Ambient Air Pollution and Dysanapsis: Associations with Lung Function and Chronic Obstructive Pulmonary Disease in the Canadian Cohort Obstructive Lung Disease Study.

Rationale: Outdoor air pollution is a potential risk factor for lower lung function and chronic obstructive pulmonary disease (COPD). Little is known about how airway abnormalities and lung growth might modify this relationship. Objectives: To evaluate the associations of ambient air pollution exposure with lung function and COPD and examine possible interactions with dysanapsis. Methods: We made use of cross-sectional postbronchodilator spirometry data from 1,452 individuals enrolled in the CanCOLD (Canadian Cohort Obstructive Lung Disease) study with linked ambient fine particulate matter (PM2.5) and nitrogen dioxide (NO2) air pollution estimates. Dysanapsis, or the ratio of the airway-to-lung volume calculated from thoracic computed tomography images, was used to examine possible interactions. Measurements and Main Results: In adjusted models, 101.7 ml (95% confidence interval [CI], -166.2 to -37.2) and 115.0 ml (95% CI, -196.5 to -33.4) lower FEV1 were demonstrated per increase of 2.4 ug/m3 PM2.5 and 9.2 ppb NO2, respectively. Interaction between air pollution and dysanapsis was not statistically significant when modeling the airway-to-lung ratio as a continuous variable. However, a 109.8 ml (95% CI, -209.0 to -10.5] lower FEV1 and an 87% (95% CI, 12% to 213%) higher odds of COPD were observed among individuals in the lowest, relative to highest, airway-to-lung ratio, per 2.4 µg/m3 increment of PM2.5. Conclusions: Ambient air pollution exposure was associated with lower lung function, even at relatively low concentrations. Individuals with dysanaptic lung growth might be particularly susceptible to inhaled ambient air pollutants, especially those at the extremes of dysanapsis.

Metabolic profiles among COPD and controls in the CanCOLD population-based cohort.

A high prevalence of intermediate cardiometabolic risk factors and obesity in chronic obstructive pulmonary disease (COPD) has suggested the existence of pathophysiological links between hypertriglyceridemia, insulin resistance, visceral adiposity, and hypoxia or impaired pulmonary function. However, whether COPD contributes independently to the development of these cardiometabolic risk factors remains unclear. Our objective was to compare ectopic fat and metabolic profiles among representative individuals with COPD and control subjects and to evaluate whether the presence of COPD alters the metabolic risk profile. Study participants were randomly selected from the general population and prospectively classified as non-COPD controls and COPD, according to the Global Initiative for Chronic Obstructive Lung Disease classification. The metabolic phenotype, which consisted of visceral adipose tissue area, metabolic markers including homeostasis model assessment of insulin resistance (HOMA-IR), and blood lipid profile, was obtained in 144 subjects with COPD and 119 non-COPD controls. The metabolic phenotype was similar in COPD and controls. The odds ratios for having pathologic values for HOMA-IR, lipids and visceral adipose tissue area were similar in individuals with COPD and control subjects in multivariate analyses that took into account age, sex, body mass index, tobacco status and current medications. In a population-based cohort, no difference was found in the metabolic phenotype, including visceral adipose tissue accumulation, between COPD and controls. Discrepancies between the present and previous studies as to whether or not COPD is a risk factor for metabolic abnormalities could be related to differences in COPD phenotype or disease severity of the study populations.

Cardiorespiratory and Muscle Oxygenation Responses to Isokinetic Exercise in Chronic Obstructive Pulmonary Disease.

