (BMI), individuals with central obesity normal BMI had a 27.9% higher risk of CVD incidence (95% confidence interval [CI]:1.074-1.524), and a 33.4% higher risk of heart disease incidence (95% CI:1.095-1.625), while no significant association was found with stroke. Additionally, those with normal WC high BMI showed a 24.6% higher risk of CVD incidence (95% CI:1.046-1.483), and a 29.1% higher risk of heart disease incidence (95% CI:1.045-1.594), again with no significant association with stroke. Finally, individuals with central obesity high BMI exhibited a 49.3% higher risk of CVD incidence (95% CI:1.273-1.751), a 61% higher risk of heart disease incidence (95% CI:1.342-1.931), and a 34.2% higher risk of stroke incidence (95% CI:1.008-1.786). Age- and sex- specific analyses further revealed varying trends in these associations.

CONCLUSIONS

We discovered that the combined association of body mass index(BMI) and central obesity with CVD incidence exhibited a significantly enhanced predictive value. Specifically, a high BMI with central obesity was notably linked to an increased risk of CVD incidence. Additionally, central obesity with a normal BMI or a normal WC coupled with a high BMI significantly augmented the risk of heart disease incidence, but not stroke. Notably, male and middle-aged adults demonstrated a greater propensity for heart disease incidence. Our study underscores the importance of maintaining an optimal BMI and preventing abdominal obesity in promoting cardiovascular health.

Associations of body mass index trajectory, waist circumference trajectory, or both with type 2 diabetes mellitus risk in Chinese adults: The China-PAR project

AIMS

To identify the trajectories of body mass index (BMI) and waist circumference (WC), and assess the associations of BMI trajectory, WC trajectory, or the two combined, with type 2 diabetes mellitus (T2DM) risk in Chinese adults.

MATERIALS AND METHODS

This study was based on a prospective project-the Prediction for Atherosclerotic Cardiovascular Disease Risk in China (China-PAR). A total of 54 434 participants (39.21% men) who were measured on at least two occasions were included. Three slowly increasing trajectory patterns were identified for BMI, and four for WC, by latent mixed modelling. A nine-category variable was derived by combining the WC trajectory (low, moderate, moderate-high/high) and the BMI trajectory (low, moderate, high). Logistic regression models were applied to estimate the odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

The risk of developing T2DM increased with elevated BMI or WC trajectory levels (all ptrend <0.001). The risks were 2.85 (2.59-3.14) for high BMI trajectory and 4.34 (3.78-4.99) for high WC trajectory versus low trajectory groups, respectively. The association was more pronounced among younger individuals (pinteraction <0.001). In the joint analysis, compared to participants with low WC and BMI trajectory, those with moderate-high/high WC combined with high BMI trajectory had the highest risk of T2DM (OR 3.96, 95% CI 3.48-4.50); even those who maintained moderate-high/high WC but low BMI trajectory showed a higher T2DM risk (OR 3.00, 95% CI 2.31-3.91).

CONCLUSIONS

This study suggests that simultaneous dynamic and continuous monitoring of BMI and WC may contribute more than single measurements to predicting T2DM risk and determining preventive strategies.

Cardiorespiratory fitness and submaximal exercise dynamics in normal-weight obesity and metabolically healthy obesity

PURPOSE

Cardiorespiratory fitness (CRF) is critical for cardiovascular health. Normal-weight obesity (NWO) and metabolically healthy obesity (MHO) may be at increased risk for cardiovascular disease, but a comparison of CRF and submaximal exercise dynamics against rigorously defined low- and high-risk groups is lacking.

METHODS

Four groups (N = 40; 10/group) based on body mass index (BMI), body fat %, and metabolic syndrome (MetS) risk factors were recruited: healthy controls (CON; BMI 18.5-24.9 kg/m2, body fat < 25% [M] or < 35% [F], 0-1 risk factors), NWO (BMI 18.5-24.9 kg/m2, body fat ≥ 25% [M] or ≥ 35% [F]), MHO (BMI > 30 kg/m2, body fat ≥ 25% [M] or ≥ 35% [F], 0-1 risk factors), or metabolically unhealthy obesity (MUO; BMI > 30 kg/m2, body fat ≥ 25% [M] or ≥ 35% [F], 2 + risk factors). All participants completed a V ˙ O2peak test on a cycle ergometer.

RESULTS

V ˙ O2peak was similarly low in NWO (27.0 ± 4.8 mL/kg/min), MHO (25.4 ± 6.7 mL/kg/min) and MUO (24.6 ± 10.0 mL/kg/min) relative to CON (44.2 ± 11.0 mL/kg/min) when normalized to total body mass (p's < 0.01), and adjusting for fat mass or lean mass did not alter these results. This same differential V ˙ O2 pattern was apparent beginning at 25% of the exercise test (PGroup*Time < 0.01).

CONCLUSIONS

NWO and MHO had similar peak and submaximal CRF to MUO, despite some favorable health traits. Our work adds clarity to the notion that excess adiposity hinders CRF across BMI categories.

CLINICALTRIALS

gov registration: NCT05008952.

Revisiting Waist Circumference: A Hypertension Risk Factor that Requires a More In-depth Understanding

As a major cause of various cardiovascular diseases, the prevalence of hypertension has been increasing in the past 30 years, leading to significant socioeconomic and health burdens. Obesity is one of the major risk factors for hypertension. Body mass index (BMI) is the most used anthropometric index to measure obesity in clinical practice and to assess the risk of obesity-related diseases. However, obesity is a heterogeneous disease, and the accumulation of fat in different body regions leads to differences in cardiovascular and metabolic risks. BMI only reflects the overall obesity but does not consider the distribution of fat and muscle mass. The limitation of BMI makes it insufficient to assess the risk of hypertension attributed to obesity. In addition, waist circumference is an easily obtainable anthropometric index to evaluate abdominal fat distribution. High waist circumference is an independent risk factor for various cardiovascular diseases and all-cause mortality regardless of BMI. Preliminary data indicate that waist circumference is significantly associated with the risk of hypertension at different BMI levels. However, routine measurement of waist circumference is currently not required in current clinical guidelines or is only recommended for obese populations, indicating an insufficient understanding of waist circumference. In this review, we summarize the measurement methods and diagnostic thresholds of waist circumference for abdominal obesity, the trend of central obesity prevalence, the superiority of waist circumference over other anthropometric indices, and recent cross-sectional and longitudinal studies on the association between obesity and hypertension.

Clinical Classification of Obesity and Implications for Metabolic Dysfunction-Associated Fatty Liver Disease and Treatment

Obesity,and metabolic dysfunction-associated fatty liver disease (MAFLD) have reached epidemic proportions globally. Obesity and MAFLD frequently coexist and act synergistically to increase the risk of adverse clinical outcomes (both hepatic and extrahepatic). Type 2 diabetes mellitus (T2DM) is the most important risk factor for rapid progression of steatohepatitis and advanced fibrosis. Conversely, the later stages of MAFLD are associated with an increased risk of T2DM incident. According to the proposed criteria, MAFLD is diagnosed in patients with liver steatosis and in at least one in three: overweight or obese, T2DM, or signs of metabolic dysregulation if they are of normal weight. However, the clinical classification and correlation between obesity and MAFLD is more complex than expected. In addition, treatment for obesity and MAFLD are associated with a reduced risk of T2DM, suggesting that liver-based treatments could reduce the risk of developing T2DM. This review describes the clinical classification of obesity and MAFLD, discusses the clinical features of various types of obesity and MAFLD, emphasizes the role of visceral obesity and insulin resistance (IR) in the development of MAFLD,and summarizes the existing treatments for obesity and MAFLD that reduce the risk of developing T2DM.

Whole-body bone mineral density and markers of bone homeostasis in adults with normal-weight obesity

Background

Normal-weight obesity (NWO) describes individuals with a normal body mass index (BMI), but high body fat percent. NWO are at-risk for cardiometabolic diseases, but little is known about their bone health.

