Obesity or BMI Paradox? Beneath the Tip of the Iceberg

Exploring the Impact of the Obesity Paradox on Lung Cancer and Other Malignancies

Simple Summary

Studies have shown that obesity is associated with many adverse health effects, including worse cancer outcomes. Many studies paradoxically suggest a survival benefit for obesity in treatment outcomes of cancers such as non-small-cell lung cancer. This relationship is not seen in animal models. We hypothesize that this relationship is secondary to suboptimal quantification of adiposity, enhanced immunotherapy response, and variables such as sex, medications, and smoking status. There are many ways to measure and classify adiposity, but the ability to distinguish abdominal obesity is likely key in predicting accurate prognosis. There are many ways obesity impacts cancer treatment course from diagnosis to survivorship. In this paper, we aim to analyze the factors contributing to the obesity paradox and its effect on lung cancer. This can aid the treatment and prognosis of lung cancer and may support further research into obesity-specific impacts on this malignancy.

Abstract

There is a paradoxical relationship between obesity, as measured by BMI, and many types of cancer, including non-small-cell lung cancer. Obese non-small-cell lung cancer patients have been shown to fare better than their non-obese counterparts. To analyze the multifaceted effects of obesity on oncologic outcomes, we reviewed the literature on the obesity paradox, methods to measure adiposity, the obesity-related derangements in immunology and metabolism, and the oncologic impact of confounding variables such as gender, smoking, and concomitant medications such as statins and metformin. We analyzed how these aspects may contribute to the obesity paradox and cancer outcomes with a focus on lung cancer. We concluded that the use of BMI to measure adiposity is limited and should be replaced by a method that can differentiate abdominal obesity. We also concluded that the concomitant metabolic and immunologic derangements caused by obesity contribute to the obesity paradox. Medications, gender, and smoking are additional variables that impact oncologic outcomes, and further research needs to be performed to solidify the mechanisms.

Advances in Phenotyping Obesity and in Its Dietary and Pharmacological Treatment: A Narrative Review

In recent times, it has become evident that there are individuals who, from a metabolic point of view, are affected by obesity but have a normal body mass index. There are also metabolically healthy individuals with a high body mass index who are thus are considered as to be affected by obesity obese. Understanding that individuals with obesity are phenotypically heterogeneous is a relatively novel concept which, although present in the scientific literature, unfortunately has not yet had an impact in clinical practice. However, common dietary approaches are not effective in treating large numbers of obese patients with obesity. This narrative review, based on the material searched via PubMed and the Web of Science up to October 2021, proposes a downsizing of the role of the body mass index in identifying the individual with "true obesity" since it is only partially useful, and suggests a new approach which also integrates the body composition and assessment of metabolic parameters. This approach leads to personalized therapies that work best for each obesity phenotype in reducing the risk of non-communicable diseases.

Should knee extension strength testing be implemented as a screening test for identifying probable and confirmed sarcopenia in older T2DM patients?

Background

The accelerated loss of muscle strength and mass observed in older type 2 diabetes mellitus (T2DM) patients due to the combined effects of diabetes and obesity, greatly increases their risk for sarcopenia. Early detection and treatment of probable and confirmed sarcopenia is paramount to delay mobility disability. Using low handgrip strength cut-off points for the initial identification of sarcopenia according to the new European Working Group on Sarcopenia in Older People (EWGSOP2) guidelines may mask the presence of sarcopenia. Relative knee extension strength cut-off points using a simple hand-held dynamometer can assist clinicians in the diagnosis of probable and confirmed sarcopenia by possibly reducing false negative results.

Methods

A cohort of one hundred T2DM older patients (60% women) (mean age 74.5 years) mostly obese community dwelling older adults were evaluated for body composition by Bioelectrical impedance analysis (BIA), yielding appendicular skeletal mass index (ASMI) results. Patients underwent handgrip strength (HGS) and knee extension strength (KES) tests as well as functional ability tests. Prevalence of probable and confirmed sarcopenia using HGS and KES cut-off points were calculated. Pearson correlations were performed to evaluate the relationship between ASMI and limbs strength. A regression analysis was conducted to examine which variables best predict ASMI values. A multivariate analysis of covariance was performed to assess the effect of independent variables on KES and HGS.

Results

Using cutoff points for low KES identified 24 patients with probable sarcopenia and two with confirmed sarcopenia. Conversely, using the EWGSOP2 cut off points for low HGS, identified only one patient with probable sarcopenia and none of the patients with confirmed sarcopenia.