PURPOSE: This study aimed to describe cardiorespiratory, quadriceps oxygenation, and muscle fatigue responses during a one-legged quadriceps isokinetic endurance exercise in chronic obstructive pulmonary disease (COPD) and control subjects. METHODS: Fourteen patients with COPD and 14 control subjects performed a cardiopulmonary cycling exercise test to exhaustion to assess peak oxygen consumption (V˙O2peak), minute ventilation (V˙Epeak), and heart rate (HRpeak). They also performed a quadriceps isokinetic endurance exercise consisting in 30 maximal knee extensions at 90°·s with continuous monitoring of expired gases, cardiac output, and oxygenation of the quadriceps by near-infrared spectroscopy. Total muscle work and fatigue index were also quantified. RESULTS: The total muscle work developed during the quadriceps isokinetic endurance exercise was 2.25 ± 0.57 kJ in COPD and 3.12 ± 0.60 kJ in controls, P < 0.001. In absolute terms, there were no between-group differences in V˙O2, V˙E, cardiac output, and HR at the end of quadriceps isokinetic endurance exercise. However, V˙E and HR reported that a fraction of their respective peak values during cardiopulmonary cycling exercise test were higher in COPD (V˙E/V˙Epeak, 69% ± 3%; HR/HRpeak, 82% ± 15%) compared with controls (V˙E/V˙Epeak, 45% ± 2%; HR/HRpeak, 71% ± 13%), all P < 0.05. During quadriceps isokinetic endurance exercise, quadriceps deoxyhemoglobin increased by 47% ± 31% in patients versus 33% ± 41% in controls (P < 0.05 from rest values) with a significant between-group differences (P = 0.025). The fatigue index during the quadriceps exercise was higher in COPD compared with controls. CONCLUSIONS: Although one-legged quadriceps isokinetic endurance exercise resulted in substantial central cardiorespiratory demands in COPD, this exercise was nevertheless associated with muscle overload as evidenced by muscle deoxygenation and higher muscle fatigue index in COPD compared with controls. These findings may have implications of the design of exercise training programs in COPD.

Ectopic adiposity and cardiometabolic health in COPD.

RATIONALE: Obesity/overweight is the most prevalent body composition abnormality in COPD. However, little is known about the impact of fat distribution on cardiometabolic health in COPD. OBJECTIVE: To study the associations between ectopic adiposity, cardiometabolic health, and COPD. METHODS: A total of 263 subjects (166 males; age=65±9 years) were randomly selected from the general population. Subjects were classified as non-COPD controls and COPD, according to the Global initiative for chronic Obstructive Lung Disease (GOLD) classification, and the presence of cardiometabolic comorbidities was recorded. Ectopic fat accumulation was documented from computed tomography measurements of visceral adipose tissue cross-sectional areas and muscle mean attenuation, assessed at L4-L5. Blood glucose, lipid, and adipokine profiles were also evaluated. RESULTS: After correcting for age, sex, and tobacco exposure, visceral adipose tissue cross-sectional area was higher in GOLD 2+ compared to GOLD 1 individuals. Consistent with this, mean muscle tissue attenuation was lower in GOLD 2+ vs GOLD 1 and non-COPD controls (P<0.001). In multiple regression models, visceral adipose tissue cross-sectional area was strongly associated with hypertension (P<0.001) and diabetes (P<0.001), while muscle attenuation was associated with coronary artery disease (P<0.001). Blood glucose, lipid, and adipokine profiles were similar across groups with the exception of leptin level which was higher in GOLD 2+ subjects compared to GOLD 1 and controls. CONCLUSION: GOLD 2+ COPD was associated with ectopic fat accumulation which modulated cardiometabolic health.

Users' Perception and Readiness of the eChez-Soi In-Home Telerehabilitation Platform.

This longitudinal preliminary study aims to describe the components and features of the eChez-Soi home-based telerehabilitation platform, and present preliminary results on practitioners' readiness for and perception of its usability. Four patients receiving chemotherapy treatments for lung cancer followed an 8-week home-based telerehabilitation program with the new eChez-Soi platform and four healthy adults used it for 2 weeks. The users' perception was very good, with an overall satisfaction rate of 4.6±0.4 (max. score=5) for the patients, 4.8±0.2 for the healthy adults and 4.4±0.3 for the practitioners. Total practitioner telehealth readiness was 73.5±9.1 (max score=85), suggesting that certain items, for at least one practitioner, may adversely impact the use of telehealth. These preliminary results support the usability of this new platform and suggest that practitioner telehealth readiness is reinforced with experience.

Test-retest reliability of lower limb isokinetic endurance in COPD: A comparison of angular velocities.