Methods

Adults (N = 24) were classified as NWO (n = 12; 5M/7F) or low body fat percent controls (Con; n = 12; 6M/6F). Body composition and whole-body bone mineral density (BMD) were assessed using DXA. A serum bioplex assay was performed to examine markers related to bone formation and resorption.

Results

In addition to higher body fat percent and visceral fat, NWO had lower whole-body BMD relative to Con (p's < 0.05). Circulating leptin was higher in NWO than Con (p < 0.05). Two biomarkers generally associated with lower bone mass - sclerostin and parathyroid hormone - were higher in NWO compared to Con (p's < 0.05).

Conclusion

In this preliminary study, adults with NWO displayed lower whole-body BMD alongside evidence of bone resorption. Impaired bone health may be another subclinical risk factor present in NWO.

Associations between Normal-Weight Obesity and Disturbances in the Lipid Profile of Young Adults

BACKGROUND

Normal-weight obesity (NWO) is characterized by normal body mass index (BMI) but high body fat percentage (%BF) that increases the risks of cardiometabolic comorbidities. Accurate assessment and interpretation of body composition data are necessary to reduce these risks.

OBJECTIVES

To compare the cardiometabolic profile of individuals with NWO and normal %BF and evaluate the associated risk factors.

METHODS

A cross-sectional study was conducted with 222 Brazilian adults from a university community, of whom 157 had NWO and 65 had normal BMI and %BF (non-NWO). All participants reported being asymptomatic and without underlying health conditions. Socioeconomic, lifestyle, food intake, anthropometry, body composition measures (using dual-energy radiological absorptiometry), and lipid and glycemic profiles were evaluated. A p < 0.05 was established as significant.

RESULTS

The median age of the participants was 23 years (interquartile range: 21 to 25), and most were female (67.1%). No significant differences were found in blood pressure, age, or physical activity levels between the NWO and non-NWO groups. However, the frequency of lipid profile disturbances was higher in the NWO group (54%) compared to the non-NWO group (34%) (p < 0.006). Neck circumference, %BF, and lipid profile disturbances were positively associated with NWO.

CONCLUSION

Individuals with NWO have a worse cardiometabolic profile than those without NWO, and this condition is associated with important biomarkers. Addressing these outcomes is important for preventing long-term cardiometabolic complications. Accurate assessment and interpretation of body composition data, regardless of BMI, are crucial in this scenario.

The Prevalence of Metabolically Unhealthy Normal Weight and Its Influence on the Risk of Diabetes

CONTEXT

Diabetes is a major health problem and metabolically unhealthy is an important risk factor.

OBJECTIVE

To conduct the first nationally representative study on epidemiological data of metabolically unhealthy normal weight (MUNW) focused only on nondiabetic subjects and determine the predictive effect on diabetes in China.

METHODS

A longitudinal study was conducted using data from the Rich Healthcare Group in China. Metabolic status was determined by the revised National Cholesterol Education Program Adult Treatment Panel III criteria, and individuals with 2 or more criteria were categorized as MUNW and diagnosed with metabolic syndrome (MetS) if they met 3 or more.

RESULTS

Of a total of 63 830 nondiabetic normal-weight individuals, 8935 (14.0%) were classified as MUNW and 1916 (3.00%) were diagnosed with MetS. After adjusting for potential confounders, individuals with MUNW had a greater diabetes risk (4.234, 95% CI 3.089-5.803) than those without MUNW during an average of 3.10 years of follow-up. Also, the multivariable-adjusted hazard ratios for developing diabetes were 3.069 (95% CI 1.790-5.263), 7.990 (95% CI 4.668-13.677), and 11.950 (95% CI 6.618-21.579) for participants with 1, 2, and 3 or more components, respectively, compared with those without any components. Further analyses suggested that the number of MetS components present is associated with the risk of diabetes, especially in metabolically unhealthy normal-weight young male adults. Multivariable-adjusted hazard ratios (95% CI) for incident diabetes among individuals with 1, 2, and at least 3 components were 4.45 (1.45-13.72), 9.82 (3.05-31.64), and 15.13 (3.70-61.84) for participants aged ≤44 years, and 3.55 (1.81-6.97), 8.52 (4.34-16.73), and 13.69 (6.51-28.77) for male participants, respectively.

CONCLUSIONS

The prevalence of MUNW is 14% in Chinese normal-weight nondiabetic individuals, and active intervention is necessary for this category of people. The presence of MUNW significantly increases the risk of diabetes, and the risk of diabetes is associated with the number of MetS components present in the patient.

Normal-Weight Obesity and Metabolic Syndrome in Korean Adults: A Population-Based Cross-Sectional Study

BACKGROUND

The disadvantage of using body mass index (BMI) as an obesity diagnostic tool is that it cannot distinguish between fat mass and lean mass, which may understate the impact of obesity on metabolic complications. This population-based cross-sectional study aimed to investigate the relationship between normal-weight obesity (NWO) and metabolic syndrome in Korean adults aged 20 years (5962 males and 6558 females) who took part in the Korea National Health and Nutrition Examination Surveys from 2008 to 2011.

METHODS

NWO was defined as having a BMI of 18.5 to 24.9 kg/m2 and a body fat percentage of 26.0% in males or 36.0% in females. Metabolic syndrome (MetS) was defined using the revised National Cholesterol Education Program definition, with a Korean-specific waist circumference threshold of >90 cm for males and >85 cm for females.

RESULTS

NWO males and females were 2.7 times (p < 0.001) and 1.9 times (p < 0.001) more likely to develop metabolic syndrome than normal-weight non-obese males and females, respectively. Additionally, NWO females were 1.3 times (p = 0.027) more likely to develop MetS even after adjustments for all measured covariates.

CONCLUSIONS

The current findings of the study show that NWO is a proxy biomarker of MetS to be considered for early intervention.

Factors associated with normal-weight obesity in adolescents

A new phenotype of obesity has been studied: normal-weight obesity (NWO), which describes individuals with normal-weight by BMI and excess body fat. Despite normal-weight, individuals with NWO have a higher cardiometabolic risk. There is still a gap in the literature on the subject, especially in adolescents, as studies with this population are scarce. This study aims to investigate the sociodemographic factors, family history of chronic non-communicable diseases, body perception, lifestyle and food consumption associated with NWO in adolescents. This is a cross-sectional study, with 506 normal-weight adolescents aged 10–19 years, of both sexes. Weight and height were obtained, and BMI/age was calculated. Body fat analysis was performed using dual-energy X-ray absorptiometry. Sociodemographic data, level of physical activity, food consumption, body self-perception and lifestyle habits were also obtained. Logistic regression with hierarchical approach was used to analyse the associations. The odds of NWO are greater with age (OR = 1·14; 95 % CI = 1·04, 1·26), lower in male adolescents (OR = 0·21; 95 % CI = 0·11, 0·41) and higher in those with a history of familial dyslipidemia (OR = 1·81; 95 % CI = 1·01, 3·28). Adolescents satisfied with their body (OR = 0·30; 95 % CI 0·16, 0·56) and physically active (OR = 0·44; 95 % CI = 0·24, 0·81) have a lower odds of NWO, compared with the others. In addition, it was observed that the odds of NWO is greater among adolescents who use sweeteners (sugar substitutes) (OR = 3·84; 95 % CI = 1·70, 8·65). The factors associated with NWO were female sex, older age, positive family history of dyslipidemia, lower body satisfaction, lower level of physical activity and greater use of sweeteners.

