The paradox of obesity with normal weight; a cross-sectional study

Estimation of the population atributable fraction due a to excess body fat in primary care patients: IBERICAN study

The burden of disease attributable to excess body fat (EBF) in type 2 diabetes mellitus (T2DM) may be underestimated due to problems correlating BMI with body fat. The aim of this study is to compare the population attributable fraction (PAF) of EBF in T2DM assessed with various parameters.

MATERIAL AND METHODS

Prevalence study based on the baseline visit of the IBERICAN study. Mixed unconditional logistic regression models were used to estimate the risk of T2DM for the various categories of BMI, of the estimation of EBF according to the CUN-BAE (Clínica Universidad de Navarra-Body Adiposity Estimator) and of waist circumference (WC), stratifying by sex. The PAF was calculated for each of the EBF estimates.

RESULTS

A total of 7752 patients from IBERICAN study were eligible, of them 1536 (19.8 %) achieved T2DM criterion, The prevalence of diabetes was higher in men, in those with a lower level of education, and in those who reported a low level of physical activity. Subjects with diabetes were older, had a higher BMI, a higher CUN-BAE-estimated body fat percentage (eBFP) and a higher waist circumference. One in three cases T2DM risk was attributed to elevated BMI, whereas in the CUN-BAE case it was attributed to 9 out of 10 men and 2 out of 3 women. One out of two cases of T2DM in women, and less in men, was attributed to an excess WC.

CONCLUSIONS

The burden of disease attributable to EBF in the case of T2DM may be underestimated. Therefore, EBF should be used, together with BMI, WC -especially in women-, and the CUN-BAE to better estimate the risk of T2DM and to adapt dietary or lifestyle recommendations in daily clinical practice.

Adolescents with Normal Weight Obesity Have Less Dry Lean Mass Compared to Obese Counterparts

Normal weight obesity (NWO) is a condition characterized by a normal body mass index (BMI; 18.5-24.9 kg·m-2) yet excess body fat. Those with this condition have an increased risk of cardiometabolic diseases associated with obesity. The prevalence of NWO is not well investigated in adolescents, particularly in the United States. This study examined the prevalence of NWO and dietary behaviors among adolescents aged 14-19 years old (n = 139) who live in a rural area in the United States. Data were collected from December 2019 through February 2020. Body composition was assessed via bioelectrical impedance analysis and diet was assessed using an Automated Self-Administered 24 h food recall questionnaire. Participants were categorized by BMI and body fat percentage as NWO, normal weight lean (NWL), or obese (OB). The sample prevalence of NWO was 13.6%, with girls having a higher prevalence (22.2%) than boys (1.8%). Those with NWO had significantly lower dry lean mass than OB (p = 0.02), but there were no differences between NWL and OB (p = 0.08). There was significantly higher caloric intake (p = 0.02) among NWL compared to OB, and NWL consumed more fiber than both NWO (p = 0.02) and OB (p = 0.03). Overall, this study gives us a better understanding of the prevalence of NWO in the adolescent population and the dietary habits associated with each group. Those with NWO may be at increased risk for negative long-term health outcomes commonly associated with obesity. Additionally, the higher caloric intake among NWL was unexpected and should be investigated further.

Validity between dual-energy x-ray absorptiometry and bioelectrical impedance for segmental fat analysis and a novel low-cost model developed using anthropometry in young adults

BACKGROUND

Accurate body fat distribution assessment is essential for managing cardiovascular disease and metabolic disorders. Although several methods are available for segmental fat analysis, few studies have examined the validity of affordable methods such as Bioelectrical Impedance Analysis (BIA) against the reference method, Dual-Energy X-ray Absorptiometry (DXA). This study aimed to assess the validity of BIA as compared to DXA for segmental fat mass assessment, and to develop anthropometric multivariate regression models that offer a cost-effective alternative for health professionals in clinical and public health settings.

METHODS

Cross-sectional study that included 264 young adults (161 males, mean age = 23.04 ± 5.61 years; and 103 females, mean age = 22.29 ± 5.98 years). Segmental fat mass was measured using DXA and BIA, and anthropometric measurements were collected following the ISAK protocol.

