Effects of obesity and fat distribution on ventilatory function: the normative aging study

Preserved ratio impaired spirometry and severity of obstructive sleep apnea: An observational cross-sectional study

BACKGROUND AND OBJECTIVE

Lung function abnormality of obstructive sleep apnea (OSA) has not been explored well. Preserved ratio impaired spirometry (PRISm) is known for its association with obesity and cardiovascular morbidity, which are also characteristic features of OSA. This study aims to investigate whether the prevalence of PRISm increases according to apnea-hypopnea index levels among subjects with OSA.

METHODS

Conducted as an observational cross-sectional study, the study included 372 patients ≥40 years of age with definitive diagnoses of OSA and pulmonary function assessment from 2000 to 2004. Study subjects were classified based on OSA severity (mild/moderate versus severe). The prevalence of PRISm was estimated and compared between mild/moderate and severe OSA groups.

RESULTS

The prevalence of PRISm was 9.4 % in study subjects, with a higher prevalence in the severe OSA group than the mild/moderate group (12.9 % and 6.2 %, respectively, P = 0.04). The positive association between severe OSA and PRISm remained robust after multivariable adjustment for age, gender, and obesity (multivariable-adjusted odds ratio 2.29 (95 % confidence intervals 1.08-4.86), P = 0.03).

CONCLUSION

Severe OSA is an independent risk factor for PRISm, highlighting the need for comprehensive management of OSA that addresses the potential risk of PRISm.

Physical Activity Predicts Better Lung Function in Children and Adolescents

PURPOSE

To investigate (1) whether physical activity is associated with lung function in children and adolescents, (2) whether this association is modified by the subjects' weight status, and (3) whether this association is mediated by the body mass index.

METHODS

This is a cross-sectional study including 460 participants aged 7-17 years, randomly selected from 13 public schools in southern Brazil. Collected data included anthropometric measures, physical activity, screen time, and spirometric measures expressed as percent predicted values. Data were analyzed using multiple linear regression and 2-way analysis of variance.

RESULTS

There were positive associations between physical activity and forced vital capacity (β = 3.897, P = .001) and forced expiratory volume in the first second (β = 2.931, P = .021). The effect modification by weight status was not statistically significant (forced vital capacity: Pinteraction = .296 and forced expiratory volume in the first second: Pinteraction = .057). Body mass index did not mediate the association between physical activity and spirometric outcomes (P > .05).

CONCLUSION

Regular physical activity was associated with higher forced vital capacity and forced expiratory volume in the first second in children and adolescents. The observed associations were not modified by weight status nor mediated by body mass index. Our results reinforce the importance of regular physical activity for the development of lung function during childhood and adolescence.

Factors associated with postpartum fatigue: an exploration of the moderating role of resilience

Background

Postpartum fatigue (PPF) can impair the physical and mental well-being of women. The aims of this study were to assess the associations between fatigue and maternal health-related variables, specifically, sleep quality, depression symptoms, and resilience, and to explore the moderating role of resilience in the relationships between sleep quality, depression symptoms, and fatigue.

Methods

This cross-sectional study used data collected from mothers during the postpartum period via an online platform. PPF was assessed using the Fatigue Severity Scale, whereas sleep quality and depression symptoms were assessed using the Pittsburgh Sleep Quality Index and Edinburgh Postnatal Depression Scale, respectively. The Brief Resilience Scale was used to assess resilience. Simple and multiple binary logistic regression analyses were performed to examine the association of each independent variable with PPF and to determine the most significant predictors of PFF. The data were analyzed using SPSS, and structural equation modeling was performed using AMOS 23. A moderation analysis was performed to explore the moderating role of resilience using the Hayes PROCESS macro.

Results

A total of 1,443 postpartum mothers were included in the analysis. The simple binary logistic regression analysis showed that having chronic disease (odds: 1.52; p = 0.02), mother's age (odds: 0.97; p = 0.03), mother's body mass index (BMI; odds: 1.03; p = 0.01), depression symptoms (odds: 1.09; p ≤ 0.0001), sleep quality (odds: 1.17; p ≤ 0.0001), and resilience (odds: 0.42; p ≤ 0.0001) all contributed to fatigue during postpartum. Multivariate logistic regression showed that the mother's BMI, sleep quality, depression symptoms, and resilience were significant predictors of PPF. Moderation analyses showed that resilience was not a significant moderator between the main effects of sleep quality and fatigue (interaction effect: β = 0.01, p = 0.31, 95% CI: -0.01 to 0.04) or between the main effects of depression symptoms and fatigue during postpartum (interaction effect: β = 0.01, p = 0.82, 95% CI: -0.01 to 0.02).

Conclusion

Given the deleterious effects of PPF on maternal health outcomes, factors associated with PPF should be assessed regularly. In addition to mothers' BMI, sleep quality, and depression symptoms, resilience could also be a crucial factor in predicting fatigue severity during this critical time for mothers even though it was not a significant moderator among this sample.

Effects of Weight Change and Weight Cycling on Lung Function in Overweight and Obese Adults

Rationale: Epidemiological studies have reported on the detrimental effects on lung function after natural, and thus limited, weight gain in unselected populations. Studies on bariatric surgery, on the contrary, have indicated large improvements in lung function after substantial weight loss. Objectives: To study the associations between profound weight loss or gain and pulmonary function within the same population. A second objective was to investigate the effect of weight cycling on pulmonary function. Methods: From our lung function database, we selected the records of subjects in follow-up for continuous positive airway pressure therapy for sleep apnea with a weight change of ⩾20 kg within 5 years. Lung function (N = 255) at baseline was normal except for a tendency toward mild restriction in morbid obesity. Within this sample, 73 subjects were identified with significant "weight cycling", defined as a ⩾10-kg opposite change in body weight before or after the ⩾20-kg weight change. Results: Weight change affected pulmonary function more in men than in women (P < 0.001). In men, forced vital capacity (FVC) increased an average of 1.4% predicted per unit of body mass index after weight loss and the reverse after weight gain, whereas women exhibited a smaller change of 0.9% predicted per unit of body mass index. Weight loss slightly increased the ratio of forced expiratory volume in 1 second to FVC and decreased the specific airway resistance, whereas the opposite occurred with weight gain. Greater effects of weight change on lung function were observed in leaner subjects (P = 0.02) and in older subjects (P < 0.002). Changes in total lung capacity followed the changes in FVC, with no change in residual volume, and the greatest change was observed in functional residual capacity. In subjects with weight cycling, the improvement in lung function due to weight loss was reversed by subsequent weight gain and vice versa. Conclusions: This study provides evidence that the detrimental effect of obesity on lung function is a passive and reversible process.

Prolonged mechanical ventilation after lung transplantation: risks factors and consequences on recipient outcome

Background

Risk factors and the incidence of prolonged mechanical ventilation (PMV) after lung transplantation (LT) have been poorly described. The study assessed predictive factors of PMV after LT.

Methods

This observational, retrospective, monocentric study included all patients who received LT in Bichat Claude Bernard Hospital between January 2016 and December 2020. PMV was defined as a duration of MV > 14 days. Independent risk factors for PMV were studied using multivariate analysis. One-year survival depending on PMV was studied using Kaplan Meier and log-rank tests. A p value <0.05 was defined as significant.

Results

224 LT recipients were analysed. 64 (28%) of them received PMV for a median duration of 34 [26-52] days versus 2 [1-3] days without PMV. Independent risk factors for PMV were higher body mass index (BMI) (p = 0.031), diabetes mellitus of the recipient (p = 0.039), ECMO support during surgery (p = 0.029) and intraoperative transfusion >5 red blood cell units (p < 0.001). Increased mortality rates were observed at one-year in recipients who received PMV (44% versus 15%, p < 0.001).

Conclusion

PMV was associated with increased morbidity and mortality one-year after LT. Preoperative risk factors (BMI and diabetes mellitus) must be considered when selecting and conditioning the recipients.

Association between body composition, sarcopenia and pulmonary function in chronic obstructive pulmonary disease

Background

Chronic Obstructive Pulmonary Disease (COPD) is characterized by progressive and irreversible airflow limitation. Different factors that modify pulmonary function include age, sex, muscular strength, and a history of exposure to toxic agents. However, the impact of body composition compartments and sarcopenia on pulmonary function is not well-established. This study aimed to evaluate how body composition compartments and sarcopenia affect pulmonary function in COPD patients.

Methods

In a cross-sectional study, patients with a confirmed diagnosis of COPD, > 40 years old, and forced expiratory volume in the first second /forced vital capacity ratio (FEV₁/FVC) < 0.70 post-bronchodilator were included. Patients with cancer, HIV, and asthma were excluded. Body composition was measured with bioelectrical impedance. Sarcopenia was defined according to EWGSOP2, and pulmonary function was assessed by spirometry.

