Ubiratan de Paula Santos

Repercussões clínicas da exposição à poluição atmosférica

Atmospheric pollution is a topic of extensive discussion the world over. The clinical repercussions of exposure to the principal atmospheric pollutants are summarized herein. According to the American Environmental Protection Agency, air quality standards for these agents are set based on their primary and half-life values. The respiratory effects of the burning of fossil fuels and biomass are succinctly presented, with a special focus on alerting health care professionals of the increased morbidity related to environmental pollution.

A poluição do ar e o sistema respiratório

A poluicao atmosferica encontra-se presente nos mais diferentes cenarios ao longo dos ultimos 250 anos, desde que a Revolucao Industrial acelerou o processo de emissao de poluentes que, ate entao, estava limitado ao uso domestico de combustiveis vegetais e minerais e as emissoes vulcânicas intermitentes. Hoje, aproximadamente 50% da populacao do planeta vivem em cidades e aglomerados urbanos e estao expostas a niveis progressivamente maiores de poluentes do ar. Este estudo e uma revisao nao sistematica sobre os diferentes tipos e fontes de poluentes do ar e os efeitos respiratorios atribuidos a exposicao a esses contaminantes. Podem ser creditados aos poluentes particulados e gasosos, emitidos por diferentes fontes, aumentos nos sintomas de doencas, na procura por atendimentos em servicos de emergencia e no numero de internacoes e de obitos. Mais do que descompensar doencas pre-existentes, exposicoes cronicas tem ajudado a aumentar o numero de casos novos de asma, de DPOC e de câncer de pulmao, tanto em areas urbanas quanto em areas rurais, fazendo com que os poluentes atmosfericos rivalizem com a fumaca do tabaco pelo papel de principal fator de risco para estas doencas. Na rotina de clinicos e pneumologistas, esperamos contribuir para consolidar a importância da investigacao sobre a exposicao aos poluentes do ar e o reconhecimento de que esse fator de risco merece ser levado em conta na adocao da melhor terapeutica para o controle das descompensacoes agudas das doencas respiratorias e para a sua manutencao entre as crises.Over the past 250 years-since the Industrial Revolution accelerated the process of pollutant emission, which, until then, had been limited to the domestic use of fuels (mineral and vegetal) and intermittent volcanic emissions-air pollution has been present in various scenarios. Today, approximately 50% of the people in the world live in cities and urban areas and are exposed to progressively higher levels of air pollutants. This is a non-systematic review on the different types and sources of air pollutants, as well as on the respiratory effects attributed to exposure to such contaminants. Aggravation of the symptoms of disease, together with increases in the demand for emergency treatment, the number of hospitalizations, and the number of deaths, can be attributed to particulate and gaseous pollutants, emitted by various sources. Chronic exposure to air pollutants not only causes decompensation of pre-existing diseases but also increases the number of new cases of asthma, COPD, and lung cancer, even in rural areas. Air pollutants now rival tobacco smoke as the leading risk factor for these diseases. We hope that we can impress upon pulmonologists and clinicians the relevance of investigating exposure to air pollutants and of recognizing this as a risk factor that should be taken into account in the adoption of best practices for the control of the acute decompensation of respiratory diseases and for maintenance treatment between exacerbations.

Burnt sugarcane harvesting is associated with acute renal dysfunction

Sugarcane harvesting has been associated with an epidemic of chronic kidney disease in Central America mainly affecting previously healthy young workers. Repeated episodes of acute kidney dysfunction are hypothesized to be one of the possible mechanisms for this phenomenon. Therefore, this exploratory study aimed to assess the acute effects of burnt sugarcane harvesting on renal function among 28 healthy non-African Brazilian workers. Urine and blood samples were collected at the beginning and at the end of the harvesting season and before and at the end of a harvesting workday. All individuals decreased their estimated glomerular filtration rate by ∼20% at the end of the daily shift, and 18.5% presented with serum creatinine increases consistent with acute kidney injury. Those changes were associated with increased serum creatine phosphokinase (a known marker for exertional rhabdomyolysis) and oxidative stress-associated malondialdehyde levels, increased peripheral blood white cell counts, decreased urinary and serum sodium, decreased calculated fractional sodium excretion, and increased urine density. Thus, burnt sugarcane harvesting caused acute renal dysfunction in previously healthy workers. This was associated with a combination of dehydration, systemic inflammation, oxidative stress, and rhabdomyolysis.

