Incidence of metabolic syndrome in adults with healthy weight, normal weight obesity, and overweight/obesity

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.

Dietary pattern changes, obesity and excess body fat in adults of a Brazilian birth cohort

BACKGROUND

Few studies have assessed dietary patterns (DPs) and the changes in these patterns over time in adults. The present study aimed to investigate whether possible changes in DPs in two assessments are associated with obesity and excess body fat.

METHODS

A prospective study was conducted in which data were collected from 1082 adults of a Brazilian birth cohort during two periods 15 years apart (T1: 2002-2004; T2: 2016-2017). Food consumption was assessed in both periods using validated food frequency questionnaires. Three similar DPs were found in the two assessments, and adherence to these patterns was classified as prudent, risk or mixed. Nine DPs changes were defined. At T2, subjects with a body mass index ≥ 30.0 kg m^- ² were classified as obese, and men and women with a body fat (BF) percentage ≥ 25.0 and ≥ 35.0, respectively, were classified as having excess BF. A directed acyclic graph was built to adjust the association for confounding variables.

RESULTS

At T2, 34.4% of the subjects were obese and 61.4% had excess BF. In the adjusted analysis, the changes associated with obesity and excess BF were prudent-mixed (prevalence ratio [PR] 1.55; 95% confidence interval [CI] = 1.04-2.29 and PR = 1.35; 95% CI = 1.10-1.65), risk-risk (PR = 1.49; 95% CI = 1.03-2.13 and PR = 1.27; 95% CI = 1.04-1.53), risk-mixed (PR = 1.56; 95% CI = 1.05-2.31 and PR = 1.33; 95% CI = 1.07-1.63) and mixed-risk (PR = 1.61; 95% CI = 1.10-2.35 and PR = 1.29; 95% CI = 1.04-1.58).

CONCLUSIONS

A decline in food quality over time or stagnation in an unhealthy DP can lead to obesity and excess BF.

Combining Fat-to-Muscle Ratio and Alanine Aminotransferase/Aspartate Aminotransferase Ratio in the Prediction of Cardiometabolic Risk: A Cross-Sectional Study

PURPOSE

Altered body composition and liver enzymes are known to be related to cardiometabolic risk. Our study aimed to evaluate the association between fat-to-muscle ratio (FMR), alanine aminotransferase/aspartate aminotransferase (ALT/AST) ratio and cardiometabolic risk.

METHODS

In total, 1557 participants aged ≥40 years were included. A bioelectrical impedance analyzer (BIA) was used to measure fat mass and muscle mass. We created a cardiometabolic risk score with one point for each cardiometabolic risk factor, including elevated triglycerides (TGs), decreased high-density lipoprotein cholesterol (HDL-C), elevated blood pressure (BP), and abnormal blood glucose, yielding a score of 0-4 for each participant (≥2 for high-risk and <2 for low-risk). Logistic regression analyses were used to analyze the relationship between FMR, ALT/AST ratio and cardiometabolic risk.

RESULTS

FMR and ALT/AST ratio were significantly higher in the high-risk group than in the low-risk group (P<0.001). FMR and ALT/AST ratio were both positively correlated with a higher cardiometabolic risk score and the presence of each cardiometabolic risk factor. In subgroup analyses categorized according to FMR and ALT/AST ratio cutoffs, the high-FMR/high-ALT/AST group had the highest cardiometabolic risk (OR=8.51; 95% CI 4.46-16.25 in women and OR=5.09; 95% CI 3.39-7.65 in men) after adjusting for confounders.

CONCLUSION

FMR and ALT/AST ratio were positively associated with cardiometabolic risk. Combining these two indicators improved the prediction of cardiometabolic risk.

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%, P_{heterogeneity}  < 0.001), hypertension (OR = 1.60[1.36, 1.89]; p < .001; I²  = 76%, P_{heterogeneity}  < 0.001), diabetes mellitus (OR = 1.72[1.54, 1.92]; p < .001; I²  = 47%, P_{heterogeneity}  < 0.001), dyslipidaemia (OR = 1.50 [1.03, 2.18]; p = .03; I²  = 94%, P_{heterogeneity}  < 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.

