Issue 2 - "Update on adverse respiratory effects of indoor air pollution". Part 2): Indoor air pollution and respiratory diseases: Perspectives from Italy and some other GARD countries

OBJECTIVE

to synthesize the Italian epidemiological contribution to knowledge on indoor pollution respiratory impact, and to analyze the perspective of some GARD countries on the health effects of indoor air pollution.

RESULTS

Italian epidemiological analytical studies confirmed a strong relationship between indoor air pollution and health in general population. Environmental tobacco smoke, biomass (wood/coal) fuel for cooking/heating and indoor allergens (house dust mites, cat and dog dander, mold/damp) are the most relevant indoor pollution sources and are related to respiratory and allergic symptoms/diseases in Italy and in other GARD countries such as Mexico, Brazil, Vietnam, India, Nepal and Kyrgyzstan. Community-based global health collaborations are working to improve prevention, diagnosis and care of respiratory diseases around the world, specially in low- and middle-income countries, through research and education.

CONCLUSIONS

in the last thirty years, the scientific evidence produced on respiratory health effects of indoor air pollution has been extensive, but the necessity to empower the synergies between scientific community and local administrations remains a challenge to address in order to implement effective interventions. Based on abundant evidence of indoor pollution health effect, WHO, scientific societies, patient organizations and other members of the health community should work together to pursue the GARD vision of "a world where all people breathe freely" and encourage policy makers to increase their engagement in advocacy for clean air.

Association of coronary calcification with prognosis of Covid-19 patients without known heart disease

Risk factors that determine the severity of Covid-19 have not been fully elucidated. The aim of this study was to evaluate the role of coronary artery calcification (CAC) as a risk factor for death or mechanical ventilation (MV) of patients without known heart disease infected with Covid-19. We analyzed 283 consecutive in-patients with acute respiratory symptoms with chest computed tomography (chest-CT), without previous heart disease, and criteria for Covid-19 (RT-PCR positive and/or typical clinical and chest-CT findings). CAC was classified by the number of coronary segments affected as absent (0), mild (1-3), and severe calcification (more than 3). The association between CAC, CAC severity, and death or MV due to severe respiratory failure was assessed by logistic regression. The mean age was 58.7±15.7 years and 54.1% were men. Patients with CAC were older, more likely to have hypertension, and less likely to be obese. CAC was present in 75 patients (26.5%), of which 42 had a mild calcification and 33 had severe calcification, and was associated with death (OR=2.35, 95%CI: 1.01-5.48) or MV (OR=2.72, 95%CI: 1.20-6.20) adjusted for multiple confounders, with significant and increased odds ratio for the severe form of CAC (death: OR=3.70, 95%CI: 1.20-11.42; MV: OR=3.30, 95%CI: 1.09-9.95). We concluded that CAC was an independent risk factor for death or MV in Covid-19 patients without previous heart disease, particularly for those with severe calcification. CAC can be easily visualized on common chest-CT, widely used in evaluation of moderate to severe Covid-19.

Asthma similarities across ProAR (Brazil) and U-BIOPRED (Europe) adult cohorts of contrasting locations, ethnicity and socioeconomic status

BACKGROUND

Asthma prevalence is 339 million globally. 'Severe asthma' (SA) comprises subjects with uncontrolled asthma despite proper management.

OBJECTIVES

To compare asthma from diverse ethnicities and environments.

METHODS

A cross-sectional analysis of two adult cohorts, a Brazilian (ProAR) and a European (U-BIOPRED). U-BIOPRED comprised of 311 non-smoking with Severe Asthma (SAn), 110 smokers or ex-smokers with SA (SAs) and 88 mild to moderate asthmatics (MMA) while ProAR included 544 SA and 452 MMA. Although these projects were independent, there were similarities in objectives and methodology, with ProAR adopting operating procedures of U-BIOPRED.

RESULTS

Among SA subjects, age, weight, proportion of former smokers and FEV₁ pre-bronchodilator were similar. The proportion of SA with a positive skin prick tests (SPT) to aeroallergens, the scores of sino-nasal symptoms and quality of life were comparable. In addition, blood eosinophil counts (EOS) and the % of subjects with EOS > 300 cells/μl were not different. The Europeans with SA however, were more severe with a greater proportion of continuous oral corticosteroids (OCS), worse symptoms and more frequent exacerbations. FEV₁/FVC pre- and post-bronchodilator were lower among the Europeans. The MMA cohorts were less comparable in control and treatment, but similar in the proportion of allergic rhinitis, gastroesophageal reflux disease and EOS >3%.