Conclusion

KES cut-off points using a simple hand-held dynamometer can assist in the identification of probable and confirmed sarcopenia using EWGSOP2 cut off points for low muscle mass in a population of older T2DM patients for further analysis and early treatment. This is notably true in patients possessing high body mass index (BMI) alongside normal ASMI and HGS, potentially reducing false positive sarcopenia screening results.

Trial registration

ClinicalTrials.gov PRS: NCT03560375. Last registration date (last update): 06/06/2018. The trial was a-priori registered before actual recruitment of subjects.

Dysfunctional adiposity index as a marker of adipose tissue morpho-functional abnormalities and metabolic disorders in apparently healthy subjects

Compared to body mass index, waist circumference (WC), and adiposity measurements, adipose tissue (AT) morpho-functionality evaluations are better predictors of cardiometabolic abnormalities (CA). The present study establishes a dysfunctional adiposity index (DAI) as an early marker of CA based on adipocytes morpho-functional abnormalities. DAI was established in 340 subjects without cardiovascular risk factors selected from a cross-sectional study (n=1600). Then, DAI was calculated in 36 healthy subjects who underwent subcutaneous AT biopsy. The correlation of DAI with adipocyte morphology (size/number) and functionality (adiponectin/leptin ratio) was analyzed. The DAI cut-off point was identified and its independent association with CA was determined in 1418 subjects from the cross-sectional study. The constant parameters to calculate the DAI were [WC/[22.79+[2.68*BMI]]]*[triglycerides (TG, mmol/L)/1.37]*[1.19/high density lipoprotein-cholesterol (HDL-C, mmol/L)] for males, and [WC/[24.02+[2.37*BMI]]]*[TG(mmol/L)/1.32]*[1.43/HDL-C(mmol/L)] for females. DAI correlated with adipocytes mean area, adipocyte number and adiponectin/leptin ratio. DAI ≥1.065 was independently associated with diabetes, non-alcoholic fatty liver disease, subclinical atherosclerosis, and hypertension. The present study highlights that DAI is associated with early CA independently of adiposity and other risk factors. Since DAI is obtained using accessible parameters, it can be easily incorporated into clinical practice for early identification of AT abnormalities in apparently healthy subjects.

Smoking, Obesity, and the Elective Operation

Smoking and obesity are commonly encountered problems in the elective, perioperative setting. This article reviews the risks posed by smoking and diabetes and explores way to mitigate such risks. Other means of perioperative optimization are also discussed in an effort to describe perioperative strategies that can improve patient outcomes.

Peri-Prostatic Adipocyte-Released TGFβ Enhances Prostate Cancer Cell Motility by Upregulation of Connective Tissue Growth Factor

Periprostatic adipose tissue (PPAT) has emerged as a key player in the prostate cancer (PCa) microenvironment. In this study, we evaluated the ability of PPAT to promote PCa cell migration, as well as the molecular mechanisms involved.

METHODS

We collected conditioned mediums from in vitro differentiated adipocytes isolated from PPAT taken from PCa patients during radical prostatectomy. Migration was studied by scratch assay.

RESULTS

Culture with CM of human PPAT (AdipoCM) promotes migration in two different human androgen-independent (AI) PCa cell lines (DU145 and PC3) and upregulated the expression of CTGF. SB431542, a well-known TGFβ receptor inhibitor, counteracts the increased migration observed in presence of AdipoCM and decreased CTGF expression, suggesting that a paracrine secretion of TGFβ by PPAT affects motility of PCa cells.

CONCLUSIONS

Collectively, our study showed that factors secreted by PPAT enhanced migration through CTGF upregulation in AI PCa cell lines. These findings reveal the potential of novel therapeutic strategies targeting adipocyte-released factors and TGFβ/CTGF axis to fight advanced PCa dissemination.

Liver disease in obesity and underweight: the two sides of the coin. A narrative review

PURPOSE

Malnutrition, whether characterized by not enough or too much nutrient intake, is detrimental to the liver. We herein provide a narrative literature revision relative to hepatic disease occurrence in over or undernourished subjects, to shed light on the paradox where both sides of malnutrition lead to similar liver dysfunction and fat accumulation.

METHODS

Medline, EMBASE, and Cochrane Library were searched for publications up to July 2020. Articles discussing the association between both chronic and acute liver pathology and malnutrition were evaluated together with studies reporting the dietary intake in subjects affected by malnutrition.

