Association of serum ferritin levels with smoking and lung function in the Korean adult population: analysis of the fourth and fifth Korean National Health and Nutrition Examination Survey

Iron Deficiency Among Hospitalized Patients With Congestive Heart Failure

INTRODUCTION

Studies have demonstrated the efficacy of intravenous (IV) iron when administered to patients with congestive heart failure (CHF) and iron deficiency (ID). We aimed to better understand the adherence of treatment for ID among a population with CHF, with particular interest in high-risk groups not often studied due to inadequate recruitment.

METHODS

A retrospective chart review at our institution was conducted from January 1, 2012, to July 7, 2021. Analysis included hospitalized patients with CHF and ID and dividing these patients into two time periods based on changes in iron treatment patterns and treatment between sexes.

RESULTS

Four thousand eight hundred thirteen patients were included in this study. During the "early era," 7.0% of patients with CHF and ID received IV iron compared with 20.9% of "late-era" patients. Female patients with ID were statistically less likely to receive IV iron when compared with male patients, both unadjusted (0.66, confidence interval [CI] 0.55-0.79, p < .0001) and adjusted (0.72, CI 0.59-0.87, p < .0001) for covariates.

CONCLUSION

This study illustrates improved adherence to treatment for ID among hospitalized population with CHF and ID over time but persistent undertreatment remains. Future studies will need to identify the barriers to treating female patients with CHF and ID to reduce these disparities.

Systemic Manifestations of COPD and the Impact of Dual Bronchodilation with Tiotropium/Olodaterol on Cardiac Function and Autonomic Integrity

Background: Chronic obstructive pulmonary disease (COPD) has significant systemic manifestations, including cardiovascular morbidity. The main aim of our study was to evaluate the effect of short-term COPD treatment with tiotropium/olodaterol (TIO/OLO) 5/5 μg on cardiac function and autonomic integrity. Methods: Twenty-nine patients with newly diagnosed moderate-to-severe COPD were enrolled. We performed pulmonary function tests, cardiac magnetic resonance, cardiac 123I-metaiodobenzylguanidine (123I-MIBG) imaging and analysis of blood biomarkers on our study subjects. The correlations between the tests' results were evaluated at baseline. The changes in pulmonary and cardiac parameters from baseline through 12 weeks were assessed. Results: Significant associations between pulmonary function tests' results and high-sensitivity C-reactive protein (hs-CRP), as well as interleukin-22 (IL-22), were observed at baseline. Treatment with TIO/OLO significantly improved lung function as measured by spirometry and body plethysmography. Moreover, we found that the cardiac index increased from 2.89 (interquartile range (IQR) 1.09) to 3.21 L/min/m2 (IQR 0.78) (p = 0.013; N = 18) and the late heart-to-mediastinum ratio improved from 1.88 (IQR 0.37) to 2 (IQR 0.41) (p = 0.026; N = 16) after 12 weeks of treatment. Conclusions: Treatment with TIO/OLO improves lung function and positively impacts cardiac function and autonomic integrity, suggesting that dual bronchodilation might have a potential in decreasing the risk for cardiac events in COPD. Hs-CRP and IL-22 might be beneficial in determining the intensity of systemic inflammation in COPD. Further research with a larger cohort is needed to enhance the initial results of this study.

Blood multiple heavy metals exposure and lung function in young adults: A prospective Cohort study in China

The content of single heavy metal in blood is associated with lung function decline, but there is little evidence on the joint effect of multiple heavy metals on lung function. To explore whether heavy metal mixture exposure is associated with lung function reduction among young adults. The study based on a cohort of 518 students recruited from a college in Shandong, China. We measured their lung function and blood heavy metal concentrations. The BKMR model was used to analyse the association between blood heavy metals mixture levels and lung function, and to identify the critical single heavy metal which contributes most to joint effects. As the sensitivity analysis, we used quantile g-computation model and GLM to explore the joint effect and independent effects of heavy metals. Our findings revealed a significant reduction of FVC and FEV1 levels after exposure to heavy metals mixture. An IQR increase in Cu was associated with a 0.079 L and 0.083 L decrease in FEV1 and FVC, respectively. And an IQR increase in Fe was associated with 0.036 L higher FEV1 and 0.033 L higher FVC. For adults, reducing blood heavy metals concentration might be an effective intervention to protect lung function.

