The effect of obesity on spirometry tests among healthy non-smoking adults

Factors Responsible for Nonselection of Donors in Living Related Kidney Transplantation

OBJECTIVES

Living donor kidney transplant is the preferred method of renal transplant in Pakistan as deceased donor transplant has not yet been estab-lished. However, many patients who are dialysis-dependent, particularly younger patients, lack suitable living related donors. We aimed to determine factors contributing to nonselection of donors for living related renal transplant in Pakistan.

MATERIALS AND METHODS

For this cross-sectional study, we included patients seen at the Sindh Institute of Urology & Transplantation Karachi, Pakistan) from March to November 2019. Potential donors were adult family members who accompanied patients with end-stage kidney disease to the clinic. Demographic and clinical information were recorded on predesigned proforma. After workup and baseline investigations had been completed, potential living related donors were selected. Factors leading to nonselection of donors were noted for those who did not qualify for donation. We used SPSS version 20 for analysis.

RESULTS

During the study period, 253 potential donors (151 males, 102 females) with mean age of 35.68 ± 6.14 years were found to be ineligible for kidney donation. ABO incompatibility was the most common factor leading to nonselection (n = 101; 39.92%), followed by diabetes mellitus (n = 71; 28.06%), hypertension (n= 50; 19.76%), renal disease (n = 15; 5.92%), liver disease (n = 8; 3.16%), crossmatch positive (n = 5; 1.97%), and ischemic heart disease (n = 3; 1.18%). No differences were shown between potential male and female donors regarding factors leading to nonselection; diabetes was significantly more prevalent among those <40 years of age (P = .025).

CONCLUSIONS

ABO incompatibility, diabetes mellitus, and hypertension were the most common factors leading to nonselection of potential donors in living related kidney transplant. More efforts are needed to expand the donor pool by considering second- or third-degree relatives to tackle the scarcity of organs for transplantation.

Predictive Roles of Basal Metabolic Rate and Muscle Mass in Lung Function among Patients with Obese Asthma: A Prospective Cohort Study

BACKGROUND

The metabolic-status-related mechanisms underlying the deterioration of the lung function in obese asthma have not been completely elucidated.

OBJECTIVE

This study aimed to investigate the basal metabolic rate (BMR) in patients with obese asthma, its association with the lung function, and its mediating role in the impact of obesity on the lung function.

METHODS

A 12-month prospective cohort study (n = 598) was conducted in a real-world setting, comparing clinical, body composition, BMR, and lung function data between patients with obese (n = 282) and non-obese (n = 316) asthma. Path model mediation analyses for the BMR and skeletal muscle mass (SMM) were conducted. We also explored the effects of the BMR on the long-term lung function in patients with asthma.

RESULTS

Patients with obese asthma exhibited greater airway obstruction, with lower FEV1 (1.99 vs. 2.29 L), FVC (3.02 vs. 3.33 L), and FEV1/FVC (65.5 vs. 68.2%) values compared to patients with non-obese asthma. The patients with obese asthma also had higher BMRs (1284.27 vs. 1210.08 kcal/d) and SMM (23.53 vs. 22.10 kg). Both the BMR and SMM mediated the relationship between obesity and the lung function spirometers (FEV1, %FEV1, FVC, %FVC, and FEV1/FVC). A higher BMR or SMM was associated with better long-term lung function.

CONCLUSIONS

Our study highlights the significance of the BMR and SMM in mediating the relationship between obesity and spirometry in patients with asthma, and in determining the long-term lung function. Interventions for obese asthma should focus not only on reducing adiposity but also on maintaining a high BMR.

Obesity Prevalence and Association with Spirometry Profiles, ICU Admission, and Comorbidities Among Patients with COPD: Retrospective Study in Two Tertiary Centres in Saudi Arabia

Background

Obesity is common among chronic obstructive pulmonary disease (COPD) patients and is associated with an increase in acute exacerbation episodes. However, data on obesity's impact on and association with clinical outcomes among patients with COPD are limited. This study aimed to determine overweight and obesity prevalence and associations with spirometry profiles, intensive care unit (ICU) admission, and comorbidities in patients with COPD.

Methods

In this retrospective cohort study, we reviewed the electronic health records of adult individuals diagnosed with COPD who visited the studied pulmonary clinics between 1 January 2018 and 31 December 2022 and then collected key demographic variables and relevant clinical outcomes and comorbidities.

Results

A total of 474 patients with COPD were included in the final analysis, of whom 60% were male. The occurrences of overweight and obesity were 32.7% and 38.2%, respectively. The presence of comorbidities was high in obese patients (78.4%), followed by overweight patients (63.8%) with COPD. Obese and overweight patients had the highest ward admission rates (38.3% and 34.2%, respectively). ICU admissions were higher in obese and overweight patients (16% and 12%, respectively) compared with normal-weight patients (9%). Although no significant correlation was found between body mass index and spirometry parameters, comorbidities and ICU admission were linked to overweight and obesity in COPD patients (AOR: 1.82 95% CI: 1.15 to 2.86 and AOR: 3.34 95% CI 1.35 to 8.22, respectively).