RESULTS

The association between overnutrition and non-alcoholic fatty liver disease (NAFLD) is well recognized, as the beneficial effects of calorie restriction and very low carbohydrate diets. Conversely, the link between undernutrition and liver injury is more complex and less understood. In developing countries, early exposure to nutrient deficiency leads to marasmus and kwashiorkor, accompanied by fatty liver, whereas in developed countries anorexia nervosa is a more common form of undernutrition, associated with liver injury. Weight gain in undernutrition is associated with liver function improvement, whereas no study on the impact of macronutrient distribution is available. We hypothesized a role for very low carbohydrate diets in the management of undernutrition derived liver pathology, in addition to the established one in overnutrition-related NAFLD.

CONCLUSIONS

Further studies are warranted to update the knowledge regarding undernutrition-related liver disease, and a specific interest should be paid to macronutrient distribution both in the context of refeeding and relative to its role in the development of hepatic complications of anorexia nervosa.

LEVEL OF EVIDENCE

Narrative review, Level V.

Explaining the obesity paradox in healthcare utilization among people with type 2 diabetes

Background

Several studies of diabetes suggest an obesity paradox: persons without diabetes have an increased risk of death due to obesity, whereas obesity decreases the risk of death for people with diabetes. A recent study finds the same obesity paradox with the number of healthcare visits. Whether empirical biases and confounding lead to this paradox is yet to be determined.

Objective

To examine changes in the relationship between BMI and number of visits in diabetic vs nondiabetic populations, controlling for confounding risk factors.

Methods

Using adults in the nationally representative Medical Expenditure Panel Survey (MEPS) from 2008 to 2016, N = 210,317, we examine the proposed relationship using six measures of healthcare visits with zero-inflated negative binomial regressions controlling for age, gender, race/ethnicity, income, education, region, health insurance, chronic conditions, and smoking. We excluded persons with type 1 diabetes and gestational diabetes.

Results

We find an obesity paradox among people with diabetes for three measures. That is, relative to people without diabetes, normal weight people with diabetes have more emergency room visits, inpatient, and office-based physician visits than do the obese with diabetes. However, we do not find an obesity paradox in any of the six measures once we exclude smokers and persons ever diagnosed with cancer or cardiovascular disease.

Conclusion

The obesity paradox does not exist at the utilization level and is due to the presence of statistical biases such as confounding and reverse causation. Physicians should continue to focus on efforts to prevent obesity in patients with diabetes.

[Nutraceutical correction in the complex non-drug treatment of metabolic syndrome]

The use of complex non-drug technologies at the stage of rehabilitation of metabolic syndrome (MS) includes multifactorial correction of its main manifestations: abdominal obesity, insulin resistance, arterial hypertension and dyslipidemia. A prospective randomized study on the use of low-calorie diet (LCD) and nutraceutical correction of the nutritional status of patients with MS was carried out.

OBJECTIVE

To study the effect of a non-drug complex including LCD, physical exercises, as well as correction of the gut microbiome and hepatic protection in relation to reduction of visceral fat volume in abdominal obesity and the dynamics of lipid and carbohydrate metabolism hormones in metabolic syndrome.

MATERIAL AND METHODS

120 patients with MS were randomized into 2 groups: Group 1 received LCD, physical exercises in the gym, and physical activity like daily walking up to 3-5 km/day. Group 2 received LCD, physical exercises in the gym, physical activity like daily walking up to 3-5 km/day, as well as nutraceutical correction of increased appetite, gut probiotic composition, hepatic protection. The treatment duration was 4 weeks. Anthropometric methods in order to control the body weight, waist and hip circumferences and bioimpedansometry were used.

RESULTS

As a treatment result, patients in group 1 represented a reduction in body weight, lean and active cell mass, a decrease in musculoskeletal mass and a decrease in total fluid due to extracellular fluid. A decrease in total cholesterol and blood triglyceride fraction was noted. Leptin decreased by 13.96%. Patients of the 2^nd group represented a decrease in body weight, fat mass, lean mass, total fluid and extracellular fluid. There was a statistically significant increase in active cell mass, skeletal muscle mass. There was a decrease in total cholesterol, triglycerides and transaminases. Due to weight loss and fat mass reduction a decrease in leptin expression by 29.85% and decrease in blood insulin levels by 11.2% were noted.