Results

185 patients were studied. The mean age was 72.20 ± 8.39 years; 55.14% were men. A linear regression adjusted model showed associations between body mass index, fat-free mass, skeletal muscle mass index, appendicular skeletal muscle mass index, and phase angle (PhA), and sarcopenia with FEV₁ (%). As regards FVC (%), PhA and exercise tolerance had positive associations.

Conclusion

Body composition, especially PhA, SMMI, ASMMI, and sarcopenia, has a significant impact on pulmonary function. Early detection of disturbances of these indexes enables the early application of such therapeutic strategies in COPD patients.

Evaluation of obesity and asthma as risk factors for moderate to severe obstructive sleep apnea in children

STUDY OBJECTIVES

Asthma and obesity are risk factors for obstructive sleep apnea (OSA) in children but their link to OSA severity is uncertain. We aimed at determining whether asthma or obesity were associated with an increased risk of moderate/severe OSA.

METHODS

Children undergoing a one-night polysomnography for suspicion of OSA were retrospectively included. Univariate and multivariate analyses were conducted to assess the clinical and demographic characteristics linked to moderate/severe OSA (obstructive apnea-hypopnea index ≥ 5/h of sleep) with odds ratio (OR) and 95% confidence interval reported.

RESULTS

490 children (311 (64%) boys) were included with a median [25th; 75th percentile] age of 8.7 [5.4; 12.9] years, 164 (33%) non-asthmatics non-obese, 122 (25%) obese non-asthmatics, 125 (26%) asthmatics non-obese, 79 (16%) asthmatics and obese. Moderate/severe OSA was present in 157 (32%) children (75/157 (48%) obese and 52/157 (33%) asthmatics). Independent factors associated with increased or decreased risk of moderate/severe OSA were: obesity and male sex (OR 1.82 [1.16; 2.87], P = 0.01, and 1.55 [1.02; 2.36], P = 0.04, respectively), and current asthma, age >6 years or behavioral disorders (OR 0.45 [0.29; 0.70], P < 0.001; 0.44 [0.27; 0.73], P < 0.001; and 0.55 [0.33; 0.92], P = 0.02, respectively). Abnormal resistance of the respiratory system (measured in 241 children), but not abnormal spirometry (measured in 213 children), increased the risk of moderate/severe OSA (OR 2.95 [1.46-5.96], P = 0.003).

CONCLUSIONS

In our cohort enriched in obese and asthmatic children, obesity was associated with higher risk of moderate/severe OSA whereas current asthma was not.

Association of Body Composition with Pulmonary Function in Ningxia: The China Northwest Cohort

BACKGROUND

In recent decades, obesity has become an epidemic worldwide and is a risk factor for many chronic diseases. Lung function is also a predictor of various chronic diseases. However, research results on the association between obesity and lung function are inconsistent and few studies have evaluated the association between central obesity indicators and lung function. Therefore, this study explored the correlation between central obesity and lung function.

METHODS

This study is a cross-sectional study. The basic participant characteristics were collected by questionnaire. A tape measure was used to measure waist circumference (WC) and hip circumference (HC). Body fat percentage was measured using an InBody370. Lung function parameters were measured using a digital spirometer connected to a computer (Chestgraph HI-101). R (R4.0.5) software was used for data analysis. A generalized linear model was used to analyze the association between obesity and lung function.

RESULTS

This study found that body mass index (BMI) adjusted for WC was negatively correlated with forced vital capacity (FVC) (β=-0.05 [-0.06, -0.03] in men, β=-0.05 [-0.07, -0.04] in women) and forced expiratory volume in 1 s (FEV1)(β=-0.02 [-0.03, -0.00] in men, β=-0.03 [-0.04, -0.02] in women). Body fat percentage was negatively correlated with FVC (β=-0.01 [-0.01, -0.01] in men, β=-0.01 [-0.01, -0.00] in women).

CONCLUSION

Central obesity and combined central and general obesity were more strongly positively correlated with lung function. WC-adjusted BMI was negatively correlated with lung function. Body fat percentage was negatively correlated with lung function.

Obesity-Related Indices Are Associated with Longitudinal Changes in Lung Function: A Large Taiwanese Population Follow-Up Study

The global pandemic of obesity and the increasing incidence of chronic respiratory diseases are growing health concerns. The association between obesity and pulmonary function is uncertain. Therefore, this study aimed to explore associations between changes in lung function and obesity-related indices in a large longitudinal study. A total of 9059 participants with no personal histories of asthma, smoking, bronchitis, or emphysema were enrolled from the Taiwan Biobank and followed for 4 years. Lung function was assessed using spirometry measurements including forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC). Changes in FEV1/FVC (∆FEV1/FVC) between baseline and follow-up were calculated. The following obesity-related indices were studied: lipid accumulation product (LAP), body roundness index (BRI), conicity index (CI), body adiposity index (BAI), abdominal volume index (AVI), body mass index (BMI), waist–hip ratio (WHR), and waist-to-height ratio (WHtR). In multivariable analysis, the subjects with high BMI (p < 0.001), WHR (p < 0.001), WHtR (p < 0.001), LAP (p = 0.002), BRI (p < 0.001), CI (p = 0.005), BAI (p < 0.001), and AVI (p < 0.001) were significantly associated with a high baseline FEV1/FVC. After 4 years of follow-up, the subjects with high BMI (p < 0.001), WHR (p < 0.001), WHtR (p < 0.001), LAP (p = 0.001), BRI (p < 0.001), CI (p = 0.002), BAI (p < 0.001), and AVI (p < 0.001) were significantly associated with a low △FEV1/FVC. High obesity-related index values were associated with better baseline lung function and a rapid decrease in lung function at follow-up.

Hypoxic Exercise Exacerbates Hypoxemia and Acute Mountain Sickness in Obesity: A Case Analysis

Acute mountain sickness (AMS) is a common syndrome characterized by headache, dizziness, loss of appetite, weakness, and nausea. As a major public health issue, obesity has increased in high altitude urban residents and intermittent commuters to high altitudes. The present study investigated acute hypoxic exposure and hypoxic exercise on hypoxemia severity and AMS symptoms in a physically active obese man. In this case analysis, peripheral oxygen saturation (SpO₂) was used to evaluate hypoxemia, heart rate (HR) and blood pressure (BP) were used to reflect the function of autonomic nervous system (ANS), and Lake Louise scoring (LLS) was used to assess AMS. The results showed that acute hypoxic exposure led to severe hypoxemia (SpO₂ = 72%) and tachycardia (HRrest = 97 bpm), and acute hypoxic exercise exacerbated severe hypoxemia (SpO₂ = 59%) and ANS dysfunction (HRpeak = 167 bpm, SBP/DBP = 210/97 mmHg). At the end of the 6-h acute hypoxic exposure, the case developed severe AMS (LLS = 10) symptoms of headache, gastrointestinal distress, cyanosis, vomiting, poor appetite, and fatigue. The findings of the case study suggest that high physical activity level appears did not show a reliable protective effect against severe hypoxemia, ANS dysfunction, and severe AMS symptoms in acute hypoxia exposure and hypoxia exercise.

Cardiopulmonary Pathophysiological Aspects in the Context of COVID-19 and Obesity

Obesity is a significant public health concern associated with high morbidity. Obese patients are at risk of severe COVID-19 infection, and obesity is a high-risk factor for admission to the intensive care unit. We aimed to write a narrative review of cardiac and pulmonary pathophysiological aspects of obese patients in the context of COVID-19 infection. Obesity affects lung volume, with a decrease in expiratory reserve volume, which is associated with a decrease in lung and chest wall compliance, an increase in airway resistance, and an increase in work of breathing. Obesity affects cardiac structure and hemodynamics. Obesity is a risk factor for hypertension and cardiovascular disorders. Moreover, obesity is associated with a low-grade inflammatory state, endothelial dysfunction, hyperinsulinemia, and metabolic disorders. Obesity is associated with severe COVID-19 and invasive mechanical ventilation. These previous cardiopulmonary pathological aspects may explain the clinical severity in obese patients with COVID-19. Obese patients are at risk of severe COVID-19 infection. Understanding cardiorespiratory pathophysiological aspects may help physicians manage patients in hospitals.

