Lung function and diabetes

Characteristics of human donor lungs utilized for research

Introduction

Many fundamental discoveries have occurred using primary cells from deceased donor lungs. These cells respond differently to injury when there are underlying co-morbidities like diabetes mellitus, hypertension, aging and exposures to cigarette smoke, cocaine and chronic alcohol use. However, the prevalence of these characteristics in donor lungs utilized for research is currently unknown.

Methods

This retrospective cohort study procured data of lung transplant donors from Mid-America Transplant from January 2017 until July 2023. The donors were characterized based on lung utilization into three groups - lungs used for research, lungs used for transplant, and lungs not recovered from donors for either research or transplantation.

Results

The mean age of donors whose lungs were utilized for research was 41±18 years. 25% of them were expanded criteria donors (ECD) while 10% of the donors in the transplant cohort were ECD. 14% of the donors whose lungs were utilized for research had history of diabetes compared to 8% of donors whose lungs were transplanted. A quarter of the research donor population had positive history of cigarette use within the preceding 20 years. At least 40% of donors had a positive history of non-intravenous drug use, of whom a majority had a history of continued non-intravenous drug use.

Conclusions

No strict selection criteria or protocols exist when human donor lungs are obtained for ex-vivo research. There is a high prevalence of diabetes mellitus, history of smoking and non-intravenous drug use along with older age distribution in donors whose lungs used are for research.

Exendin-4 blockade of T1R2/T1R3 activation improves Pseudomonas aeruginosa-related pneumonia in an animal model of chemically induced diabetes

OBJECTIVE

Poorly controlled diabetes frequently exacerbates lung infection, thereby complicating treatment strategies. Recent studies have shown that exendin-4 exhibits not only hypoglycemic but also anti-inflammatory properties. This study aimed to explore the role of exendin-4 in lung infection with diabetes, as well as its association with NOD1/NF-κB and the T1R2/T1R3 sweet taste receptor.

METHODS

16HBE human bronchial epithelial cells cultured with 20 mM glucose were stimulated with lipopolysaccharide (LPS) isolated from Pseudomonas aeruginosa (PA). Furthermore, Sprague‒Dawley rats were fed a high-fat diet, followed by intraperitoneal injection of streptozotocin and intratracheal instillation of PA. The levels of TNF-α, IL-1β and IL-6 were evaluated using ELISAs and RT‒qPCR. The expression of T1R2, T1R3, NOD1 and NF-κB p65 was assayed using western blotting and immunofluorescence staining. Pathological changes in the lungs of the rats were observed using hematoxylin and eosin (H&E) staining.

RESULTS

At the same dose of LPS, the 20 mM glucose group produced more proinflammatory cytokines (TNF-α, IL-1β and IL-6) and had higher levels of T1R2, T1R3, NOD1 and NF-κB p65 than the normal control group (with 5.6 mM glucose). However, preintervention with exendin-4 significantly reduced the levels of the aforementioned proinflammatory cytokines and signaling molecules. Similarly, diabetic rats infected with PA exhibited increased levels of proinflammatory cytokines in their lungs and increased expression of T1R2, T1R3, NOD1 and NF-κB p65, and these effects were reversed by exendin-4.

CONCLUSIONS

Diabetic hyperglycemia can exacerbate inflammation during lung infection, promote the increase in NOD1/NF-κB, and promote T1R2/T1R3. Exendin-4 can ameliorate PA-related pneumonia with diabetes and overexpression of NOD1/NF-κB. Additionally, exendin-4 suppresses T1R2/T1R3, potentially through its hypoglycemic effect or through a direct mechanism. The correlation between heightened expression of T1R2/T1R3 and an intensified inflammatory response in lung infection with diabetes requires further investigation.

