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

Association Between the Non-High-Density Lipoprotein Cholesterol-to-High-Density Lipoprotein Cholesterol Ratio (NHHR) and Mortality in Patients with COPD: Evidence From the NHANES 1999-2018

Purpose

The non-high-density lipoprotein cholesterol-to-high-density lipoprotein cholesterol ratio (NHHR) is a new composite blood lipid index. We aimed to investigate the relationships of the NHHR with mortality from all-causes, cardiovascular disease (CVD), and chronic lower respiratory disease (CLRD) in US patients with COPD.

Methods

We assessed the association between the NHHR and mortality via weighted multivariate Cox proportional hazards regression models with restricted cubic splines (RCSs). Between-group survival rates at specific time points were compared via Kaplan‒Meier (KM) curves and Log rank tests. Receiver operating characteristic (ROC) curves were constructed to evaluate the efficiency of the NHHR for predicting mortality risk in COPD patients.

Results

After adjusting for confounding factors, weighted multivariate Cox proportional hazards regression model showed that higher NHHR was not significantly associated with all-cause mortality (HRs = 1.74), CVD mortality (HRs = 1.19), and CLRD-related mortality (HRs = 0.65), but HRs tended to increase as NHHR increased. RCS revealed U-shaped associations between the NHHR and all-cause mortality. KM survival analysis revealed a significantly lower survival rate for patients in the high-NHHR group (Log rank test P<0.001). In addition, the NHHR had superior performance in predicting mortality, with AUC values of 0.85 and 0.883 for all-cause mortality, 0.769 and 0.815 for CVD mortality, and 0.765 and 0.815 for CLRD-related mortality at 5 and 10 years, respectively.

Conclusion

The higher the NHHR is, the greater the risk of all-cause mortality in COPD patients. The NHHR was significantly superior to other haematological biomarkers in predicting mortality.

Associations between metabolic score for visceral fat and adult lung functions from NHANES 2007-2012

Background

Obesity is a significant part of the factors affecting lung function, and the assessment of obesity using the Metabolic Score for Visceral Fat (METS-VF) is more precise than other indicators like waist circumference and body mass index. This study investigated the relationship between lung function and METS-VF in The National Health and Nutrition Examination Survey (NHANES) database from 2007 to 2012.

Method

The data utilized in this study was obtained from National Health and Nutrition Examination Survey spanning the years 2007 to 2012. A multivariate linear regression analysis was employed to investigate the association between METS-VF and lung function, followed by subgroup analysis to identify populations that may exhibit heightened sensitivity. Nonlinear correlations were assessed by fitting a restricted cubic spline, with validation of results conducted via threshold effect analysis.

Result

In a study involving 4,356 participants, a weighted multiple linear regression model revealed a significant negative association between the METS-VF and forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), FEV1/FVC ratio, and forced expiratory flow between 25 and 75% of FVC (FEF25-75%). However, no association was observed with peak expiratory flow rate (PEF). When dividing the METS-VF into thirds, participants in the highest third exhibited significantly decreased levels of FEV1 (β: -342, 95%CI: -440, -245, p < 0.001), FVC (β: -312, 95%CI: -431, -192, p < 0.001), FEV1/FVC (β: -0.020, 95%CI: -0.030, -0.010, p < 0.001), and FEF25-75% (β: -424, 95%CI: -562, -285, p < 0.001). However, there was no significant relationship with PEF (β: -89, 95%CI: -325, 147, p = 0.446). RCS curve indicated a nonlinear negative correlation between METS-VF and FEV1, FVC, and FEV1/FVC. For FEV1, a significant negative correlation was found when the METS-VF < 6.426 (β = -158.595, 95%CI: -228.183, -89.007). This negative association became more pronounced when the METS-VF > 6.426 (β = -314.548, 95%CI: -387.326, -241.770). For FVC, a negative association was observed when the METS-VF < 6.401, (β = -5.477, 95%CI: -91.655, 80.702), but it did not reach statistical significance. However, METS-VF > 6.401, METS VF and lung function show a significant negative correlation (β = -399.288, 95%CI: -486.187, -312.388). FEV1/FVC showed a negative correlation only before the inflection point (METS-VF < 6.263) (β = -0.040, 95%CI: -0.047, -0.032), after the inflection point (METS-VF > 6.263), no correlation was found, but there was no statistical significance (β = 0.000; 95%CI: -0.006, 0.007), and METS-VF had a linear negative correlation with FEF25-75%. Subgroup analysis showed that the association was consistent across a variety of demographic factors, including age, sex, race, hypertension, and coronary heart disease. In addition, we found a stronger association between men under 40 and lung function.