Obesity and asthma

Obesity has been well recognized as an important comorbidity in patients with asthma, representing a unique phenotype and endotype. This association indicates a close relationship between metabolic and inflammatory dysregulation. However, the detailed organ-organ, cellular, and molecular interactions are not completely resolved. Because of that, the relationship between obesity and asthma remains unclear. In this article, clinical and epidemiological studies, as well as data from experimental animal work, are being summarized to provide a state of the art update on this important topic. Much more work is needed, particularly mechanistic, to fully understand the interaction between obesity and asthma and to develop novel preventive and therapeutic strategies.

Impact of obesity on pulmonary function: current understanding and knowledge gaps

PURPOSE OF REVIEW

Obesity is an increasing world-wide public health concern. Obesity both causes respiratory symptoms and contributes to many cardiorespiratory diseases. The effects of obesity on commonly used lung function tests are reviewed.

RECENT FINDINGS

The effects of obesity on lung function are attributed both to mechanical factors and to complex metabolic effects that contribute to a pro-inflammatory state. The effects of obesity on lung function correlate with BMI and correlate even better when the distribution of excess adipose tissue is taken into account, with central obesity associated with more prominent abnormalities. Obesity is associated with marked decreases in expiratory reserve volume and functional residual capacity. Total lung capacity, residual volume, and spirometry are less affected by obesity and are generally within the normal range except with severe obesity. Obesity decreases total respiratory system compliance primarily because of decreased lung compliance, with only mild effects on chest wall compliance. Obesity is associated with impaired gas transfer with decreases in oxygenation and varied but usually mild effects on diffusing capacity for carbon monoxide, while the carbon monoxide transfer coefficient is often increased.

SUMMARY

Obesity has significant effects on lung function. The relative contribution of the mechanical effects of obesity and the production of inflammatory cytokines by adipose tissue on lung function needs further study.

Association between the body mass index and outcomes of patients resuscitated from out-of-hospital cardiac arrest: a prospective multicentre registry study

Background

The effects of the body mass index (BMI) on outcomes of patients resuscitated from cardiac arrest are controversial. Therefore, the current study investigated the association between the BMI and the favourable neurologic outcomes and survival to discharge of patients resuscitated from out-of-hospital cardiac arrest (OHCA).

Methods

This multicentre, prospective, nationwide OHCA registry-based study was conducted using data from the Korean Cardiac Arrest Resuscitation Consortium (KoCARC). We enrolled hospitals willing to collect patient height and weight and included patients who survived to the hospital between October 2015 and June 2018. The included patients were categorised into the underweight (< 18.5 kg/m²), normal weight (≥18.5 to < 25 kg/m²), overweight (≥25 to < 30 kg/m²), and obese groups (≥30 kg/m²) according to the BMI per the World Health Organization (WHO) criteria. The primary outcome was a favourable neurologic outcome; the secondary outcome was survival to discharge. Univariate and multivariate analyses were performed to investigate the association between BMI and outcomes.

Results

Nine hospitals were enrolled; finally, 605 patients were included in our analysis and categorised per the WHO BMI classification. Favourable neurologic outcomes were less frequent in the underweight BMI group than in the other groups (p = 0.002); survival to discharge was not significantly different among the BMI groups (p = 0.110). However, the BMI classification was not associated with favourable neurologic outcomes or survival to discharge after adjustment in the multivariate model.

Conclusion

The BMI was not independently associated with favourable neurologic and survival outcomes of patients surviving from OHCA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13049-021-00837-x.

Anthropometric determinants of lung function in apparently healthy individuals

Background

Forced vital capacity (FVC) and peak expiratory flow rate (PEFR) are used to assess and monitor the management of lung pathology.

Objectives

Our study documented spirometry reference values for apparently healthy Nigerians and developed predictive equations for pulmonary function.

Method

A cross-sectional survey involving healthy adult Nigerians included anthropometric measurements of weight, height, waist, hip circumference (HC), sagittal abdominal diameter (SAD) and percentage body fat. Anthropometric indices (body mass index [BMI] and waist-to-hip ratio [WHR]) were estimated and pulmonary function tests (FVC, forced expiratory volume in 1 s [FEV1], PEFR, FEV1/FVC ratio) measured. The association amongst selected anthropometric and socio-demographic variables and pulmonary function test parameters were established using t-tests and Pearson’s product moment correlation tests. The predictors of pulmonary function were established using stepwise multiple linear regression models.

Results

Four hundred and forty-four adults (156 [35.1%] men) were included, mean age 37.3 ± 8.25 (range 22–25) years. Male participants had significantly higher lung volumes than females (p < 0.05). Age, height, weight and percentage body fat had significant low correlations with lung function test parameters (p < 0.05). Fat-free mass (FFM), fat mass (FM), SAD, height and age of participants were main predictors of FVC and FEV1 (R² = 0.43 and 0.41, respectively). Fat-free mass and SAD were main predictors of PEFR (R² = 0.53). Sagittal abdominal diameter and age were main predictors of FEV1/FVC ratio (R² = 0.34).

Conclusion

Fat-free mass, FM, height, age and SAD are important determinants of lung volumes and key variables for predictive equations of pulmonary function.

Clinical implications

An accurate documentation of pulmonary function values for apparently healthy Nigerian adults may be useful in identifying deviations from normative values thereby giving an index of suspicion for the diagnosis of pulmonary dysfunction.

Keywords

anthropometric; lung function; spirometry; fat-free mass; apparently healthy.

Comparing the effects of six-months aerobic training on pulmonary function tests in obese and nonobese women

BACKGROUND

Obesity is becoming a serious public health issue in the world and is associated with a wide range of health conditions, including respiratory diseases. Prolonged aerobic exercises are thought to improve aerobic capacity and to have a favorable effect on lung function. Thus, the purpose of this study was to determine the comparison the effects of six months of aerobic training on pulmonary function tests in obese and nonobese women.

METHODS

The subjects of this study were nineteen healthy and inactive females assigned into the obese (N.=10) and nonobese (N.=9) groups. The exercise protocol included aerobic exercise training lasted for 6 months and 3 sessions per week and every session lasted for 60 minutes and with intensity of 55-65 percent of maximum heart rate reserve. Before starting program, the anthropometric measurements of subjects such as weight, percent body fat and body mass Index was measured by body composition analyzer and lung function tests were carried out by using a spirometer.

RESULTS

Obese women have lower values of FEV1, FVC, FEV1/FVC, PEF, Vt and MVV when compared with nonobese group but the difference did not reach significant level. Also, the results of this study showed that there are significant differences in FVE1 Index and MVV tests in obese and nonobese groups in pretest and post-test, but FVC Index increased significantly just in obese group.

CONCLUSIONS

It seems that if the training program is done in appropriate time and intensity, which leads to weight loss in obese people, it can lead to improve all Index of pulmonary function.

[Deterioration of gas exchange in subjects with an increase in body mass index at an altitude of 2,240 meters above sea level]

Introducción

Las alteraciones del intercambio gaseoso se han reconocido en la obesidad mórbida; sin embargo, no se conoce su comportamiento conforme se incrementa el índice de masa corporal.

Objetivo

Conocer el comportamiento del intercambio gaseoso a la altura de la Ciudad de México en el desarrollo de obesidad mórbida.

Métodos

Mediante un diseño transversal analítico se estudió a sujetos pareados por género y edad de cuatro grupos diferentes de índice de masa corporal (kg/m2): normal (18.5-24.9), sobrepeso (25-29.9), obesidad (30-39.9) y obesidad mórbida (≥ 40). Se obtuvieron sus antecedentes patológicos y demográficos, variables de gasometría arterial y espirometría simple. Las variables se determinaron de acuerdo con las características de la muestra; las diferencias entre grupos se realizaron mediante Anova de una vía con ajuste de Bonferroni, así como la correlación de Pearson para las variables relacionadas. Una p < 0.05 se consideró con significación estadística.

Resultados

Se estudió a 560 pacientes en cuatro grupos. La edad promedio fue de 49 ± 11 años. La mayor frecuencia de diabetes mellitus (34.29%), hipertensión arterial (50%) e hiperlipidemia (36.43%) se registró en el grupo de obesidad, y la de roncador (73.57%) en la obesidad mórbida. Se identificaron diferencias desde el grupo normal respecto de la obesidad mórbida: PaCO2 31.37 ± 2.08 vs. 38.14 ± 5.10 mmHg; PaO2 68.28 ± 6.06 vs. 59.86 ± 9.28 mmHg y SaO2 93.51 ± 1.93 vs. 89.71 ± 5.37%, todas con p = 0.0001. Correlación IMC-PaCO2: 0.497, e IMC-PaO2: -0.365, p = 0.0001, respectivamente.

Conclusiones

A la altitud de la Ciudad de México y con índice de masa corporal > 30 kg/m2, las variables relacionadas con el intercambio gaseoso y espirometría simple comienzan a deteriorarse; son evidentes con IMC > 40 kg/m2.