Association of triglyceride-glucose index with incident hypertension among non-overweight healthy adults: A cohort study in China

BACKGROUND AND AIMS

Overweight and obesity are well recognized as important and traditional risk factors for hypertension (HTN), but the prevalence of HTN tends to increase in non-overweight people. Triglyceride-glucose (TyG) index has been observed to be associated with HTN. However, whether such association still persists in non-overweight people remains unclear. The aim of our cohort study was to explore the link between TyG index and incident HTN in non-overweight Chinese population.

METHODS AND RESULTS

As many as 4678 individuals without HTN at baseline were involved, who underwent at least two years of health check-ups in the eight-year study period and maintained non-overweight at follow-up. According to baseline TyG index quintiles, participants were classified into five groups. Compared with the 1st quantile, those in the 5th quantile of TyG index had a 1.73-fold (HR 95% CI 1.13-2.65) risk of incident HTN. The results remained consistent when analyses were restricted to participants without abnormal TG or FPG level at baseline (HR 1.62, 95% CI 1.17-2.26). Furthermore, the subgroup analyses were conducted, the risk of incident HTN was still significantly increased with increasing TyG index for subgroups of older participants (age≥ 40 years), males, females and higher BMI group (BMI≥ 21 kg/m²).

CONCLUSIONS

The risk of incident HTN increased with increasing TyG index among Chinese non-overweight adults, so TyG index might be a reliable predictor of incident HTN among adults maintaining non-overweight.

Body mass index combined with (waist + hip)/height accurately screened for normal-weight obesity in Chinese young adults

OBJECTIVES

Only a few studies have explored the prevalence of normal-weight obesity in young adults or the development of a simple evaluation index for body fat percentage. Therefore, this study aimed to examine the prevalence of normal-weight obesity in young Chinese adults and use anthropometric measurements to develop an evaluation index.

METHODS

In total, 1322 college students participated in the study and were divided into the normal-weight lean, normal-weight obese, and overweight and obese groups based on their body mass index and body fat percentage. The differences in body composition, circumference, and circumference ratio among these three groups were examined.

RESULTS

When exploring the correlation between the circumference ratio and body fat percentage, the circumference ratio was suitable for early screening of abnormal body fat percentage, and the cutoff value was calculated. Body composition and circumference were significantly different among the three groups: (waist + hip)-to-height, hip-to-height, and waist-to-height ratios were strongly correlated with body fat percentage.

CONCLUSIONS

(Waist + hip)-to-height ratio can be used as a simple evaluation index for indicating abnormal body fat percentage when higher than 1.032 in male and 1.047 in female individuals. Downregulating the normal upper limit for body mass index to 24.4 and 23.8 kg/m² in male and female individuals, respectively, is recommended. Body mass index combined with (waist + hip)-to-height ratio allowed for more accurate screening of normal-weight obesity as an easy and cost-free evaluation measure for abnormal body fat percentage.

The Relationship of Body Fat Ratio to Anthropometric and Metabolic Parameters in Normal Weight and Overweight Women; The Concept of Normal Weight Obesity

Aim: We aimed to underline the importance of “normal weight obesity concept”, prevent the overlooking of Normal Weight Obesity patients, administrate their treatments and explain them the risks regarding their future lives along with making emphasis on the necessity of change in polyclinical practices about the subject. Methods: We selected 200 female patients that were either normal or overweighted for this study. Patients have been divided into 4 groups with respect to their body mass index and body fat percent values. Differences of bioelectrical impedance analysis measurements between the groups, relation of the anthropometric and metabolic parameters and those parameters’ inner correlations have been inspected. Results: Serum levels of fasting plasma glucose, insulin, HOMA-IR, total cholesterol, LDL, triglyceride and TSH were higher in “Normal Weight Obesity” subjects than “Normal Weight Lean” subjects. The mean LDL levels were found to be higher in the Normal Weight Obesity group compared to the other groups and it was found to be statistically significant. Body fat percent was positively correlated to insulin, HOMA-IR, visceral fat rating, waist – hip circumferences, waist to height – hip to height ratios. Conclusion: The importance of measurement of body fat percent and not to overlook the Normal Weight Obesity patients should be emphasized once more. Therefore, in the primary care, during public screening and polyclinical assessment states, patients should be checked for obesity with not only measuring their weights and heights, but also detection of their detailed body composition. Keywords: obesity, body fat distribution, waist to height ratio

Staple Food Preference and Obesity Phenotypes: The Regional Ethnic Cohort Study in Northwest China

Staple food preference vary in populations, but evidence of its associations with obesity phenotypes are limited. Using baseline data (n = 105,840) of the Regional Ethnic Cohort Study in Northwest China, staple food preference was defined according to the intake frequency of rice and wheat. Overall and specifically abdominal fat accumulation were determined by excessive body fat percentage and waist circumference. Logistic regression and equal frequency substitution methods were used to evaluate the associations. We observed rice preference (consuming rice more frequently than wheat; 7.84% for men and 8.28% for women) was associated with a lower risk of excessive body fat (OR, 0.743; 95%CI, 0.669-0.826) and central obesity (OR, 0.886; 95%CI, 0.807-0.971) in men; and with lower risk of central obesity (OR, 0.898; 95%CI, 0.836-0.964) in women, compared with their wheat preference counterparties. Furthermore, similar but stronger inverse associations were observed in participants with normal body mass index. Wheat-to-rice (5 times/week) reallocations were associated with a 36.5% lower risk of normal-weight obesity in men and a 20.5% lower risk of normal-weight central obesity in women. Our data suggest that, compared with wheat, rice preference could be associated with lower odds ratios of certain obesity phenotypes in the Northwest Chinese population.

Trends in general and abdominal obesity in US adults: Evidence from the National Health and Nutrition Examination Survey (2001-2018)

Aim

This study investigates the trend in general obesity and abdominal obesity in US adults from 2001 to 2018.

Methods

We included 44,184 adults from the nine cycles of the continuous NHANES (2001-2002, 2003-2004, 2005-2006, 2007-2008, 2009-2010, 2011-2012, 2013-2014, 2015-2016, and 2017-2018). The age-adjusted mean body mass index and waist circumference were calculated, and the sex-specific annual change was estimated by the survey cycle. We used the weighted sex-specific logistic regression models to analyze the prevalence of general obesity and abdominal obesity from 2001 to 2018. The weighted adjusted odds ratio (OR) with a 95% confidence interval (CI) was calculated.

Results

Our study showed that general obesity and abdominal obesity account for about 35.48 and 53.13% of the US population. From 2001-2002 to 2017-2018, the age-adjusted prevalence of general obesity increased from 33.09 to 41.36% in females and from 26.88 to 42.43% in males. During 2001-2018, the age-adjusted prevalence of abdominal obesity increased from 57.58 to 67.33% in females and from 39.07 to 49.73% in males. A significant time-dependent increase was observed in the prevalence of general obesity (adjusted OR, 1.007; 95% CI 1.005-1.009, P < 0.001) and abdominal obesity (adjusted OR, 1.006; 95% CI, 1.004-1.008; P < 0.001).

Conclusion

General obesity and abdominal obesity are a heavy health burden among US adults, and the increasing trend remains in both males and females from 2001 to 2018.

Postprandial triglycerides, endothelial function, and inflammatory cytokines as potential candidates for early risk detection in normal-weight obesity

PROBLEM

Normal-weight obesity (NWO) is associated with increased cardiovascular disease (CVD) risk. However, NWO's clinical presentation is often unremarkable based on common risk factors. We examined whether CVD risk factors not routinely measured clinically including postprandial triglycerides, flow-mediated dilation (FMD), and inflammatory cytokines would be abnormal in NWO, consistent with their future risk.

METHODS

Individuals were recruited into 3 groups (n = 10/ group): controls (Con), NWO, and metabolic syndrome (MetS). Con was defined as a normal body mass index (BMI), < 25% (M) or < 35% (F) body fat, and < 1 International Diabetes Federation (IDF) criteria. NWO were above this body fat cutoff while maintaining a normal BMI and MetS was defined per the IDF. Participants underwent an abbreviated fat tolerance test (i.e., difference in fasting and 4 h triglycerides following a high-fat meal [9 kcal/kg; 73% fat)] and fasting and postprandial lipid and glucose metrics, as well as FMD were measured. A T cell cytokine bioplex was also performed using fasting serum.