Association between iron deficiency and hospitalization rate in community-dwelling older adults: A 3-year prospective observational study of DO-HEALTH

BACKGROUND

Iron deficiency (ID) is associated with negative health outcomes in older adults. However, data on the impact of ID on the number of hospitalizations and length of hospital stay (LOS) is lacking.

OBJECTIVE

To explore the associations between baseline ID and the number of hospitalizations and between baseline ID and at least one LOS ≥5 days in community-dwelling older adults.

METHODS

This is a secondary observational analysis of a randomized controlled trial including 2157 community-dwelling adults aged ≥70 years without major diseases at baseline. The main exposure was defined as ID (soluble transferrin receptor [sTfR] concentrations >28.1 nmol/L) at baseline. The primary outcome was the number of hospitalizations over a 3-year follow-up. The secondary outcome was having at least one LOS ≥5 days over the study period among individuals with one or more hospitalizations. Interaction between ID and anemia (hemoglobin <130 g/L for men and <120 g/L for women) was also investigated.

RESULTS

Baseline sTfR concentration was determined in 2141 participants (median age 74.0 years). At 3 year, 1497 hospitalizations were reported with an incidence rate of hospitalization of 0.26 per person-year (95% CI: 0.24, 0.28). Overall, baseline ID was associated with a 24% increased incidence rate of hospitalization (incidence rate ratio: 1.24; 95% CI: 1.05, 1.45) over 3 years. This association was independent of anemia status at baseline since the interaction between ID and anemia at baseline was not significant. Moreover, ID was not significantly associated with having a LOS ≥5 days (OR: 1.40; 95% CI: 1.00, 1.97) among participants with at least one hospitalization over 3 years.

CONCLUSIONS

ID is associated with increased hospitalization rate and not associated with LOS ≥5 days among generally healthy older adults. Efforts to minimize ID in older adults may improve overall health and optimize healthcare costs.

Smoking is associated with altered serum and hair essential metal and metalloid levels in women

The objective of the study was to evaluate the association between smoking and essential metal (Co, Cr, Cu, Fe, Mn, V, Zn) and metalloid (Se) levels in hair and serum of adult women using inductively coupled plasma-mass spectrometry (ICP-MS). In this cross-sectional study, a total of 344 women 20-70 years old including 199 smokers and 145 non-smoking women were enrolled. Serum Cu, Fe, and Zn levels in smoking women were found to be 6%, 8%, and 3% lower of levels in non-smokers, respectively. In contrast, circulating Mn, V, and especially Cr concentrations in smoking women exceeded the respective values in non-smoking women by 5%, 14%, and 54%. Hair Fe and Se levels in smoking women were 17% and 23% lower as compared to non-smoking controls, respectively. In multiple regression models, smoking severity was inversely associated with serum and hair Se concentrations, whereas the relationship to serum and hair Cr was positive. In addition, serum Zn and hair Fe levels were found to be inversely associated with the number of cigarettes per day. These findings hypothesize that health hazards of smoking may be at least in part be mediated by alteration in essential metal and metalloid metabolism.

Factors associated with serum ferritin levels and iron excess: results from the EPIC-EurGast study

PURPOSE

Excess iron is involved in the development of non-communicable diseases such as cancer, type 2 diabetes and cardiovascular conditions. We aimed to describe the prevalence of excess iron and its determinants in healthy European adults.

METHODS

Sociodemographic, lifestyle, iron status, dietary information, and HFE genotyping were obtained from controls from the nested case-control study EPIC-EurGast study. High sensitivity C-reactive protein (hsCRP) was measured to address possible systemic inflammation. Descriptive and multivariate analyses were used to assess iron status and its determinants.

RESULTS

Out of the 828 participants (median age: 58.7 years), 43% were females. Median serum ferritin and prevalence of excess iron were 143.7 µg/L and 35.2% in males, respectively, and 77 µg/L and 20% in females, both increasing with latitude across Europe. Prevalence of HFE C282Y mutation was significantly higher in Northern and Central Europe (~ 11%) than in the South (5%). Overweight/obesity, age, and daily alcohol and heme iron intake were independent determinants for iron status, with sex differences even after excluding participants with hsCRP > 5 mg/L. Obese males showed a greater consumption of alcohol, total and red meat, and heme iron, compared with those normal weight.

CONCLUSION

Obesity, higher alcohol and heme iron consumption were the main risk factors for excess iron in males while only age was associated with iron overload in females. Weight control and promoting healthy lifestyle may help prevent iron overload, especially in obese people. Further research is needed to clarify determinants of excess iron in the healthy adult population, helping to reduce the associated comorbidities.