Diabetes-related perturbations in the integrity of physiologic barriers

One of the hallmarks of health is the integrity of barriers at the cellular and tissue levels. The two cardinal functions of barriers include preventing access of deleterious elements of the environment (barrier function) while facilitating the transport of essential ions, signaling molecules and nutrients needed to maintain the internal milieu (transport function). There are several cellular and subcellular barriers and some of these barriers can be interrelated. The principal physiologic barriers include blood-retinal barrier, blood-brain barrier, blood-testis barrier, renal glomerular/tubular barrier, intestinal barrier, pulmonary blood-alveolar barrier, blood-placental barrier and skin barrier. Tissue specific barriers are the result of the vasculature, cellular composition of the tissue and extracellular matrix within the tissue. Uncontrolled diabetes and acute hyperglycemia may disrupt the integrity of physiologic barriers, primarily through altering the vascular integrity of the tissues and may well contribute to the clinically recognized complications of diabetes. Although diabetes is a systemic disease, some of the organs display clinically significant deterioration in function while others undergo subclinical changes. The pathophysiology of the disruption of these barriers is not entirely clear but it may be related to diabetes-related cellular stress. Understanding the mechanisms of diabetes related dysfunction of various physiologic barriers might help identifying novel therapeutic targets for reducing clinically significant complications of diabetes.

The melatonergic pathway and its interactions in modulating respiratory system disorders

Melatonin is a key intracellular neuroimmune-endocrine regulator and coordinator of multiple complex and interrelated biological processes. The main functions of melatonin include the regulation of neuroendocrine and antioxidant system activity, blood pressure, rhythms of the sleep-wake cycle, the retardation of ageing processes, as well as reseting and optimizing mitochondria and thereby the cells of the immune system. Melatonin and its agonists have therefore been mooted as a treatment option across a wide array of medical disorders. This article reviews the role of melatonin in the regulation of respiratory system functions under normal and pathological conditions. Melatonin can normalize the structural and functional organization of damaged lung tissues, by a number of mechanisms, including the regulation of signaling molecules, oxidant status, lipid raft function, optimized mitochondrial function and reseting of the immune response over the circadian rhythm. Consequently, melatonin has potential clinical utility for bronchial asthma, chronic obstructive pulmonary disease, lung cancer, lung vascular diseases, as well as pulmonary and viral infections. The integration of melatonin's effects with the alpha 7 nicotinic receptor and the aryl hydrocarbon receptor in the regulation of mitochondrial function are proposed as a wider framework for understanding the role of melatonin across a wide array of diverse pulmonary disorders.

Vascular Endothelial Function as a Valid Predictor of Variations in Pulmonary Function in T2DM Patients Without Related Complications

To assess the variations in pulmonary function and vascular endothelial function in their early stages (without related complications). A total of 162 type 2 diabetes mellitus (T2DM) patients without diabetes complications and 55 healthy people were selected, comprising the T2DM group and the control group, respectively, to evaluate changes in vascular endothelial function and lung function and determine the correlation between them. In this study, the T2DM group exhibited significantly lower pulmonary function than that of the control group (P < 0.05). The T2DM group also showed significantly lower flow-mediated dilation (FMD) and nitric oxide (NO) (P < 0.05) than those of the control group. Pulmonary functional indexes correlated positively with FMD and NO (P < 0.05) and correlated negatively with endothelin-1 (ET-1) (P < 0.05). FMD and NO correlated negatively with diabetes duration/HbA1c (P < 0.05), whereas ET-1 correlated positively with glycosylated hemoglobinA1c (HbA1c)/diabetes duration (P < 0.05). Pulmonary functional indexes negatively correlated with HbA1c/diabetes duration (P < 0.05). Multiple linear regression was used to analyze the relationship between vascular endothelial function indexes (FMD, ET-1, and NO) and pulmonary functional indexes. The results indicated that each vascular endothelial function index (FMD, ET-1, and NO) was significantly correlated with the pulmonary functional index (P < 0.05). The patients with T2DM presented changes in the subclinical vascular endothelial and pulmonary function. They also had impaired vascular endothelial functions, which were characterized by reduced vascular endothelial function relative to those of healthy people. Regulating glycemia may improve vascular endothelial and pulmonary functions. Moreover, microvascular lesions in preclinical stages, vascular endothelial function indexes (FMD, ET-1, and NO) were valid predictors of alterations in pulmonary function in T2DM patients without related complications.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, identifier NCT03575988.