RESULTS

NWO and MetS had similar body fat% and both were higher than Con (p < 0.0001). Despite having similar fasting triglycerides to Con, NWO had 4-hour triglycerides 66% greater than Con, but 46% lower than MetS (p < 0.01). FMD decreased in all groups after the high-fat meal (p < 0.0001). MetS displayed lower fasting FMD than Con, and NWO was similar to both groups (p < 0.05). No group differences were observed with postprandial FMD and the majority of fasting cytokines assessed. However, MetS exhibited higher fasting TNF-α than Con (p < 0.05), and NWO was similar to both groups.

CONCLUSIONS

Overall, NWO was associated with higher postprandial triglycerides than Con, but displayed little evidence of impaired vascular health or inflammation.

Cardiometabolic risk factors in adults with normal weight obesity: A systematic review and meta-analysis

Normal weight obesity (NWO) is a new emerging phenotype of obesity, defined as a normal body mass index with a high body fat percentage. While several studies have described the impact of NWO on cardiometabolic risk factors, the association between them remains uncertain. This meta-analysis systematically evaluated cardiometabolic risk factors in adults with NWO compared to adults with normal weight lean (NWL). A systematic literature search was performed from the inception until September 21, 2021 in order to comprehensively search for all observational studies that had three important variables, including adults (age ≥18 years old), NWO and cardiometabolic risk factors including metabolic syndrome, hypertension, diabetes mellitus, dyslipidaemia or all laboratory findings related to cardiometabolic risk factors. Twenty-four cross-sectional studies with a total of 75 201 subjects are included in the qualitative and quantitative analysis. Overall, older age and female sex are more likely in NWO population. Compared to NWL, NWO is significantly associated with cardiometabolic risk factors, including metabolic syndrome (OR = 2.24 [1.74, 2.89]; p < .001; I2  = 76%, Pheterogeneity  < 0.001), hypertension (OR = 1.60[1.36, 1.89]; p < .001; I2  = 76%, Pheterogeneity  < 0.001), diabetes mellitus (OR = 1.72[1.54, 1.92]; p < .001; I2  = 47%, Pheterogeneity  < 0.001), dyslipidaemia (OR = 1.50 [1.03, 2.18]; p = .03; I2  = 94%, Pheterogeneity  < 0.001) and other laboratory findings, except for C-reactive protein in both sexes group; and adiponectin levels in female group. Our meta-analysis showed that NWO was associated with cardiometabolic risk factors. Thus, the traditional definition of obesity using the BMI criteria should be challenged, as those with NWO might still be exposed to a heightened risk of cardiometabolic disorders. Nonetheless, further prospective cohort studies are needed better to understand this syndrome.

High-Fat or High-Carbohydrate Meal-Does It Affect the Metabolism of Men with Excess Body Weight?

Excessive adipose tissue in the body may lead to adverse health effects, carbohydrate and lipid metabolism disorders, and cardiovascular diseases. The aim of this study was to analyze the effect of a standardized high-fat meal (HF) on changes in energy expenditure and changes in the oxidation of energy substrates as well as the concentration of glucose, insulin, triglycerides and homocysteine in blood serum in relation to a standardized high-carbohydrate (non-fat, HC) meal in men with different nutritional status. In this study, 26 men (aged 19-60) without carbohydrate disorders (study group GS = 13 overweight/obese; control group GC = 13 normal body weight) were examined. It was observed that following a high-fat or high-carbohydrate meal, men with excessive body weight metabolized the main nutrients differently than men with normal body weight, and postprandial insulin secretion was also different (even without any significant differences in glucose concentrations). Overweight/obesity, which is in itself a risk factor for cardiovascular disease, contributes to an increase in the concentration of other risk factors, such as the concentration of homocysteine and triglycerides, which is referred to as cardiometabolic risk. Consumption of a high-fat meal increased the number of potential risk factors for cardiovascular disease (homocysteine and triglycerides) compared to a high-carbohydrate meal.

Normal Weight Obesity and Cardiometabolic Risk Factors: A Systematic Review and Meta-Analysis

BACKGROUND

Obesity is one of the most significant causes of morbidity and mortality worldwide. Current studies suggest a new type of obesity, normal weight obesity (NWO), which is defined as having a normal body mass index (BMI), but a high-fat percentage increases the risk of cardiometabolic risk factors (CMRFs). This systematic review and meta-analysis aimed to pool the association between NWO with CMRFs.

METHODS

A systematic search of the literature in all available electronic databases, including Scopus, Web of Science, EMBASE, and PubMed, was performed until October 2021. All English studies that assessed the association of NWOs [compared to normal weight non-obese (NWNO)] and the CMRFs were included. Two investigators extracted data and performed a quality assessment. The heterogeneity between studies was assessed with I-squared and Cochran's Q tests. Odds ratio (OR) was used as an effect size to pool the association of NWO with CMRFs.

RESULTS

Twenty-five articles that met the inclusion criteria entered the study. The total number of participants was 177,792, with an age range of 13 to 75 years. Most studies were conducted on the general population (adults) and were from China. The result of fixed-effect model meta-analysis indicated an increased odds of hyperglycemia (OR:1.50, 95%:1.23, 1.76), high TG (OR:1.90, 95% CH:1.44, 2.35), low HDL (OR: 1.28, 95% CI:1.06, 1.49) and diabetes (OR:1.39, 95% CI:1.30, 1.49). Moreover, the random effect meta-analysis showed that NWO increased the odds of dyslipidemia (OR:1.83, 95% CI:1.61, 20.4), HTN (OR:1.40, 95% CI:1.28, 1.51) and metabolic syndrome (OR:1.92, 95% CI:1.58, 2.26). Moreover, the mean of all CMRFs except plasma glucose in NWO subjects was statistically higher than NWNO subjects (p-value<0.05).

CONCLUSION

The present study showed that NWO increased the odds of CMRFs. These findings indicate the inadequacy of the BMI measurement and the need for body fat assessment for a better obesity risk assessment.

Using noninvasive anthropometric indices to develop and validate a predictive model for metabolic syndrome in Chinese adults: a nationwide study

PURPOSE

Metabolic syndrome (Mets) is a pathological condition that includes many abnormal metabolic components and requires a simple detection method for rapid use in a large population. The aim of the study was to develop a diagnostic model for Mets in a Chinese population with noninvasive anthropometric and demographic predictors.

PATIENTS AND METHODS

Least absolute shrinkage and selection operator (LASSO) regression was used to screen predictors. A large sample from the China National Diabetes and Metabolic Disorders Survey (CNDMDS) was used to develop the model with logistic regression, and internal, internal-external and external validation were conducted to evaluate the model performance. A score calculator was developed to display the final model.

RESULTS

We evaluated the discrimination and calibration of the model by receiver operator characteristic (ROC) curves and calibration curve analysis. The area under the ROC curves (AUCs) and the Brier score of the original model were 0.88 and 0.122, respectively. The mean AUCs and the mean Brier score of 10-fold cross validation were 0.879 and 0.122, respectively. The mean AUCs and the mean Brier score of internal-external validation were 0.878 and 0.121, respectively. The AUCs and Brier score of external validation were 0.862 and 0.133, respectively.

CONCLUSIONS

The model developed in this study has good discrimination and calibration performance. Its stability was proved by internal validation, external validation and internal-external validation. Then, this model has been displayed by a calculator which can exhibit the specific predictive probability for easy use in Chinese population.