Conclusion

METS-VF showed a linear negative correlation with FEF25-75%, and a nonlinear negative correlation with FEV1, FVC, FEV1/FVC, and FEF25-75%, but was not associated with PEF, particularly among males under the age of 40. These findings offer valuable insights into managing lung function by controlling visceral fat.

Forced vital capacity and body mass index of Xinjiang children and adolescents: an analysis based on seven successive national surveys, 1985-2014

BACKGROUND

Pulmonary function is very important for the healthy development of children and adolescents. However, fewer studies have been conducted on pulmonary function trends in children and adolescents in remote areas. The aim of this study was to estimate the forced vital capacity (FVC) trend and its relationship with body mass index (BMI) among young people in Xinjiang during 1985-2014 using data from seven successive national surveys.

METHODS

A total of 19,449 Xinjiang children and adolescents aged 7-18 years were extracted from the Chinese National Survey on Students' Constitution and Health. Height, weight, and FVC were measured repeatedly in each survey. FVC comparisons between adjacent surveys by age and sex were conducted by nonparametric Kruskal-Wallis after Kolmogorov-Smirnov of normality. One-way ANOVA and least significant difference(LSD) method was used to compare differences in FVC levels of Xinjiang children and adolescents with different BMI. The relationship between BMI and FVC was investigated using a nonlinear regression model.

RESULTS

The FVC levels of Xinjiang children and adolescents peaked in 2000, with overall FVC levels being 8.7% higher in 2000 than in 1985. Since then, a substantial decline occurred, contrasting to 2000, with FVC levels decreasing by 27% in 2014, which was still lower than that in 1985 by 20.73%. The proportion of overnutrition boys increased from 0.2% in 1985 to 22.1% in 2014, and girls from 0.5% in 1985 to 14.5% in 2014. An inverted U-shape association between FVC and BMI values was obtained for Xinjiang children and adolescents.

CONCLUSIONS

Targeted measures should be carried out in schools to control BMI levels to ensure good lung function in children and adolescents in Xinjiang. Future studies should pay more attention to other factors affecting FVC, such as dietary behaviour, physical activity, and racial differences among children and adolescents.

Mediterranean Diet and Lung Function in Adults Current Smokers: A Cross-Sectional Analysis in the MEDISTAR Project

BACKGROUND

Previous studies have shown that adherence to the Mediterranean Diet (MeDi) has a positive impact on lung function in subjects with lung disease. In subjects free of respiratory diseases, but at risk, this association is not yet well established.

METHODS

Based on the reference data from the MEDISTAR clinical trial (Mediterranean Diet and Smoking in Tarragona and Reus; ISRCTN 03.362.372), an observational study was conducted with 403 middle-aged smokers without lung disease, treated at 20 centres of primary care in Tarragona (Catalonia, Spain). The degree of MeDi adherence was evaluated according to a 14-item questionnaire, and adherence was defined in three groups (low, medium, and high). Lung function were assessed by forced spirometry. Logistic regression and linear regression models were used to analyse the association between adherence to the MeDi and the presence of ventilatory defects.

RESULTS

Globally, the pulmonary alteration prevalence (impaired FEV1 and/or FVC) was 28.8%, although it was lower in participants with medium and high adherence to the MeDi, compared to those with a low score (24.2% and 27.4% vs. 38.5%, p = 0.004). Logistic regression models showed a significant and independent association between medium and high adherence to the MeDi and the presence of altered lung patterns (OR 0.467 [95%CI 0.266, 0.820] and 0.552 [95%CI 0.313, 0.973], respectively).

CONCLUSIONS

MeDi adherence is inversely associated with the risk impaired lung function. These results indicate that healthy diet behaviours can be modifiable risk factors to protect lung function and reinforce the possibility of a nutritional intervention to increase adherence to MeDi, in addition to promoting smoking cessation.

Sex Differences in Airway Remodeling and Inflammation: Clinical and Biological Factors

Asthma is characterized by an increase in the contraction and inflammation of airway muscles, resulting in airflow obstruction. The prevalence of asthma is lower in females than in males until the start of puberty, and higher in adult women than men. This sex disparity and switch at the onset of puberty has been an object of debate among many researchers. Hence, in this review, we have summarized these observations to pinpoint areas needing more research work and to provide better sex-specific diagnosis and management of asthma. While some researchers have attributed it to the anatomical and physiological differences in the male and female respiratory systems, the influences of hormonal interplay after puberty have also been stressed. Other hormones such as leptin have been linked to the sex differences in asthma in both obese and non-obese patients. Recently, many scientists have also demonstrated the influence of the sex-specific genomic framework as a key player, and others have linked it to environmental, social lifestyle, and occupational exposures. The majority of studies concluded that adult men are less susceptible to developing asthma than women and that women display more severe forms of the disease. Therefore, the understanding of the roles played by sex- and gender-specific factors, and the biological mechanisms involved will help develop novel and more accurate diagnostic and therapeutic plans for sex-specific asthma management.

