Body Composition Analysis and Changes in Airways Function in Obese Adults After Hypocaloric Diet

Obesity and Body Composition in Man and Woman: Associated Diseases and the New Role of Gut Microbiota

BACKGROUND

Obesity is now recognized as a worldwide health issue and has reached epidemic proportions, affecting both developed and developing countries. The World Obesity Federation stated that "Obesity is a chronic relapsing disease process": as a result, obesity has been recognized internationally as a chronic disease. The primary cause of the metabolic syndrome and increase of the cardiovascular risk have been identified in "sick fat", a condition then defined as adiposopathy. Heart attacks, strokes and renal failures are pathologies that have mid-risk factors such as dyslipidemia, hypertension and diabetes, which in turn are caused by obesity, whose primary risk factor is represented by the diet. The aim of the present review is to consider the importance of body composition, together with chronic inflammation and a new gut microbiota data that may turn out to be crucial elements of some target treatment of human obesity.

METHODS

In this review, we performed research using PubMed database reviewing the evidence in the literature of evidence information regarding the link between obesity and body composition in the development of metabolic disease via inflammation markers and in particular, the new role exerted by gut microbiota.

RESULTS

Several papers were evaluated searching for differences in fat mass and disease risk. We also identified the same papers dealing with differences in body composition and metabolic syndrome. Our attention focuses also on a new frontier of gut microbiota composition in the body weight decrease and anti-inflammatory effects.

CONCLUSION

To the saving of lean mass, for the prevention of cardiometabolic diseases, also considering the relationship with obesity, it is necessary to reduce the inflammatory state, acting on the gut-microbiota and on the intestinal permeability. To improve the health of the intestinal flora, we propose a 4P medicine and treatment with probiotics, prebiotics, postbiotics, and polyphenols.

The effects of truncal adiposity in forced spirometry: Sex differences

The aim of the current paper is to establish the influence of truncal fat accumulation on the spirometric results of a group of healthy individuals. A cross-sectional study of 305 healthy, non-smoking adult subjects (144 males, 161 females) was conducted. Forced spirometry and dual-energy X-ray absorptiometry to quantify body fat were performed. Partial correlation and multiple linear regression analyses were performed. In females, abdominal fat was negatively correlated with forced vital capacity (FVC) and forced expiratory volume in one second (FEV₁). In males, thoracic fat was negatively correlated with respiratory variables, as was abdominal fat. In the multiple linear regression, FEV₁ was the spirometric parameter that showed higher R² values in both sexes. Truncal fat had a greater influence on FEV₁ than on FVC. In males, no significant differences between the influence of thoracic and abdominal fat on spirometric results were found, and total body fat was shown to have more influence than regional. In females, the influence of abdominal fat was higher.

Relationship between Body Composition and Pulmonary Function in Early Adult Life: A Cross-Sectional Analysis Nested in Two Birth Cohort Studies

BACKGROUND

Overweight/obesity has been reported to worsen pulmonary function (PF). This study aimed to examine the association between PF and several body composition (BC) measures in two population-based cohorts.

METHODS

We performed a cross-sectional analysis of individuals aged 18 and 30 years from two Pelotas Birth Cohorts in southern Brazil. PF was assessed by spirometry. Body measures that were collected included body mass index, waist circumference, skinfold thickness, percentages of total and segmented (trunk, arms and legs) fat mass (FM) and total fat-free mass (FFM). FM and FFM were measured by air-displacement plethysmography (BODPOD) and by dual-energy x-ray absorptiometry (DXA). Associations were verified through linear regressions stratified by sex, and adjusted for weight, height, skin color, and socioeconomic, behavioral, and perinatal variables.

RESULTS

A total of 7347 individuals were included in the analyses (3438 and 3909 at 30 and 18 years, respectively). Most BC measures showed a significant positive association between PF and FFM, and a negative association with FM. For each additional percentage point of FM, measured by BOD POD, the forced vital capacity regression coefficient adjusted by height, weight and skin color, at 18 years, was -33 mL (95% CI -38, -29) and -26 mL (95% CI -30, -22), and -30 mL (95% CI -35, -25) and -19 mL (95% CI -23, -14) at 30 years, in men and women, respectively. All the BOD POD regression coefficients for FFM were the same as for the FM coefficients, but in a positive trend (p<0.001 for all associations).