Obesity, Body Composition, and Sex Hormones: Implications for Cardiovascular Risk

Cardiovascular disease (CVD) continues to be the leading cause of death in adults, highlighting the need to develop novel strategies to mitigate cardiovascular risk. The advancing obesity epidemic is now threatening the gains in CVD risk reduction brought about by contemporary pharmaceutical and surgical interventions. There are sex differences in the development and outcomes of CVD; premenopausal women have significantly lower CVD risk than men of the same age, but women lose this advantage as they transition to menopause, an observation suggesting potential role of sex hormones in determining CVD risk. Clear differences in obesity and regional fat distribution among men and women also exist. While men have relatively high fat in the abdominal area, women tend to distribute a larger proportion of their fat in the lower body. Considering that regional body fat distribution is an important CVD risk factor, differences in how men and women store their body fat may partly contribute to sex-based alterations in CVD risk as well. This article presents findings related to the role of obesity and sex hormones in determining CVD risk. Evidence for the role of sex hormones in determining body composition in men and women is also presented. Lastly, the clinical potential for using sex hormones to alter body composition and reduce CVD risk is outlined. © 2022 American Physiological Society. Compr Physiol 12:1-45, 2022.

Normal weight obesity and unaddressed cardiometabolic health risk-a narrative review

Normal weight obesity (NWO) is defined as having a normal body mass index (BMI), but a high body fat mass. There is growing interest in individuals with NWO, which is an underdiagnosed and understudied group, because of their increased risk for cardiometabolic morbidity and mortality. In this review, we summarized the definition, prevalence, etiology, pathophysiology, and cardiovascular outcomes seen in NWO. We have also summarized the available literature on interventions for NWO. There is a wide variation in the body fat percent cutoffs used to diagnose excess body fat. Hence, the prevalence rates of NWO vary between different populations and studies. It is estimated that about 30 million Americans have NWO and the worldwide prevalence ranges from 4.5% to 22%. Genetics, diet, and physical activity are related to NWO. However, etiological factors are not clear. Changes in body composition, inflammation, oxidative stress are present in NWO in comparison to normal weight lean (NWL) who have a normal BMI and normal body fat amount. Furthermore, cardiometabolic changes are observed and some are subclinical. Thus, screening for NWO will enhance the primary prevention of cardiovascular disease. Due to the use of various body fat percent cutoffs and methods to measure body fat, it is challenging to compare between studies. Researchers working in this field should ideally work towards developing standard body fat percent cutoffs for diagnosing NWO. There are many gaps in the literature on NWO unlike for overt obesity and future studies should explore the etiology, molecular mechanisms, and adipose tissue changes of NWO as well as conduct well planned and executed randomized controlled trials testing dietary, physical, and behavioral interventions for NWO in both males and females of different racial and age groups.

Association between body mass index, waist circumference, and age at natural menopause: a population-based cohort study in Chinese women

The purpose of the study was to investigate whether premenopausal body mass index (BMI) and waist circumference (WC) influence age at menopause. A total of 2116 women aged 35-64 years from two communities of the CMCS Beijing cohort were recruited in 1992 and followed up to 2018. Of 1439 premenopausal women at baseline, 6 women data were missing. Finally, 1433 women were included for analysis. Overweight was defined as BMI 24-27.99 kg/m2. Central obesity was defined as WC ≥80 cm. Age at menopause was categorized as <45 years, 45-49 years, 50-51 years (reference), and >51 years. Multinomial logistic regression models were used to estimate relative odds ratios (RORs) and 95% confidence intervals (CIs). Compared to women with normal weight and normal WC, overweight women with normal WC had higher risk of menopause at >51 years (ROR 1.64, 95% CI 1.10-2.45; P = .01); and overweight women with central obesity had higher risk of menopause at not only >51 years (ROR 1.82, 95% CI 1.13-2.93; P = .01) but also <45 years (ROR 3.13, 95% CI 1.20-8.43; P = .02) and 45-49 years (ROR 2.76, 95% CI 1.71-4.46; P < .001). When overweight women combine with central obesity, the risk of early menopause will increase in some of them.

Characteristics of Body Composition and Lifestyle in Chinese University Students with Normal-Weight Obesity: A Cross-Sectional Study

PURPOSE

Normal weight obesity (NWO), defined as normal body mass index (BMI) and excessive body fat percentage (BF%), has been shown to be associated with a significantly higher risk of developing metabolic syndrome, cardiometabolic dysfunction and with higher mortality. However, there is limited literature regarding the potential associations between NWO and lifestyles. This study aimed to investigate the associations of lifestyles with NWO in Chinese university students.

PARTICIPANTS AND METHODS

A total of 279 university students with normal BMI were recruited and divided into NWO and normal weight non-obesity (NWNO) groups by BF%. Body composition and anthropometrics were measured, and participants were asked to finish the Healthy Lifestyle Scale for University Students (HLSUS) questionnaire.

RESULTS

A total of 26 male (25.5%) and 71 female (40.1%) students were identified as NWO. Compared to NWNO students, body weight, BMI, body fat mass, visceral fat area, waist circumference and hip circumference of NWO students were all significantly higher both in male and female students (P < 0.05). The body fat mass, BF% and visceral fat area were significantly negatively correlated with the total HLSUS, physical exercise behavior, and dietary nutrition behavior scores in NWNO males, NWO and NWNO females (P < 0.05). The risk of NWO was lower in those students with higher scores in physical exercise behavior in both males (OR = 0.298, 95% CI = 0.121~0.733) and females (OR = 0.653, 95% CI = 0.505~0.843), while dietary nutrition behavior (OR = 0.759, 95% CI = 0.584~0.986) and stress management behavior (OR = 0.503, 95% CI = 0.335~0.755) decreased the risk of NWO only in females.

CONCLUSION

The incidence of NWO was high among university students, especially in females, which might be related with unhealthy lifestyles. NWO university students should pay attention to lifestyle adjustments, especially physical exercise, dietary nutrition and stress management, for preventing the health risk in NWO.

Distinct metabolite profiles of adiposity indices and their relationships with habitual diet in young adults

BACKGROUND AND AIMS

Obesity is characterized as overall or regional adiposity accumulation. However, the metabolic status underlying fat accumulation was not well understood. We sought to identify metabolite profiles based on their correlations with body mass index (BMI), body fat percentage (BFP), waist circumference (WC), and visceral adiposity index (VAI) in young Chinese adults (19-37 years old), and their associations with dietary consumption were also explored.

METHODS AND RESULTS

A total of 86 plasma samples were analyzed using untargeted lipidomics and metabolomics approaches. Metabolite profiles of adiposity indices were identified using random forest modelling. Ridge regression was used to generate metabolite scores. Overall, 30, 46, 30, and 20 metabolites correlated with BMI, BFP, WC, and VAI, respectively, which resulted in metabolite scores for each index. Top three enriched categories of the identified metabolites were glycerophospholipids, glycerolipids, and sphingolipids, with some specific metabolites (such as phosphatidylserine (37:2), phatidylethanolamine (42:4), and ceramide (40:0)) exclusively associated with overall adiposity, and some other metabolites exclusively associated with abdominal adiposity indices, e.g., triradylglycerol (45:0, 52:4, and 35:0) and diacylglycerol (38:4, 36:3, and 36:5). Moreover, metabolite scores were negatively associated with the intake of food rich in protein or fiber, while they were positively associated with food rich in carbohydrate, with similar results for adiposity indices.

CONCLUSION

We observed unique metabolite profiles of regional or overall fat deposition in young adults. Glycerophospholipids, glycerolipids, or sphingolipids may be involved in the regulation of adiposity accumulation, affected by dietary exposures.

Relationships between plasma apelin and adiponectin with normal weight obesity, body composition, and cardiorespiratory fitness in working adults

Background

A significant proportion of adults have normal weight obesity (NWO), defined as a normal body mass index (BMI) but disproportionately high body fat percentage. Individuals with NWO may have increased risk of cardiometabolic disorders and lower exercise tolerance, but it is unclear if this obesity phenotype is linked with dysregulated production of adipokines or myokines such as adiponectin and apelin, respectively.