RESULTS

Significant differences were found between DXA and BIA for segmental fat mass (p < 0.001). Sex significantly influenced the results (p < 0.05), while BMI and hydration status had no significant impacts. The Bland-Altman analysis revealed significant differences (p < 0.001) between BIA and DXA for fat mass in the upper and lower limbs. Trunk fat mass also differed significantly in males and females (p < 0.001), except for the overall sample (p = 0.088). Anthropometric multivariate regression models showed a high predictive accuracy for both females (R²=0.766-0.910; p < 0.001) and males (R²=0.758-0.887; p < 0.001). Key predictors of segmental fat mass included body mass (r = 0.606-0.867; p < 0.001), skinfold thickness (r = 0.688-0.893; p < 0.001), and waist girth (r = 0.883 - 0.810; p < 0.001). Peripheral skinfolds were highly predictive for upper and lower limbs, while waist girth was relevant for trunk fat mass.

CONCLUSIONS

DXA and BIA are not interchangeable for segmental fat analysis due to the significant differences observed. However, the anthropometric multivariate regression models developed provide a cost-effective and reliable alternative for predicting segmental fat mass in clinical settings where DXA is unavailable.

TRIAL REGISTRATION

Not applicable.

Phenotyping of Obesity Treatment Candidates: A Narrative Review

PURPOSE OF REVIEW

This review explores characterizing candidates for obesity treatments including pharmacotherapy, endoscopic bariatric therapies, and metabolic bariatric surgery (MBS), focusing on established clinical parameters for diagnosing obesity beyond body mass index alone.

RECENT FINDINGS

Existing literature primarily provides rates for fat mass percentage (i.e., a marker for adiposity quantity), waist circumference (i.e., a marker for adiposity distribution), and C-reactive protein levels (i.e., a marker for adiposity functionality) among obesity treatment candidates. Limited data on abnormal values and sex-based differentiation exist. The literature indicates high central-tendency measures for fat mass percentage and waist circumference, while C-reactive protein levels vary. Data on the Edmonton Obesity Staging System (i.e., a marker for adiposity-related disease severity) is predominantly available for MBS candidates. Future studies in obesity interventions should improve screening and diagnosis of obesity by incorporating sex-specific considerations and providing abnormal value rates for measurements to enhance understanding of patients' characteristics.

Association between body fat distribution and asthma in adults: results from the cross-sectional and bidirectional Mendelian randomization study

Background

Many studies define obesity based on body mass index (BMI) and explore its relationship with adult asthma. However, BMI only considers height and weight, ignoring other factors such as body fat, which may have a greater impact on health. We investigated the relationship between body fat distribution and adult asthma using both a cross-sectional study and bidirectional Mendelian randomization (MR) analysis.

Methods

Weighted logistic regression models were used to examine the relationship between body fat distribution measurements and adult asthma in the cross-sectional study from National Health and Nutrition Examination Survey (NHANES) 2011-2018. Restricted cubic spline (RCS) curves were employed to explore the dose-response relationship between them. The inverse-variance weighted (IVW) method was used as the main method of MR analysis to explore the causal effect of exposure on outcome.

Results

After adjusting for all covariates, weighted logistic regression analysis indicated that fat mass in the left arm, left leg, right arm, right leg, trunk, and total body is associated with an increased risk of developing adult asthma (p < 0.05). RCS curves showed that all six fat mass indicators exhibit a J-shaped relationship with adult asthma. Forward MR analysis found a causal effect of six fat mass indicators on the increased risk of adult asthma (p < 0.05). However, reverse MR did not reveal any causal effect of adult asthma on these six fat mass indicators (p > 0.05).

Conclusion

Our study supports a positive correlation and a unidirectional causality between body fat distribution measurements and the risk of adult asthma. Further studies are needed to validate our findings.

Predictive values of relative fat mass and body mass index on cardiovascular health in community-dwelling older adults: Results from the Longevity Check-up (Lookup) 7

OBJECTIVES

To assess the predictive value of relative fat mass compared to body mass index for hypertension, diabetes, hyperlipidemia, and heightened cardiovascular risk in a cohort of community-dwelling older adults from the Longevity Check-up 7+ cohort.

STUDY DESIGN

Retrospective cross-sectional study.

MAIN OUTCOME MEASURES

Hyperlipidemia was defined as total cholesterol ≥200 mg/dL or ongoing lipid-lowering treatment. Diabetes was defined either as self-reported diagnosis or fasting blood glucose >126 mg/dL or a random blood glucose >200 mg/dL. Hypertension was defined as blood pressure ≥ 140/90 mmHg or requiring daily antihypertensive medications. Heightened cardiovascular risk was operationalized as having at least two of these conditions.