CONCLUSIONS

All measures that distinguish FM from FFM (skinfold thickness-FM estimation-BOD POD, total and segmental DXA measures-FM and FFM proportions) showed negative trends in the association of FM with PF for both ages and sexes. On the other hand, FFM showed a positive association with PF.

Influence of Body Composition on Lung Function and Respiratory Muscle Strength in Children With Obesity

Background

Obesity affects lung function and respiratory muscle strength. The aim of the present study was to assess lung function and respiratory muscle strength in children with obesity and determine the influence of body composition on these variables.

Methods

A cross-sectional study was conducted involving 75 children (40 with obesity and 35 within the ideal weight range) aged 6 - 10 years. Body mass index, z score, waist circumference, body composition (tetrapolar bioimpedance), respiratory muscle strength and lung function (spirometry) were evaluated.

Results

Children with obesity exhibited larger quantities of both lean and fat mass in comparison to those in the ideal weight range. No significant differences were found between groups regarding the respective reference values for respiratory muscle strength. Male children with obesity demonstrated significantly lower lung function values (forced expiratory volume in the first second % (FEV₁%) and FEV₁/forced vital capacity % (FVC%) : 93.76 ± 9.78 and 92.29 ± 3.8, respectively) in comparison to males in the ideal weight range (99.87 ± 9.72 and 96.31 ± 4.82, respectively). The regression models demonstrated that the spirometric variables were influenced by all body composition variables.

Conclusion

Children with obesity demonstrated a reduction in lung volume and capacity. Thus, anthropometric and body composition characteristics may be predictive factors for altered lung function.

Environmental perturbations: Obesity

Obesity currently affects about one-third of the U.S. population, while another one-third is overweight. The importance of obesity for certain conditions such as heart disease and type 2 diabetes is well appreciated. The effects of obesity on the respiratory system have received less attention and are the subject of this article. Obesity alters the static mechanical properties of the respiratory system leading to a reduction in the functional residual capacity (FRC) and the expiratory reserve volume (ERV). There is substantial variability in the effects of obesity on FRC and ERV, at least some of which is related to the location rather than the total mass of adipose tissue. Obesity also results in airflow obstruction, which is only partially attributable to breathing at low lung volume, and can also promote airway hyperresponsiveness and asthma. Hypoxemia is common is obesity and correlates well with FRC, as well as with measures of abdominal obesity. However, obese subjects are usually eucapnic, indicating that hypoventilation is not a common cause of their hypoxemia. Instead, hypoxemia results from ventilation-perfusion mismatch caused by closure of dependent airways at FRC. Many obese subjects complain of dyspnea either at rest or during exertion, and the dyspnea score also correlates with reductions in FRC and ERV. Weight reduction should be encouraged in any symptomatic obese individual, since virtually all of the respiratory complications of obesity improve with even moderate weight loss.

Serum metabolomics reveals pathways and biomarkers associated with asthma pathogenesis

BACKGROUND

Asthma is a chronic inflammatory disease caused by complex interactions of genetic, epigenetic, and environmental factors. For this reason, new approaches are required to clarify the pathogenesis of asthma by systemic review.

OBJECTIVE

We applied a (1)H-NMR metabolomics approach to investigate the altered metabolic pattern in sera from patients with asthma and sought to identify the mechanism underlying asthma and potential biomarkers.

METHOD

A global profile of sera from patients with asthma (n = 39) and controls (n = 26) was generated using (1)H-NMR spectroscopy coupled with multivariate statistical analysis. Endogenous metabolites in serum were rapidly measured using the target-profiling procedure.