Methods

This cross-sectional, secondary analysis included 177 working adults (mean age 49.6 ± 9.9 yrs, 64% female). Plasma high-molecular weight adiponectin and apelin levels were measured by ELISA. Body composition and fat distribution were assessed using dual energy X-ray absorptiometry. Exercise tolerance (VO₂ maximum) was determined by treadmill testing. NWO was defined as a BMI <25 kg/m² and body fat >30% for women or >23% for men. Participants were categorized as lean, NWO, or overweight-obese.

Results

A total of 14.7% of subjects were categorized as lean, 23.7% as having NWO, and 61.6% as having overweight-obesity. Plasma adiponectin levels were elevated in the overweight-obesity group (P < 0.05) compared to the lean and NWO groups, which did not differ from each other (P > 0.05). Adiponectin concentrations were inversely associated with BMI, fat mass, fat mass percent, visceral fat, and trunk to leg fat ratio and positively associated with leg fat mass (all P < 0.001). Plasma apelin levels were similar between the three body composition groups (P < 0.05) and were not significantly associated with any body composition indices. Apelin concentrations were inversely related to VO₂ maximum (β = −0.03 ± 0.01, p = 0.002).

Conclusion

Plasma adiponectin and apelin levels did not distinguish between lean and NWO groups. Positive relationships with leg fat mass and adiponectin suggest the importance of assessing body composition and fat distribution when studying adipokines and cardiometabolic disorders. Further investigations are needed to understand relationships between exercise, body composition, and apelin secretion.

Normal weight obesity and the risk of diabetes in Chinese people: a 9-year population-based cohort study

We evaluated the risk of developing diabetes in Chinese individuals with normal weight obesity (NWO). This 9-year population-based cohort study was based on the China National Diabetes and Metabolic Disorders Survey. A total of 1128 subjects without diabetes were included. Body fat percentage (BF%) was assessed by electrical bioimpedance. NWO was defined as subjects with a normal BMI (< 24 kg/m²) and an excess BF% (≥ 24% in men; ≥ 33% in women). Of 1128 individuals, 528 individuals were normal weight non-obese (NWNO), 118 (10.5%) were normal weight obese (NWO), 63 were overweight non-obese (OWNO), and 419 were overweight obese (OWO). During a follow-up of 9.0 years (interquartile range: 8.9–9.3), 113 (10.0%) individuals developed diabetes. The incidence rates of diabetes in NWNO, NWO, OWNO and OWO people were 5.69 (27 cases), 11.30 (12 cases), 3.53 (2 cases) and 19.09 (72 cases) per 1000 person-years, respectively. Cox regression analyses indicated multivariate-adjusted hazard ratios of diabetes in NWO, OWNO and OWO people were 2.110 (95% CI 1.026–4.337, p = 0.025), 0.441 (95% CI 0.101–1.928, p = 0.232) and 3.465 (95% CI 2.163–5.551, p < 0.001), respectively, relative to NWNO people. Chinese people with NWO are at increased risk of developing diabetes. We strongly suggest the incorporation of BF% measurement into the regular physical examination in Chinese medical practice.

Metabolically healthy obesity and metabolically obese normal weight: a review

Despite the general relationship between obesity and its co-morbidities, there are both obese individuals who scarcely present the associated pathologies (metabolically healthy obese; MHO) and individuals who present obesity alterations despite having normal weight (metabolically obese normal weight; MONW). It is still difficult to define metabolically MHO and MONW individuals because different classifications have been used in the studies reported. Indeed, different inclusion criteria have been used to discriminate between metabolically healthy and metabolically unhealthy subjects. Due to this and other reasons, such as differences in ethnicity, genetics, and lifestyle of the populations, data concerning the prevalence of MHO and MONW are very variable. The main determinants of MHO are type of growth (hypertrophy or hyperplasia), anatomical location, inflammation of adipose tissue, ectopic fat accumulation, genetic factors, and lifestyles factors. In the case of MONW, the main determinants are genetic background and lifestyle factors. With regard to treatment, it is not clear whether MHO subjects would benefit from traditional lifestyle interventions, based on diet energy restriction and increased physical activity. For MONW subjects, there is still no specialized treatment, and the therapies are the same as those used in obese subjects.

Leukocyte related parameters in older adults with metabolically healthy and unhealthy overweight or obesity

It remains unclear whether leukocyte-related parameters could be used as biomarkers to differentiate metabolically unhealthy overweight/obesity (MUO) from metabolically healthy overweight/obesity (MHO). We aimed to examine the differences in the distribution of leukocyte-related parameters between older adults with MHO and MUO and the correlations of leukocyte-related parameters with individual components of metabolic abnormality. In the Weitang Geriatric Diseases Study on older Chinese adults aged 60 years or above, 404 individuals with MHO and 480 with MUO contributed to the analysis. Overweight/obesity was defined as body mass index (BMI) of 25 kg/m2 or more. MHO and MUO were discriminated based on the Adult Treatment Panel III (ATP III) criteria. Leukocyte-related parameters were assessed using an automated hematology analyzer. All leukocyte-related parameters except monocytes were elevated in MUO group compared with MHO group (all P < 0.05). The prevalence of MUO increased by 24% with each 109/L increase of leukocytes after adjusting for confounders in the multiple-adjusted model (P < 0.01) and each unit elevation of other parameters except lymphocytes and monocytes were significantly associated with the presence of MUO (all P < 0.01). Trend tests revealed a linear trend for the association between MUO and all the leukocyte-related parameters (all P for trend < 0.05). Significant interactions between leukocyte-related parameters and sex on the presence of MUO were observed (all P value for interaction < 0.05). Higher leukocyte-related parameters were found in patients with MUO than those with MHO and were associated with higher prevalence of MUO which seems to be sex-dependent. Further studies are needed to see whether these parameters could be used as biomarkers for the screening or diagnosis for MUO in clinical or public health practice.

Physical Fitness but Not Diet Quality Distinguishes Lean and Normal Weight Obese Adults

BACKGROUND

Individuals with normal weight obesity (NWO) have increased cardiometabolic disease and mortality risk, but factors contributing to NWO development are unknown.

OBJECTIVE

The objective of this study was to determine whether diet quality scores and physical fitness levels differed between adults classified as lean, NWO, and overweight-obese. Secondary objectives of the study were to compare clinical biomarkers and food groups and macronutrient intakes between the three groups, and to test for associations between body composition components with diet quality scores and physical fitness levels.

DESIGN

This is a secondary data analysis from a cross-sectional study that included metropolitan university and health care system employees. Body composition was measured by dual energy x-ray absorptiometry. Individuals with a body mass index <25 kg/m2 and body fat >23% for men and >30% for women were classified as having NWO. Alternate Healthy Eating Index, Dietary Approaches to Stop Hypertension score, and Mediterranean Diet Score were calculated from Block food frequency questionnaires. Physical fitness was assessed by measuring maximal oxygen uptake (VO2 maximum) during treadmill testing.

PARTICIPANTS/SETTING

This study included 693 adults (65% women, mean age 48.9 ± 11.5 years) enrolled between 2007 and 2013 in Atlanta, GA.

MAIN OUTCOME MEASURES

The main outcome measures were Alternate Healthy Eating Index, Dietary Approaches to Stop Hypertension, and Mediterranean Diet Score diet quality scores and maximal oxygen uptake.

STATISTICAL ANALYSES

Multiple linear regression analyses with post hoc comparisons were used to investigate group differences in fitness, diet quality, and biomarkers. Regression analyses were also used to examine relationships between diet quality scores and fitness with body composition.