Conclusion

Our findings imply that obesity in COPD is prevalent and is associated with adverse clinical outcomes including a greater number of comorbidities and higher rates of hospitalization and admission to ICUs although no associations were found between body weight and spirometry parameters. Further studies are needed to assess whether implementing and optimising obesity screening and management at an early stage in COPD can prevent further deterioration.

Static respiratory mechanics are unaltered in males and females with obesity

We tested the hypothesis that independent of the obesity-related shift in lung volume subdivisions, obesity would not reduce the interrelationships of expiratory flow, lung volume, and static lung elastic recoil pressure in males and females. Simultaneous measurements of expiratory flow, volume, and transpulmonary pressure were continuously recorded while flow-volume loops of varying expiratory efforts were performed in a pressure-corrected, volume-displacement body plethysmograph in males and females with obesity. Static compliance curves were collected using the occlusion technique. Flow-volume, static pressure-volume, and static pressure-flow relationships were examined. Isovolume pressure-flow curves were constructed for the determination of the critical pressure for maximal flow. Data were compared with that collected in lean males and females. Individuals with obesity displayed a notable decrease in functional residual capacity. The interrelationships of flow, lung volume, static elastic recoil pressure, and the minimum pressure required for maximal expiratory flow in males and females with obesity were not different from that in lean males and females (all P > 0.05). Obesity does not alter the interrelationships of flow-volume-pressure of the lung in adult males and females (all P > 0.05). We further explored potential sex differences in static mechanics independent of obesity and observed that females have lower maximal expiratory flow due to a combination of smaller lungs and greater upstream flow resistance compared with males (all P ≤ 0.05).NEW & NOTEWORTHY The potential influence of obesity on the interrelationships between maximal expiratory flow, lung volume, and static lung elastic recoil pressure is unclear. These data show that the presence of obesity does not alter the relationship of flow and pressure across the mid-expiratory range in males and females. In addition, independent of obesity, females have smaller lungs and greater upstream flow resistance, which contributes to reduced maximal flow, when compared with males.

Spirometry profiles among pregnant and non-pregnant African women: a cross-sectional study

BACKGROUND

Spirometry is a commonly used lung function test. It assesses respiratory functions by measuring the air volume and the rate at which a person can exhale from lungs filled to their total capacity. The most helpful spirometry parameters are: forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and peak expiratory flow (PEF). Pregnancy derives an altered physiological state due to hormonal and anatomical changes that affect the respiratory system. Despite that, spirometry is less commonly done during pregnancy, and if done, test results are evaluated against non-pregnancy references.

OBJECTIVE

This study aimed to explore spirometry profiles in pregnant and non-pregnant women and describe their differences.

METHODOLOGY

This cross-sectional study involved age-matched pregnant and non-pregnant participants recruited from Mnazi Moja ANC and Muhimbili University (MUHAS). A digital spirometer was used to assess respiratory function. Data were entered and analyzed using SPSS version 23. The mean spirometry values of pregnant participants were compared to those of non-pregnant participants using an independent sample t-test. A p-value of < 0.05 was considered statistically significant.

RESULTS

The study included 92 pregnant and 98 non-pregnant participants subjected to spirometry. Both FVC and FEV1 values were significantly lower in pregnant than in non-pregnant participants (2.7 ± 0.5 L vs. 2.9 ± 0.5 L; p < 0.01 and 2.2 ± 0.4 L vs. 2.5 ± 0.4 L; p < 0.01 respectively). In addition, pregnant participants had significantly lower mean PEF values than their non-pregnant counterparts (303 ± 84 L/min versus 353 ± 64 L/min; p < 0.01).

CONCLUSION

Spirometry test values are lower in pregnancy than in non-pregnant participants.

RECOMMENDATIONS

Interpreting the spirometry test values of pregnant women using references obtained from non-pregnant women may be inappropriate. Future studies should evaluate the appropriateness of predicting spirometry values of pregnant women using reference equations derived from non-pregnant women.

The associations between body composition and vital capacity index of medical students in Shenyang of China: a cross-sectional survey

Objectives

This study aimed to examine the associations between body composition and vital capacity index (VCI) among medical students of Shenyang, China.

Study design

The design of this study is a cross-sectional study.

Methods

Participants were 2063 individuals (17–25 years) from a medical college in Shenyang, who participated in this survey from April to May 2017. Height, weight, fat mass (FM), fat free mass (FFM), protein mass (PM), total body water (TBW), mineral mass (MM), vital capacity were measured, then BMI and VCI were calculated. Stepwise multiple linear regression analysis was used to evaluate the effect of body composition on VCI of participants in different genders. In addition, subgroup analysis was carried out according to BMI levels.