CONCLUSIONS

ProAR and U-BIOPRED cohorts, with varying severity, ethnicity and environment have similarities, which provide the basis for global external validation of asthma phenotypes. This should stimulate collaboration between asthma consortia with the aim of understanding SA, which will lead to better management.

Age is associated with asthma phenotypes

BACKGROUND AND OBJECTIVE

The relationship between age and asthma phenotypes is important as population is ageing, asthma is becoming common in older ages and recently developed treatments for asthma are guided by phenotypes. The aim of this study is to evaluate whether age is associated with specific asthma phenotypes.

METHODS

This is a cross-sectional study. We included subjects with asthma of varied degrees of severity. Subjects underwent spirometry, skin prick test to aeroallergens, answered the Asthma Control Questionnaire and had blood samples collected. We performed binary logistic regression analysis to evaluate whether age is associated with asthma phenotypes.

RESULTS

We enrolled 868 subjects. In comparison with subjects ≤ 40 years, older subjects had high odds of irreversible airway obstruction (from 41 to 64 years, OR: 1.83 (95% CI: 1.32-2.54); ≥65 years, OR: 3.45 (2.12-5.60)) and severe asthma phenotypes (from 41 to 64 years, OR: 3.23 (2.26-4.62); ≥65 years, OR: 4.55 (2.39-8.67)). Older subjects had low odds of atopic (from 41 to 64 years, OR: 0.56 (0.39-0.79); ≥65 years, OR: 0.47 (0.27-0.84)) and eosinophilic phenotypes (from 41 to 64 years, OR: 0.63 (0.46-0.84); ≥65 years, OR: 0.39 (0.24-0.64)).

CONCLUSION

Older subjects with asthma have low odds of atopic and eosinophilic phenotypes, whereas they present high odds of irreversible airway obstruction and severe asthma.

Longitudinal trends in clinical characteristics and lung function of patients with severe asthma under treatment in Brazil

BACKGROUND

The structural changes of the respiratory system related to ageing determine lung function decline in healthy subjects after 25 years of age. An annual reduction of 25 ml in Forced Expiratory Volume in 1 s (FEV1) is expected. We aimed to describe the longitudinal lung function variation of subjects with severe asthma receiving appropriate treatment.

METHODS

Consecutive patients enrolled in a Brazilian reference clinic between 2003 and 2006 were invited to participate. The study participants were followed up for a median of 8 years, and were evaluated with spirometry in three distinct occasions (V0, V1 and V8), at least. At V0, upon enrollment, subjects with previous severe untreated asthma were evaluated by a specialist, had their health resource utilization in the last 12 months recorded, and performed spirometry. In V1, 1 year after V0, under proper management, subjects repeated the procedures and answered the Asthma Control Questionnaire (ACQ) and the Asthma Quality of Life Questionnaire (AQLQ). In the last study visit (V8), 7 years after V1, all patients underwent a pre and post-broncodilator (postBD) spirometry, skin prick test for aeroallergens, answered the ACQ and the AQLQ and had another interview with the specialist.

RESULTS

Two hundred thirty-four subjects were followed up between V0 and V8. A comparison between spirometries of V1 and V8, after the initial improvement has supposedly reached a plateau, shows that the FEV₁ and FVC declined significantly both in absolute and percent of predicted values. FEV_1postBD did not change significantly between V0 and V1, but declined by -27.1 (-51.1-1.4) ml/yr between V1 and V8.

CONCLUSIONS

Currently available treatment with a combination of inhaled corticosteroids and LABA may not be sufficient to prevent lung function decline in subjects with severe asthma.

The impact of a program for control of asthma in a low-income setting

The prevalence of asthma is increasing in developing countries and the burden of uncontrolled asthma affects patients, families, and the health system. This is to summarize, evaluate, and discuss previous reports on the impact of a targeted and comprehensive approach to the most severe cases of asthma in a low-income setting. A Program for Control of Asthma (ProAR) was developed in Salvador, Bahia, Brazil, prioritizing the control of severe asthma. By facilitating referrals from the public health system and providing proper multidisciplinary but simple management including education and medication, for free, the Program enrolled 2385 patients in 4 reference clinics. They are offered regular follow up and discharged back to primary health care only when asthma control can be maintained without requirement of a combination of an inhaled corticosteroid and a long-acting β2 agonist. ProAR has markedly reduced health resource utilization and decreased the rate of hospital admissions because of asthma in the entire City (2.8 million inhabitants) by 74%. Moderate to severe rhinitis was associated with lack of control of asthma. The average income of the families in the ProAR was US$2955 a year, and they spent 29% of all their income attempting to control the severe asthma of one member, a unbearable expenditure for a low-income family. The ProAR was shown to be cost-effective, reducing costs to the public health system (US$387 patient/year) and the families (US$789 patient/year). In a low-income setting of Brazil, an intervention prioritizing the control of severe asthma was feasible, effective, and reduced costs.