Cigarette Smoke Particle-Induced Lung Injury and Iron Homeostasis

It is proposed that the mechanistic basis for non-neoplastic lung injury with cigarette smoking is a disruption of iron homeostasis in cells after exposure to cigarette smoke particle (CSP). Following the complexation and sequestration of intracellular iron by CSP, the host response (eg, inflammation, mucus production, and fibrosis) attempts to reverse a functional metal deficiency. Clinical manifestations of this response can present as respiratory bronchiolitis, desquamative interstitial pneumonitis, pulmonary Langerhans’ cell histiocytosis, asthma, pulmonary hypertension, chronic bronchitis, and pulmonary fibrosis. If the response is unsuccessful, the functional deficiency of iron progresses to irreversible cell death evident in emphysema and bronchiectasis. The subsequent clinical and pathological presentation is a continuum of lung injuries, which overlap and coexist with one another. Designating these non-neoplastic lung injuries after smoking as distinct disease processes fails to recognize shared relationships to each other and ultimately to CSP, as well as the common mechanistic pathway (ie, disruption of iron homeostasis).

Causal effect of iron status on lung function: A Mendelian randomization study

Background

The association between systemic iron status and lung function was conflicting in observational studies. We aim to explore the potential causal relationships between iron status and the levels of lung function using the two-sample Mendelian randomization (MR) design.

Methods

Genetic instruments associated with iron status biomarkers were retrieved from the Genetics of Iron Status (GIS) consortium (N = 48,972). Summary statistics of these genetic instruments with lung function were extracted from a meta-analysis of UK Biobank and SpiroMeta consortium (N = 400,102). The main analyses were performed using the inverse-variance weighted method, and complemented by multiple sensitivity analyses.

Results

Based on conservative genetic instruments, MR analyses showed that genetically predicted higher iron (beta: 0.036 per 1 SD increase, 95% confidence interval (CI): 0.016 to 0.056, P = 3.51 × 10^-4), log10-transformed ferritin (beta: 0.081, 95% CI: 0.047 to 0.116, P = 4.11 × 10^-6), and transferrin saturation (beta: 0.027, 95% CI: 0.015 to 0.038, P = 1.09 × 10^-5) were associated with increased forced expiratory volume in 1 s (FEV1), whereas higher transferrin was associated with decreased FEV1 (beta: -0.036, 95% CI: -0.064 to -0.008, P = 0.01). A significant positive association between iron status and forced vital capacity (FVC) was also observed. However, there is no causal association between iron status and FEV1-to-FVC ratio (P = 0.10). Similar results were obtained from the liberal instruments analyses and multiple sensitivity analyses.

Conclusion

Our study provided strong evidence to support that higher iron status is causally associated with higher levels of FEV1 and FVC, but has no impact on airway obstruction, confirming iron status as an important target for lung function management.

The effect of smoking on COVID-19-linked biomarkers in hospitalized patients with COVID-19

Background

The coronavirus pandemic, an infection (coronavirus disease 2019—COVID‐19), caused by severe acute respiratory disease coronavirus 2 (SARS‐CoV‐2), continues to have a strong influence worldwide. Although smoking is a major known risk factor for respiratory infectious disease, the effects of smoking on COVID‐19 are unclear. In this study, we aimed to evaluate the relationship between smoking and important hematologic (lymphocyte count, neutrophil count, platelet count, neutrophil‐lymphocyte ratio [NLR], platelet‐lymphocyte ratio [PLR]), inflammatory, and biochemical biomarkers in the prognosis of hospitalized patients with COVID‐19.

Methods

In a COVID‐19 pandemic hospital between June and August 2020, 200 adult patients aged over 18 years were hospitalized with COVID‐19 inflammatory and hematologic biomarkers at their first admission and smoking data were selected for this study.

Results

The rate of smokers was much higher among men (91.5%) than in women (8.5%) (p = 0.001). Neutrophil counts were evaluated and was significantly higher in current smokers (p < 0.001) and ex‐smokers (p = 0.001), and NLR (p = 0.008) and ferritin (p = 0.004) levels were higher than in never smokers. The saturation of patients had a negative significant linear correlation of NLR, PLR, and pack years of smoking. Compared with never smokers, current smokers had higher neutrophil counts (OR = 0.828 [0.750–0.915]; p = 0.041), NLR values (OR = 0.948 [0.910–0.987]; p = 0.009), and CRP levels (OR = 0.994 [0.990–0.999]; p = 0.019).