RESULTS

Multivariate statistical analysis showed a clear distinction between patients with asthma and healthy subjects. Sera of asthma patients were characterized by increased levels of methionine, glutamine, and histidine and by decreased levels of formate, methanol, acetate, choline, O-phosphocholine, arginine, and glucose. The metabolites detected in the sera of patients with asthma are involved in hypermethylation, response to hypoxia, and immune reaction. Furthermore, the levels of serum metabolites from patients with asthma correlated with asthma severity; in particular, lipid metabolism was altered in patients with lower forced expiratory volume in 1 s percentage (FEV(1)%) predicted values. In addition, potential biomarkers showed strong predictive power in ROC analysis, and the presence of asthma in external validation models was predicted with high accuracy (90.9% for asthma and 100% for control subjects).

CONCLUSION & CLINICAL RELEVANCE

These data showed that (1)H-NMR-based metabolite profiling of serum may be useful for the effective diagnosis of asthma and a further understanding of its pathogenesis.

Obesidade e testes de função pulmonar em crianças e adolescentes: uma revisão sistemática

OBJETIVO: Realizar uma revisão sistemática sobre os estudos observacionais que analisaram a relação entre os parâmetros espirométricos e a obesidade em crianças e adolescentes. FONTES DE DADOS: Os dados foram selecionados sem restrição de idioma, utilizando-se as bases de dados PubMed/Medline, Scopus, Lilacs e SciELO, sem data inicial até dezembro de 2010. Os descritores foram extraídos do Medical Subject Headings e incluíram "respiratory function tests" e "childhood obesity". SINTESE DOS DADOS: Por meio da estratégia de busca, 89 artigos foram encontrados, dos quais apenas cinco foram selecionados. Foram incluídos estudos observacionais com descrição dos parâmetros espirométricos e do índice de massa corpórea, sendo excluídos estudos com outros métodos de avaliação da função pulmonar, população não exclusiva de crianças/adolescentes e presença de comorbidades associadas à obesidade. Para avaliação da qualidade dos estudos utilizou-se a escala para estudos observacionais da Agency for Healthcare Research and Quality. Os estudos avaliaram a capacidade vital forçada e o volume expiratório forçado no primeiro segundo. Quatros artigos avaliaram também o fluxo expiratório forçado entre 25 e 75%, aquele em 50%, o pico de fluxo expiratório e a relação entre o volume expiratório forçado no primeiro segundo e a capacidade vital forçada. CONCLUSÕES: Os artigos mostram evidências significativas de associação entre a diminuição dos valores de capacidade vital forçada e volume expiratório forçado no primeiro segundo com a obesidade em crianças e adolescentes.

Lung function and cardiovascular risk: effect of cardiac rehabilitation

PURPOSE

Reduced lung function, as measured by the forced expiratory volume in 1 second (FEV1) and the forced vital capacity (FVC), is an independent risk factor for increased cardiovascular morbidity and mortality. Cardiac rehabilitation is known to reduce cardiovascular morbidity and mortality. We therefore investigated whether cardiac rehabilitation would lead to an improvement in lung function.

METHODS

We measured FEV1 and FVC by using spirometry in 49 participants (age = 65 ± 9 years; 38 men and 11 women) before and after participation in a comprehensive cardiac rehabilitation program.

RESULTS

At baseline, participants were obese with a body mass index (BMI) of 31 ± 6 kg/m, had normal lung function (FEV1 = 89 ± 16% predicted, FVC = 93 ± 14% predicted), and had a peak oxygen uptake (VO2) of 92 ± 21% of predicted. Following cardiac rehabilitation, participants lost weight (ΔBMI = -1.7 ± 4.3%, P = .01) and increased peak VO2 (Δ peak VO2)= 15 ± 17%, P < .0001). There were no statistically significant changes in FEV1 and FVC. However, in the subset of participants with a BMI 30 kg/m or higher (n = 27), there were statistically significant increases in FEV1 (5.1 ± 8.3%, P = .003) and FVC (4.9 ± 9.3%, P = .01), and changes in FEV1 were significantly correlated with changes in BMI (r = -0.58, P = .002).