RESULTS

VO2 maximum was significantly lower in the NWO compared with the lean group (36.2 ± 0.8 mL/min/kg vs 40.2 ± 1.0 mL/min/kg; P < 0.05). Individuals with NWO reported similar diet quality to lean individuals and more favorable Alternate Healthy Eating Index and Dietary Approaches to Stop Hypertension scores than individuals with overweight-obesity (P < 0.05). Diet quality scores and physical fitness levels were inversely associated with percent body fat and visceral adipose tissue (P < 0.05), regardless of weight status. Individuals with NWO exhibited higher fasting blood insulin concentrations, insulin resistance, low-density lipoprotein cholesterol, and triglyceride levels, and significantly lower high-density lipoprotein cholesterol levels than lean individuals (P < 0.05).

CONCLUSIONS

Physical fitness was significantly decreased in individuals with NWO compared with lean individuals. Higher diet quality was associated with decreased total and visceral fat but did not distinguish individuals with NWO from lean individuals.

Association of adipocytokines with lipid and glycemic profiles in women with normal weight obesity

BACKGROUND

Individuals with normal weight obesity (NWO) are predisposed to having cardiometabolic disorders. This study aims to investigate the circulating levels of vaspin, leptin and their association with glycemic and lipid profiles in women with NWO.

METHODS

Forty women with body mass index (BMI) = 18.5-24.9 kg/m2 and fat mass (FM) ≥ 30% were assigned in the NWO group. Thirty age-matched women with identical BMI range, and FM < 30% (normal weight non-obese; NWNO) were considered as a control group. In addition to anthropometric measurements, glycemic and lipid profiles and circulating levels of leptin and vaspin were measured.

RESULTS

The mean ± standard deviation (SD) age of participants was 28.76 ± 4.76 years in the NWO group and 29.23 ± 4.50 years in the control group. The NWO group had the higher mean serum levels of insulin (9.02 ± 4.75 vs. 6.24 ± 2.51, P = 0.009), leptin (17.31 ± 8.10 vs. 9.94 ± 4.30, P < 0.001) and homeostatic model assessment of insulin resistance (HOMA-IR) (33.77 ± 20.71 vs. 23.48 ± 10.03, P = 0.009) compared to the NWNO group. The serum level of vaspin was higher in the NWO group compared to the control group (34.82 pg/ml vs. 27.72 pg/ml, respectively, P = 0.12). In NWO group, the serum levels of leptin had positive correlation with FBS (r = 0.45, P = 0.02), insulin (r = 0.51, P = 0.008), and HOMA-IR (r = 0.46, P = 0.02) and vaspin concentration was associated with insulin (r = 0.36, P = 0.02) and HOMA-IR (r = 0.30, P = 0.06), positively.

CONCLUSION

It is concluded that the concentration of insulin and HOMA-IR index were significantly higher in women with NWO compared to NWNO. Higher concentrations of leptin and vaspin in the NWO group were associated with glycemic profile.

Characteristics of Physical Fitness and Cardiometabolic Risk in Chinese University Students with Normal-Weight Obesity: A Cross-Sectional Study

PURPOSE

To (i) describe the characteristics of physical fitness and cardiometabolic risk in Chinese university students with normal-weight obesity (NWO); (ii) assess the association between NWO with physical fitness and cardiometabolic risk.

METHODS

A total of 249 participants from the 2018 Shanghai University of Sport Alumni Health Cohort Study in China formed the study cohort. NWO was defined as normal body mass index (17.9-23.9 kg/m2 for males; 17.2-23.9 kg/m2 for females) but with excess body-fat percentage (≥20% for males; ≥30% for females). Body composition was assessed by dual-energy X-ray absorptiometry. Physical-fitness scores were calculated from a battery of sex-specific tests. Cardiometabolic risk was calculated using a continuous clustered risk (MetS) score.

RESULTS

We found that 16.7% of male and 45.3% of female university students were classified as having NWO. Participants with NWO showed worse cardiorespiratory fitness than those with normal weight (NW) (male NWO (37±8) vs male NW (41±6) mL/kg/min, p<0.01; female NWO (31±4) vs female NW (33±6) mL/kg/min, p<0.01). NWO was associated negatively with the fitness score (OR = 0.853; 95% CI = 0.793-0.917) and was associated positively with the MetS score (1.280; 1.162-1.410).

CONCLUSION

University students with NWO were characterized by higher cardiometabolic risk and lower levels of physical fitness. Our findings implied that university students with NWO should be mindful of the potential hidden health risks of excess body fat and participate in exercise to enhance physical fitness.

Prevalence of Normal-Weight Obesity in Community-Dwelling Chinese Older Adults: Results from the Beijing Longitudinal Study of Aging

OBJECTIVE

Normal-weight obesity (NWO) is characterized by high body fat percentage (BFP) in individuals with normal body mass index (BMI). This condition may increase the risk of serious health problems, such as cardiovascular diseases, diabetes, insulin resistance, hypertension, and metabolic syndrome. However, the prevalence of NWO in older adults in Beijing remains unclear. This study aimed to investigate the prevalence of overweight and obesity among older adults in Beijing, using three obesity assessment indicators: BMI, waist circumference, and BFP.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

Data were obtained from the 2012 Beijing Longitudinal Study of Aging, which used a stratified, sectional, random, and cluster sampling method.

METHODS

Questionnaires, physical examinations, and laboratory tests were completed. Obesity was divided into four categories based on combinations of BMI and BFP: non-obese, muscle-type obesity, NWO and fatty obesity.

RESULTS

A total of 2393 community-dwelling older adults with an average age of 72.98±8.09 years old were recruited. Of them, 1051 were male (43.92%) and 1245 were living in rural areas (52.03%). The prevalence of overweight and obesity among older people in Beijing was 35.5% and 16.1%, respectively. When the sample was divided according to obesity classification, the proportion of muscular obesity, NWO and adipose obesity was 14.7%, 10.7%, and 41.8%, respectively. The prevalence of central obesity was 62.3%. The prevalence of obesity decreased with age, but it was higher in females than in males as well as among individuals living in urban areas than in individuals living in rural areas.

CONCLUSION

The prevalence of NWO was 10.7% among older adults in Beijing and increased with age. Older adults who are female or living in urban areas should be instructed to take measures aimed at reducing body fat and increasing muscle strength.

Associations between normal weight central obesity and cardiovascular disease risk factors in Japanese middle-aged adults: a cross-sectional study

BACKGROUND

Several studies have shown that normal weight central obesity (NWCO) is associated with cardiovascular disease (CVD) risk factors. However, studies conducted in the Japanese population have been very limited. Thus, the relationships between normal weight central obesity, classified using body mass index (BMI), the waist-to-height ratio (WHtR), and CVD risk factors in middle-aged Japanese adults were investigated.

METHODS

The participants were Japanese adults aged 40-64 years who had undergone periodic health examinations in Japan during the period from April 2013 to March 2014. The participants were categorized into the following four groups: normal weight (BMI 18.5-24.9 kg/m²) and no central obesity (WHtR < 0.5) (NW); normal weight and central obesity (WHtR ≥ 0.5) (NWCO); obesity (BMI ≥ 25 kg/m²) and no central obesity (OB); and obesity and central obesity (OBCO). Hypertension was defined as systolic blood pressure ≥ 140 mmHg, diastolic blood pressure ≥ 90 mmHg, or taking medication for hypertension. Dyslipidemia was defined as LDL-C ≥ 140 mg/dl, HDL-C < 40 mg/dl, triglyceride ≥ 150 mg/dl, or taking medication for dyslipidemia. Diabetes was defined as fasting plasma glucose ≥ 126 mg/dl, random plasma glucose ≥ 200 mg/dl, HbA1c ≥ 6.5%, or receiving medical treatment for diabetes mellitus. A logistic regression model was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) for hypertension, dyslipidemia, and diabetes.