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.

Association between abdominal obesity and pulmonary function in apparently healthy adults: A systematic review

BACKGROUND

Obesity, especially abdominal obesity as a chronic disorder is associated with a high risk of developing non-communicable diseases such as respiratory diseases. Impaired lung function is a sign of early respiratory injury. This review summarizes the current knowledge of the effects of abdominal obesity on pulmonary function in apparently healthy adults.

METHODS

Google Scholar, PubMed, Science Direct, and Scopus databases were searched from 2014 up to August 2020 using relevant keywords. All original articles written in English evaluating the effects of abdominal obesity on pulmonary function in apparently healthy adults were eligible for this review.

RESULTS

A total of 26 studies (23 cross-sectional and three cohort) involving 68,024 participants were included in this review. More than 88% of the included studies reported that abdominal obesity significantly inversely was associated with pulmonary function.

CONCLUSION

The findings indicate that in subjects with abdominal obesity respiratory function decline possibly due to mechanical compression and obesity-induced airway inflammation. Therefore, nutrition and lifestyle interventions are required for the reduction of abdominal obesity that leads to improving pulmonary function and metabolic disease.

Nonlinear relationship between visceral adiposity index and lung function: a population-based study

Background

As one of the critical indicators of obesity, the interaction between visceral fat content and lung disease is the focus of current research. However, the exact relationship between Visceral adipose index (VAI) and lung function is not fully understood. The purpose of this study was to evaluate the relationship between VAI and lung function,

Methods

Our study included all participants from the baseline survey population in Xinjiang in the Natural Population Cohort Study in Northwest China. A field survey was conducted in rural areas of Moyu County, Xinjiang, China, between 35 and 74 years old from June to December 2018. We collected standard questionnaires and completed physical examinations, visceral fat tests, and lung function measurements.

Results

The study included 2367 participants with a mean VAI of 10.35 ± 4.35, with males having a significantly higher VAI than females: 13.17 ± 3.91 vs. 7.58 ± 2.65. The piecewise linear spline models indicated a significant threshold effect between lung function and VAI in the general population and the males population, showing an inverted U-shaped curve. But there was no significant association between VAI and lung function in females. FEV1% predicted and FVC% predicted increased with the increase of VAI (β 0.76; 95% CI 0.30, 1.21) and (β 0.50; 95% CI 0.06, 0.94) in males with VAI ≤ 14, while FEV1% predicted and FVC% predicted decreased with the increase of VAI (β − 1.17; 95% CI − 1.90, − 0.45) and (β − 1.36; 95% CI − 2.08, − 0.64) in males with VAI ≥ 15.

Conclusions

The relationship between lung function and VAI in male participants showed an inverted U-shaped curve, with the turning point of VAI between 14 and 15. The association between visceral fat and lung function was more robust in males than in females.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01751-7.

Visceral adiposity index is associated with lung function impairment: a population-based study

Background

The effects of visceral adiposity on decreased lung function have drawn much attention. Recently, the visceral adiposity index (VAI) has been proposed as a visceral fat distribution and dysfunction marker. However, the relationship between the VAI and lung function has not been investigated. The objective of the study was to analyze the association between the VAI and lung function and evaluate the potential of VAI as a predictor of lung function.

Methods

We collected data from a population-based study of 1786 subjects aged 40 years or older. All subjects completed a questionnaire and underwent anthropometric measurements and laboratory tests. Linear and logistic regression models were developed to assess the association between the VAI and lung function.

Results

The VAI was inversely related to FVC%predicted in men and negatively associated with both FVC%predicted and FEV1%predicted in women. In the linear regression analysis, the decrease in FVC%predicted associated with each 10% increase in the VAI was 1.127% in men and 1.943% in women; the decrease in FEV1%predicted associated with each 10%increase in the VAI was 0.663% in men and 1.738% in women. Further regression analysis revealed that the VAI was positively correlated with FVC and FEV1 impairment in women.

Conclusions

We were the first to show a clear correlation between the VAI and lung function impairment in the Chinese population. The VAI could be a simple and reliable approach in daily practice, and individuals, especially women with a high VAI, should receive additional screening and preventive interventions for respiratory disease.