RESULTS

Analyses were conducted in 1990 participants (mean age 73.2 ± 6.0 years; 54.1 % women). Higher proportions of men than women had hypertension and diabetes, while hyperlipidemia was more prevalent in women. Receiver operating curve analysis indicated relative fat mass was a better predictor of hypertension in women and diabetes in both sexes. Body mass index performed better in predicting hyperlipidemia in women. Relative fat mass thresholds of ≥27 % for men and ≥40 % for women were identified as optimal indicators of heightened cardiovascular risk and so were used to defined high adiposity. Moderate correlations were found between high adiposity or body mass index ≥25 kg/m2 and the presence of hypertension, hyperlipidemia and heightened cardiovascular risk, while a strong correlation was found with diabetes. Logistic regression analysis highlighted significant associations between high adiposity and increased odds of hypertension, diabetes, and heightened cardiovascular risk.

CONCLUSIONS

Proposed cut-offs for relative fat mass were more reliable indices than the usual cut-offs for body mass index for identifying individuals at heightened cardiovascular risk. Our findings support the role of anthropometric measures in evaluating body composition and the associated metabolic and cardiovascular conditions in older adults.

Predictive markers of metabolically healthy obesity in children and adolescents: can AST/ALT ratio serve as a simple and reliable diagnostic indicator?

This study aimed to estimate the prevalence of metabolically healthy obesity (MHO) according to two different consensus-based criteria and to investigate simple, measurable predictive markers for the diagnosis of MHO. Five hundred and ninety-three obese children and adolescents aged 6-18 years were included in the study. The frequency of MHO was calculated. ROC analysis was used to estimate the predictive value of AST/ALT ratio, waist/hip ratio, MPV, TSH, and Ft4 cut-off value for the diagnosis of MHO. The prevalence of MHO was 21.9% and 10.2% according to 2018 and 2023 consensus-based MHO criteria, respectively. AST/ALT ratio cut-off value for the diagnosis of MHO was calculated as ≥ 1 with 77% sensitivity and 52% specificity using Damanhoury et al.'s criteria (AUC = 0.61, p = 0.02), and 90% sensitivity and 51% specificity using Abiri et al.'s criteria (AUC = 0.70, p = 0.01). Additionally, using binomial regression analysis, only the AST/ALT ratio is independently and significantly associated with the diagnosis of MHO (p = 0.03 for 2018 criteria and p = 0.04 for 2023 criteria).

CONCLUSION

The ALT/AST ratio may be a useful indicator of MHO in children and adolescents.

WHAT IS KNOWN

• Metabolically healthy obesity refers to people who are obese but do not have any of the standard cardio-metabolic risk factors. • Metabolically healthy obesity is not entirely harmless; the metabolic characteristics of individuals with this phenotype are less favorable than those of healthy lean groups. Moreover, it is not a constant state, and there may be a transition to metabolically unhealthy phenotypes over time.

WHAT IS NEW

• The prevalence of MHO is 21.9% and 10.2% according to 2018 and 2023 consensus-based metabolically healthy obesity criteria, respectively. • The ALT/AST ratio may be a useful indicator of metabolically healthy obesity in children and adolescents.

Lower Adherence to a Mediterranean Diet Is Associated with High Adiposity in Community-Dwelling Older Adults: Results from the Longevity Check-Up (Lookup) 7+ Project

High adiposity impacts health and quality of life in old age, owing to its association with multimorbidity, decreased physical performance, and frailty. Whether a high adherence to a Mediterranean diet (Medi-Diet) is associated with reduced body adiposity in older adults is unclear. The present study was conducted to assess the prevalence of high adiposity in a large sample of community-dwelling older adults. We also explored the relationship between whole-body adiposity estimated through relative fat mass (RFM) and Medi-Diet adherence. Data were obtained from the Longevity Check-up 7+ (Lookup7+) project database. RFM was estimated from anthropometric and personal parameters using a validated equation. RFM was categorized as high if ≥40% in women and ≥30% in men. Information on diet was collected using a food frequency questionnaire, while Medi-Diet adherence was assessed through a modified version of the Medi-Lite scoring system. Analyses were conducted in 2092 participants (mean age 73.1 ± 5.9 years; 53.4% women). Mean RFM was 39.6 ± 5.14% in women and 29.0 ± 3.6% in men. High adiposity was found in 971 (46.4%) participants and was more frequent in those with a low (54.2%) or moderate (46.4%) Medi-Diet adherence compared with the high-adherence group (39.7%, p < 0.001). Logistic regression indicated that older adults with high Medi-Diet adherence were less likely to have a high RFM. Other factors associated with a greater risk of having high adiposity were older age, female sex, and physical inactivity. Our findings support an association between healthy lifestyles, including a greater adherence to a Mediterranean-style diet, and lower body adiposity in older adults.