Primary and secondary prevention of chronic obstructive pulmonary disease: where to next?

Associations between vitamin A and K intake and lung function in the general US population: evidence from NHANES 2007-2012

Introduction

While nutrition's critical role in enhancing respiratory health is acknowledged, the specific impacts of vitamins A and K on lung function remain largely unexplored. The study aimed to evaluate the relationships between vitamins A and K intake and lung function.

Methods

The cross-sectional study focused on adults aged 20-79 with utilizing data from US National Health and Nutrition Examination Survey (NHANES) 2007-2012. Lung function was assessed by measuring forced expiratory volume (FEV1), forced vital capacity (FVC), and the ratio of these two values (FEV1/FVC). Regression model was performed to determine the associations between intake of vitamins A and K and outcomes.

Results

Data of 10,034 participants (representing 142,965,892 adults in the US) were analyzed. After adjusting for relevant confounders, multivariable analysis revealed 1 μg/day increase of vitamin A intake was significantly associated with 0.03 ml increased FEV1 (p = 0.004) and 0.04 ml increased forced vital capacity (FVC) (p < 0.001). In addition, 1 μg/day increase in vitamin K intake was significantly associated with 0.11 ml increased FEV1 (p = 0.022). Neither vitamin A and K intake was associated with FEV1/FVC or presence of airway obstruction.

Conclusions

In relatively healthy population of the US, greater vitamin A or K intake was independently associated with better lung function assessed by spirometry. Benefits of such vitamins for pulmonary health should be confirmed in future randomized controlled trials.

The Association Between BMI and Cardiorespiratory Functions Among Medical Students at Northern Border University

BACKGROUND

Cardiorespiratory function is one of the key health indicators that promote good health. Knowing the correlation between body mass index (BMI) and cardiorespiratory functioning might assist in the creation of evidence-based therapies that focus on addressing difficulties associated with obesity.

OBJECTIVE

To assess the correlation between BMI and cardiorespiratory functions among medical students at Northern Border University.

MATERIALS AND METHODS

A cross-sectional study was conducted among medical students at Northern Border University, Saudi Arabia. The blood pressure (BP), respiratory rate (RR), heart rate (HR), mean arterial pressure (MAP), pulse pressure (PP), and BMI of the students were measured.

RESULTS

The mean age of the students was 17.1 ± 1.9 years. Nearly 40% of students were overweight or obese. Our study revealed a significant positive correlation between BMI and BP, RR, tidal volume (TV), and MAP.

CONCLUSIONS

 The correlation analysis of our study revealed a significant positive correlation of BMI with BP, RR, TV, and MAP.

Metabolically healthy and unhealthy obesity and the development of lung dysfunction

We investigated the association of metabolically healthy (MH) and unhealthy (MU) obesity with incident lung dysfunction. This cohort study included 253,698 Korean lung disease-free adults (mean age, 37.4 years) at baseline. Spirometry-defined lung dysfunction was classified as a restrictive pattern (RP) or obstructive pattern (OP). We defined obesity as BMI ≥ 25 kg/m² and MH as the absence of any metabolic syndrome components with a homeostasis model assessment of insulin resistance < 2.5: otherwise, participants were considered MU. During a median follow-up of 4.9 years, 10,775 RP cases and 7140 OP cases develped. Both MH and MU obesity showed a positive association with incident RP, with a stronger association in the MU than in the MH group (P_interaction = 0.001). Multivariable-adjusted hazard ratios (95% CI) for incident RP comparing obesity to the normal-weight category was 1.15 (1.05-1.25) among the MH group and 1.38 (1.30-1.47) among MU group. Conversely, obesity was inversely associated with OP because of a greater decline in forced vital capacity than forced expiratory volume in 1 s. Both MH and MU obesity were positively associated with RP. However, the associations between obesity, metabolic health, and lung functions might vary depending on the type of lung disease.