Results

Male students showed significantly higher height, weight, BMI, FFM, PM, TBW, MM, VC, and VCI, but lower FM in comparison with female students. Stepwise multiple linear regression analysis showed that in both sexes FM was negatively correlated with VCI which represents pulmonary function (r < 0; P < 0.001). After dividing the whole participants by BMI, further correlation analysis showed FM was positively correlated with VCI only for male subgroups with BMI < 18.5 (r > 0; P = 0.050).

Conclusion

Overall, FM is highly negatively correlated with the VCI of Chinese medical students of both genders. However, there was a positive correlation between FM and VCI among low-weight male students.

Predictive Equations for Adult Pulmonary Function in Zhejiang Province, China

Background

Accurate interpretation of lung function tests requires appropriate spirometry reference values derived from large-scale population-specific epidemiological surveys. The aim of this cross-sectional study was to establish normal spirometric values for the population of healthy, nonsmoking Han Chinese adults residing in Zhejiang province, China.

Methods

We measured lung function parameters such as forced expiratory volume in 1 s, forced vital capacity, peak expiratory flow, maximal midexpiratory flow, and diffusion capacity for carbon monoxide and considered age, height, and weight as independent factors that may modify these parameters. The clinical data were divided into the study arm and validation group. The study arms were used to construct predictive equations using stepwise multiple linear regression, and data from the validation group were used to assess the robustness of the equations.

Results

The 3866 participants were randomized into a study arm (n = 1,949) and a validation arm (n = 1,917). Lung function parameters had a negative association with age and a positive association with height. Data from the two groups were similar. Predictive equations were constructed from the study arm, and the validation group was used to test the feasibility of the reference equations.

Conclusions

The reference values we derived can be used to evaluate lung function in this cohort in both epidemiological studies and clinical practice.

Nutrition, Obesity and Asthma Inception in Children. The Role of Lung Function

Obesity is an important public health problem. WHO estimates that about 39 million children younger than 5 years of age are overweighted or obese. On the other hand, asthma is the most prevalent chronic disease in childhood, and thus, many children share those two conditions. In the present paper we review the epidemiology of children with asthma and obesity, as well as the consequences of being obese on the respiratory system. On the one hand obesity produces an underlying T-helper 2 (TH2) low inflammation state in which numerous cytokines, which could have an impact in the respiratory system play, a role. On the other hand, some respiratory changes have been described in obese children and, specially, the development of the so called “dysanapsis” (the disproportionate scaling of airway dimensions to lung volume) which seems to be common during the first stages of life, probably related to the early development of this condition. Finally, this review deals with the role of adipokines and insulin resistance in the inception and worsening of asthma in the obese child.

Changes in children's lung function over two decades in relation to socioeconomic, parental and household factors in Wuhan, China

Background

It is important to identify risk and beneficial factors for children's lung function. This study aims to ascertain potential changes in children's lung function in relation to changes in socioeconomic, parental and household factors, based on a comparison between two periods spanning 25 years in Wuhan, the largest metropolis in central China.

Methods

In two cross-sectional studies, lung function measurements and questionnaire surveys were conducted on school-age children in 1993-1996 (Period I) and in 2018 (Period II). Children of 6-12 years old from elementary schools were selected by a multistage sampling method. Demographic information, socioeconomic status, feeding methods, parental illness and behavior patterns, as well as household characteristics, were collected through a questionnaire survey. Spirometric lung function was measured, including forced vital capacity (FVC), forced expiratory volume in the first second (FEV₁), forced expiratory flow at 25% and 75% of the pulmonary volume (FEF25-75), and peak expiratory flow (PEF). Wilcoxon analysis of variances was used to assess the differences in lung function indexes between Period I and Period II. Multiple linear regression models were used to estimate the association of lung function with regard to socioeconomic, parental and household factors, respectively.

Results

Significant prevalence reductions were observed for household coal use, paternal smoking and maternal asthma, while the prevalence increased significantly for children sleeping in their own rooms or own beds and breastfeeding, ventilation use during cooking, and parental education level from Period I to Period II. When adjusted for age, height, weight, sex and other factors assessed in the study, children had significant lower values of FVC, FEV₁, and PEF in Period II than in Period I. Enclosed kitchen was significantly associated with lower lung function in children in Period I. Urban living condition and higher maternal education level were each associated with a higher FVC, while father having no fixed income was associated with a lower FVC and a lower FEV₁, respectively, in Period II. In comparison with Period I, the beneficial impact of urban living and that of breastfeeding were enhanced and the detrimental effect of poor household condition was weakened in Period II.

Conclusions

Lung function was lower in 2018 than in 1993-1996 in school-age children living in Wuhan. Although improvements in urban living and household environmental conditions as well as increased breastfeeding in Period II could have contributed to increased lung function, other unmeasured risk factors may have played a more dominant role in leading to a net decrease in lung function from Period I to Period II. Future studies are needed to identify these risk factors.