BACKGROUND: The purpose of this study was to determine and compare the test-retest reliability of quadriceps isokinetic endurance testing at two knee angular velocities in patients with chronic obstructive pulmonary disease (COPD). METHODS: After one familiarization session, 14 patients with moderate to severe COPD (mean age 65±4 years; forced expiratory volume in 1 second (FEV1) 55%±18% predicted) performed two quadriceps isokinetic endurance tests on two separate occasions within a 5-7-day interval. Quadriceps isokinetic endurance tests consisted of 30 maximal knee extensions at angular velocities of 90° and 180° per second, performed in random order. Test-retest reliability was assessed for peak torque, muscle endurance, work slope, work fatigue index, and changes in FEV1 for dyspnea and leg fatigue from rest to the end of the test. The intraclass correlation coefficient, minimal detectable change, and limits of agreement were calculated. RESULTS: High test-retest reliability was identified for peak torque and muscle total work at both velocities. Work fatigue index was considered reliable at 90° per second but not at 180° per second. A lower reliability was identified for dyspnea and leg fatigue scores at both angular velocities. CONCLUSION: Despite a limited sample size, our findings support the use of a 30-maximal repetition isokinetic muscle testing procedure at angular velocities of 90° and 180° per second in patients with moderate to severe COPD. Endurance measurement (total isokinetic work) at 90° per second was highly reliable, with a minimal detectable change at the 95% confidence level of 10%. Peak torque and fatigue index could also be assessed reliably at 90° per second. Evaluation of dyspnea and leg fatigue using the modified Borg scale of perceived exertion was poorly reliable and its clinical usefulness is questionable. These results should be useful in the design and interpretation of future interventions aimed at improving muscle endurance in COPD.

Feasibility and effectiveness of a home-based exercise training program before lung resection surgery.

BACKGROUND: Patients with lung cancer often experience a reduction in exercise tolerance, muscle weakness and decreased quality of life. Although the effectiveness of pulmonary rehabilitation programs is well recognized in other forms of cancers and in many pulmonary diseases, few researchers have studied its impact in patients with lung cancer, particularly in those awaiting lung resection surgery (LRS). OBJECTIVES: To investigate the feasibility of a short, home-based exercise training program (HBETP) with patients under investigation for non-small cell lung cancer and potential candidates for LRS, and to determine the effectiveness of this program on exercise tolerance, skeletal muscle strength and quality of life. METHODS: Sixteen patients with lung cancer awaiting LRS participated in a four-week HBETP including moderate aerobic activities (walking and cycling) and muscle training performed three times weekly. Before and after the intervention, a cardiopulmonary exercise test, a 6 min walk test and the assessment of muscle strength and quality of life were performed. RESULTS: Thirteen patients completed the four-week HBETP and all the patients completed >75% of the prescribed exercise sessions. The duration of the cycle endurance test (264±79 s versus 421±241 s; P<0.05) and the 6 min walk test distance (540±98 m versus 568±101 m; P<0.05) were significantly improved. Moreover, the strength of the deltoid, triceps and hamstrings were significantly improved (∆ post-pre training 1.82±2.83 kg, 1.32±1.75 kg and 3.41±3.7 kg; P<0.05, respectively). CONCLUSION: In patients with lung cancer awaiting LRS, HBETP was feasible and improved exercise tolerance and muscle strength. This may be clinically relevant because poor exercise capacity and muscle weakness are predictors of postoperative complications.

Distal leg muscle function in patients with COPD.

Quadriceps muscle weakness and increased fatigability are well described in patients with chronic obstructive pulmonary disease (COPD). Whether these functional alterations also exist in distal leg muscles in patients with COPD is uncertain. Fifteen patients with COPD and 15 aged-matched healthy controls performed a 12-minute standardized treadmill exercise during which a fixed total expense of 40 Kcal was reached. The strength of i) dorsiflexors, ii) plantar flexors and iii) quadriceps was assessed at rest and after exercise using maximal voluntary contraction (MVC) and potentiated twitch force (Twpot). Resting MVC and Twpot were significantly lower in patients with COPD when compared with controls respectively for i) dorsiflexors (24.9 ± 8.4 vs. 31.2 ± 8.5 Nm, p < 0.05 and 4.3 ± 1.3 vs. 5.7 ± 1.8 Nm, p < 0.05), ii) plantar flexors (49.5 ± 11.8 vs. 62.1 ± 19.6 Nm, p < 0.05 and 10.8 ± 3.5 vs. 13.4 ± 2.7 Nm, p < 0.05), and iii) quadriceps muscles. There was a greater force loss in the distal leg muscles 15 minutes post-exercise in patients with COPD, while the strength of the quadriceps muscle remained stable in both groups. Patients with COPD had weaker dorsiflexor and plantar flexor muscles when compared to age-matched healthy controls. In addition, when exposed to the same absolute walking task, the fatigability of the distal leg muscles was higher in patients with COPD.