Conclusion

Serum neutrophil, NLR, and ferritin levels, which are widely used in determining the prognosis of COVID‐19, were found higher in current smokers/ex‐smokers. These results support the view that a poor prognosis of COVID‐19 is associated with smoking.

Smoking induces sex-specific changes in the small airway proteome

Introduction

Cigarette smoke triggers many cellular and signaling responses in the lung and the resulting inflammation plays a central role in smoke-related lung diseases, such as COPD. We explored the effects of smoking on the small airway proteome in samples obtained by collection of exhaled particles with the aim to identify specific proteins dysregulated by smoking.

Methods

Exhaled particles were obtained from 38 current smokers, 47 former smokers and 22 healthy controls with the PExA method. 120 ng of sample was collected from individual subjects and analyzed with the SOMAscan proteomics platform. General linear model-based statistics were performed.

Results

Two hundred and three proteins were detected in at least half of 107 total samples. Active smoking exerted a significant impact on the protein composition of respiratory tract lining fluid (RTLF), with 81 proteins altered in current smokers compared to never smokers (p < 0.05, q < 0.124). Among the proteins most clearly discriminating between current and never smokers were sRAGE, FSTL3, SPOCK2 and protein S, all of them being less abundant in current smokers. Analysis stratified for sex unveiled sex differences with more pronounced proteomic alterations due to active smoking in females than males. Proteins whose abundance was altered by active smoking in women were to a larger extent related to the complement system. The small airway protein profile of former smokers appeared to be more similar to that observed in never smokers.

Conclusions

The study shows that smoking has a strong impact on protein expression in the small airways, and that smoking affects men and women differently, suggesting PExA sampling combined with high sensitivity protein analysis offers a promising platform for early detection of COPD and identification of novel COPD drug targets.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01825-6.

Evaluation of the relationship between laboratory parameters and pulmonary function tests in COVID-19 patients

OBJECTIVE

The novel coronavirus SARS-CoV-2 (COVID-19) rapidly escalated from its origin in an animal market in Wuhan, China in December 2019 to a global pandemic, and the lungs are the most frequently affected organ. The aim of this study was to investigate the relationship between pulmonary function test parameters and laboratory parameters in COVID-19.

METHOD

A total of 60 patients who were admitted to the chest diseases department and intensive care unit of our hospital and were diagnosed with COVID-19 by real-time PCR analysis of nasopharyngeal swabs were evaluated. Pulmonary function tests and laboratory parameters at admission and on day 7 of treatment were analysed.

RESULTS

On day 7 of treatment, white blood cell count, CRP, and fibrinogen level were significantly lower than at admission (P = .002, 0.001, and 0.001, respectively), while forced expiratory volume in the first second (FEV₁ ) and forced vital capacity (FVC) values were significantly higher compared with admitting values (P = .001 for both). Correlation analysis showed that the decrease in CRP from admission to day 7 of treatment correlated with the increase in FEV₁ (r = 0.616, P = .01) and FVC (r = 0.51, P = .01) during the same period. A decrease in the fibrinogen level was also correlated with an increase in FEV₁ (r = 0.345, P = .01) and FVC (r = 0.357, P = .01).

CONCLUSION

Fibrinogen and CRP levels are easily accessible parameters that may help identify improvement or deterioration in pulmonary function in COVID-19 patients during follow-up and discharge while reducing the risk of transmission.

Nutritional Biomarkers and Associated Factors in Community-Dwelling Older Adults: Findings from the SHIELD Study