Critical analysis of spirometric patterns in correlation to chest computed tomography among adult Indigenous Australians with chronic airway diseases

Background: There is sparse literature evidence in the spirometric patterns of adult Indigenous Australians with and without chest computed tomography (CT)-proven chronic airway diseases (CADs).Methods: Participants spirometry testing graded as acceptable for quality and had a chest CT scan showing radiographic evidence of CADs were included for analysis.Results: Of the 1350 spirometric tests performed between 2012 and 2020, a total of 212 patients with a mean age of 53 years and 54% females were eligible to be included. One-third (30%) had normal chest CT (without CADs), 35% had predominant COPD, 19% bronchiectasis and 16% combined COPD and bronchiectasis. Percentage predicted values for forced vital capacity (FVC) and forced expiratory volume in one second (FEV₁) both pre- and post- bronchodilator were significantly reduced for all participants - FVC: CT-normal 64%, 65%; COPD 58%, 62%; bronchiectasis 54%, 54%; combined COPD and bronchiectasis 50%, 53%. FEV₁: CT-normal 62%, 65%; COPD 46%, 49%; bronchiectasis 48%,51%; combined COPD and bronchiectasis 36%,40%. FEV₁/FVC was only reduced for CT abnormality patients - CT-normal 96%,98%; COPD 77%,77%; bronchiectasis 87%,89%; combined COPD and bronchiectasis 71%,72%.Conclusions: Restrictive spirometric pattern is common and an obstructive pattern with COPD, in isolation or when COPD coexists with bronchiectasis.

Causal Effects of Body Mass Index on Airflow Obstruction and Forced Mid-Expiratory Flow: A Mendelian Randomization Study Taking Interactions and Age-Specific Instruments Into Consideration Toward a Life Course Perspective

Obesity has complex links to respiratory health. Mendelian randomization (MR) enables assessment of causality of body mass index (BMI) effects on airflow obstruction and mid-expiratory flow. In the adult SAPALDIA cohort, recruiting 9,651 population-representative samples aged 18–60 years at baseline (female 51%), BMI and the ratio of forced expiratory volume in 1 second (FEV₁) to forced vital capacity (FVC) as well as forced mid-expiratory flow (FEF25–75%) were measured three times over 20 follow-up years. The causal effects of BMI in childhood and adulthood on FEV1/FVC and FEF25–75% were assessed in predictive (BMI averaged over 1st and 2nd, lung function (LF) averaged over 2nd and 3rd follow-up; N = 2,850) and long-term cross-sectional models (BMI and LF averaged over all follow-ups; N = 2,728) by Mendelian Randomization analyses with the use of weighted BMI allele score as an instrument variable and two-stage least squares (2SLS) method. Three different BMI allele scores were applied to specifically capture the part of BMI in adulthood that likely reflects tracking of genetically determined BMI in childhood. The main causal effects were derived from models containing BMI (instrumented by BMI genetic score), age, sex, height, and packyears smoked as covariates. BMI interactions were instrumented by the product of the instrument (BMI genetic score) and the relevant concomitant variable. Causal effects of BMI on FEV1/FVC and FEF25–75% were observed in both the predictive and long-term cross-sectional models. The causal BMI- LF effects were negative and attenuated with increasing age, and stronger if instrumented by gene scores associated with childhood BMI. This non-standard MR approach interrogating causal effects of multiplicative interaction suggests that the genetically rooted part of BMI patterns in childhood may be of particular relevance for the level of small airway function and airflow obstruction later in life. The methodological relevance of the results is first to point to the importance of a life course perspective in studies on the etiological role of BMI in respiratory health, and second to point out novel methodological aspects to be considered in future MR studies on the causal effects of obesity related phenotypes.

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.

Relationship between peak expiratory flow and impaired functional capacity in obese individuals

Abstract Introduction: Obesity, characterized by the accumulation of excess body fat, can alter respiratory mechanics and compromise functional capacity. Given its increasing prevalence and the significant morbidity associated with the condition, it is important to investigate techniques that enable rapid, easy measurement of lung function and the possible correlation between obesity and functional capacity. Objective: To assess lung function and functional capacity in obese adults and determine whether there is a correlation between reduced peak expiratory flow and impaired functional capacity. Methods: 30 participants, distributed into two groups: obese (36 ± 13 years) and normal weight (31 ± 9 years) were evaluated based on anthropometric measurements, the six-minute walk test (6MWT) and peak expiratory flow (PEF). Results: The obese individuals showed reduced PEF (382 ± 99 vs. 497 ± 104 L/min, p < 0.01), walked shorter distances in the 6MWT (453 ± 37 vs. 617 ± 50 m, p < 0.01), had higher blood pressure and perceived exertion (p < 0.05) when compared to normal weight participants. Additionally, there was a positive significant association between expiratory flow and distance walked in the 6MWT (r = 0.635 and p < 0.001). Conclusion: Obese individuals exhibited lower PEF and walked shorter distances in the 6MWT, indicating a positive correlation between these two variables. In light of this outcome, the assessment methods used could contribute to improving analysis of respiratory and functional status in this population and aid in exercise prescription.