CONCLUSIONS

Lung function improves in association with cardiac rehabilitation only in those participants with a baseline bmi 30 kg/m or higher, and these changes are inversely correlated with loss of weight. this finding suggests that obesity partly explains the association between lung function and cardiovascular risk.

Surgically induced weight loss, including reduction in waist circumference, is associated with improved pulmonary function in obese patients

BACKGROUND

Obesity is associated with impaired pulmonary function. We evaluated the effect of bariatric surgery on pulmonary function among obese patients and identified potential anthropometric factors of obesity corresponding to the reversal of impaired pulmonary function.

METHODS

Pulmonary function and anthropometric factors were studied in 94 obese patients aged 18-65 years with a body mass index >32 kg/m(2). Pulmonary function tests were performed preoperatively and 3 months after bariatric surgery. The measurements included forced vital capacity (FVC), forced expiratory volume in the first second (FEV(1)), total lung capacity, expiratory reserve volume, residual volume, and diffusing capacity of the lung for carbon monoxide. The anthropometric factors included the body weight, body mass index, waist circumference (WC), hip circumference, waist/height ratio, and waist/hip ratio. The changes in anthropometric parameters were analyzed in relation to pulmonary function test results. Multiple linear regression models were applied to identify the factors that influenced pulmonary function after bariatric surgery.

RESULTS

When measured 3 months after surgery, all anthropometric parameters for the 94 patients studied had significantly decreased, and the pulmonary function test parameters had significantly improved. Of the anthropometric parameters, the reduction in body weight, WC, and waist/height ratio correlated significantly with increases in the FEV(1) and FVC. In the multiple linear regression analysis, only the reduction in WC correlated significantly with the reductions in the FEV(1) and FVC.

CONCLUSION

After bariatric surgery, all anthropometric parameters of obesity decreased significantly and the pulmonary function improved. This improvement correlated best with the reduction in the WC and perhaps a decreased intra-abdominal pressure.

Physiology of obesity and effects on lung function

In obese people, the presence of adipose tissue around the rib cage and abdomen and in the visceral cavity loads the chest wall and reduces functional residual capacity (FRC). The reduction in FRC and in expiratory reserve volume is detectable, even at a modest increase in weight. However, obesity has little direct effect on airway caliber. Spirometric variables decrease in proportion to lung volumes, but are rarely below the normal range, even in the extremely obese, while reductions in expiratory flows and increases in airway resistance are largely normalized by adjusting for lung volumes. Nevertheless, the reduction in FRC has consequences for other aspects of lung function. A low FRC increases the risk of both expiratory flow limitation and airway closure. Marked reductions in expiratory reserve volume may lead to abnormalities in ventilation distribution, with closure of airways in the dependent zones of the lung and ventilation perfusion inequalities. Greater airway closure during tidal breathing is associated with lower arterial oxygen saturation in some subjects, even though lung CO-diffusing capacity is normal or increased in the obese. Bronchoconstriction has the potential to enhance the effects of obesity on airway closure and thus on ventilation distribution. Thus obesity has effects on lung function that can reduce respiratory well-being, even in the absence of specific respiratory disease, and may also exaggerate the effects of existing airway disease.

Análise da função respiratória em pacientes obesos submetidos à operação Fobi-Capella

INTRODUÇÃO: O objetivo deste trabalho foi mensurar quantitativamente essas alterações respiratórias desses pacientes comparando-os até 30 dias de pós-operatório. MÉTODO: Foram realizadas avaliações respiratórias nos períodos pré e pós-operatório de cirurgia bariátrica em obesos mórbidos com IMC superior a 39kg/m², através de gasometria arterial, prova de função respiratória, manovacuômetria, incentivador da respiração e cirtometrias. Foram realizadas também orientações fisioterápicas respiratórias e tratamento no pós-operatório, com dados comparativos entre as avaliações feitas no préoperatório, no 1º, 14º·e 30º dia pós-operatórios. RESULTADOS: Até o 30º dia de pós-operatório, esses indivíduos não obtiveram diferença significativa nos parâmetros estudados, não havendo, em decorrência do tratamento fisioterápico, complicações respiratórias. CONCLUSÃO: Não houve alterações dos parâmetros analisados, nem complicações respiratórias neste estudo com intervenção fisioterápica pré e pós-operatório de cirurgia bariátrica. Estudos devem ser realizados, para mensuração de um tempo maior de pós-operatório e de exercícios específicos, podendo, assim apresentar resultados diferentes.