Circadian Clock and Sirtuins in Diabetic Lung: A Mechanistic Perspective

Diabetes-induced tissue injuries in target organs such as the kidney, heart, eye, liver, skin, and nervous system contribute significantly to the morbidity and mortality of diabetes. However, whether the lung should be considered a diabetic target organ has been discussed for decades. Accumulating evidence shows that both pulmonary histological changes and functional abnormalities have been observed in diabetic patients, suggesting that the lung is a diabetic target organ. Mechanisms underlying diabetic lung are unclear, however, oxidative stress, systemic inflammation, and premature aging convincingly contribute to them. Circadian system and Sirtuins have been well-documented to play important roles in above mechanisms. Circadian rhythms are intrinsic mammalian biological oscillations with a period of near 24 h driven by the circadian clock system. This system plays an important role in the regulation of energy metabolism, oxidative stress, inflammation, cellular proliferation and senescence, thus impacting metabolism-related diseases, chronic airway diseases and cancers. Sirtuins, a family of adenine dinucleotide (NAD⁺)-dependent histone deacetylases, have been demonstrated to regulate a series of physiological processes and affect diseases such as obesity, insulin resistance, type 2 diabetes (T2DM), heart disease, cancer, and aging. In this review, we summarize recent advances in the understanding of the roles of the circadian clock and Sirtuins in regulating cellular processes and highlight the potential interactions of the circadian clock and Sirtuins in the context of diabetic lung.

Early changes in pulmonary function and intrarenal haemodynamics and the correlation between these sets of parameters in patients with T2DM

PURPOSE

The main objectives of this study were to assess the early changes in pulmonary function and intrarenal haemodynamics and to determine the correlation between pulmonary function and intrarenal haemodynamics in patients with type 2 diabetes mellitus (T2DM).

METHODS

96 patients with T2DM (diabetes group) without diabetes kidney disease (DKD) and 33 healthy subjects (control group) were enrolled in studies intended to assess the early changes in pulmonary function and intrarenal haemodynamics associated with diabetes, as well as to determine the correlation between pulmonary function and intrarenal haemodynamics.

RESULTS

Pulmonary functional parameters were negatively correlated with HbA1c levels and diabetes duration (P< 0.05). Moreover, renal functional parameters were positively correlated with HbA1c levels and diabetes duration (P<0.05). Additionally, pulmonary functional parameters were negatively correlated with renal functional parameters (P<0.05). Multiple linear regression analysis of the relationship between pulmonary functional parameters and the bilateral kidney arterial resistivity index (RI) showed that all the pulmonary functional parameters were significantly correlated with the arterial RI (P< 0.05).

CONCLUSIONS

Patients displayed changes in pulmonary function and intrarenal haemodynamics during the preclinical stages of DKD. Regulating glycaemia may improve intrarenal haemodynamics in the bilateral interlobular renal arteries. Moreover, during the preclinical stages of DKD, the right kidney RI is a effective predictor of early changes in pulmonary function in adult T2DM patients.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT02798198); registered 8 June 2016.

Diabetic lung disease: fact or fiction?

Diabetes mellitus is a chronic, progressive, incompletely understood metabolic disorder whose prevalence has been increasing steadily worldwide. Even though little attention has been paid to lung disorders in the context of diabetes, its prevalence has recently been challenged by newer studies of disease development. In this review, we summarize and discuss the role of diabetes mellitus involved in the progression of pulmonary diseases, with the main focus on pulmonary fibrosis, which represents a chronic and progressive disease with high mortality and limited therapeutic options.

A prospective study of the impact of diabetes mellitus on restrictive and obstructive lung function impairment: The Saku study

BACKGROUND

To assess the impact of diabetes on restrictive and obstructive lung function impairment.