Predictors of accelerated FEV1 decline in adults with airflow limitation-Findings from the Health2006 cohort

To investigate predictors of accelerated decline in forced expiratory volume in 1 s (FEV₁) in individuals with preexisting airflow limitation (AL). Participants in the Health2006 baseline study aged ≥ 35 with FEV₁/ forced vital capacity (FVC) < lower limit of normal (LLN) were invited for a 10-year follow-up. At both examinations, data were obtained on demographics, spirometry, fitness level, allergy, and exhaled nitric oxide. We used multiple regression modeling to predict the annual decline in FEV₁, reported as regression coefficients ( R) and 95% confidence intervals (CIs). A total of 123 (43% of those invited) participated in the follow-up examination, where more had exercise-induced dyspnea but fewer had asthma symptoms. Being female ( R = -29.8 ml, CI: -39.7 to -19.8), diagnosed with asthma ( R = -13.7, CI: -20.4 to -7.0) or atopic dermatitis ( R = -29.0, CI: -39.7 to -18.4), and having current asthma symptoms or nightly respiratory symptoms ( R = -22.1, CI: -31.9 to -12.4 and R = -14.3, CI: -19.9 to -8.7, respectively) were significantly associated with a steeper decline in FEV₁. Although to a smaller extent, a steeper decline was also predicted by age, baseline FEV₁, waist/hip-ratio, and number of pack-years smoked. In individuals with preexisting AL, being female and having ever or current respiratory symptoms were associated with an accelerated annual decline in FEV₁.

Screening for obstructive lung disease in hospitalized psychiatric patients

Objective: Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of mortality worldwide and it remains under-diagnosed. Unrecognized somatic disease contributes significantly to the observed increased mortality rate in patients with psychiatric diseases.Aims: To investigate whether screening with spirometry and simple questions on respiratory symptoms were efficacious in identifying previously unknown cases of COPD and/or asthma in patients admitted to psychiatric wards.Methods: In this observational cohort study, we included hospitalized psychiatric patients in2013. All were assessed with handheld spirometry, medical history and completion of a simple, short questionnaire on respiratory symptoms, the COPD assessment test (CAT questionnaire).Results: In total, 106 patients were screened and 45 patients (age: median 45, range 19-75, 43% female gender) were included whereas 61 patients (age: median 42, range 19-73) 34% female gender) were excluded. Prior to screening three patients (6.5%) reported having a diagnosis of COPD whereas eight patients (17%) reported having a diagnosis of asthma. Six new cases were diagnosed with COPD and four new cases with asthma. The number needed to screen to find one new case was 3.4 (total cohort 4.5).Conclusion: We present a simple study where the patients are screened for obstructive lung disease with a handheld spirometry and a questionnaire on respiratory symptoms. Number needed to screen is low at 3.4-4.5. In all, 10 new cases of obstructive lung disease were diagnosed. This study illustrates that screening for COPD and asthma is feasible even in a psychiatric population.

Isotonic Saline Nebulization and Lung Function in Children With Mild Respiratory Ailments

Nebulization with saline solution, although commonly used to alleviate respiratory symptoms, particularly in children, is often questioned concerning its effectiveness. In this study, we investigated the effects of isotonic saline nebulization on lung function in 40 children (mean age of 14±1 years) suffering from different types of airway disorders. Measurements were carried out directly before and up to 15 min after nebulization, for six days in a row, always on the same day time in the morning. The children were divided into two study groups according to the baseline ratio of forced expired volume in one second/forced vital capacity (FEV1/FVC), below and above 80 %. We found significant improvements after saline nebulization in FEV1, mid-expiratory flow at 50 % and 75 % of FVC (MEF50 and MEF75), and peak expiratory flow (PEF) in the group with the baseline FEV1/FVC less than 80 %. In contradistinction, children with an index greater than 80 % displayed no appreciable changes in the lung function variables when compared with the baseline level before saline nebulization. We conclude that isotonic saline nebulization might mitigate the functional signs of threatening pulmonary obstruction and as such may be clinically useful in pediatric patients with mild respiratory problems.

A Bayesian assessment of occupational health surveillance in workers exposed to silica in the energy and construction industry

Medical records generated during occupational health surveillance processes have large amounts of unexploited information that can help to reduce silica-related health risks and many occupational diseases. The methodology applied in this study consists in analyzing through machine learning techniques a database with 70,000 medical examinations from workers in the energy and construction industry in Spain. First, a general unsupervised Bayesian model is built and node force analysis is used to identify the factors with the greatest impact on the worker's health surveillance process. Second, a predictive Bayesian model is created and mutual information is employed to assess the more relevant factors affecting the medical capability of workers exposed to silica dust. The lung auscultation and the breathing exploration are the two factors that influence the most the medical capability of silica-exposed employees. Probabilistic inference shows a remarkable gender effect, where women present more resilience towards occupational diseases than men showing a higher proportion of normal results in certain key factors, such as body mass index (♀49.73%, ♂25.17%) or spirometry (♀53.73%, ♂48.91%). Finally, environmental conditions demonstrate to have a major influence on spatial variability of occupational diseases. The design of health prevention programs based on geographical variations can be crucial to the attainment of an ongoing and sustained healthier workforce with a reduction in the number of chronic workplace illnesses.