Respiratory muscle strength in obese individuals and influence of upper-body fat distribution

CONTEXT AND OBJECTIVE

Pulmonary dysfunction in obese individuals may be associated with respiratory muscle impairment, and may be influenced by predominance of upper-body fat distribution. The objective of this study was to evaluate the strength of respiratory muscles in obese individuals and to analyze the influence of adipose tissue distribution.

DESIGN AND SETTING

Cross-sectional study on the preoperative period prior to bariatric surgery. Research developed within the Postgraduate General Surgery Program, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista (Unesp).

METHOD

Respiratory muscle strength was quantified by measuring maximum inspiratory and expiratory pressures (PImax and PEmax) in obese candidates for bariatric surgery. Adipose tissue distribution was assessed using the waist-hip circumference ratio (WHR). PImax, PEmax and WHR were compared with normal reference values and also in groups with different body mass index (BMI).

RESULTS

We evaluated 23 men and 76 women. All underwent PImax evaluation and 86 underwent PEmax. The mean BMI was 44.42 kg/m2. PImax and PEmax were within normal values; WHR showed that there was predominance of upper-body fat distribution; and there were no correlations among the variables studied. There was no significant variance among the variables PImax, PEmax and WHR when the study population was divided into groups with different BMI.

CONCLUSION

In the obese population studied, the excess weight did not result in impairment of respiratory muscle strength, and their predominant upper-body fat distribution also did not influence respiratory muscle strength.

Association of expiratory airway dysfunction with marked obesity in healthy adult dogs

OBJECTIVE

To evaluate the effects of obesity on pulmonary function in healthy adult dogs.

ANIMALS

36 Retrievers without cardiopulmonary disease.

PROCEDURES

Dogs were assigned to 1 of 3 groups on the basis of body condition score (1 through 9): nonobese (score, 4.5 to 5.5), moderately obese (score, 6.0 to 6.5), and markedly obese (score, 7.0 to 9.0). Pulmonary function tests performed in conscious dogs included spirometry and measurement of inspiratory and expiratory airway resistance (R(aw)) and specific R(aw) (sR(aw)) during normal breathing and during hyperpnea via head-out whole-body plethysmography. Functional residual capacity (FRC; measured by use of helium dilution), diffusion capacity of lungs for carbon monoxide (DLCO), and arterial blood gas variables (PaO(2), PaCO(2), and alveolar-arterial gradient) were assessed.

RESULTS

During normal breathing, body condition score did not influence airway function, DLCO, or arterial blood gas variables. During hyperpnea, expiratory sR(aw) was significantly greater in markedly obese dogs than nonobese dogs and R(aw) was significantly greater in markedly obese dogs, compared with nonobese and moderately obese dogs. Although not significantly different, markedly obese dogs had a somewhat lower FRC, compared with other dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

In dogs, obesity appeared to cause airflow limitation during the expiratory phase of breathing, but this was only evident during hyperpnea. This suggests that flow limitation is dynamic and likely occurs in the distal (rather than proximal) portions of the airways. Further studies are warranted to localize the flow-limited segment and understand whether obesity is linked to exercise intolerance via airway dysfunction in dogs.

Pulmonary function and sleep-related breathing disorders in severely obese children

BACKGROUND & AIMS

To evaluate the frequency of pulmonary function and sleep-breathing disorders in severely obese children and to search for their association with obesity phenotypes.

METHODS

Sleep studies and spirometry were performed for 54 severely obese children.