Polymorphisms in the sialic acid-binding immunoglobulin-like lectin-8 (Siglec-8) gene are associated with susceptibility to asthma

Sialic acid-binding immunoglobulin-like lectin-8 (Siglec-8) promotes the apoptosis of eosinophils and inhibits FcvarepsilonRI-dependent mediator release from mast cells. We investigated the genetic association between sequence variants in Siglec-8 and diagnosis of asthma, total levels of serum IgE (tIgE), and diagnosis of eosinophilic esophagitis (EE) in diverse populations. The effect of sequence variants on Siglec-8 glycan ligand-binding activity was also examined. Significant association with asthma was observed for SNP rs36498 (odds ratios (OR), 0.69, P=8.8 x 10(-5)) among African Americans and for SNP rs10409962 (Ser/Pro) in the Japanese population (OR, 0.69, P=0.019). Supporting this finding, we observed association between SNP rs36498 and current asthma among Brazilian families (P=0.013). Significant association with tIgE was observed for SNP rs6509541 among African Americans (P=0.016), and replicated among the Brazilian families (P=0.02). In contrast, no association was observed with EE in Caucasians. By using a synthetic polymer decorated with 6'-sulfo-sLe(x), a known Siglec-8 glycan ligand, we did not find any differences between the ligand-binding activity of HEK293 cells stably transfected with the rs10409962 risk allele or the WT allele. However, our association results suggest that the Siglec8 gene may be a susceptibility locus for asthma.

Rapid reduction in hospitalisations after an intervention to manage severe asthma

Asthma is the third cause of hospitalisations due to clinical illnesses in Brazil. The Programme for Control of Asthma in Bahia (ProAR) leads an initiative in Salvador City (Brazil) to manage severe asthma for free. The aim of this study was to identify trends in asthma hospitalisation in the entire city and to evaluate the impact of ProAR. Information on asthma hospitalisations from 1998 to 2006 was collected. We analysed trends in Salvador (2.8 million inhabitants) before and after ProAR, taking pneumonia and myocardial infarction into account for local comparison. As an external control we obtained information on asthma from Recife, which is the most comparable Brazilian city. In Salvador, asthma hospital admissions declined by 82.3% (1998-2006). A greater proportion of this reduction (74%) occurred after 2003, in parallel with the implementation of ProAR. The reduction in asthma admissions in Recife was smaller. The rates of hospitalisation in 2006 were 2.25 per 10,000 inhabitants in Salvador and 17.06 in Recife. In Salvador, we found an inverse correlation between the provision of medication for asthma and hospitalisation (-0.801; p<0.0001). A rapid reduction in asthma admissions in the entire city of Salvador was associated with ProAR, a public health intervention targeting severe asthma.

The economic impact of severe asthma to low-income families

BACKGROUND

To estimate the direct and indirect costs of severe asthma and the economic impact of its management to low-income families in Salvador, Brazil.

METHODS

One hundred and ninety-seven patients with severe asthma and referred to a state-funded asthma center providing free treatment were evaluated. At registration, they were asked about family cost-events in the previous year and had a baseline assessment of lung function, symptoms and quality of life. During the subsequent year, they were reassessed prospectively.

RESULTS

One hundred-eighty patients concluded a 12-month follow-up. Eighty-four percent were female patients, and the median family income was US$ 2955/year. Forty-seven percent of family members had lost their jobs because of asthma. Total cost of asthma management took 29% of family income. After proper treatment, asthma control scores improved by 50% and quality of life by 74%. The income of the families increased by US$ 711/year, as their members went back to work. The total cost of asthma to the families was reduced by a median US$ 789/family/year. Consequently, an annual surplus of US$ 1500/family became available.

CONCLUSIONS

Family costs of severe asthma consumed over one-fourth of the family income of the underprivileged population in a middle-income country. Adequate management brings major economic benefit to individuals and families.

[Controversies in the association between type 1 diabetes and asthma]

OBJECTIVE

Critical review of the literature to investigate the relationship between asthma and type 1 diabetes mellitus (DM1).

SOURCE OF DATA

Bibliography search in MEDLINE and LILACS databases in the last twenty years.

SUMMARY OF DATA

Several studies demonstrate an inverse relationship between asthma, atopic diseases and the risk to develop DM1. According to the "Hygiene Hypothesis", the risk of allergic diseases decreases with infections early in childhood, towards distance of Th2 profile, common at birth, to the Th1 phenotype. Other articles described lack of association or positive association between DM1 and allergies. There is a possibility of environmental factors interfering in the development of disorders mediated by Th1 and Th2 cells, in the same individual, due to the absence of immunomodulatory mechanisms mediated by interleukin-10 and regulatory cells.