Gender Differences and Obesity Influence on Pulmonary Function Parameters

Objectives

Overweight and obesity are known to cause various patterns of alteration to the pulmonary function test (PFT) parameters. We sought to investigate gender differences in PFT parameters and examine the relationship between body mass index (BMI) and PFT parameters.

Methods

We conducted a retrospective study of 126 patients referred for a PFT by various medical specialties between January and December 2015. PFT was measured using spirometry, and BMI was calculated using Quetelet’s index.

Results

Female patients exhibited lower mean values for all PFT parameters compared to male patients. The forced vital capacity (FVC)% predicted was less than 80% for all patients while the ratio of forced expiratory volume in 1 second (FEV₁)/FVC was higher with increased BMI. BMI was positively correlated with peak expiratory flow in all patients, and with FEV₁/FVC ratio in males but not in females.

Conclusions

In our studied population, males exhibited higher mean values of PFT parameters than females. Increased BMI may be associated with a restrictive pattern on spirometry.

Reference values for spirometric variables for allegedly healthy workers

Introducción. La espirometría permite identificar de forma precoz el deterioro pulmonar en trabajadores expuestos a contaminantes laborales. No se tienen valores de referencia (VR) para variables espirométricas (VE) en trabajadores cubanos (TC).Objetivo. Obtener VR para VE en TC supuestamente sanos.Materiales y métodos. Estudio retrospectivo-analítico. Se obtuvo la capacidad vital forzada (CVF), el volumen espiratorio forzado en el primer segundo (VEF1), el cociente VEF1/CVF y la fracción de la espiración forzada al 25-75% de la CVF (FEF25-75) de 1 086 TC supuestamente sanos, no fumadores, de ambos sexos, con edades entre 20 y 65 años y atendidos en el Instituto Nacional de la Salud de los Trabajadores de La Habana, Cuba, entre 2009 y 2015. Los VR se obtuvieron para cada sexo de las funciones de regresión Y=α+β x Edad+χ x Talla+ε (Y=CVF, VEF1, VEF1/CVF, FEF25-75).Resultados. Edades avanzadas se asociaron con CVF y VEF1 disminuidos; la talla elevada se asoció con mayores CVF y VEF1; una FR construida se asoció con la edad, y la talla implicó un coeficiente r2 de determinación superior y un error menor. El comportamiento de la VE predicho con la ecuación desarrollada fue menos sesgado que el observado con otras importadas.Conclusiones. Los VR construidos localmente pueden ser más efectivos en el diagnóstico de las afecciones pulmonares de los TC.

Factors Affecting Lung Function: A Review of the Literature

Lung function reference values are traditionally based on anthropometric factors, such as weight, height, sex, and age. FVC and FEV₁ decline with age, while volumes and capacities, such as RV and FRC, increase. TLC, VC, RV, FVC and FEV₁ are affected by height, since they are proportional to body size. This means that a tall individual will experience greater decrease in lung volumes as they get older. Some variables, such as FRC and ERV, decline exponentially with an increase in weight, to the extent that tidal volume in morbidly obese patients can be close to that of RV. Men have longer airways than women, causing greater specific resistance in the respiratory tract. The increased work of breathing to increase ventilation among women means that their consumption of oxygen is higher than men under similar conditions of physical intensity. Lung volumes are higher when the subject is standing than in other positions. DLCO is significantly higher in supine positions than in sitting or standing positions, but the difference between sitting and standing positions is not significant. Anthropometric characteristics are insufficient to explain differences in lung function between different ethnic groups, underlining the importance of considering other factors in addition to the conventional anthropometric measurements.

Chronic obstructive pulmonary disease associated with biomass fuel use in women: a systematic review and meta-analysis

Introduction

Chronic obstructive pulmonary disease (COPD) is a major and growing cause of morbidity and mortality worldwide. The global prevalence of COPD is growing faster in women than in men. Women are often exposed to indoor pollutants produced by biomass fuels burning during household activities.

Methods

We conducted a meta-analysis to establish the association between COPD and exposure to biomass smoke in women.Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we searched MEDLINE and Scopus databases in 31December 2016, with the terms: "wood", "charcoal", "biomass", "solid fuels", "organic fuel", "biofuel", "female", "women", "COPD", "chronic bronchitis", "emphysema", "chronic obstructive pulmonary disease". Studies were eligible if they were case-control or cross-sectional studies involving exposure to indoor biomass smoke, conducted at any time and in any geographic location. Fixed-effects or random-effects meta-analysis was used to generate pooled OR.