RESULTS

Upper airway resistances (RAWs) were increased with RAW>200% and forced 25s expiratory volume<80% in 83% and 60% of individuals, respectively. A decrease in functional residual capacity (FRC)<80% was found in 43%. Fifty-two percent of the children had a desaturation index>10 during sleep, and 41% of children presented at least one of three severity criteria (snoring index>300 per hour, respiratory events index (REI)>10 and arousal index>10). Univariate analyses showed a positive correlation between snoring index and BMI Z-score and neck/height ratio (P=0.01 and 0.04, respectively) as between REI and the same parameters (P=0.01 and 0.03, respectively). In a multivariate model with BMI Z-score, NHR still correlated with the snoring index (P=0.02) and REI (P=0.01).

CONCLUSIONS

In our cohort, obese children showed frequent pulmonary function and sleep-breathing disorders. The later were associated with impaired upper airway respiratory conductance.

Pulmonary function and abdominal adiposity in the general population

BACKGROUND

The prevalence of obesity is increasing, and there is evidence that obesity, in particular abdominal obesity as a marker of insulin resistance, is negatively associated with pulmonary function. The mechanism for this association and the best marker of abdominal adiposity in relation to pulmonary function is not known.

STUDY OBJECTIVE

We assessed the association between pulmonary function and weight, body mass index (BMI), waist circumference, waist/hip ratio, and abdominal height as markers of adiposity and body fat distribution. We used multiple linear regression to analyze the association of pulmonary function (ie, FEV(1) and FVC) [with maneuvers performed in the sitting position] with overall adiposity markers (ie, weight and BMI) and abdominal adiposity markers, stratified by gender, and adjusted for height, age, race, smoking, and other covariates.

SETTING AND PARTICIPANTS

A random sample of individuals (n = 2,153) from the general population living in western New York state, 35 to 79 years of age.

RESULTS

In women, abdominal height and waist circumference were negatively associated with FEV(1) percent predicted, while all five adiposity markers were negatively associated with FVC percent predicted. In men, all overall and abdominal adiposity markers were inversely associated with FEV(1) percent predicted and FVC percent predicted.

CONCLUSION

These results suggest that abdominal adiposity is a better predictor of pulmonary function than weight or BMI, and investigators should consider it when investigating the determinants of pulmonary function.

Volumes, capacidades pulmonares e força muscular respiratória no pós-operatório de gastroplastia

INTRODUÇÃO: A gastroplastia tem sido cada vez mais indicada no tratamento de obesos mórbidos, pacientes nos quais podemos identificar alteração pronunciada de volumes e capacidades pulmonares. OBJETIVO: Avaliar o comportamento dos volumes e capacidades pulmonares, força muscular respiratória, padrão respiratório e as possíveis complicações pulmonares pós-operatórias. MÉTODO: Vinte e um pacientes (três homens) com média de idade de 39 ± 9,7 anos, média de índice de massa corpórea de 50,4 Kg/m², candidatos à gastroplastia, foram avaliados no pré-operatório, primeiro, terceiro e quinto dias de pós-operatório e submetidos a mensuração de volume corrente, capacidade vital, volume minuto, pressões máximas expiratória e inspiratória, e circunferências abdominal e torácica. Observou-se a ocorrência de complicações pulmonares pós-operatórias e mortalidade. RESULTADOS: No primeiro e terceiro dias de pós-operatório houve queda de 47% e 30,5% na capacidade vital, 18% e 12,5% no volume minuto, 28% e 21% no volume corrente, 47% e 32% no índice diafragmático, 51% e 26% na pressão inspiratória máxima, e 39,5% e 26% na pressão expiratória máxima, respectivamente (p < 0,05). No quinto dia de pós-operatório, todos os valores das variáveis analisadas apresentaram-se maiores que os do primeiro pós-operatório, evidenciando um crescimento linear, com retorno total aos seus valores pré-operatórios apenas de volume corrente, volume minuto e índice diafragmático. Houve uma incidência de complicações pulmonares pós-operatórias de 4,7% e não houve óbitos. CONCLUSÃO: Pacientes submetidos a gastroplastia apresentam redução da função pulmonar, evidenciando um comportamento bastante semelhante ao já observado no pós-operatório de outras cirurgias do andar superior do abdome.