Aging is associated with intrinsic and extrinsic changes which affect the nutrient intake and nutritional status of an older individual. Suboptimal nutritional status is linked with adverse health outcomes. There are limited data in this area for community-dwelling older adults who are not at risk of malnutrition. The objective of this study was to describe the nutritional biomarkers in 400 community-dwelling older adults (aged ≥65 years) with normal nutritional status (Malnutrition Universal Screening Test score of 0) in Singapore and to identify factors associated with these biomarkers. The majority of the participants had normal levels of pre-albumin, albumin, total protein, creatinine, zinc, corrected calcium, vitamin B12, ferritin and hemoglobin. Females had significantly higher levels of corrected calcium and vitamin B12 than males, whereas males had significantly higher levels of pre-albumin, albumin, creatinine, serum ferritin, 25-hydroxyvitamin D (25(OH)D) and hemoglobin than females. About half of the participants (52%) had low level of 25(OH)D (<30 μg/L) and 10% had low zinc level (<724 μg/L). Among those with low level of 25(OH)D, 74% had 25(OH)D insufficiency (20–<30 μg/L) and 26% had 25(OH)D deficiency (<20 μg/L). Younger age, female gender, non-Chinese ethnicity and no intake of vitamin D supplement were associated with lower serum 25(OH)D level, whereas higher body mass index (BMI) was associated with low zinc level. These findings highlight the problem of hidden nutritional insufficiencies can be missed in seemingly normal nourished community-dwelling older adults.

Novel insights into ferroptosis: Implications for age-related diseases

Rapid increase in aging populations is an urgent problem because older adults are more likely to suffer from disabilities and age-related diseases (ARDs), burdening healthcare systems and society in general. ARDs are characterized by the progressive deterioration of tissues and organs over time, eventually leading to tissue and organ failure. To date, there are no effective interventions to prevent the progression of ARDs. Hence, there is an urgent need for new treatment strategies. Ferroptosis, an iron-dependent cell death, is linked to normal development and homeostasis. Accumulating evidence, however, has highlighted crucial roles for ferroptosis in ARDs, including neurodegenerative and cardiovascular diseases. In this review, we a) summarize initiation, regulatory mechanisms, and molecular signaling pathways involved in ferroptosis, b) discuss the direct and indirect involvement of the activation and/or inhibition of ferroptosis in the pathogenesis of some important diseases, and c) highlight therapeutic targets relevant for ARDs.

Association between Iron Status and Incident Type 2 Diabetes: A Population-Based Cohort Study

Type 2 diabetes poses a major public health challenge. Here, we conducted a cohort study with a large sample size to determine the association of baseline serum ferritin (SF), a marker of iron status, with incident type 2 diabetes in primary healthcare patients in Catalonia, a western Mediterranean region. A total of 206,115 patients aged 35–75 years without diabetes and with available baseline SF measurements were eligible. The variables analyzed included sociodemographic characteristics, anthropometry, lifestyle, morbidity and iron status (SF, serum iron and hemoglobin). Incident type 2 diabetes during follow-up (2006–2016) was ascertained using the International Classification of Diseases, 10th edition. Cox proportional-hazards models adjusted for multiple baseline confounders/mediators were used to estimate hazard ratios (HRs). Over a median follow-up of 8.4 years, 12,371 new cases of type 2 diabetes were diagnosed, representing an incidence rate of 7.5 cases/1000 persons/year. Since at baseline, the median SF concentration was higher in subjects who developed type 2 diabetes (107.0 µg/L vs. 60.3 µg/L; p < 0.001), SF was considered an independent risk predictor for type 2 diabetes; the multivariable-adjusted HRs for incident type 2 diabetes across SF quartiles 1–4 were 1.00 (reference), 0.95 (95% CI = 0.85–1.06), 1.18 (95% CI = 1.65–1.31) and 1.51 (95% CI = 1.36–1.65), respectively. Our study suggested that higher baseline SF was significantly associated with an increased risk of new-onset type 2 diabetes in Catalan primary healthcare users, supporting the relevance of monitoring iron stores in order to improve the diagnosis and management of diabetes in clinical practice.

Association of serum ferritin and lung function in tobacco-naïve postmenopausal women: Analysis of population-based nationally representative data

INTRODUCTION

Ferritin regulates iron homeostasis, and is involved in the inflammation in the lung, especially in smokers; however, its associations on pulmonary function in nonsmokers remain unclear.

OBJECTIVES

The present study aimed to evaluate the association between serum ferritin and lung function in a tobacco-naïve postmenopausal women.

METHODS

In this study, 25 534 individuals were enrolled, among who 5338 tobacco-naïve individuals were identified; of those, 342 men and 2879 women (742 pre- and 2137 postmenopausal) with data of serum ferritin, lung function and covariates were included. To evaluate the association of ferritin and lung function, multivariable-adjusted linear regression analyses was used including the factors of predicted value of forced expiratory volume in 1 second (FEV1 %) and forced vital capacity (FVC%). Logistic regression analyses were used to measure the relationship between ferritin and restrictive and obstructive lung disease.