Introduction

Alterations of gas exchange have been recognized in morbid obesity, however, it is not known how their behavior would be as the body mass index increases.

Objective

To know the behavior of gas exchange at the level of Mexico City in the development of morbid obesity.

Methods

Through analytical design, subjects matched by gender and age were studied from four different groups of body mass index (kg/m2), normal (18.5-24.9), overweight (25-29.9), obesity (30-39.9) and morbid obesity (≥ 40). Their pathological and demographic antecedents, arterial blood gas and simple spirometry variables were obtained. The variables were shown according to their sample characteristic. The differences between groups were made using one way Anova with Bonferroni adjustment, as well as Pearson’s correlation for the related variables. Statistical significance was considered with p < 0.05.

Results

560 subjects were studied in 4 groups. The average age 49 ± 11 years old. The highest frequency of diabetes mellitus (34.29%), arterial hypertension (50%) and hiperlipidemia (36.43%) was in the obesity group, and being snoring (73.57%) in morbid obesity. There were differences from the normal group versus. morbid obesity: PaCO2 31.37 ± 2.08 versus. 38.14 ± 5.10 mmHg; PaO2 68.28 ± 6.06 versus. 59.86 ± 9.28 mmHg and SaO2 93.51 ± 1.93 versus. 89.71 ± 5.37%, all with p = 0.0001. The IMC-PaCO2 correlation: 0.497, and IMC-PaO2: −0.365, p = 0.0001 respectively.

Conclusions

At the altitude of Mexico City and body mass index > 30 kg/m2 the variables related to gas exchange and simple spirometry begin to deteriorate; are evident with BMI > 40 kg/m2.

Involvement of overweight and lipid metabolism in the development of pulmonary hypertension under conditions of chronic intermittent hypoxia

There is growing evidence that exposure to hypoxia, regardless of the source, elicits several metabolic responses in individuals. These responses are constitutive and are usually observed under hypoxia but vary according to the type of exposure. The aim of this review was to describe the involvement of obesity and lipid metabolism in the development of high-altitude pulmonary hypertension and in the development of acute mountain sickness under chronic intermittent hypoxia. Overweight or obesity, which are common in individuals with long-term chronic intermittent hypoxia exposure (high-altitude miners, shift workers, and soldiers), are thought to play a major role in the development of acute mountain sickness and high-altitude pulmonary hypertension. This association may be rooted in the interactions between obesity-related metabolic and physical alterations, such as increased waist circumference and neck circumference, among others, which lead to critical ventilation impairments; these impairments aggravate hypoxemia at high altitude, thereby triggering high-altitude diseases. Overweight and obesity are strongly associated with higher mean pulmonary artery pressure in the context of long-term chronic intermittent hypoxia. Remarkably, de novo synthesis of triglycerides by the sterol regulatory element-binding protein-1c pathway has been demonstrated, mainly due to the upregulation of stearoyl-CoA desaturase-1, which is also associated with the same outcomes. Therefore, overweight, obesity, and other metabolic conditions may hinder proper acclimatization. The involved mechanisms include respiratory impairment, alteration of the nitric oxide pathways, inflammatory status, reactive oxygen species imbalance, and other metabolic changes; however, further studies are required.

A Comprehensive Genome-Wide and Phenome-Wide Examination of BMI and Obesity in a Northern Nevadan Cohort

The aggregation of Electronic Health Records (EHR) and personalized genetics leads to powerful discoveries relevant to population health. Here we perform genome-wide association studies (GWAS) and accompanying phenome-wide association studies (PheWAS) to validate phenotype-genotype associations of BMI, and to a greater extent, severe Class 2 obesity, using comprehensive diagnostic and clinical data from the EHR database of our cohort. Three GWASs of 500,000 variants on the Illumina platform of 6,645 Healthy Nevada participants identified several published and novel variants that affect BMI and obesity. Each GWAS was followed with two independent PheWASs to examine associations between extensive phenotypes (incidence of diagnoses, condition, or disease), significant SNPs, BMI, and incidence of extreme obesity. The first GWAS examines associations with BMI in a cohort with no type 2 diabetics, focusing exclusively on BMI. The second GWAS examines associations with BMI in a cohort that includes type 2 diabetics. In the second GWAS, type 2 diabetes is a comorbidity, and thus becomes a covariate in the statistical model. The intersection of significant variants of these two studies is surprising. The third GWAS is a case vs. control study, with cases defined as extremely obese (Class 2 or 3 obesity), and controls defined as participants with BMI between 18.5 and 25. This last GWAS identifies strong associations with extreme obesity, including established variants in the FTO and NEGR1 genes, as well as loci not yet linked to obesity. The PheWASs validate published associations between BMI and extreme obesity and incidence of specific diagnoses and conditions, yet also highlight novel links. This study emphasizes the importance of our extensive longitudinal EHR database to validate known associations and identify putative novel links with BMI and obesity.

[The impact of obesity on respiratory function]

The respiratory impact of obesity can be both symptomatic (resting and exertional breathlessness) and functional (pulmonary function at rest and on exercise). The prevalence of breathlessness is increased in adult obese individuals, ∼50% at rest and ∼75% on exertion (mMRC score>0). Pulmonary function abnormalities in obese adults include reduced functional residual capacity (FRC) and expiratory residual volume (ERV), and less frequently reduced total lung capacity (a restrictive defect, with TLC below the 5th percentile of predicted is present in around 15% in severe obese adults), with normal residual volume (RV). Airflows are barely affected by obesity, but bronchial hyperresponsiveness (BHR) is very prevalent, which may be due to the loss of bronchoprotective effect of deep inspiration in obesity (mechanical pathophysiology of BHR). In children, the modifications of lung volumes seen are quite different: TLC is normal while FRC and RV are reduced, explaining the increase in FVC. FEV1/FVC is therefore reduced by obesity, without true airflow obstruction (dysanaptic growth). Resting oxygen consumption (V'O₂) is increased due to obesity and normally increases with exercise. Maximum V'O₂ is normal or weakly reduced in obese patients; on the other hand, the increase in respiratory load increases the oxygen cost of ventilation, which tends to be rapid, both at rest and during exertion. Finally, it should be noted that there is only limited statistical correlation between exercise dyspnoea and respiratory function abnormalities in obesity.

Obesity and sarcoidosis: consequence or contributor?

PURPOSE OF REVIEW

Sarcoidosis is a multisystem disease of unknown cause. Obesity can affect many physiological factors. The relationship between obesity and sarcoidosis is unclear, and can been described as posing a 'chicken and egg' scenario for the patient as it is not always clear whether it is a consequence of, or a risk factor for any disease. The purpose of this review is to examine the dual roles of obesity on sarcoidosis morbidity and the incidence.

RECENT FINDINGS

Obesity magnifies the symptoms of sarcoidosis and corticosteroid therapy increases BMI. Prospective epidemiologic studies started to explore the role of obesity as a potential risk factor for sarcoidosis. Three studies in the United States, and one study in Denmark, have demonstrated significantly increased risks of sarcoidosis among obese compared with nonobese patients; risk estimates ranged from 1.42 [95% confidence interval (CI), 1.07-1.89] to 3.59 (95% CI, 2.31-5.57).

SUMMARY

Obesity can be both a consequence of sarcoidosis treatment, and a contributor to disease risk likely through the pro-inflammatory environment of obesity. Prospective epidemiologic cohort studies are needed to explore the cause of sarcoidosis and insight into possible avenues of treatment development and prevention.

Trends in the prevalence of airflow limitation in a general Japanese population: two serial cross-sectional surveys from the Hisayama Study

OBJECTIVES

Chronic obstructive airway disease, which is characterised by airflow limitation, is a major burden on public health. Reductions in environmental pollution in the atmosphere and workplace and a decline in the prevalence of smoking over recent decades may have affected the prevalence of airflow limitation in Japan. The present epidemiological study aimed to evaluate trends in the prevalence of airflow limitation and in the influence of risk factors on airflow limitation in a Japanese community.

DESIGN

Two serial cross-sectional surveys.

SETTING

Data from the Hisayama Study, a population-based prospective study that has been longitudinally conducted since 1961.

PARTICIPANTS

A total of 1842 and 3033 residents aged ≥40 years with proper spirometric measurements participated in the 1967 and 2012 surveys, respectively.

MAIN OUTCOME MEASURES

Airflow limitation was defined as forced expiratory volume in 1 s/forced vital capacity <70% by spirometry. For each survey, the age-adjusted prevalence of airflow limitation was evaluated by sex. ORs and population attributable fractions of risk factors on the presence of airflow limitation were compared between surveys.