METHODS

This 5-year prospective study included 7524 participants aged 40-69years without lung function impairment at baseline who underwent a comprehensive medical check-up between April 2008 and March 2009 at Saku Central Hospital. Diabetes was defined by fasting plasma glucose ≥7.0mmol/l (126mg/dl), HbA1c≥6.5% (48mmol/mol), or a history of diabetes, as determined by interviews conducted by the physicians. Restrictive and obstructive lung function impairment were defined as forced vital capacity (FVC) <80% predicted and forced expiratory volume in 1s (FEV₁) to FVC ratio (FEV₁/FVC) <0.70, respectively. Participants were screened until they developed restrictive or obstructive lung function impairment or until March 2014.

RESULTS

During the follow-up period, 171 and 639 individuals developed restrictive and obstructive lung function impairment, respectively. Individuals with diabetes had a 1.6-fold higher risk of restrictive lung function impairment than those without diabetes after adjusting for sex, age, height, abdominal obesity, smoking status, exercise habits, systolic blood pressure, HDL-cholesterol, log-transformed high-sensitivity C-reactive protein, and baseline lung function [multivariable-adjusted HR and 95% CI; 1.57 (1.04-2.36)]. In contrast, individuals with diabetes did not have a significantly higher risk of obstructive lung function impairment [multivariable-adjusted HR and 95% CI; 0.93 (0.72-1.21)].

CONCLUSION

Diabetes was associated with restrictive lung function impairment but not obstructive lung function impairment.

Cystic Fibrosis-Related Diabetes

Cystic fibrosis (CF) is the most common autosomal recessive disorder in Caucasian populations. Individuals with CF have seen significant increases in life expectancy in the last 60 years. As a result, previously rare complications are now coming to light. The most common of these is cystic fibrosis-related diabetes (CFRD), which affects 40-50% of CF adults. CFRD significantly impacts the pulmonary function and longevity of CF patients, yet a lack of consensus on the best methods to diagnose and treat CFRD remains. We begin by reviewing our understanding of the pathogenesis of CFRD, as emerging evidence shows the cystic fibrosis transmembrane conductance regulator (CFTR) also has important roles in the release of insulin and glucagon and in the protection of β cells from oxidative stress. We then discuss how current recommended methods of CFRD diagnosis are not appropriate, as continuous glucose monitoring becomes more effective, practical, and cost-effective. Finally, we evaluate emerging treatments which have narrowed the mortality gap within the CF patient group. In the future, pharmacological potentiators and correctors directly targeting CFTR show huge promise for both CFRD and the wider CF patient groups.

Occupation exposed to road-traffic emissions and respiratory health among Congolese transit workers, particularly bus conductors, in Kinshasa: a cross-sectional study

Objectives

Road-traffic emissions (RTE) induce adverse health effects, notably respiratory symptoms and respiratory diseases, as a result of pollutants deposited into the respiratory tract. The aim of this study was to evaluate the association between occupation groups of Congolese transit workers exposed to RTE, particularly bus conductors and respiratory health, in Kinshasa.

Methods

A cross-sectional study was conducted from 2015 April 20^th to May 14^th, whose participants were bus conductors (n = 110), bus drivers (n = 107), taxi-motorcyclists (n = 102) and high school teachers (control group; n = 106). Subjects had completed the American Thoracic Society respiratory symptom questionnaire. Lung function test was performed by spirometry. Air pollutants levels of PM_2.5, NO₂ and SO₂ were measured between 7:30 and 8:30 and 16:30–17:30 using a portable gas monitor.

Multivariate analysis was performed to evaluate the association between occupation exposed to RTE and impaired pulmonary function, after adjustment by plausible confounders.