Body mass index and weight change are associated with adult lung function trajectories: the prospective ECRHS study

BACKGROUND

Previous studies have reported an association between weight increase and excess lung function decline in young adults followed for short periods. We aimed to estimate lung function trajectories during adulthood from 20-year weight change profiles using data from the population-based European Community Respiratory Health Survey (ECRHS).

METHODS

We included 3673 participants recruited at age 20-44 years with repeated measurements of weight and lung function (forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1)) in three study waves (1991-93, 1999-2003, 2010-14) until they were 39-67 years of age. We classified subjects into weight change profiles according to baseline body mass index (BMI) categories and weight change over 20 years. We estimated trajectories of lung function over time as a function of weight change profiles using population-averaged generalised estimating equations.

RESULTS

In individuals with normal BMI, overweight and obesity at baseline, moderate (0.25-1 kg/year) and high weight gain (>1 kg/year) during follow-up were associated with accelerated FVC and FEV1 declines. Compared with participants with baseline normal BMI and stable weight (±0.25 kg/year), obese individuals with high weight gain during follow-up had -1011 mL (95% CI -1.259 to -763) lower estimated FVC at 65 years despite similar estimated FVC levels at 25 years. Obese individuals at baseline who lost weight (<-0.25 kg/year) exhibited an attenuation of FVC and FEV1 declines. We found no association between weight change profiles and FEV1/FVC decline.

CONCLUSION

Moderate and high weight gain over 20 years was associated with accelerated lung function decline, while weight loss was related to its attenuation. Control of weight gain is important for maintaining good lung function in adult life.

Dietary antioxidants and 10-year lung function decline in adults from the ECRHS survey

The relationship between lung function decline and dietary antioxidants over 10 years in adults from three European countries was investigated.In 2002, adults from three participating countries of the European Community Respiratory Health Survey (ECRHS) answered a questionnaire and underwent spirometry (forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC)), which were repeated 10 years later. Dietary intake was estimated at baseline with food frequency questionnaires (FFQ). Associations between annual lung function decline (mL) and diet (tertiles) were examined with multivariable analyses. Simes' procedure was applied to control for multiple testing.A total of 680 individuals (baseline mean age 43.8±6.6 years) were included. A per-tertile increase in apple and banana intake was associated with a 3.59 mL·year-1 (95% CI 0.40, 7.68) and 3.69 mL·year-1 (95% CI 0.25, 7.14) slower decline in FEV1 and FVC, respectively. Tomato intake was also associated with a slower decline in FVC (4.5 mL·year-1; 95% CI 1.28, 8.02). Only the association with tomato intake remained statistically significant after the Simes' procedure was performed. Subgroup analyses showed that apple, banana and tomato intake were all associated with a slower decline in FVC in ex-smokers.Intake of fruits and tomatoes might delay lung function decline in adults, particularly in ex-smokers.

The Gut-Liver-Lung Axis. Modulation of the Innate Immune Response and Its Possible Role in Chronic Obstructive Pulmonary Disease

Evidence from epidemiological studies suggests that a diet high in fiber is associated with better lung function and reduced risk of chronic obstructive pulmonary disease (COPD). The mechanism for this benefit remains unknown, but, as fiber is not absorbed by the gut, this finding suggests that the gut may play an active role in pathogenic pathways underlying COPD. There is a growing awareness that aberrant activity of the innate immune system, characterized by increased neutrophil and macrophage activation, may contribute to the development or progression of COPD. Innate immunity is modulated in large part by the liver, where hepatic cells function in immune surveillance of the portal circulation, as well as providing a rich source of systemic inflammatory cytokines and immune mediators (notably, IL-6 and C-reactive protein). We believe that the beneficial effect of dietary fiber on lung function is through modulation of innate immunity and subsequent attenuation of the pulmonary response to inflammatory stimuli, most apparent in current or former smokers. We propose that the "gut-liver-lung axis" may play a modifying role in the pathogenesis of COPD. In this review, we summarize lines of evidence that include animal models, large prospective observational studies, and clinical trials, supporting the hypothesis that the gut-liver-lung axis plays an integral part in the pathogenic mechanisms underlying the pathogenesis of COPD.