Waist to Height Ratio and Metabolic Syndrome as lung dysfunction predictors

Metabolic Syndrome (MetS) has been related to pulmonary diseases but its relationship with lung age has not been sufficiently studied. In addition, anthropometric variables have been associated with pulmonary dysfunction, highlighting the waist-to-height ratio (WHtR). The aim was to evaluate the relationship between MetS and: lung age, anthropometric variables and the alteration of lung function. A cross-sectional study was carried out in 1901 workers, evaluating lung function through lung age (Morris & Temple equation) and spirometric values. The diagnosis of MetS was based on the harmonized criteria. We measured anthropometric variables (WHtR, waist circumference, body mass index, waist to hip ratio), blood pressure and biochemical variables (glucose, cholesterol total, HDL, triglycerides). Workers suffering from MetS showed an accelerated lung aging (59.4 ± 18.7 years vs 49 ± 18.4 years). The WHtR ≥ 0.55 was significantly related to an increase in lung age (β = 6.393, p < 0.001). In addition, a significant linear trend was found between clinical categories of WHtR and lung dysfunction, restrictive and mixed pattern. MetS caused an accelerated lung aging and favored the presence of restrictive lung impairment. In addition, WHtR ≥ 0.55 has been shown as the best predictor for pulmonary health.

Systemic Inflammation Mediates the Associations Between Abdominal Obesity Indices and Lung Function Decline in a Chinese General Population

BACKGROUND

Previous studies reported that obesity indices were inversely associated with lung function. However, the underlying mechanisms remain unclear. We aimed to assess the potential mediating effect of systemic inflammation in the associations between obesity indices and lung function decline among a general population.

METHODS

We conducted a cross-sectional study among 3442 participants from the Wuhan-Zhuhai cohort. Plasma C-reactive protein (CRP) was assayed as a marker of systemic inflammation. The relationships among several obesity indices (body mass index, BMI; waist circumference, WC; waist-to-hip ratio, WHR; waist-to-height ratio, WHtR), plasma CRP and lung function were assessed by generalized linear models. The role of CRP in the associations between obesity indices and lung function was analyzed using mediation analysis.

RESULTS

We observed inverse associations between abdominal obesity indices (WC, WHR and WHtR) and lung function parameters, including forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC) (all P<0.05). Each 1-unit increase in WC was associated with a 3.39 mL decrease in FEV₁ and a 3.96 mL decrease in FVC (all P<0.05). Each 1% increase in WHR and WHtR was associated with a 5.42 mL and a 14.23 mL decrease in FEV₁, and a 5.70 mL and a 16.92 mL decrease in FVC (all P<0.05). Mediation analysis indicated that plasma CRP partly mediated the associations between abdominal obesity and lung function. The mediated proportions of CRP in associations of WC, WHR and WHtR with FEV₁ were 7.96%, 9.59% and 5.76%, respectively. The mediated proportions of CRP in associations of WC and WHR with FVC were 8.33% and 11.40%, respectively.

CONCLUSION

Abdominal obesity indices were negatively associated with lung function, and the associations may be partly mediated by systemic inflammation.

Characteristics in Stages of Change and Decisional Balance among Smokers: The Burden of Obstructive Lung Diseases (BOLD)-Australia Study

Smoking cessation remains a health promotion target. Applying the Transtheoretical Model to Australian Burden of Obstructive Lung Diseases (BOLD) data, we examined differences in stages of change (SoC) and readiness to quit decisional behaviours. Factors were identified likely to influence readiness of smokers, ≥40 years old, to quit. Analysis was restricted to current smokers classified to one of three stages: pre-contemplation (PC), contemplation (C) or preparation (P) to quit. Their ability to balance positive and negative consequences was measured using decisional balance. Among 314 smokers, 43.0% females and 60.8% overweight/obese, the distribution of SoC was: 38.1% PC, 38.3% C and 23.5% P. Overweight/obesity was associated with readiness to quit in stages C and P and there were more negative than positive attitudes towards smoking in those stages. Males were significantly heavier smokers in PC and C stages. Females used smoking cessation medication more frequently in PC stage, were more embarrassed about smoking and had greater negative reinforcements from smoking. Age started smoking and factors related to smoking history were associated with readiness to quit and increased the odds of being in stage C or P. An overweight/obese smoker was likely to be contemplating or preparing to quit. In these stages, smokers have more negative attitudes toward smoking. Starting smoking later, taking advice on cessation from health providers and using quit medications indicate increased readiness to quit. Evaluating these factors in smokers and developing cessation gain-framed messages may prove useful to healthcare providers.