Tuberculose e silicose: epidemiologia, diagnóstico e quimioprofilaxia

Silicosis, the most prevalent of the pneumoconioses, is caused by inhalation of crystalline silica particles. Silica-exposed workers, with or without silicosis, are at increased risk for tuberculosis and nontuberculous mycobacteria-related diseases. The risk of a patient with silicosis developing tuberculosis is higher (2.8 to 39 times higher, depending on the severity of the silicosis) than that found for healthy controls. Various regimens for tuberculosis chemoprophylaxis in patients with silicosis have been studied, all of which present similar efficacy and overall risk reduction to about one half of that obtained with placebo. Long-term regimens have potential side effects (particularly hepatotoxicity). In addition, the use of such regimens can jeopardize adherence to treatment. The current guidelines recommend that tuberculin skin tests be performed, and, if positive, that chemoprophylaxis be instituted. There are several possible regimens, varying in terms of the drugs prescribed, as well as in terms of treatment duration. We recommend the use of isoniazid at 300 mg/day (or 10 mg/kg/day) for six months for patients with silicosis, as well as for healthy patients with periods of exposure to silica longer than 10 years and strongly positive tuberculin skin test results (induration > 10 mm). Nevertheless, further studies are necessary so that indications, drugs, doses and duration of chemoprophylaxis regimens can be more properly defined.

A review of low-level air pollution and adverse effects on human health: implications for epidemiological studies and public policy

The aim of this study was to review original scientific articles describing the relationship between atmospheric pollution and damage to human health. We also aimed to determine which of these studies mentioned public policy issues. Original articles relating to atmospheric pollution and human health published between 1995 and 2009 were retrieved from the PubMed database and analyzed. This study included only articles dealing with atmospheric pollutants resulting primarily from vehicle emissions. Three researchers were involved in the final selection of the studies, and the chosen articles were approved by at least two of the three researchers. Of the 84 non-Brazilian studies analyzed, 80 showed an association between atmospheric pollution and adverse effects on human health. Moreover, 66 showed evidence of adverse effects on human health, even at levels below the permitted emission standards. Three studies mentioned public policies aimed at changing emission standards. Similarly, the 29 selected Brazilian studies reported adverse associations with human health, and 27 showed evidence of adverse effects even at levels below the legally permitted emission standards. Of these studies, 16 mentioned public policies aimed at changing emission standards. Based on the Brazilian and non-Brazilian scientific studies that have been conducted, it can be concluded that, even under conditions that are compliant with Brazilian air quality standards, the concentration of atmospheric pollutants in Brazil can negatively affect human health. However, as little discussion of this topic has been generated, this finding demonstrates the need to incorporate epidemiological evidence into decisions regarding legal regulations and to discuss the public policy implications in epidemiological studies.

Emprego da determinação de monóxido de carbono no ar exalado para a detecção do consumo de tabaco

Introduction: Smoking is the major preventable risk of morbidity and mortality. However, its prevalence is high in developed countries and increasing in developing countries, even though its effects are now better known. The purpose of this study was to compare the exhaled carbon monoxide concentration (exCO) between smokers and nonsmokers, evaluate the factors that influence this parameter among smokers and the potential influence of passive smoking by measuring exCO in workers and patients of Instituto do Coracao HC-FMUSP. Materials and methods: This cross study included 256 volunteers who responded to a questionnaire and were submitted to exCO measuring with the MicroCo meter device. Results: There were 106 males and 150 females. Mean age was 43.4 years (Vmin-max: 15-83). There were 107 smokers, 118 nonsmokers and 31 passive smokers. Mean exCO was 14.01 ppm (Vmin-max: 1-44) among smokers, 2.03 ppm (Vmin-max: 0-5) among passive smokers and 2.50 ppm (Vmin-max: 0-9) among nonsmokers. Significant statistical difference was observed between smokers and the other groups (p < 0.001), but not between nonsmokers and passive smokers. A positive correlation was found between the number of cigarettes smoked per day and exCO values while there was a negative correlation between the exCO values and the timing of the last cigarette. For a reference limit value of 6 ppm, sensitivity was 70% and specificity was 96%. Conclusion: exCO metering is easy to perform, low-cost, noninvasive and allows the obtention of immediate results and the reference limit value of 6 ppm has good specificity to evaluate the smoking habit.

Pulmonary alterations in cocaine users

CONTEXT Brazilian researchers have recently recognized a marked increase in the number of people using abusable drugs and the consequences of this habit. It has become a major public health problem in a potentially productive segment of the general population. In the last few years, several medical articles have given special emphasis to pulmonary complications related to cocaine use. This review is based on this information and experience acquired with groups of cocaine users. OBJECTIVE To present to physicians the pulmonary aspects of cocaine use and warn about the various effects this drug has on the respiratory system, stressing those related to long-term use. DESIGN Narrative review. METHOD Pulmonary complications are described. These may include infections (Staphylococcus aureus, pulmonary tuberculosis, acquired immunodeficiency syndrome/aids, etc.), aspiration pneumonia, lung abscess, empyema, septic embolism, non-cardiogenic pulmonary edema, barotrauma, pulmonary granulomotosis, branchiolitis obliterans and organizing pneumonia, pneumonitis and interstitial fibrosis, pneumonitis hypersensitivity, lung infiltrates and eosinophilia in individuals with branchial hyperreactivity, diffuse alveolar hemorrhage, vasculitis, pulmonary infarction, pulmonary hypertension and alterations in gas exchange. It is concluded that physicians should give special attention to the various pulmonary and clinical manifestations related to cocaine use, particularly in young patients.