CONCLUSION

Thus, LCD accompanied by nutraceutical correction of the gut microbiota and hepatic protection can be effectively used in combination with physical training in order to reduce the fat mass without pre-sarcopenia development that was confirmed by positive dynamics of volume indices, bioimpedance measurements and reduction in leptin and insulin expression.

Age and comorbidities are crucial predictors of mortality in severe obstructive sleep apnoea syndrome

BACKGROUND

Obstructive sleep apnoea syndrome (OSAS) is a highly prevalent disorder. The prognostic role of comorbidity in patients with OSAS and their role for risk stratification remain poorly defined.

METHODS

We studied 1,592 patients with severe OSAS diagnosed by polysomnography. The primary outcome was all-cause mortality. The standardized mortality ratio (SMR) was estimated as the ratio of observed deaths to expected number of deaths in the general population. The expected numbers of deaths were derived using mortality rates from the general Apulian population. The association of comorbidities with all-cause mortality was assessed using multivariable Cox regression analysis. Finally, recursive-partitioning analysis was applied to identify the combinations of comorbidities that were most influential for mortality and to cluster the patients into risk groups according to individual comorbidities RESULTS: During 11,721 person-years of follow-up, 390 deaths (3.33 deaths/100 person-years) occurred. The median follow-up was 7 (4-10) years. The SMR was 1.47 (95% confidence intervals 1.33-1.63). Age, sex, obesity, cardiovascular diseases (CVD), moderate-to-severe chronic obstructive pulmonary disease (COPD), chronic kidney disease (CKD) and malignancy were independently associated with mortality risk. Recursive-partitioning analysis allowed distinguishing three clinical phenotypes differentially associated with mortality risk. The combination of CKD with CVDs or with moderate-to-severe COPD conferred the highest risk.

CONCLUSIONS

Severe OSAS is associated with increased risk for all-cause death. Age and comorbidity are crucial predictors of mortality in patients with severe OSAS. Clustering patients according to comorbidities allows identifying clinically meaningful phenotypes.

Cord Blood IGF-I, Proinsulin, Leptin, HMW Adiponectin, and Ghrelin in Short or Skinny Small-for-Gestational-Age Infants

CONTEXT

Small-for-gestational-age (SGA) is an indicator of poor fetal growth "programming" an elevated risk of type 2 diabetes in adulthood. Little is known about early-life endocrine characteristics in SGA subtypes. Stunting (short) and wasting (skinny) are considered distinct SGA phenotypes in neonatal prognosis.

OBJECTIVES

This work aimed to assess whether SGA infants with stunting or wasting have similar alterations in neonatal endocrine metabolic health biomarkers.

METHODS

This was a nested case-control study based on the 3D (Design, Develop, and Discover) birth cohort in Canada. The study subjects were 146 SGA (birth weight < 10th percentile) and 155 optimal-for-gestational age (OGA, 25th-75th percentiles) infants. Stunting was defined as birth length less than the 10th percentile, and wasting as body mass index less than the 10th percentile for sex and gestational age, respectively. Main outcome measures included cord plasma concentrations of insulin-like growth factor I (IGF-I), proinsulin, leptin, high-molecular-weight (HMW) adiponectin, and ghrelin.

RESULTS

Comparing to OGA infants adjusted for maternal and neonatal characteristics, SGA infants with either stunting only or wasting only had lower cord plasma IGF-I and leptin concentrations. HMW adiponectin concentrations were lower in SGA infants with wasting only (P = .004), but similar in SGA infants with stunting only (P = .816). Only SGA infants with both stunting and wasting had substantially lower proinsulin (P < .001) and higher ghrelin concentrations (P < .001) than OGA infants.

CONCLUSION

This study is the first to demonstrate that SGA infants with wasting only are characterized by low HMW adiponectin concentrations, whereas those with stunting only are not. SGA with both stunting and wasting are characterized by low proinsulin and high ghrelin concentrations.

