Lung function, COPD and Alternative Healthy Eating Index in US adults

Dietary patterns and risk of Chronic Obstructive Pulmonary Disease (COPD) and clinical outcomes in diagnosed patients: A scoping review

BACKGROUND & AIMS

Limited research exists on the association between dietary patterns (DP) and COPD risk or health-related outcomes. We reviewed existing literature to identify DP as a potential factor influencing COPD development and associated health outcomes in diagnosed individuals.

METHODS

We followed the Joanna Briggs Institute methodology for this scoping review, conducting searches on PubMed, Scopus, Embase, and Web of Science to identify studies meeting our inclusion criteria (P, population - adults from the general population with or without COPD diagnosis; C, concept - DP; C, context - any setting). Two reviewers screened titles and abstracts, confirmed eligibility through full-text examination, extracted data using Redcap®, and assessed bias risk with the Newcastle Ottawa Scale.

RESULTS

We analyzed 24 studies with sample sizes ranging from 121 to 421,426 individuals aged 20 to 75. Eighty-three percent investigated the role of DP in the COPD etiology, while 16.7 % examined health-related COPD outcomes. Food frequency questionnaires predominated (75 %) in exploring 23 distinct DP. Sixty-seven percent employed a priori-defined DP, focusing on the Mediterranean Diet (MedDiet) and Healthy Eating Index (HEI), while 33.3 % utilized a posteriori-defined DP, mainly represented by the Prudent and Traditional DP. Sixty percent of the studies reported significant associations between DP and COPD risk/odds. However, studies examining DP and COPD patient outcomes produced varied results.

CONCLUSIONS

Most studies focused on assessing COPD risk using a priori-defined DP, particularly emphasizing the Med Diet and HEI. Overall, the studies found that healthy DPs are associated with reduced risk of COPD and improved outcomes in diagnosed patients.

Obesity and Asthma: Implementing a Treatable Trait Care Model

Recognition of obesity as a treatable trait of asthma, impacting its development, clinical presentation and management, is gaining widespread acceptance. Obesity is a significant risk factor and disease modifier for asthma, complicating treatment. Epidemiological evidence highlights that obese asthma correlates with poorer disease control, increased severity and persistence, compromised lung function and reduced quality of life. Various mechanisms contribute to the physiological and clinical complexities observed in individuals with obesity and asthma. These encompass different immune responses, including Type IVb, where T helper 2 cells are pivotal and driven by cytokines like interleukins 4, 5, 9 and 13, and Type IVc, characterised by T helper 17 cells and Type 3 innate lymphoid cells producing interleukin 17, which recruits neutrophils. Additionally, Type V involves immune response dysregulation with significant activation of T helper 1, 2 and 17 responses. Finally, Type VI is recognised as metabolic-induced immune dysregulation associated with obesity. Body mass index (BMI) stands out as a biomarker of a treatable trait in asthma, readily identifiable and targetable, with significant implications for disease management. There exists a notable gap in treatment options for individuals with obese asthma, where asthma management guidelines lack specificity. For example, there is currently no evidence supporting the use of incretin mimetics to improve asthma outcomes in asthmatic individuals without Type 2 diabetes mellitus (T2DM). In this review, we advocate for integrating BMI into asthma care models by establishing clear target BMI goals, promoting sustainable weight loss via healthy dietary choices and physical activity and implementing regular reassessment and referral as necessary.

Food Insecurity is Associated With COPD Morbidity and Perceived Stress

Background

Low socioeconomic status (SES) has been associated with worse clinical outcomes in chronic obstructive pulmonary disease (COPD). Food insecurity is more common among individuals with low SES and has been associated with poor outcomes in other chronic illnesses, but its impact on COPD has not been studied.

Methods

Former smokers with spirometry-confirmed COPD were recruited from low-income areas of Baltimore, Maryland, and followed for 9 months as part of a cohort study of diet and indoor air pollution. Food insecurity and respiratory outcomes, including COPD exacerbations and patient-reported outcomes, were assessed at regular intervals. The association between food insecurity and COPD outcomes was analyzed using generalized linear mixed models. Additional analyses examined the association of COPD morbidity with subdomains of food insecurity and the association of food insecurity with psychological well-being measures.

Results

Ninety-nine participants had available data on food insecurity and COPD outcomes. A total of 26.3% of participants were food insecure at 1 or more times during the study. After adjusting for individual SES, neighborhood poverty, and low healthy food access, food insecurity was associated with a higher incidence rate of moderate and severe exacerbations and worse dyspnea, COPD health status, and respiratory-specific quality of life. Subdomains of food insecurity were independently associated with worse patient-reported outcomes. Food insecurity was additionally associated with higher perceived stress.

Discussion

Among former smokers with COPD, food insecurity was associated with a higher incidence of exacerbations, worse patient-reported outcomes, and higher perceived stress. Subdomains of food insecurity were independently associated with worse patient-reported outcomes.