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.

Cardiometabolic risk in adolescents with normal weight obesity

BACKGROUND

Normal weight obesity (NWO), which is defined by the excess of body fat in normal weight individuals, has been neglected among adolescents, due to their normal weight and young age. Few studies were carried out on the topic with adolescents.

OBJECTIVE

To analyze whether the NWO is associated with cardiometabolic risk factors in adolescents.

SUBJECTS/METHODS

Cross-sectional study, with 506 normal weight adolescents aged 10-19 years, selected in schools in Brazil. Weight, height, waist circumference (WC) and neck circumference were obtained and the body mass index (BMI) and waist/height ratio (WHR) were calculated. Body composition analysis was performed using dual-energy X-ray absorptiometry. The clinical evaluation included lipid and glycid profile, platelets, leukocytes, lymphocytes, monocytes, uric acid and blood pressure, as well as the presence of metabolic syndrome (MS) and its components. NWO was defined by the presence of normal weight, according to BMI for age, and excess body fat (≥25% and ≥30% in males and females, respectively). Logistic regression models were used to analyze associations between normal weight adolescents with and without the NWO phenotype.

RESULTS

NWO associated positively with abdominal obesity, analyzed through WC (OR = 1.36;95%CI = 1.27-1.47), WHR (OR = 25.89;95%CI = 10.43-64.26) and android fat (OR = 1.49;95%CI = 1.36-1.63); insulin resistance (OR = 4.09;95%CI = 1.72-9.70), hyperinsulinemia (OR = 3.83;95%CI = 1.50-9.76) and the highest values of the triglycerides-glycemia index (OR = 4.28;95%CI = 1.21-15.08); uric acid (OR = 1.81;95%CI = 1.29-2.55), as well as the changes in LDL (OR = 3.39;95%CI = 1.47-7.81), total cholesterol (OR = 2.77;95%CI = 1.22-6.29), and in at least one (OR = 1.87;95%CI = 1.04-3.37) or two (OR = 6.61;95%CI = 1.45-30.19) components of MS.

CONCLUSION

NWO is associated with the presence of cardiometabolic risk factors in adolescents.

Association of Red Meat and Poultry Consumption With the Risk of Metabolic Syndrome: A Meta-Analysis of Prospective Cohort Studies

Objective: This study aims to investigate the association of red meat (processed and unprocessed) and poultry consumption with the risk of metabolic syndrome (MetS).

Methods: Prospective cohort studies on the association of red meat (processed and unprocessed) and poultry consumption with the risk of MetS were identified by comprehensive literature search in the PubMed, Web of Science, and Embase databases up to March 2021. The pooled relative risk (RR) of MetS with 95% CIs for the highest vs. lowest category of red meat or poultry consumption was extracted for meta-analysis.

Results: A total of nine prospective cohort studies were included in this study. Among them, eight studies were identified for red meat consumption. The overall multi-variable adjusted RR demonstrated that red meat consumption was associated with a higher risk of MetS (RR = 1.35, 95% CI: 1.13–1.62; P = 0.001). Moreover, four and three studies were specifically related to processed and unprocessed red meat consumption, respectively. Both processed (RR = 1.48, 95% CI: 1.11–1.97; P = 0.007) and unprocessed red meat (RR = 1.32, 95% CI: 1.14–1.54; P = 0.0003) consumption was associated with a higher risk of MetS. With regard to poultry consumption, three studies were included. The overall multi-variable adjusted RR suggested that poultry consumption was associated with lower risk of MetS (RR = 0.85, 95% CI: 0.75–0.97; P = 0.02).

Conclusions: The current evidence indicates that red meat (processed and unprocessed) consumption is associated with a higher risk of MetS, whereas, poultry consumption is associated with a lower risk of MetS. More well-designed randomized controlled trials are still needed to address the issues further.