Periprostatic adipose tissue promotes prostate cancer resistance to docetaxel by paracrine IGF-1 upregulation of TUBB2B beta-tubulin isoform

Growing evidence supports the pivotal role played by periprostatic adipose tissue (PPAT) in prostate cancer (PCa) microenvironment. We investigated whether PPAT can affect response to Docetaxel (DCTX) and the mechanisms associated. Conditioned medium was collected from the in vitro differentiated adipocytes isolated from PPAT which was isolated from PCa patients, during radical prostatectomy. Drug efficacy was studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide citotoxicity assay. Culture with CM of human PPAT (AdipoCM) promotes DCTX resistance in two different human prostate cancer cell lines (DU145 and PC3) and upregulated the expression of BCL-xL, BCL-2, and TUBB2B. AG1024, a well-known IGF-1 receptor inhibitor, counteracts the decreased response to DCTX observed in presence of AdipoCM and decreased TUBB2B expression, suggesting that a paracrine secretion of IGF-1 by PPAT affect DCTX response of PCa cell. Collectively, our study showed that factors secreted by PPAT elicits DCTX resistance through antiapoptotic proteins and TUBB2B upregulation in androgen independent PCa cell lines. These findings reveal the potential of novel therapeutic strategies targeting adipocyte-released factors and IGF-1 axis to overcome DCTX resistance in patients with PCa.

Therapeutic strategies for sarcopenic obesity: a systematic review

PURPOSE OF REVIEW

Tough plenty of literature investigated therapeutic options for body composition changes targeting elderly people, evidence concerning potential treatments of sarcopenic obesity as a unique condition is scarce. The aim of the present review was to summarize recent evidence regarding treatment of sarcopenic obesity in adult and older individuals.

RECENT FINDINGS

Exercise-based interventions were effective in ameliorating lean mass or sarcopenia-related indices and reducing total adiposity. Importantly, in one study, modifications of body composition were obtained in the absence of significant changes in body mass index. The majority of studies relied on resistance training, and all provided with beneficial effects in body composition. Conversely, effects in terms of muscle strength and functional ability were heterogeneous. Electrical acupuncture and whole-body electromyostimulation associated with nutritional supplementation resulted to be novel effective strategies in inducing body composition changes. Nonetheless, findings from nutritional supplementations are not conclusive, leading to conflicting results on strength and functional outcomes.

SUMMARY

Specific interventions could improve sarcopenic obesity, but overall significance is limited by scarcity of data and lack of uniformity in the definition of sarcopenic obesity itself. Further research should clarify optimal treatment options for sarcopenic obesity in age classes other than the geriatric population.

NLRP3 Inflammasome: The Stormy Link Between Obesity and COVID-19

Several countries around the world have faced an important obesity challenge for the past four decades as the result of an obesogenic environment. This disease has a multifactorial origin and it is associated with multiple comorbidities including type 2 diabetes, hypertension, osteoarthritis, metabolic syndrome, cancer, and dyslipidemia. With regard to dyslipidemia, hypertriglyceridemia is a well-known activator of the NLRP3 inflammasome, triggering adipokines and cytokines secretion which in addition induce a systemic inflammatory state that provides an adequate scenario for infections, particularly those mediated by viruses such as HIV, H1N1 influenza, and SARS-CoV-2. The SARS-CoV-2 infection causes the coronavirus disease 2019 (COVID-19) and it is responsible for the pandemic that we are currently living. COVID-19 causes an aggressive immune response known as cytokine release syndrome or cytokine storm that causes multiorgan failure and in most cases leads to death. In the present work, we aimed to review the molecular mechanisms by which obesity-associated systemic inflammation could cause a more severe clinical presentation of COVID-19. The SARS-CoV-2 infection could potentiate or accelerate the pre-existing systemic inflammatory state of individuals with obesity, via the NLRP3 inflammasome activation and the release of pro-inflammatory cytokines from cells trough Gasdermin-pores commonly found in cell death by pyroptosis.

Dietary Energy Partition: The Central Role of Glucose

Humans have developed effective survival mechanisms under conditions of nutrient (and energy) scarcity. Nevertheless, today, most humans face a quite different situation: excess of nutrients, especially those high in amino-nitrogen and energy (largely fat). The lack of mechanisms to prevent energy overload and the effective persistence of the mechanisms hoarding key nutrients such as amino acids has resulted in deep disorders of substrate handling. There is too often a massive untreatable accumulation of body fat in the presence of severe metabolic disorders of energy utilization and disposal, which become chronic and go much beyond the most obvious problems: diabetes, circulatory, renal and nervous disorders included loosely within the metabolic syndrome. We lack basic knowledge on diet nutrient dynamics at the tissue-cell metabolism level, and this adds to widely used medical procedures lacking sufficient scientific support, with limited or nil success. In the present longitudinal analysis of the fate of dietary nutrients, we have focused on glucose as an example of a largely unknown entity. Even most studies on hyper-energetic diets or their later consequences tend to ignore the critical role of carbohydrate (and nitrogen disposal) as (probably) the two main factors affecting the substrate partition and metabolism.