Results

The prevalence of mixed syndrome was 21.9% for bus conductors, 10.9% for bus drivers, 15.4% for taxi-motorcyclists and 7.1% for high school teachers with (p < 0.05). The risk of developing a mixed syndrome was seven times higher among bus conductors [OR = 7.64; 95% CI: 1.83–31.67; p < 0.05] than other groups. Additionally, the prevalence of respiratory syndromes increased with the duration of exposure.

Conclusions

Occupation exposed to RTE is associated with impaired pulmonary function and the prevalence of respiratory symptoms among transit workers, especially bus conductors. Furthermore, this association increases with the duration of exposure suggesting the necessity to regulate these categories of occupations and to apply preventives measures.

The effect of alogliptin on pulmonary function in obese patients with type 2 diabetes inadequately controlled by metformin monotherapy

BACKGROUND

To observe the effect of alogliptin combined with metformin on pulmonary function in obese patients with type 2 diabetes inadequately controlled by metformin monotherapy (500 mg, bid po, for at least 3 months), and evaluate its efficacy and safety.

METHODS

After a 2-week screening period, adult patients (aged 36-72 years) entered a 4-week run-in/stabilization period. Then, patients were randomly assigned to either the intervention group (n = 55) or the control group (n = 50) for 26 weeks. The patients in the control group were given metformin (1000 mg, bid po) and the patients in the intervention group were given metformin (500 mg, bid po) combined with alogliptin (25 mg, qd po). All the patients received counseling about diet and exercise from a nutritionist during run-in and treatment periods.The primary endpoints were the between-group differences in the changes in pulmonary function parameters (vital capacity [VC]%, forced vital capacity [FVC]%, forced expiratory volume in 1 second (FEV1)%, peak expiratory force [PEF]%, maximal voluntary ventilation [MVV]%, total lung capacity [TLC%], forced expiratory volume in 1 second/forced vital capacity [FEV1/FVC%], diffusing capacity for carbon monoxide of lung [DLCO]%, and diffusing capacity for carbon monoxide of lung/unit volume [DLCO/VA%]) between pretherapy and posttreatment. The secondary endpoints were changes from baseline to week 26 in glycosylated hemoglobinA1c (HbA1c), FPG, 2hPG, homeostasis model assessment insulin resistance (HOMA-IR), waist circumference (WC), and BMI. The tertiary endpoints were the changes from baseline to week 26 in blood-fat (total cholesterol [TC], high-density lipoprotein cholesterol [HDL-C], low-density lipoprotein cholesterol [LDL-C], and triglycerides [TG]). The quartus endpoints were the changes from baseline to week 26 in systolic blood pressure (SBP) and diastolic blood pressure (DBP). The 5th endpoints were the changes from baseline to week 26 in oxidative/antioxidative parameters (reactive oxygen species [ROS], malondialdehyde [MDA], superioxide dismutase [SOD], and glutathione peroxidase [GSH-Px]). In addition, safety endpoints were assessed (AEs, clinical laboratory tests, vital signs, and electrocardiographic readings).

RESULTS

Eighty-one patients completed our clinical trial: intervention group (n = 44) and control group (n = 37). At week 26, pulmonary function parameters (VC%, FVC%, FEV1%, PEF%, MVV%, TLC%, FEV1/FVC%, DLCO%, and DLCO/VA%) had increased significantly from pretherapy values in both groups (P < 0.05), and the pulmonary function tests were significantly greater (P < 0.05) in intervention group than in controls posttherapy. Pulmonary function (FVC%, FEV1%, PEF%, TLC%, FEV1/FVC%, DLCO%, and DLCO/VA%) was lower in the group with HbA1c levels ≥8.0 at 26 weeks, but VC%, FEV1%, MVV%, and TLC% were not significantly lower (P > 0.05). Pulmonary function parameters were positively correlated with GSH-Px and SOD and negatively correlated with ROS and MDA. Mean declines in HbA1c, FPG, 2hPG, HOMA-IR, and blood-fat (TC, HDL-C, LDL-C, and TG) were significantly greater (P < 0.05) in intervention group compared with the controls, but mean declines in BMI, WC, and BP (SBP, DBP) did not differ significantly between the 2 groups (P > 0.05). SOD and GSH-Px increased more (P < 0.05) in the intervention group, compared with the controls; ROS and MDA declined more (P < 0.05) in intervention group, as compared with the control group. The most common AEs were gastrointestinal events, headaches, skin-related AEs (mostly pruritic events), and hypoglycemia. The incidences of AEs did not differ significantly (P > 0.05) between the 2 groups except for the headache and skin-related adverse events (the incidence of headache was higher in the intervention group than in controls; P < 0.05). No patient died during the study.