RESULTS

The age-standardised prevalence of airflow limitation decreased from 1967 to 2012 in both sexes (from 26.3% to 16.1% in men and from 19.8% to 10.5% in women). Smoking was significantly associated with higher likelihood of airflow limitation in both surveys, although the magnitude of its influence was greater in 2012 than in 1967 (the multivariable-adjusted OR was 1.63 (95% CI 1.19 to 2.24) in 1967 and 2.26 (95% CI 1.72 to 2.99) in 2012; p=0.007 for heterogeneity). Accordingly, the population attributable fraction of smoking on airflow limitation was 33.5% in 2012, which was 1.5-fold higher than that in 1967 (21.1%).

CONCLUSIONS

The prevalence of airflow limitation was decreased over 45 years in Japan, but the influence of smoking on airflow limitation increased with time.

Does Dietary-Induced Obesity in Old Age Impair the Contractile Performance of Isolated Mouse Soleus, Extensor Digitorum Longus and Diaphragm Skeletal Muscles?

Ageing and obesity independently have been shown to significantly impair isolated muscle contractile properties, though their synergistic effects are poorly understood. We uniquely examined the effects of 9 weeks of a high-fat diet (HFD) on isometric force, work loop power output (PO) across a range of contractile velocities, and fatigability of 79-week-old soleus, extensor digitorum longus (EDL) and diaphragm compared with age-matched lean controls. The dietary intervention resulted in a significant increase in body mass and gonadal fat pad mass compared to the control group. Despite increased muscle mass for HFD soleus and EDL, absolute isometric force, isometric stress (force/CSA), PO normalised to muscle mass and fatigability was unchanged, although absolute PO was significantly greater. Obesity did not cause an alteration in the contractile velocity that elicited maximal PO. In the obese group, normalised diaphragm PO was significantly reduced, with a tendency for reduced isometric stress and fatigability was unchanged. HFD soleus isolated from larger animals produced lower maximal PO which may relate to impaired balance in older, larger adults. The increase in absolute PO is smaller than the magnitude of weight gain, meaning in vivo locomotor function is likely to be impaired in old obese adults, with an association between greater body mass and poorer normalised power output for the soleus. An obesity-induced reduction in diaphragm contractility will likely impair in vivo respiratory function and consequently contribute further to the negative cycle of obesity.

Comparison of Maximum Oxygen Uptake and Rating Perceived Exertion in Woman's Kabaddi Athletes (Without Breathy Voice to Severe Breathy Voice)

OBJECTIVE

There is limited research on voice problems of athletes, especially Kabaddi athletes who use their voice during Kabaddi exercises and may damage their vocal folds and impair their voice quality. The present study aimed to compare maximum oxygen uptake (VO₂max) and rating perceived exertion (RPE) in Woman's Kabaddi athletes without breathy voice (BV) to severe BV.

MATERIALS AND METHODS

Seventy woman's Kabaddi athletes (mean age of 20.5 ± 2.7 years, height of 163 ± 3.6 cm, weight of 61.4 ± 5.4 kg) at the club and national team level (without BV to severe BV) were compared in this study. Data were collected by imaging the larynx by a stroboscopic device (there is gap and asymmetry between vocal folds, presence of mass on vocal folds, muscle tension dysphonia, hoarseness, and harshness), evaluating the voice parameters by Vocal Assessment software (mean F₀ (Hz), F₀SD (Hz), jitter (%), shimmer (%), Normal Noise Energy (NNE) (dB)), and calculating VO₂max by Bruce treadmill test. RPE was calculated by a 15-point (6-20) Borg test.

RESULTS

The results showed that 39 (55.17%) subjects had moderate and high BV symptoms and 31 (44.28%) had no symptoms of BV and low BV. The mean fundamental frequency in the group with moderate and severe BV was equal to 2.59 Hz opposite the mean fundamental frequency in the group without BV and low BV was equal to 0.65 Hz, and in contrast, the jitter (0.47%) opposite (0.19%) and the shimmer was equal to (6.64%) opposite (0.67%) and the NNE was equal to (-3.08 dB) In front of (-11.95 dB). There was no significant difference between VO2max in two groups of Woman's Kabaddi athletes as well as RPE in two groups of Woman's Kabaddi athletes at significant level of P ≤ 0.05.

CONCLUSIONS

Severe BV is affected by voice abuse. Voice abuse during Kabaddi is negatively affecting the quality of voice. After Kabaddi sport, athletes are complained from obstruction, hoarseness, and harshness due to disturbances in vocal folds and throat dryness. According to the data obtained from this study, abuse has a negative effect on vocal folds, which is followed by BV in various degrees in Kabaddi athletes.

The multi-ethnic global lung initiative 2012 (GLI-2012) norms reflect contemporary adult's Algerian spirometry

Background

The validation of the multi-ethnic GLI-2012 spirometric norms has been debated in several countries. However, its applicability in Algeria has not been verified.

Aim

To ascertain how well the GLI-2012 norms fit contemporary adult Algerian spirometric data.

Methods

This was a cross-sectional study of a convenience sample of 300 healthy non-smoker adults (50% men, age range: 18–85 years) recruited from the Algiers region general population. All participants underwent a clinical examination and a plethysmography measurement. Z-scores for some spirometric data [FEV₁, FVC, FEV₁/FVC and forced expiratory flow at 25–75% of FVC (FEF_25-75%)] were calculated. If the average Z-score deviated by “< ± 0.5” from the overall mean, the GLI-2012 norms would be considered as reflective of contemporary Algerian spirometry.

Results

The means±SDs of age, height, weight, FVC, FEV₁, FEV₁/FVC and FEF_25-75% of the participants were, respectively, 48±17 years, 1.65±0.10 m, 73±14 kg, 4.04±1.04 L, 3.18±0.82 L, 0.79±0.05 and 4.09±1.09 L/s. Almost the quarter of participants were obese. The total sample means±SDs Z-scores were 0.22±0.87 for FVC, 0.04±0.88 for FEV₁, -0.34±0.67 for FEV₁/FVC and 0.93±0.79 for FEF_25-75%. For men and women, only the means±SDs of the FEF_25-75% Z-scores exceeded the threshold of “± 0.5”, respectively, 1.13±0.77 and 0.73±0.76.

Conclusion

Results of the present study, performed in an Algerian population of healthy non-smoking adults, supported the applicability of the GLI-2012 norms to interpret FEV₁, FVC and FEV₁/FVC but not the FEF_25-75%.

The effect of obesity on lung function

INTRODUCTION

There is a major epidemic of obesity, and many obese patients suffer with respiratory symptoms and disease. The overall impact of obesity on lung function is multifactorial, related to mechanical and inflammatory aspects of obesity. Areas covered: Obesity causes substantial changes to the mechanics of the lungs and chest wall, and these mechanical changes cause asthma and asthma-like symptoms such as dyspnea, wheeze, and airway hyperresponsiveness. Excess adiposity is also associated with increased production of inflammatory cytokines and immune cells that may also lead to disease. This article reviews the literature addressing the relationship between obesity and lung function, and studies addressing how the mechanical and inflammatory effects of obesity might lead to changes in lung mechanics and pulmonary function in obese adults and children. Expert commentary: Obesity has significant effects on respiratory function, which contribute significantly to the burden of respiratory disease. These mechanical effects are not readily quantified with conventional pulmonary function testing and measurement of body mass index. Changes in mediators produced by adipose tissue likely also contribute to altered lung function, though as of yet this is poorly understood.

Can physical training minimize the gender differences in lung capacity of trained tennis players aged 14 – 17 years old ?

Background: This study was based on gender differences in male and female trained tennis players. Aim of the study: The aim of this study was to determine the extent that physical training could minimize the gender differences in lung capacities in trained tennis players aged 14–17 years. Material and methods: The participants were ten male and seven female lawn tennis players, with a mean ± standard deviation (SD) age of 15.5 ± 1.27 and 14.43 ± 1.13 years, respectively. Physical characteristics and lung volumes were measured on the same day for each participant. Data were presented as mean ± SD, and Student’s t-test to compare the measured variables was performed. Results: Differences between genders were insignificant in terms of age (years), weight (kg), body fat (%), lean body mass (kg) and chest circumference (cm). However, height (cm), and W/H ratio were significantly (p < 0.05) higher in male tennis players in comparison to female players. Insignificant differences were found for TV (L), SVC (L), FVC (L), FEV1 (L), FEV1/FVC (%), FEF25-75% (L/s), PEF (L/s) and MVV (L/min). The only significant difference (p < 0.05) in lung function measures between male and female trained tennis players was for PIF (L/s). Conclusions: Male tennis players were taller than female tennis players of same age range, which might be advantageous for males while playing. Insignificant differences between male and female players in the various lung variables measured indicated that the influence of height and gender differences could be minimized by proper training during puberty. A significantly higher PIF in male players indicated stronger and more powerful inspiratory muscle activity compared with female tennis players.