RESULTS

A total of 117,163 participants (82,487 men and 34,676 women) were analyzed. The prevalence of NWCO was 15.6% in men and 30.2% in women. With reference to NW, the ORs for hypertension (adjusted OR 1.22, 95% CI 1.17-1.27 in men, 1.23, 1.16-1.31 in women), dyslipidemia (1.81, 1.74-1.89 in men, 1.60, 1.52-1.69 in women), and diabetes (1.35, 1.25-1.46 in men, 1.60, 1.35-1.90 in women) were significantly higher in NWCO.

CONCLUSIONS

Normal weight with central obesity was associated with CVD risk factors, such as hypertension, dyslipidemia, and diabetes, compared with normal weight without central obesity, regardless of sex. It is important to focus on normal weight with central obesity for the prevention of CVD in Japanese middle-aged adults.

Normal Weight Obesity: An Underrecognized Problem in Individuals of South Asian Descent

PURPOSE

Obesity has attained pandemic proportions across the world, and its prevalence in developing countries is also on the rise. Nevertheless, there is still a large gap in understanding the reasons behind a disproportionately high prevalence of diabetes as opposed to a lesser degree of obesity seen in individuals of South Asian origin. This research letter highlights the importance of identifying individuals with normal weight obesity, which may partially bridge this knowledge gap.

METHODS

We reviewed recently published evidence on normal weight obesity.

FINDINGS

Normal weight obesity is a common public health problem and may be prevalent in up to one-third of individuals of certain Asian ethnicities. Literature is emerging on its pathophysiology and association with metabolic diseases, such as type 2 diabetes mellitus, hypertension, and dyslipidemia. More recently, normal weight obesity was also identified as an independent strong predictor of cardiovascular mortality. However, evidence is particularly lacking on its appropriate management.

IMPLICATIONS

Normal weight obesity is an underrecognized yet widely prevalent problem in individuals of Asian descent. Further research on pathogenic mechanisms, diagnostic modalities, and therapeutic options in individuals with normal weight obesity is needed to appropriately manage this condition.

Waist circumference trajectories and risk of type 2 diabetes mellitus in Korean population: the Korean genome and epidemiology study (KoGES)

BACKGROUND

To classify waist circumference (WC) trajectories and examine each trajectory's association with risk of incident type 2 diabetes mellitus (T2DM).

METHODS

In Korean Genome and Epidemiology Study (KoGES 2001-2014), 4992 participants aged 40 years and above who received biennial health examinations from wave 1 to wave 4 (2001-2008) were selected. Five distinct trajectory groups were identified for WC using group-based trajectory modeling methods such as censored normal model. Cox proportional hazards model was used to examine the association of trajectories with risk of T2DM.

RESULTS

During 31,118 person-years of follow-up (mean follow-up duration, 6.2 years), 276 incident cases of T2DM were identified. Through trajectory analysis, 5 distinct WC patterns were found during wave1 to wave 4, which were "Group A" was stable on very low levels, "Group B" was stable on low levels, "Group C" was stable on moderate levels, "Group D" had increasing pattern on elevated levels, "Group E" was shown increasing on high levels. Age-standardized incidences rates per 100,000 person-years were increased with WC expanding trajectory group (193.9 for Group A, 498.4 for Group B, 661.9 for Group C, 1845.9 for Group D, and 2045.0 for Group E). In multivariate analysis after adjusting for confounding variable at wave 4, Group B (Hazard ratio (HR), 2.2; 95% confidence interval (CI), and 1.1-4.6), Group C (HR: 2.5, 95% CI: 1.2-5.0), Group D (HR: 5.4, 95% CI: 2.7-10.9), Group E (HR: 7.3, 95% CI: 3.5-15.4) had a higher risk of T2DM than Group A. After further adjusting for body mass index strongly correlated with WC, the association was attenuated.

CONCLUSIONS

WC trajectory was a significant predictor of T2DM risk in increasing trajectories on high level. This finding indicate the importance of WC management across prolong lifespan by assessing the prognosis and prevention strategies of high-risk populations for T2DM in middle-aged adults.

Expanded normal weight obesity and blood pressure in Chinese adults: a community-based cross-sectional study

The study aimed to explore the independent association between expanded normal weight obesity categories and blood pressure among adults aged 20-80 years in China. By cross-sectional design, a total of 4279 adults living in Shaanxi Province, China, were selected from communities via multi-stage stratified cluster sampling in 2014. Information on anthropometric, body composition and blood pressure was collected and analysed. Expanded normal weight obesity (ENWO) categories were used to identify the level of bodyweight based on the combination of body mass index (BMI) and body fat percentage (BFP) categories. The age- and sex-standardised prevalence of hypertension increased within ENWO groups, from 10.12% in the underweight-low body fat group to 45.92% in the obesity-high body fat group. In under or normal weight participants, body fat percentage was found independently associated with hypertension in men, with an adjusted odds ratio of 3.69 in the fourth quartile of BFP compared with the first one. However, this effect was not observed in women. BFP was independently associated with increased risk of hypertension, especially in men. People with normal BMI should be re-identified as a high-risk population based on BFP level when it comes to hypertension prevention in primary healthcare settings.

Why primary obesity is a disease?

Obesity must be considered a real pathology. In the world wide, obesity represent one of the major public health issue associated with increased morbidity and mortality. Overweight or obesity, in fact, significantly increases the risk of contracting diseases, such as: arterial hypertension, dyslipidemia, type 2 diabetes mellitus, coronary heart disease, cerebral vasculopathy, gallbladder lithiasis, arthropathy, ovarian polycytosis, sleep apnea syndrome, and some neoplasms. Despite numerous informative campaigns, unfortunately, the fight against obesity does not seem to work: in the last years, the prevalence continued to increase. The progressive and rapid increase in the incidence of obesity, which has characterized most of the economically advanced countries in the last decade, has been the main stimulus for the research of the mechanisms underlying this pathology and the related disorders. The aims of this review is to provide a revision of the literature in order to define obesity as diseases, secondly to highlight the limits and the inaccuracy of common tools used for the diagnosis of obesity, and as a third thing to strengthen the concept of the complexity of obesity as a disease among political health care providers. Obesity may be viewed as a multifactorial pathology and chronic low-grade inflammatory disease. In fact, people affected by obesity have greater risk of developing comorbility and morbility, respect to healthy. Hence, the absolute therapeutic benefit is directly proportional to the basic risk. So, internationally interest on early diagnosis of obesity is growing to avoid under- and overdiagnosis consequences. Therefore, the consequences are an aggravation of the disease and an increase in obesity related pathology like diabetes, cardiovascular disease, and cancer. The most widely used parameter for diagnosis, body mass index (BMI) is not suitable for assessing the body fat. In fact, several studies demonstrate that BMI alone cannot define obesity, which consists not so much in weight gain as in excess fat mass. The use of suitable tools for the assessment of fat mass percentage combined with clinical and genetic analysis allowed to identify different phenotypes of obesity, which explain the various paradoxes of obesity. It is essential to adopt all possible strategies to be able to combat obesity, ameliorate the suffering of patients, and reduce the social and treatment costs of obesity.

The BMI-adiposity conundrum in South Asian populations: need for further research

High body fat in apparently lean individuals is a commonly described phenotype in individuals of Asian descent, but very limited consolidated scientific literature is available on this topic. This phenotype is known as 'normal-weight obesity' and may explain the large disparity between the prevalence of obesity (as measured by BMI) and diabetes that occurs in these individuals. Routine use of obesity indicators that best predict body fat content would help to identify these individuals in clinical practice. In this debate, we would like to highlight that even though fat and BMI have a good correlation, as suggested by Kryst et al. (2019), clinicians, public health researchers and policymakers should consider the use of these indicators in conjunction with each other rather than individually. Future research is needed on pathogenic mechanisms, diagnostic modalities and therapeutic options in these individuals which will help to further characterize and manage these patients appropriately.