CONCLUSION

In patients with type 2 diabetes mellitus (T2DM) inadequately controlled by metformin monotherapy, the addition of alogliptin contributed to clinically significant increases in pulmonary function through regulating glycemia and improving the imbalance of the oxidative-related substances in the serum, without increasing the incidence of hypoglycemia, dyslipidemia, dysarteriotony, and any notable increase in body weight.

Type 2 diabetes affects sleep quality by disrupting the respiratory function

BACKGROUND

The effects of diabetes on the respiratory system were investigated with arterial blood gas, sleep quality index and respiratory functions tests.

METHODS

Fifty-three patients with type II diabetes and 41 healthy cases were included. Their biochemical data, demographic characteristics, anthropometric measurements and echocardiographic findings were collected from polyclinic records. Respiratory function tests were performed for all subjects and Pittsburgh Sleep Quality Index questionnaire was conducted. Aforementioned data were compared between these two groups.

RESULTS

The age, body weight and body mass index were similar but oxygen pressure, oxygen saturation, forced vital capacity (FVC; %), and sleep quality were decreased in patients with diabetes. Sleep quality was correlated with the presence of diabetes and hypertension, duration of diabetes, fasting and postprandial blood glucose levels, homeostasis model of assessment-insulin resistance, Glycosylated hemoglobin levels, and FVC. Half of the diabetic patients exhibited respiratory failure during sleep. Especially diabetic patients with autonomic neuropathy, experienced a more severe and prolonged decrease in oxygen saturation.

CONCLUSIONS

Blood gas, respiratory functions and sleep quality, which need to be evaluated as a whole, were affected in patients with diabetes. Assessment of sleep and its quality requires special attention in patients with diabetes.

Cardiorespiratory fitness, pulmonary function and C-reactive protein levels in nonsmoking individuals with diabetes

The objective of this study was to evaluate cardiorespiratory fitness and pulmonary function and the relationship with metabolic variables and C-reactive protein (CRP) plasma levels in individuals with diabetes mellitus (DM). Nineteen men with diabetes and 19 age- and gender-matched control subjects were studied. All individuals were given incremental cardiopulmonary exercise and pulmonary function tests. In the exercise test, maximal workload (158.3±22.3 vs 135.1±25.2, P=0.005), peak heart rate (HR_peak: 149±12 vs 139±10, P=0.009), peak oxygen uptake (VO_2peak: 24.2±3.2 vs 18.9±2.8, P<0.001), and anaerobic threshold (VO_2VT: 14.1±3.4 vs 12.2±2.2, P=0.04) were significantly lower in individuals with diabetes than in control subjects. Pulmonary function test parameters, blood pressure, lipid profile (triglycerides, HDL, LDL, and total cholesterol), and CRP plasma levels were not different in control subjects and individuals with DM. No correlations were observed between hemoglobin A1C (HbA1c), CRP and pulmonary function test and cardiopulmonary exercise test performance. In conclusion, the results demonstrate that nonsmoking individuals with DM have decreased cardiorespiratory fitness that is not correlated with resting pulmonary function parameters, HbA1c, and CRP plasma levels.

The diabetic lung--a new target organ?