High-Frequency Percussive Ventilation Rescue Therapy in Morbidly Obese Patients Failing Conventional Mechanical Ventilation

BACKGROUND

Morbidly obese patients with respiratory failure who do not improve on conventional mechanical ventilation (CMV) often undergo rescue therapy with extracorporeal membrane oxygenation (ECMO). We describe our experience with high-frequency percussive ventilation (HFPV) as a rescue modality.

METHODS

In a retrospective analysis from 2009 to 2016, 12 morbidly obese patients underwent HFPV after failing to wean from CMV. Data were collected regarding demographics, cause of respiratory failure, ventilation settings, and hospital course outcomes. Our end point data were pre- and post-HFPV partial pressure of arterial oxygen and PaO₂ to fraction of inspired oxygen (PF) ratios measured at initiation, 2, and 24 hours.

RESULTS

Twelve morbidly obese patients required HFPV for respiratory failure. Causes of respiratory failure overlapped and included cardiogenic pulmonary edema (n = 8), pneumonia (n = 5), septic shock (n = 5), and asthma (n = 1). After HFPV initiation, mean fraction of inspired oxygen FiO₂ was tapered from 98% to 82% and 66% at 2 and 24 hours, respectively. Mean PaO₂ increased from 60.9 mm Hg before HFPV to 175.1 mm Hg (P < .05) at initiation of HFPV, then sustained at 129.5 mm Hg (P < .05) and 88.1 mm Hg (P < .005) at 2 and 24 hours, respectively. Mean PF ratio improved from 66.1 before HFPV to 180.3 (P < .05), 181.0 (P < .05) and 148.9 (P < .0005) at initiation, 2, and 24 hours, respectively. The improvement in mean PaO₂ and PF ratios was durable at 24 hours whether or not the patient was returned to CMV (n = 10) or remained on HFPV (n = 2). Survival to discharge was 66.7%.

CONCLUSION

In our cohort of morbidly obese patients, HFPV was successfully utilized as a rescue therapy precluding the need for ECMO. Despite our small sample size, HFPV should be considered as a rescue therapy in morbidly obese patients failing CMV prior to the initiation of ECMO. Our retrospective analysis supports consideration for HFPV as another form of rescue therapy for obese patients with refractory hypoxemia and respiratory failure who are not improving with CMV.

Body weight and mortality in COPD: focus on the obesity paradox

The positive association between overweight, obesity, and cardiovascular and all-cause mortality is well established, even though this relation is typically U shaped with an increased risk also in low-weight subjects. However, being overweight or obese has been associated with a better prognosis in subjects suffering from chronic diseases, id est the "obesity paradox". In both community-dwelling and hospitalized patients with COPD, several studies have reported a significant protective effect of obesity on all-cause mortality, indicating that also in obstructive pulmonary diseases, an obesity paradox may be present. Interestingly, the "paradox" is more evident for subjects with severe bronchial obstruction (i.e., a lower FEV1), while in mild-moderate conditions, the weight-related mortality shows a behavior similar to that observed in the general population. Several factors may confound the relation between COPD, obesity and mortality. The lower FEV1 found in obese people may be linked to a restrictive defect rather than to an obstructive one. Due to the modified chest wall mechanical properties-related to increased fat mass-obese COPD patients may present, respect to their lean counterpart, a lower lung hyperinflation which is associated with higher mortality. The traditional classification of COPD attributes to obese "blue bloaters" a low-grade emphysema in opposition to lean "pink puffers"; the fact that emphysema extent is related to mortality may bias the relationship between weight and survival. It is also to underline that the majority of the studies, consider BMI rather than body composition (a better predictor of mortality) when studying the intriguing relation between weight, COPD, and mortality. Reverse bias has also to be taken into account, hypothesizing that an unintentional weight loss may be the deleterious factor related to mortality, rather than considering obesity a protective one. Further prospective studies are needed to shed light on the complexity of this emerging issue.

LEVEL OF EVIDENCE

Level V: Narrative Review.

Voluntary breath-holding duration in healthy subjects with obesity: Role of peripheral chemosensitivity to carbon dioxide

OBJECTIVE

The present study aimed to explore the peripheral chemoreflex sensitivity in healthy subjects with high body mass index (BMI).

METHODS

We studied 26 healthy men with obesity and 23 healthy men without obesity. All participants performed the breath-holding test in the morning, and the single-breath carbon dioxide (SB-CO₂) test on the next day.

RESULTS

The sensitivity of peripheral chemoreceptors to CO₂ did not differ between two groups (P = .47). In contrast, the duration of breath-holding was significantly lower in participants with elevated BMI (40.6 ± 10.5 s versus 47.2 ± 8.7 s; P < .05). In the multifactor regression model, only differences in waist-to-hip ratio (WHR) and SB-CO₂ remained statistically significant (R² for the model = 0.62, P < .001).

CONCLUSIONS

The sensitivity of peripheral chemoreflex to CO₂ was preserved in healthy men with obesity. The higher sensitivity of peripheral chemoreflex to CO₂ and higher WHR were associated with a decrease in the duration of voluntary apnea in subjects with obesity.

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.

Association of adiposity with pulmonary function in older Chinese: Guangzhou Biobank Cohort Study

OBJECTIVE

We examined the association between different adiposity indices and pulmonary function in Chinese adults in the Guangzhou Biobank Cohort Study (GBCS).

METHODS

Participants with body mass index (BMI) < 18.5 (underweight) were excluded. Adiposity indices including BMI, waist circumference (WC), waist hip ratio, waist height ratio and body fat percentage were measured. Lung function was assessed by spirometry using a turbine flowmeter. We analyzed percent predicted for forced expiratory volume in 1 s (FEV₁%), forced vital capacity (FVC %) and restrictive respiratory defect (FEV₁/FVC ratio > low limits of normal and FVC % <0.80).

RESULTS

Of 16186 participants (mean age 61.4 ± 7.2 years; 74.0% women), 116 (0.7%) had only general obesity (BMI ≥28 kg/m²), 4079 (25.2%) had only central obesity (WC: ≥90 cm in men, ≥80 cm in women) and 1591 (9.8%) had both central obesity and general obesity. Comparing to those with neither central nor general obesity, those with only central adiposity and with both central and general obesity had lower pulmonary function (adjusted β range from -2.85 to -6.02 for FEV₁% and FVC%, adjusted OR range from 1.14 to 1.70, all P < 0.05). But those with only general obesity had better but non-significant pulmonary function. (Crude β range from 1.46 to 2.92 for FEV₁% and FVC%, crude OR range from 0.68 to 0.93, all P > 0.05). Both FEV₁% and FVC% decreased per standard deviation increase in obesity indices (adjusted β from -0.46 to -3.17, all P < 0.002). A positive association of central or general obesity with restrictive respiratory defect was observed (adjusted odds ratio (AOR) from 1.50 to 2.04, all P < 0.002). Further adjustment for WC reversed the inverse association between BMI and pulmonary function (adjusted β from 1.93 to 6.22, all P < 0.001) and restrictive respiratory defect (adjusted AOR from 0.72 to 0.80, all P < 0.001).

CONCLUSION

Central adiposity and its indices, but not general adiposity and BMI, were independently associated with lower pulmonary function and higher risk of restrictive respiratory defect in older Chinese.

Using PaCO2 values to grade obesity-hypoventilation syndrome severity: a retrospective study

Background

To date, an important aspect that has still not been clarified is the assessment of OHS severity. The purpose of this retrospective study was to evaluate whether grading OHS severity according to PaCO₂ values may be useful in order to provide a more definite characterization and targeted management of patients. In this regard, baseline anthropometric and sleep polygraphic characteristics, treatment options, and follow up outcomes, were compared between OHS patients with different degree of severity (as assessed according to PaCO₂ values).

Methods

Patients were classified into three groups, according to PaCO₂ values: 1) mild (46 mmHg ≤ PaCO₂ ≤ 50 mmHg), moderate (51 mmHg ≤ PaCO₂ ≤ 55 mmHg), severe (PaCO₂ ≥ 56 mmHg). Therefore, differences among the groups in terms of baseline anthropometric, and sleep polygraphic characteristics, treatment modalities and follow up outcomes were retrospectively evaluated.