Burnt sugarcane harvesting: Particulate matter exposure and the effects on lung function, oxidative stress, and urinary 1-hydroxypyrene

Non-mechanised sugarcane harvesting preceded by burning exposes workers and the people of neighbouring towns to high concentrations of pollutants. This study was aimed to evaluate the respiratory symptoms, lung function and oxidative stress markers in sugarcane workers and the residents of Mendonça, an agricultural town in Brazil, during the non-harvesting and harvesting periods and to assess the population and individual exposures to fine particulate matter (PM(2.5)). Sugarcane workers and healthy volunteers were evaluated with two respiratory symptom questionnaires, spirometry, urinary 1-hydroxypyrene levels, and the measurement of antioxidant enzymes and plasma malonaldehyde during the non-harvesting and harvesting periods. The environmental assessment was determined from PM(2.5) concentration. PM(2.5) level increased from 8 μg/m³ during the non-harvesting period to 23.5 μg/m³ in the town and 61 μg/m³ on the plantations during the harvesting period. Wheezing, coughing, sneezing, and breathlessness increased significantly in both groups during the harvesting period, but more markedly in workers. A decrease in lung function and antioxidant enzyme activity was observed in both populations during harvesting; this decrease was greater among the sugarcane workers. The urinary 1-hydroxypyrene levels only increased in the sugarcane workers during the harvesting period. The malonaldehyde levels were elevated in both groups, with a higher increase observed in the workers. This research demonstrates the exposure of sugarcane workers and the inhabitants of a neighbouring town to high PM(2.5) concentrations during the sugarcane harvest period. This exposure was higher among the sugarcane workers, as illustrated by both higher PM(2.5) concentrations in the sugarcane fields and higher urinary 1-hydroxypyrene levels in the volunteers in this group. The higher incidence of respiratory symptoms, greater decrease in lung function and more marked elevation of oxidative stress markers among the sugarcane workers during the harvest confirms the greater effect magnitude in this population and a dose-dependent relationship between pollution and the observed effects.

Young “Healthy” Smokers Have Functional and Inflammatory Changes in the Nasal and the Lower Airways

BACKGROUND Smoking is responsible for most COPD. Although people with COPD often have concomitant nasal disease, there are few studies that report physiologic or inflammatory changes in the upper airways in young asymptomatic smokers. We investigated physiologic and inflammatory changes in the nasal and lower airways of young smokers and if these changes were related to smoking history. METHODS Seventy-two subjects aged between 18 and 35 years (32 healthy nonsmokers and 40 young smokers) participated in this study. We measured nasal mucociliary clearance (MCC), nasal mucus surface contact angle, cell counts, myeloperoxidase and cytokine concentrations in nasal lavage fluid, exhaled breath condensate (EBC) pH, and lung function. RESULTS Smokers had faster MCC, an increased number of cells (macrophages, ciliated cells, and goblet cells), increased lavage myeloperoxidase concentration, and decreased EBC pH compared with nonsmokers. There was a significant inverse relationship between pack-year smoking history and EBC pH. There were no differences in lung function or mucus surface properties comparing smokers to nonsmokers. CONCLUSIONS Young adult smokers have functional and inflammatory changes in the nasal and lower airways and these correlate with smoking history. However, in these young smokers, smoking history was not associated with pulmonary function decline, probably because it is unlikely that spirometry detects early physiologic changes in the airways. TRIAL REGISTRY ClinicalTrials.gov; No.: NCT01877291; URL: www.clinicaltrials.gov.

Effects of biomass burning on nasal mucociliary clearance and mucus properties after sugarcane harvesting

OBJECTIVE Biofuel from sugarcane is widely produced in developing countries and is a clean and renewable alternative source of energy. However, sugarcane harvesting is mostly performed after biomass burning. The aim of this study was to evaluate the effects of harvesting after biomass burning on nasal mucociliary clearance and the nasal mucus properties of farm workers. METHODS Twenty seven sugarcane workers (21-45 years old) were evaluated at the end of two successive time-periods: first at the end of a 6-month harvesting period (harvesting), and then at the end of a 3-month period without harvesting (non-harvesting). Nasal mucociliary clearance was evaluated by the saccharine transit test, and mucus properties were analyzed using in vitro mucus contact angle and mucus transportability by sneeze. Arterial blood pressure, heart rate, respiratory rate, pulse oximetry, body temperature, associated illness, and exhaled carbon monoxide were registered. RESULTS Data are presented as mean values (95% confidence interval). The multivariate model analysis adjusted for age, body-mass index, smoking status and years of working with this agricultural practice showed that harvesting yielded prolonged saccharine transit test in 7.83 min (1.88-13.78), increased mucus contact angle in 8.68 degrees (3.18-14.17) and decreased transportability by sneeze in 32.12 mm (-44.83 to -19.42) compared with the non-harvesting period. No significant differences were detected in any of the clinical parameter at either time-period. CONCLUSION Sugarcane harvesting after biomass burning negatively affects the first barrier of the respiratory system in farm workers by impairing nasal mucociliary clearance and inducing abnormal mucus properties.