Association of Preoperative Lung Function with Complications after Lobectomy Using Race-Neutral and Race-Specific Normative Equations

Rationale: Pulmonary function testing (PFT) is performed to aid patient selection before surgical resection for non-small cell lung cancer (NSCLC). The interpretation of PFT data relies on normative equations, which vary by race, but the relative strength of association of lung function using race-specific or race-neutral normative equations with postoperative pulmonary complications is unknown. Objectives: To compare the strength of association of lung function, using race-neutral or race-specific equations, with surgical complications after lobectomy for NSCLC. Methods: We studied 3,311 patients who underwent lobectomy for NSCLC and underwent preoperative PFT from 2001 to 2021. We used Global Lung Function Initiative equations to generate race-specific and race-neutral normative equations to calculate percentage predicted forced expiratory volume in 1 second (FEV1%). The primary outcome of interest was the occurrence of postoperative pulmonary complications within 30 days of surgery. We used unadjusted and race-adjusted logistic regression models and least absolute shrinkage and selection operator analyses adjusted for relevant comorbidities to measure the association of race-specific and race-neutral FEV1% with pulmonary complications. Results: Thirty-one percent of patients who underwent surgery experienced pulmonary complications. Higher FEV1, whether measured with race-neutral (odds ratio [OR], 0.98 per 1% change in FEV1% [95% confidence interval (CI), 0.98-0.99]; P < 0.001) or race-specific (OR, 0.98 per 1% change in FEV1% [95% CI, 0.98-0.98]; P < 0.001) normative equations, was associated with fewer postoperative pulmonary complications. The area under the receiver operator curve for pulmonary complications was similar for race-adjusted race-neutral (0.60) and race-specific (0.60) models. Using least absolute shrinkage and selection operator regression, higher FEV1% was similarly associated with a lower rate of pulmonary complications in race-neutral (OR, 0.99 per 1% [95% CI, 0.98-0.99]) and race-specific (OR, 0.99 per 1%; 95% CI, 0.98-0.99) models. The marginal effect of race on pulmonary complications was attenuated in all race-specific models compared with all race-neutral models. Conclusions: The choice of race-specific or race-neutral normative PFT equations does not meaningfully affect the association of lung function with pulmonary complications after lobectomy for NSCLC, but the use of race-neutral equations unmasks additional effects of self-identified race on pulmonary complications.

The association between diet quality and chronic obstructive pulmonary disease: a case-control study

BACKGROUND

Previous investigations have primarily examined the relationship between various dietary patterns and the risk of chronic obstructive pulmonary disease (COPD); however, there have been limited studies that have evaluated the association between diet quality presented by Healthy Eating Index 2010 (HEI-2010) and COPD. The aim of this study was to investigate this association in Iranian population.

METHODS

This case-control study recruited 84 cases and 252 healthy controls who were randomly selected. Diet, smoking, and physical activity were assessed using validated questionnaires. The HEI-2010 score ranged from zero to hundred twenty, with zero indicating an unhealthy diet and hundred twenty indicating a healthy diet. Logistic regression models were utilized to analyze the association between HEI-2010 and the odds of COPD.

RESULTS

Results from logistic regression showed that individuals with higher HEI scores had a significantly lower odds of COPD (OR: 0.34; 95% CI: 0.16-0.72). After adjusting for confounders, individuals with the highest HEI score were 82% less likely to have COPD (OR: 0.18; 95% CI: 0.03-0.96). This association remained significant after adjusting for smoking and physical activity (OR: 0.08; 95% CI: 0.01-0.93) and with additional adjustment for BMI (OR: 0.08; 95% CI: 0.01-0.92).

CONCLUSIONS

This study found a significant association between a higher HEI-2010 score and a lower odd of COPD in the Iranian population. These results suggest that a healthy diet may play a crucial role in reducing the odds of COPD and in improving the function of the lungs. However, further prospective studies are warranted to elucidate this relationship.

Mechanisms Linking COPD to Type 1 and 2 Diabetes Mellitus: Is There a Relationship between Diabetes and COPD?

Chronic obstructive pulmonary disease (COPD) patients frequently suffer from multiple comorbidities, resulting in poor outcomes for these patients. Diabetes is observed at a higher frequency in COPD patients than in the general population. Both type 1 and 2 diabetes mellitus are associated with pulmonary complications, and similar therapeutic strategies are proposed to treat these conditions. Epidemiological studies and disease models have increased our knowledge of these clinical associations. Several recent genome-wide association studies have identified positive genetic correlations between lung function and obesity, possibly due to alterations in genes linked to cell proliferation; embryo, skeletal, and tissue development; and regulation of gene expression. These studies suggest that genetic predisposition, in addition to weight gain, can influence lung function. Cigarette smoke exposure can also influence the differential methylation of CpG sites in genes linked to diabetes and COPD, and smoke-related single nucleotide polymorphisms are associated with resting heart rate and coronary artery disease. Despite the vast literature on clinical disease association, little direct mechanistic evidence is currently available demonstrating that either disease influences the progression of the other, but common pharmacological approaches could slow the progression of these diseases. Here, we review the clinical and scientific literature to discuss whether mechanisms beyond preexisting conditions, lifestyle, and weight gain contribute to the development of COPD associated with diabetes. Specifically, we outline environmental and genetic confounders linked with these diseases.

The Dietary Inflammatory Index and Early COPD: Results from the National Health and Nutrition Examination Survey

We examined 3962 people aged 20 to 49 years who had information on spirometry testing and underwent a 24 h dietary recall interview from the 2007-2012 National Health and Nutrition Examination Survey (NHANES) and used multivariable logistic regression to evaluate associations between Dietary Inflammatory Index (DII, a pro-inflammatory diet) and early COPD and lung function. The overall prevalence of early COPD was 5.05%. Higher DII was associated with increased odds of early COPD (quartile 4 vs. 1, the OR = 1.657, 95% CI = 1.100-2.496, p = 0.0156). In a full-adjusted model, each unit of increase in DII score was associated with a 90.3% increase in the risk of early COPD. Higher DII is significantly associated with lower FEV1 and FVC among individuals with early COPD, each unit increment in the DII was significantly associated with 0.43 L-0.58 L decrements in FEV1 (β = -0.43, 95% CI = -0.74, -0.12) and FVC (β = -0.58, 95% CI = -1.01, -0.16). These findings demonstrate that higher consumption of a pro-inflammatory diet may contribute to an increased risk of early COPD and lower lung function, and further support dietary interventions as part of a healthy lifestyle in order to preserve lung function and prevent or improve COPD.