Results

Patients with more severe degree of hypercapnia were assessed to have increased BMI and bicarbonate levels, worse diurnal and nocturnal hypoxemia, and a more severe impairment in pulmonary mechanics compared to milder OHS. CPAP responders rate significantly decreased from mild to severe OHS. After follow up, daytime sleepiness (as measure by the ESS), PaO₂, and PaCO₂ significantly improved with PAP therapy in all three groups.

Discussion and Conclusions

Classification of OHS severity according to PaCO₂ levels may be useful to provide a more defined characterization and, consequently, a more targeted management of OHS patients. Further studies are needed to confirm our findings.

Association of neck circumference and pulmonary function in children

BACKGROUND

Childhood obesity leads to many complications including impaired respiratory function. There are various anthropometric parameters related to obesity.

OBJECTIVE

To investigate the correlation between anthropometric indices and pulmonary function test results in children without asthma.

METHODS

Children without any respiratory disorders were enrolled in this study. Anthropometric measurements, such as height, weight, neck circumference (NC), and waist circumference, were obtained from the enrollees and body mass index was calculated. Afterward, pulmonary function tests were performed using spirometry.

RESULTS

A total of 178 children (106 boys, 59.5%) with a mean age of 9.7 years were included the study. NC was above the 90th percentile in 65 children. Importantly, pulmonary parameters, such as forced expiratory volume during the first second (FEV₁) and the ratio of FEV₁ to forced vital capacity (FVC), were lower in subjects with a large NC. Similarly, waist circumference was above the 90th percentile in 67 children, and FEV₁/FVC was significantly lower in children with a large waist circumference. Moreover, there was a statistically significant negative correlation among FEV₁, FEV₁/FVC, and body mass index SD score. Also, multivariable linear regression analysis showed that an NC above the 90th percentile was associated with lower FEV₁ and FEV₁/FVC values.

CONCLUSION

We identified NC as a novel anthropometric index that is strongly correlated with respiratory functions in children. Therefore, close monitoring of respiratory symptoms, particularly in children with obesity and a large NC, could help with early and prompt determination of respiratory complications of obesity.

Reduced Forced Vital Capacity in an African Population. Prevalence and Risk Factors

RATIONALE

Black Africans have reduced FVC compared with white persons, but the prevalence and determinants of reduced values are not well understood.

OBJECTIVES

To evaluate the prevalence and factors leading to reduced FVC in a Nigerian population and to examine current theories regarding the determinants of this difference.

METHODS

We studied the ventilatory function of 883 adults aged 40 years or older participating in the Burden of Obstructive Lung Disease Study in Ile-Ife, Nigeria. Respondents completed pre- and post-bronchodilator spirometry test and provided information on their smoking history, respiratory symptoms, risk factors, and diagnoses, including anthropometric details. We used standard categories to define body mass index as either underweight, normal, overweight, or obese. We defined reduced FVC as a post-bronchodilator FVC below the lower limit of normal using National Health and Nutrition Examination Survey (NHANES) equations, Global Lung Function Initiative 2012 equations, and local reference equations based on nonsmoking study participants without a respiratory diagnosis. We fit multivariate linear regression models to FVC as a continuous measure, adjusting for age, sex, height, and other confounders.

RESULTS

The prevalence of reduced FVC was 70.4% for men and 72.8% for women when using NHANES values for white Americans, 17.8% for men and 14.4% for women using NHANES equations for African Americans, and 15.5% for men and 20.5% for women using the Global Lung Function Initiative 2012 equations. Using the equations derived from nonsmoking respondents in the survey without a respiratory diagnosis, the prevalence of reduced FVC was less than 4% for both men and women. FVC was lower in participants who had less than 7 years of education (FVC, -96 ml; 95% confidence interval [CI], -172 to -19), were underweight (FVC, -269 ml; 95% CI, -464 to -73), were overweight (FVC, -132 ml; 95% CI, -219 to -46), and were obese (FVC, -222 ml; 95% CI, -332 to -112).

CONCLUSIONS

There is a wide variation in the prevalence of reduced FVC based on the reference standard used. This variation is not satisfactorily explained by factors thought to affect FVC within individual populations. However, the prevalence strongly associates with both education level and body mass index in this population, regardless of the specific standard used.

Obesity as a Conditioning Factor for High-Altitude Diseases

Obesity, a worldwide epidemic, has become a major health burden because it is usually accompanied by an increased risk for insulin resistance, diabetes, hypertension, cardiovascular diseases, and even some kinds of cancer. It also results in associated increases in healthcare expenditures and labor and economic consequences. There are also other fields of medicine and biology where obesity or being overweight play a major role, such as high-altitude illnesses (acute mountain sickness, hypoxic pulmonary hypertension, and chronic mountain sickness), where an increasing relationship among these two morbid statuses has been demonstrated. This association could be rooted in the interactions between obesity-related metabolic alterations and critical ventilation impairments due to obesity, which would aggravate hypobaric hypoxia at high altitudes, leading to hypoxemia, which is a trigger for developing high-altitude diseases. This review examines the current literature to support the idea that obesity or overweight could be major conditioning factors at high altitude.

Analysis of the influential factors of maximal-effort expiratory capacity of elderly women

[Purpose] The purpose of this study was to find the influential factors of maximal-effort expiratory capacity of elderly women. [Subjects and Methods] The subjects of this study were 83 healthy elderly women. The study’s methods and purpose were explained and these women agreed to participate. The maximal-effort expiratory capacity was measured using spirometry (Pony FX, COSMED Inc., Italy). We measured forced vital capacity, forced expiratory volume in 1 second, forced expiratory volume in 1 second/forced vital capacity, maximal expiratory flow 75%, maximal expiratory flow 50%, and maximal expiratory flow 25%. [Results] Regarding forced vital capacity and forced expiratory volume in 1 second, it was found that height and age were influential factors. Regarding forced expiratory volume in 1 second/forced vital capacity %, maximal expiratory flow 75%, maximal expiratory flow 50%, and maximal expiratory flow 25%, it was found that only age was an influential factor. [Conclusion] This study demonstrated that the most influential factors of maximal-effort expiratory capacity of elderly women were age, and the second influential factor was height. We noticed that weight was the least influential factor among them.

The relationship between body fat and respiratory function in young adults

The relationship between adiposity and respiratory function is poorly understood. Most studies investigating this have used indirect measures of body fat and few have assessed how changes in adiposity influence lung function.Body fat measured by bio-electrical impedance analysis, body mass index, waist circumference, spirometry, body plethysmography and transfer factor were measured at ages 32 and 38 years in 361 non-smoking, non-asthmatic participants from a population-based birth cohort.Higher percentage body fat was associated with lower spirometric and plethysmographic lung volumes, but not with airflow obstruction, or transfer factor at 32 years. Changes in adiposity between ages 32 and 38 years were inversely associated with changes in lung volumes. These associations were generally stronger in men than women, but an association between increasing adiposity and lower airway function (forced expiratory volume in 1 s/forced vital capacity) was only found in women. Similar associations were found for body mass index and waist circumference.Higher percentage body fat is associated with lower lung volumes. Direct and indirect measures of adiposity had similar associations with lung function. Adiposity had a greater effect on lung volumes in men than women but was associated with airway function only in women. There was little evidence that adiposity influenced transfer factor.

Disorders of Sleep and Ventilatory Control in Prader-Willi Syndrome

Prader-Willi syndrome (PWS) is an imprinted genetic disorder conferred by loss of paternal gene expression from chromosome 15q11.2-q13. Individuals with PWS have impairments in ventilatory control and are predisposed toward sleep disordered breathing due to a combination of characteristic craniofacial features, obesity, hypotonia, and hypothalamic dysfunction. Children with PWS progress from failure to thrive during infancy to hyperphagia and morbid obesity during later childhood and onward. Similarly, the phenotype of sleep disordered breathing in PWS patients also evolves over time from predominantly central sleep apnea in infants to obstructive sleep apnea (OSA) in older children. Behavioral difficulties are common and may make establishing effective therapy with continuous positive airway pressure (CPAP) more challenging when OSA persists after adenotonsillectomy. Excessive daytime sleepiness (EDS) is also common in patients with PWS and may continue after OSA is effectively treated. We describe here the characteristic ventilatory control deficits, sleep disordered breathing, and excessive daytime sleepiness seen in individuals with PWS. We review respiratory issues that may contribute to sudden death events in PWS patients during sleep and wakefulness. We also discuss therapeutic options for treating sleep disordered breathing including adenotonsillectomy, weight loss, and CPAP. Lastly, we discuss the benefits and safety considerations related to growth hormone therapy.