Results

24 studies were included: 5 case-control studies and 19 cross-sectional studies. Biomass-exposed individuals were 1.38 times more likely to be diagnosed with COPD than non-exposed (OR 1.38, 95% CI 1.28 to 1.57).Spirometry-diagnosed COPD studies failed to show a significant association (OR 1.20, 95% CI 0.99 to 1.40). Nevertheless, the summary estimate of OR for chronic bronchitis (CB) was significant (OR 2.11, 95% CI 1.70 to 2.52). The pooled OR for cross-sectional studies and case-control studies were respectively 1.82 (95% CI 1.54 to 2.10) and 1.05 (95% CI 0.81 to 1.30). Significant association was found between COPD and biomass smoke exposure for women living as well in rural as in urban areas.

Conclusions

This study showed that biomass smoke exposure is associated with COPD in rural and urban women.In many developing countries, modern fuels are more and more used alongside traditional ones, mainly in urban area. Data are needed to further explore the benefit of the use of mixed fuels for cooking on respiratory health, particularly on COPD reduction.

The effect of obesity on patients with mild chronic obstructive pulmonary disease: results from KNHANES 2010 to 2012

PURPOSE

A low body mass index has been associated with high mortalities in patients with chronic obstructive pulmonary disease (COPD), and studies reveal that obesity aggravates the clinical effects of COPD. We investigated the impact of obesity on patients newly identified with COPD.

PATIENTS AND METHODS

This population-based, cross-sectional study, used data from the Korea National Health and Nutrition Examination Survey (KNHANES) conducted from 2010 to 2012. Through analyses of data from this survey, we compared concurrent comorbid diseases, symptoms, and lung functions between an obese and nonobese group of patients with COPD.

RESULTS

In total, 618 participants were diagnosed with COPD and the average forced expired volume in 1 s (FEV1) was 79.47%±0.69%. Of the total, 30.5% of the subjects were categorized into an obese group. Subjects in the obese group were likely to have metabolic syndrome (P<0.001), hypertension (P=0.02), and a higher number of comorbidities compared to the nonobese group (2.3±0.1 vs 2.0±0.1, P=0.02). In addition, subjects in the obese group showed a lower forced vital capacity (FVC) than subjects in the nonobese group, even after adjusting for covariates (average FVC%, 89.32±1.26 vs 92.52%±0.72%, P=0.037). There were no significant differences in the adjusted FEV1% and adjusted FEV1/FVC between the groups.

CONCLUSIONS

Among subjects newly identified with mild COPD, participants in the obese group had more comorbid conditions and showed a lower FVC compared with subjects in the nonobese group, even after adjustment of covariates. These findings show that a combination of obesity and COPD may be a severe phenotype; therefore, early attention should be paid to obesity for the management of COPD patients.

Adiposity markers and lung function in smokers: a cross-sectional study in a Mediterranean population

Background

The aim of this study was to assess the association of key adiposity markers with lung function in smokers without respiratory disease in a Mediterranean population.

Methods

We performed a cross-sectional study with baseline data from a representative sample of the ESPITAP study in Spain. Participants were 738 smokers (52.3% men) without respiratory disease, aged 35 to 70, selected from 12 primary health care centres. We assessed weight, height, body mass index (BMI), waist circumference (WC) and waist-to-height ratio (WHtR). The pulmonary functional parameters were forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1) and FEV1/FVC ratio.

Results

In this cohort of smokers, 22.2% of individuals had central obesity. FVC% was inversely associated with all anthropometric measures (BMI, WC and WHtR) in the overall population and in men; in women, only BMI was associated with FVC%. FEV1% was inversely associated to BMI and WC in the overall population, and to all anthropometric measures in men. Furthermore, both BMI and obesity were positively associated with FEV1/FVC ratio overall and when stratified by sex; this suggests a restrictive pattern explained by the altered ventilator mechanics experienced by people with obesity.

Conclusion

In a Mediterranean population of smokers without respiratory symptoms, abdominal obesity, evaluated not only by BMI and WC but also WHtR, is inversely associated with lung function. Fat distribution appears more strongly related to pulmonary function parameters in men than in women. In smokers with high values for WC, WHtR and BMI, assessment of lung function is recommended.

Trial registration

Current Controlled Trials NCT01194596. Registered 2 September 2010.

Prediction of basal metabolic rate in overweight/obese and non-obese subjects and its relation to pulmonary function tests

BACKGROUND

Few studies investigated the association between basal metabolic rate (BMR) and indicators of pulmonary function. This study was conducted to estimate BMR in overweight/obese and non-obese healthy subjects using four commonly used predictive equations and to investigate its relation to the indicators of lung function tests (LFT). A cross sectional study was conducted in Tabuk University, Tabuk, Saudi Arabia. A total of 201 students (98 males and 103 females) participated in the study. Four different values of BMR were calculated for each participant using four different predictive equations (Harris-Benedict, Mifflin, FAO/WHO/UNU and Henry-Rees). A portable All-flow spirometer (Clement Clarke International, Harlow, UK) was used for measurements of LFT.