RESULTS

In premenopausal women, FEV1 %/FVC was weakly but positively associated with serum ferritin, and after adjusting for covariates, the association was without statistical significance. No significant association between ferritin and obstructive lung disease was observed. In postmenopausal women, predicted FVC% was negatively associated with serum ferritin, and ferritin was dose-dependently related with risk for restrictive lung disease. The odds ratio for restrictive lung disease in postmenopausal women was 2.285 at T3 and 1.560 at T2 relative to that at T1.

CONCLUSIONS

High serum ferritin level was significantly associated with lower FVC% and increased risk of restrictive lung disease in tobacco-naïve postmenopausal women. Further study is needed to determine the mechanism underlying the current findings.

Inverse Association between Iron Deficiency and Glycated Hemoglobin Levels in Ghanaian Adults-the RODAM Study

BACKGROUND

Glycated hemoglobin (HbA1c) is often used to diagnose type 2 diabetes (T2D), but studies show that iron deficiency (ID) is associated with elevated HbA1c in the absence of hyperglycemia. It is unknown whether ID prevalence varies between sub-Saharan African populations living in different locations and whether ID influences HbA1c levels in these populations.

OBJECTIVES

We assessed the prevalence of ID among Ghanaian migrants in Europe and nonmigrant Ghanaians, and the influence of ID on HbA1c categories among Ghanaians without T2D.

METHODS

We used the database from the cross-sectional RODAM (Research on Obesity and Diabetes among African Migrants) study. This contained data on 3377 Ghanaian men and women aged 25-70 y living in urban and rural Ghana and Ghanaian migrants living in Amsterdam, London, and Berlin. ID was defined as ferritin < 15 ng/mL or, if C-reactive protein was ≥5 mg/mL, as ferritin < 30 ng/mL according to the WHO. We used binary logistic regression to assess differences in ID between sites and its association with clinically defined HbA1c categories (<5.5%, ≥5.5% to <6.5%, ≥6.5%). Men and women were analyzed separately.

RESULTS

The prevalence of ID was higher in migrant [28.4%; adjusted OR (aOR): 3.08; 95% CI: 2.04, 4.65)] and urban (23.2%; aOR: 2.37; 95% CI: 1.56, 3.59) women than in rural women (11.9%). Among women, ID was associated with higher odds of HbA1c ≥ 5.5% to <6.5% in the absence of hyperglycemia (aOR: 1.43; 95% CI: 1.08, 1.87). This association was not found in men.

CONCLUSIONS

Further research is needed to identify factors underlying the high prevalence of ID among urban and migrant Ghanaian women, and the association of ID with HbA1c ≥ 5.5% to <6.5% in women. In addition, our study reinforces the need to consider iron concentrations if interpreting HbA1c among African populations.

Increased airway iron parameters and risk for exacerbation in COPD: an analysis from SPIROMICS

Levels of iron and iron-related proteins including ferritin are higher in the lung tissue and lavage fluid of individuals with chronic obstructive pulmonary disease (COPD), when compared to healthy controls. Whether more iron in the extracellular milieu of the lung associates with distinct clinical phenotypes of COPD, including increased exacerbation susceptibility, is unknown. We measured iron and ferritin levels in the bronchoalveolar lavage fluid (BALF) of participants enrolled in the SubPopulations and InteRmediate Outcome Measures In COPD (SPIROMICS) bronchoscopy sub-study (n = 195). BALF Iron parameters were compared to systemic markers of iron availability and tested for association with FEV1 % predicted and exacerbation frequency. Exacerbations were modelled using a zero-inflated negative binomial model using age, sex, smoking, and FEV1 % predicted as clinical covariates. BALF iron and ferritin were higher in participants with COPD and in smokers without COPD when compared to non-smoker control participants but did not correlate with systemic iron markers. BALF ferritin and iron were elevated in participants who had COPD exacerbations, with a 2-fold increase in BALF ferritin and iron conveying a 24% and 2-fold increase in exacerbation risk, respectively. Similar associations were not observed with plasma ferritin. Increased airway iron levels may be representative of a distinct pathobiological phenomenon that results in more frequent COPD exacerbation events, contributing to disease progression in these individuals.

Decreased lung function is associated with elevated ferritin but not iron or transferrin saturation in 42,927 healthy Korean men: A cross-sectional study

Objectives

Though elevated ferritin level and decreased lung function both predispose people to cardio-metabolic disease, few reports have investigated the association between them. Furthermore, it remains unclear whether the association reflects a change in iron stores or an epiphenomenon reflecting metabolic stress. Therefore, we looked for possible associations between ferritin, iron, and transferrin saturation (TSAT) and lung function to clarify the role of iron-related parameters in healthy men.