Exploratory study into the effect of abdominal mass loading on airways resistance and ventilatory failure

Objective

We hypothesised that the airway resistance during tidal breathing would correlate with a particular pattern of increasing obesity, particularly when supine, and would differ between participants with and without ventilatory failure.

Methods

In our cross-sectional cohort study, 72 morbidly obese patients (40 males, 32 females, mean body mass index (BMI) 47.2) had measurements of both airways resistance (by impulse oscillometry (IOS)) and adiposity (by dual-energy X-ray absorptiometry (DXA)).

Results

All measures of airways resistance increased in the supine position: total airways resistance (R5) +37% (p<0.0005); large airways resistance (R20) +29% (p<0.0005); and small airways resistance (R5–R20) +52% (p<0.0005). BMI was correlated with seated R5, seated R5–R20, supine R5 and supine R5–R20 (r=0.33 p<0.006, r=0.32 p<0.004, r=0.30 p<0.02 and r=0.36 p<0.04, respectively). Visceral adipose tissue mass was correlated with supine R5–20 (r=0.46 p<0.05). Supine measures of total airways resistance (R5) and large airways resistance (R20) differed between those with and without ventilatory failure, as did mean weight and BMI.

Conclusions

Our study identifies a potentially detrimental effect of the supine posture on tidal breathing airways resistance in obese patients. This change is correlated most with visceral adipose tissue mass and the small airways. We were able to demonstrate that supine increases in airways resistance during tidal breathing, within obese patients, are different between those with and without ventilatory failure.

Trial registration number

NCT01380418; pre-results.

Chronic Interactions Between Carotid Baroreceptors and Chemoreceptors in Obesity Hypertension

Carotid bodies play a critical role in protecting against hypoxemia, and their activation increases sympathetic activity, arterial pressure, and ventilation, responses opposed by acute stimulation of the baroreflex. Although chemoreceptor hypersensitivity is associated with sympathetically mediated hypertension, the mechanisms involved and their significance in the pathogenesis of hypertension remain unclear. We investigated the chronic interactions of these reflexes in dogs with sympathetically mediated, obesity-induced hypertension based on the hypothesis that hypoxemia and tonic activation of carotid chemoreceptors may be associated with obesity. After 5 weeks on a high-fat diet, the animals experienced a 35% to 40% weight gain and increases in arterial pressure from 106±3 to 123±3 mm Hg and respiratory rate from 8±1 to 12±1 breaths/min along with hypoxemia (arterial partial pressure of oxygen=81±3 mm Hg) but eucapnia. During 7 days of carotid baroreflex activation by electric stimulation of the carotid sinus, tachypnea was attenuated, and hypertension was abolished before these variables returned to prestimulation values during a recovery period. After subsequent denervation of the carotid sinus region, respiratory rate decreased transiently in association with further sustained reductions in arterial partial pressure of oxygen (to 65±2 mm Hg) and substantial hypercapnia. Moreover, the severity of hypertension was attenuated from 125±2 to 116±3 mm Hg (45%-50% reduction). These findings suggest that hypoxemia may account for sustained stimulation of peripheral chemoreceptors in obesity and that this activation leads to compensatory increases in ventilation and central sympathetic outflow that contributes to neurogenically mediated hypertension. Furthermore, the excitatory effects of chemoreceptor hyperactivity are abolished by chronic activation of the carotid baroreflex.

The relationship between serum fatty-acid binding protein 4 level and lung function in Korean subjects with normal ventilatory function

Background

The aim of this study was to assess the association of lung function with serum fatty-acid binding protein 4 (FABP4) in apparently healthy Korean adults.

Methods

In 495 participants in a health screening program, Force Exploratory Volume (FEV) 1 and Forced Vital Capacity (FVC) were assessed with standard spirometry. Subjects with obstructive (n = 19) and restrictive (n = 45) lung function were excluded from the analysis. Serum FABP4 level was measured by enzyme-linked immunosorbent assay and transformed into Ln(FABP4). 431 subjects with normal ventilator function (72.4 % men, mean age 41 years) were included in the final analysis.

Results

Mean Ln(FABP4) significantly decreased in subjects from 1^st quartile to 4^th quartile of FVC (p = 0.008). Ln(FABP4) did not show significant differences across the quartile groups of FEV1. The odds ratio (OR) of being in the lowest quartile of FVC was 2.704 in subject with 3^rd tertile of Ln(FABP4) after full adjustment for confounding variables {95 % confidence interval (CI) 1.397 ~ 5.357}. OR of being in the lowest quartile of FEV1 was 1.822 (95 % CI 1.021 ~ 3.298) in subjects with 3^rd tertile of Ln(FABP4) after adjustment of age and sex, which was attenuated after full adjustment for confounding variables.

Conclusion

Increased FABP4 level showed increased risk for reduced lung function in subjects with normal ventilatory function.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-016-0190-8) contains supplementary material, which is available to authorized users.

Implication of Sarcopenia and Sarcopenic Obesity on Lung Function in Healthy Elderly: Using Korean National Health and Nutrition Examination Survey

Previous studies have demonstrated a positive association between obesity and decreased lung function. However, the effect of muscle and fat has not been fully assessed, especially in a healthy elderly population. In this study, we evaluated the impact of low muscle mass (LMM) and LMM with obesity on pulmonary impairment in healthy elderly subjects. Our study used data from the Korea National Health and Nutrition Examination Survey from 2008 to 2011. Men and women aged 65 yr or older were included. Muscle mass was measured by dual-energy X-ray absorptiometry. LMM was defined as two standard deviations below the sex-specific mean for young healthy adults. Obesity was defined as body mass index ≥ 25 kg/m(2). The prevalence of LMM in individuals aged over 65 was 11.9%. LMM and pulmonary function (forced vital capacity and forced expiratory volume in 1 second) were independently associated after adjusting for age, sex, body mass index, smoking status, alcohol consumption, and frequency of exercise. LMM with obesity was also related to a decrease in pulmonary function. This study revealed that LMM is an independent risk factor of decreased pulmonary function in healthy Korean men and women over 65 yr of age.

Obesity and Pulmonary Function in African Americans

Background

Obesity prevalence in United States (US) adults exceeds 30% with highest prevalence being among blacks. Obesity is known to have significant effects on respiratory function and obese patients commonly report respiratory complaints requiring pulmonary function tests (PFTs). However, there is no large study showing the relationship between body mass index (BMI) and PFTs in healthy African Americans (AA).

Objective

To determine the effect of BMI on PFTs in AA patients who did not have evidence of underlying diseases of the respiratory system.

Methods

We reviewed PFTs of 339 individuals sent for lung function testing who had normal spirometry and lung diffusion capacity for carbon monoxide (DLCO) with wide range of BMI.

Results

Functional residual capacity (FRC) and expiratory reserve volume (ERV) decreased exponentially with increasing BMI, such that morbid obesity resulted in patients breathing near their residual volume (RV). However, the effects on the extremes of lung volumes, at total lung capacity (TLC) and residual volume (RV) were modest. There was a significant linear inverse relationship between BMI and DLCO, but the group means values remained within the normal ranges even for morbidly obese patients.

Conclusions

We showed that BMI has significant effects on lung function in AA adults and the greatest effects were on FRC and ERV, which occurred at BMI values < 30 kg/m2. These physiological effects of weight gain should be considered when interpreting PFTs and their effects on respiratory symptoms even in the absence of disease and may also exaggerate existing lung diseases.

Obesity Paradox: Origin and best way to assess severity in patients with systolic HF

OBJECTIVE

Obesity in patients with heart failure (HF) is a factor of better prognosis, supposedly partly because of the particular epidemiology of HF in this population. This study expected to compare the parameters of severity and mortality in patients with and without obesity, to better understand the origin of this paradox.

METHODS

Two hundred twenty-two patients with nonischemic HF and systolic dysfunction were divided into two groups according to their body mass index (≥ 30 vs. < 30 kg/m(2), respectively) and explored for functional parameters and prognosis.

RESULTS

B-type natriuretic peptide (BNP) levels were lower and peak oxygen consumption higher in patients with obesity. Patients with obesity had a better prognosis than patients without obesity with a 4-year mortality of 11.1% and 26.4%, respectively (P = 0.009). By univariate analysis, obesity was associated with a reduced risk of death: HR 0.52 [0.28-0.99]. This protective effect was no longer present after adjusting for VO2max and BNP level.

CONCLUSIONS

The obesity paradox is probably partly due to an overestimation of the severity of HF in patients with obesity because of the multifactorial nature of their dyspnea. Obesity no longer has a protective effect after adjustment for the usual prognostic parameters of HF.