RESULTS

Significantly higher values of spirometric indicators (p < 0.05) were found in males compared to females, except for FEF75 and FEF75-85. Mean BMR values predicted with the four equations were significantly higher in the males compared to the females and among the overweight/obese compared to the non-obese subjects (p < 0.05). The relation between mean BMR values and the indicators of LFT was statistically insignificant (p > 0.05).

CONCLUSION

Mean values of LFT indicators are not related to the estimated values of BMR. A practical calculation of BMR based on direct measurement of oxygen consumption is recommended to confirm the absence of this association.

Alterations in Lung Functions Based on BMI and Body Fat % Among Obese Indian Population at National Capital Region

BACKGROUND

In India, non-asthmatic hospital admission case study has been conducted to find out the relationship between obesity and lung functions. The main objective of the present study was to find out the alterations in lung functions due to obesity among Indian population living at National Capital Region (NCR).

MATERIALS AND METHODS

We examined 609 non obese and 211 obese subjects in a cross sectional study from National Capital Region, India with age group ranges between 18-70 years. BMI and body fat % was determined using body fat analyzer. Obese and non-obese subjects were classified based on criteria for BMI and Body fat %. Lung function test viz., FEV1 and PEFR were conducted using portable spirometer (PIKO-1).

RESULTS

A significant correlation (p<0.05) was observed between BMI and PEFR among non-obese male and female subjects. Decline in PEFR and FEV1 values for corresponding increase in body fat % was observed among study subjects. A significant (p<0.01) decline in mean FEV1 and PEFR was observed among non-obese and obese subjects, compared to their Indian reference standards for lung functions. A significant negative correlation (p<0.01) was observed between body fat % and lung functions (FEV1, PEFR).

CONCLUSION

It is concluded that obese subjects are at a risk of lung function impairment, based on the criteria followed for BMI and body fat %. The study also demonstrate that body fat% classification as a better index for determination of obese subjects compared to BMI classification, with respect to lung function impairments.

Association of Body Mass Index (BMI) with Lung Function Parameters in Non-asthmatics Identified by Spirometric Protocols

INTRODUCTION

Association between obesity and asthma has been reported widely, with disparity between males and females. Epidemiological data which indicate that obesity precedes development of asthma and increases the prevalence and incidence of asthma, raises the possibility of a causal association.

AIM

To find out the association, including gender differences, between Body Mass Index (BMI) and lung functions in non-asthmatics identified by spirometric protocols.

METHODS

A retrospective analysis was conducted of the spirometry results obtained between October 2012 and March 2013 for six months. Participants were referred by a variety of medical specialties to the pulmonary function laboratory in Physiology department, R.G. Kar Medical College, Kolkata, India of the 590 test results recorded in the study database 424 non-asthmatic subjects were reviewed.

RESULTS

Significant differences in the spirometric parameters, measured as a percentage of predicted were evident between male and female. Among obese subjects significant correlation is found between BMI and pulmonary function values, FEV1(r = -0.531, p=0.009); FEF25-75% (r= -0.653, p=0.001); FEV1/FVC (r= - 0.603, p=0.002). Significant association was found between BMI and lung function in obese female but not in obese male.

CONCLUSION

Association was found between indices of spirometry and BMI in non-asthmatic obese group along with a gender disparity.

Obesity and asthma: physiological perspective

Obesity induces some pertinent physiological changes which are conducive to either development of asthma or cause of poorly controlled asthma state. Obesity related mechanical stress forces induced by abdominal and thoracic fat generate stiffening of the lungs and diaphragmatic movements to result in reduction of resting lung volumes such as functional residual capacity (FRC). Reduced FRC is primarily an outcome of decreased expiratory reserve volume, which pushes the tidal breathing more towards smaller high resistance airways, and consequentially results in expiratory flow limitation during normal breathing in obesity. Reduced FRC also induces plastic alteration in the small collapsible airways, which may generate smooth muscle contraction resulting in increased small airway resistance, which, however, is not picked up by spirometric lung volumes. There is also a possibility that chronically reduced FRC may generate permanent adaptation in the very small airways; therefore, the airway calibres may not change despite weight reduction. Obesity may also induce bronchodilator reversibility and diurnal lung functional variability. Obesity is also associated with airway hyperresponsiveness; however, the mechanism of this is not clear. Thus, obesity has effects on lung function that can generate respiratory distress similar to asthma and may also exaggerate the effects of preexisting asthma.

Should visceral fat, strictly linked to hepatic steatosis, be depleted to improve survival?

Numerous epidemiologic studies have implicated abdominal obesity as a major risk factor for insulin resistance, type 2 diabetes mellitus, cardiovascular disease, stroke, metabolic syndrome and its further expression, i.e., nonalcoholic fatty liver disease and death. Using novel models of visceral obesity, several studies have demonstrated that the relationship between visceral fat and longevity is causal, while the accrual of subcutaneous fat does not appear to play an important role in the etiology of disease risk. The need of reducing the visceral fat to improve survival, mainly taking into account the strict link between nonalcoholic fatty liver disease and the coronary artery disease is discussed.