Methods

We conducted a cohort study of 42,927 healthy Korean men (mean age: 38.6 years). Percent predicted forced expiratory volume in one second (FEV1%) and forced vital capacity (FVC%) were categorized into quartiles. Adjusted odds ratios (aORs) and 95% confidence intervals (using the highest quartile as reference) were calculated for hyperferritinemia, high iron, and high TSAT after controlling for potential confounders.

Results

The median ferritin level was 199.8 (141.5–275.6) ng/mL. The prevalence of hyperferritinemia (defined as >300 ng/mL) was 19.3%. Subjects with hyperferritinemia had lower FEV1% and FVC% than those with normal ferritin level with a slight difference, but those were statistically significant (99.22% vs.99.61% for FEV1%, p = 0.015 and 98.43% vs. 98.87% for FVC, p = 0.001). However, FEV1/FVC ratio was not significantly different between groups (P = 0.797). Compared with the highest quartile, the aORs for hyperferritinemia across decreasing quartiles were 1.081 (1.005–1.163), 1.100 (1.007–1.200), and 1.140 (1.053–1.233) for FEV1% (p for trend = 0.007) and 1.094 (1.018–1.176), 1.101 (1.021–1.188), and 1.150 (1.056–1.252) for FVC% (p for trend = 0.001). However, neither FEV1% nor FVC% was associated with iron or TSAT.

Conclusions

Hyperferritinemia was associated with decreased lung function in healthy Korean men, but iron and TSAT were not. Longitudinal follow-up studies are required to validate our findings.

Smoking-induced iron dysregulation in the lung

Iron is one of the most abundant transition elements and is indispensable for almost all organisms. While the ability of iron to participate in redox chemistry is an essential requirement for participation in a range of vital enzymatic reactions, this same feature of iron also makes it dangerous in the generation of hydroxyl radicals and superoxide anions. Given the high local oxygen tensions in the lung, the regulation of iron acquisition, utilization, and storage therefore becomes vitally important, perhaps more so than in any other biological system. Iron plays a critical role in the biology of essentially every cell type in the lung, and in particular, changes in iron levels have important ramifications on immune function and the local lung microenvironment. There is substantial evidence that cigarette smoke causes iron dysregulation, with the implication that iron may be the link between smoking and smoking-related lung diseases. A better understanding of the connection between cigarette smoke, iron, and respiratory diseases will help to elucidate pathogenic mechanisms and aid in the identification of novel therapeutic targets.

Indices of iron homeostasis correlate with airway obstruction in an NHANES III cohort

Cigarette smoking results in the accumulation of iron both systemically and locally, in the lung thereby causing imbalance in iron homeostasis. This disruption in iron homeostasis can be associated with oxidative stress and consequent tissue injury. Therefore, in this study, we tested the association between iron homeostasis and airway obstruction by examining a large cohort of smokers and non-smokers for relationships between 1) serum ferritin and iron concentrations and transferrin saturation and 2) forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁), and their ratio (FEV₁/FVC). Data from the National Health and Examination Survey III were analyzed. The study population included persons aged 20 years and above with their following data recorded: race, gender, serum ferritin and iron concentrations, and transferrin saturation; the final sample number was 7,251. In the total population, Pearson correlation coefficients between 1) serum ferritin and iron concentrations and transferrin saturation and 2) FVC and FEV₁ were significantly positive; whereas those between 1) serum ferritin concentrations and transferrin saturation and 2) FEV₁/FVC were significantly negative. With separate analyses, serum ferritin concentrations demonstrated positive associations with FVC and FEV₁ but an inverse relationship with FEV₁/FVC in smokers and non-smokers. Serum ferritin levels increased with worsening airway obstruction among smokers, and its highest concentrations were found among those with the lowest values of FEV₁/FVC ratio (<60%). Comparable to cigarette smokers, serum ferritin concentrations among non-smokers were greatest in those with the lowest FEV₁/FVC ratio. Furthermore, elevated levels of serum iron and saturation of transferrin also corresponded with decreased FEV₁/FVC ratio among non-smokers. Thus, we conclude that indices of iron homeostasis are associated with airway obstruction in both smokers and non-smokers.