BMI but not central obesity predisposes to airway closure during bronchoconstriction

BACKGROUND AND OBJECTIVE

Obesity produces restrictive effects on lung function. We previously reported that obese patients with asthma exhibit a propensity towards small airway closure during methacholine challenge which improved with weight loss. We hypothesized that increased abdominal adiposity, a key contributor to the restrictive effects of obesity on the lung, mediates this response. This study investigates the effect of body mass index (BMI) versus waist circumference (WC) on spirometric lung function, sensitivity to airway narrowing and closure, and airway closure during bronchoconstriction in patients with asthma.

METHODS

Participants underwent spirometry and methacholine challenge. Sensitivity to airway closure and narrowing was assessed from the dose-response slopes of the forced vital capacity (FVC) and the ratio of forced expiratory volume in 1 s (FEV₁ ) to FVC, respectively. Airway closure during bronchoconstriction (closing index) was computed as the percent reduction in FVC divided by the percent reduction in FEV₁ at maximal bronchoconstriction.

RESULTS

A total of 116 asthmatic patients (56 obese) underwent methacholine challenge. Spirometric lung function was inversely related to WC (P < 0.05), rather than BMI. Closing index increased significantly during bronchoconstriction in obese patients and was related to increasing BMI (P = 0.01), but not to WC. Sensitivity to airway closure and narrowing was not associated with BMI or WC.

CONCLUSION

Although WC is associated with restrictive effects on baseline lung function, increased BMI, rather than WC, predisposes to airway closure during bronchoconstriction. These findings suggest that obesity predisposes to airway closure during bronchoconstriction through mechanisms other than simple mass loading.

Visceral and subcutaneous abdominal adiposity and pulmonary function in 30-year-old adults: a cross-sectional analysis nested in a birth cohort

BACKGROUND

Several studies have verified body fat distribution in association with pulmonary function (PF), mainly waist circumference, but few have used measures able to distinguish abdominal fat compartments. The present study aims to verify the association of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) with PF measures.

METHODS

In 1982, all hospital births occurring in Pelotas, Brazil, were identified and those livebirths have been followed. In 2012-13, the cohort participants were evaluated and VAT and SAT measured using ultrasound; forced expiratory volume in the first second (FEV₁) or forced vital capacity (FVC) were patronized in z-scores stratified by sex. The associations were verified using crude and adjusted linear regressions.

RESULTS

The present analyses comprised 3438 individuals (1721 women). VAT was inversely associated with spirometric parameters, in both crude and adjusted models. SAT showed inverse associations in the crude analyzes in males and a positive trend after adjustment, except for SAT and FVC in males. To each centimeter of VAT, mean adjusted FEV₁ z-scores decreased 0.072 (95% CI -0.107; -0.036) in men and 0.127 (95% CI -0.164; -0.090) in women, and FVC z-scores decreased -0.075 (95% CI -0.111; -0.039) and 0.121 (95% CI -0.158; -0.083), in men and women, respectively.

CONCLUSIONS

VAT has a consistent inverse association with FEV₁ and FVC in both sexes. On the other hand, SAT showed inconsistent results with PF parameters.

Analysis of the influence of respiratory disorders observed in preoperative spirometry on the dynamics of early inflammatory response in patients undergoing isolated coronary artery bypass grafting

Background

Preoperative spirometry provides measurable information about the occurrence of respiratory disorders. The aim of this study was to assess the association between preoperative spirometry abnormalities and the intensification of early inflammatory responses in patients following coronary artery bypass graft in extracorporeal circulation.

Material and methods

The study involved 810 patients (625 men and 185 women) aged 65.4±7.9 years who were awaiting isolated coronary artery bypass surgery. On the basis of spirometry performed on the day of admittance to the hospital, the patients were divided into three groups. Patients without respiratory problems constituted 78.8% of the entire group. Restricted breathing was revealed by spirometry in 14.9% and obstructive breathing in 6.3% of patients.

Results

Inter-group analysis showed statistically significant differences in C-reactive protein (CRP) between patients with restrictive spirometry abnormalities and patients without any pulmonary dysfunction. CRP concentrations differed before surgery (P=0.006) and on the second (P<0.001), fourth (P=0.005) and sixth days after surgery (P=0.029). There was a negative correlation between CRP levels and FEV₁.

Conclusion

In our study, the most common pulmonary disorders in the coronary artery bypass graft patients were restrictive. Patients with abnormal spirometry results from restrictive respiratory disorders have an elevated level of generalized inflammatory response both before and after the isolated coronary artery bypass surgery. Therefore, this group of patients should be given special postoperative monitoring and, in particular, intensive respiratory rehabilitation immediately after reconstitution.