CONCLUSION

The existing information about the inverse association between Th1-mediated diseases (e.g., DM1), and those that are Th2-mediated (e.g., allergies) are conflicting requiring more investigation to explain this question.

Gene encoding Duffy antigen/receptor for chemokines is associated with asthma and IgE in three populations

RATIONALE

Asthma prevalence and severity are high among underserved minorities, including those of African descent. The Duffy antigen/receptor for chemokines is the receptor for Plasmodium vivax on erythrocytes and functions as a chemokine-clearing receptor. Unlike European populations, decreased expression of the receptor on erythrocytes is common among populations of African descent, and results from a functional T-46C polymorphism (rs2814778) in the promoter. This variant provides an evolutionary advantage in malaria-endemic regions, because Duffy antigen/receptor for chemokines-negative erythrocytes are more resistant to infection by P. vivax.

OBJECTIVES

To determine the role of the rs2814778 polymorphism in asthma and atopy as measured by total serum IgE levels among four populations of African descent (African Caribbean, African American, Brazilian, and Colombian) and a European American population.

METHODS

Family-based association tests were performed in each of the five populations to test for association between the rs2814778 polymorphism and asthma or total IgE concentration.

MEASUREMENTS AND MAIN RESULTS

Asthma was significantly associated with the rs2814778 polymorphism in the African Caribbean, Colombian, and Brazilian families (P < 0.05). High total IgE levels were associated with this variant in African Caribbean and Colombian families (P < 0.05). The variant allele was not polymorphic among European Americans.

CONCLUSIONS

Susceptibility to asthma and atopy among certain populations of African descent is influenced by a functional polymorphism in the gene encoding Duffy antigen/receptor for chemokines. This genetic variant, which confers resistance to malarial parasitic infection, may also partially explain ethnic differences in morbidity of asthma.

Lack of control of severe asthma is associated with co-existence of moderate-to-severe rhinitis

BACKGROUND

Retrospective studies provide evidence that rhinitis is associated with more severe asthma. The aim of this study was to evaluate prospectively whether rhinitis is a predictor of increased asthma severity.

METHODS

Five hundred and fifty-seven patients with severe asthma were enrolled. During 1 year of follow-up, each patient was evaluated every 3 months with a record of emergency room visits and supply of topical corticosteroids for asthma and rhinitis. In the 1 year of follow-up visit, the patients were checked for rhinitis diagnosis, severity and answered questionnaires for asthma symptoms and quality of life.

RESULTS

Eighty-two (15%) patients had no rhinitis, 299 (54%) had mild rhinitis and 176 (31%) moderate/severe rhinitis. In logistic regression models, moderate/severe rhinitis was a predictor for any emergency room visit in the follow-up period [3.83 (2.00-7.35)], for the presence of uncontrolled asthma after 1 year of follow-up [12.68 (1.73-92.85)], for <10% improvement of the airway obstruction [2.94 (1.48-5.85)] and <50% reduction in the number of emergency room visits [2.90 (1.02-8.26)] in the year of follow-up. It was also associated with a smaller chance of more than 90% reduction in the number of emergency room visits in the year of follow-up [0.27 (0.12-0.60)]. In a multivariate linear regression model, severity of rhinitis was positively correlated with a score of asthma severity and inversely correlated to an index of quality of life.

CONCLUSIONS

In a population with severe asthma, moderate/severe rhinitis is a strong predictor for greater severity of asthma.

Geohelminth infections: a review of the role of IgE and assessment of potential risks of anti-IgE treatment

Geohelminth infections are major parasitic infections with a worldwide distribution. Immunoglobulin E (IgE) is considered to play a central role in protective immunity against these parasites although the evidence from experimental animal models infected with helminth parasites and treated with anti-IgE antibodies and from observational studies in human populations of the immunologic correlates of protective immunity against helminths do not support a critical role for IgE in mediating protection against helminths. Anti-IgE treatment of human allergic disorders using a humanized monoclonal IgE antibody (omalizumab, Xolair) has been approved for clinical use in the USA and Europe and there is concern that this treatment may be associated with increased morbidity in populations exposed to helminth infections. A recently published randomized controlled trial investigating the risk of geohelminth infections in allergic patients receiving omalizumab in Brazil has provided some evidence that omalizumab may not be associated with increased morbidity attributable to these parasites. This review examines the evidence for a role of IgE in protective immunity against helminth parasites, discusses the findings of the randomized controlled trial, assesses the potential risks and provides recommendations for anti-IgE treatment in groups of allergic patients with different exposure risks for helminth infections.