Several abnormalities of the respiratory function have been reported in patients with type 1 and type 2 diabetes. These abnormalities concern lung volume, pulmonary diffusing capacity, control of ventilation, bronchomotor tone, and neuroadrenergic bronchial innervation. Many hypotheses have emerged, and characteristic histological changes have been described in the "diabetic lung", which could explain this abnormal respiratory function. Given the specific abnormalities in diabetic patients, the lung could thus be considered as a target organ in diabetes. Although the practical implications of these functional changes are mild, the presence of an associated acute or chronic pulmonary and/or cardiac disease could determine severe respiratory derangements in diabetic patients. Another clinical consequence of the pulmonary involvement in diabetes is the accelerated decline in respiratory function. The rate of decline in respiratory function in diabetics has been found to be two-to-three times faster than in normal non-smoking subjects, as reported in longitudinal studies. This finding, together with the presence of anatomical and biological changes similar to those described in the aging lung, indicates that the "diabetic lung" could even be considered a model of accelerated aging. This review describes and analyses the current insight into the relationship of diabetes and lung disease, and suggests intensifying research into the lung as a possible target organ in diabetes.

Pulmonary complications in diabetes mellitus

Clear decrements in lung function have been reported in patients with diabetes over the past two decades, and many reports have suggested plausible pathophysiological mechanisms. However, there are no reports of functional limitations of activities of daily living ascribable to pulmonary disease in patients with diabetes. This review attempts to summarize the available information from the present literature, to describe the nature of the lung dysfunction in diabetes and the emerging clinical implications of such dysfunction.

Lung function in type 2 diabetes: the Normative Aging Study

BACKGROUND

Cross-sectional studies have noted that subjects with diabetes have lower lung function than non-diabetic subjects. We conducted this analysis to determine whether diabetic subjects have different rates of lung function change compared with non-diabetic subjects.

METHODS

We conducted a nested case-control analysis in 352 men who developed diabetes and 352 non-diabetic subjects in a longitudinal observational study of aging in men. We assessed lung function among cases and controls at three time points: Time0, prior to meeting the definition of diabetes; Time1, the point when the definition of diabetes was met; and Time2, the most recent follow-up exam.

RESULTS

Cases had lower forced expiratory volume in 1s (FEV1) and forced vital capacity (FVC) at all time points, even with adjustment for age, height, weight, and smoking. In multiple linear regression models adjusting for relevant covariates, there were no differences in rates of FEV1 or FVC change over time between cases and controls.

CONCLUSIONS

Men who are predisposed to develop diabetes have decreased lung function many years prior to the diagnosis, compared with men who do not develop diabetes. This decrement in lung function remains after the development of diabetes. We postulate that mechanisms involved in the insulin resistant state contribute to the diminished lung function observed in our subjects.

Reduced pulmonary function and its associations in type 2 diabetes: the Fremantle Diabetes Study

To determine whether diabetes is associated with reduced lung function, we studied 421 Anglo-Celt/European subjects, representing 20.5% of all patients with type 2 diabetes identified in an urban Australian catchment area of 120097 people. In addition to collection of detailed demographic and diabetes-specific data, spirometry was performed and forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), vital capacity (VC) and peak expiratory flow (PEF) measured. When expressed as a percentage of those predicted (%pred) for age, sex and height, the means of all spirometric measures were reduced by > or =9.5%. After controlling for smoking, age and gender in a linear regression model, HbA(1c) was not associated with any measure of lung function (P>0.13) but diabetes duration was significantly associated with FEV1(%pred) and PEF(%pred) (P< or =0.04) and had borderline associations with FVC(%pred) and VC(%pred) (P< or =0.064). In separate analyses controlling for smoking alone, age, body mass index (BMI), coronary heart disease (CHD) and retinopathy were independently and inversely associated with FVC(%pred), FEV1(%pred) and VC(%pred) (P<0.05). In sub-group analyses, these three spirometric measures were associated with BMI, CHD and diabetes duration in males, and age and BMI in females. Pulmonary function is reduced in type 2 diabetes. Diabetes duration seems a more important influence than glycaemic control, but obesity and vascular disease may also contribute.