Gustavo Faibischew Prado

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.

Comparison between objective measures of smoking and self-reported smoking status in patients with asthma or COPD: are our patients telling us the truth?

OBJECTIVE: Smoking prevalence is frequently estimated on the basis of self-reported smoking status. That can lead to an underestimation of smoking rates. The aim of this study was to evaluate the difference between self-reported smoking status and that determined through the use of objective measures of smoking at a pulmonary outpatient clinic. METHODS: This was a cross-sectional study involving 144 individuals: 51 asthma patients, 53 COPD patients, 20 current smokers, and 20 never-smokers. Smoking status was determined on the basis of self-reports obtained in interviews, as well as through tests of exhaled carbon monoxide (eCO) and urinary cotinine. RESULTS: All of the asthma patients and COPD patients declared they were not current smokers. In the COPD and asthma patients, the median urinary cotinine concentration was 167 ng/mL (range, 2-5,348 ng/mL) and 47 ng/mL (range, 5-2,735 ng/mL), respectively (p < 0.0001), whereas the median eCO level was 8 ppm (range, 0-31 ppm) and 5 ppm (range, 2-45 ppm), respectively (p < 0.05). In 40 (38%) of the patients with asthma or COPD (n = 104), there was disagreement between the self-reported smoking status and that determined on the basis of the urinary cotinine concentration, a concentration > 200 ng/mL being considered indicative of current smoking. In 48 (46%) of those 104 patients, the self-reported non-smoking status was refuted by an eCO level > 6 ppm, which is also considered indicative of current smoking. In 30 (29%) of the patients with asthma or COPD, the urinary cotinine concentration and the eCO level both belied the patient claims of not being current smokers. CONCLUSIONS: Our findings suggest that high proportions of smoking pulmonary patients with lung disease falsely declare themselves to be nonsmokers. The accurate classification of smoking status is pivotal to the treatment of lung diseases. Objective measures of smoking could be helpful in improving clinical management and counseling.

A real-life study of the effectiveness of different pharmacological approaches to the treatment of smoking cessation: re-discussing the predictors of success

OBJECTIVE: To evaluate the effectiveness of nicotine replacement therapy (NRT), bupropion, nortriptyline and combination therapy and describe factors associated with treatment success. INTRODUCTION: Clinical trials clearly demonstrate the efficacy of pharmacotherapy in smoking cessation. However, it is only after its use in real‐life settings that clinical effectiveness and limitations of a treatment are fully known. METHODS: Patients attended a four‐session cognitive‐behavioral program and received medicines free of charge. Abstinence from smoking was assessed at each visit. RESULTS: A total of 868 smokers (68.8% women) were included. Their mean age was 49.6 years; the amount smoked was 25 cigarettes/day and the Fagerström Score was 6.6. Abstinence rates after 6 months and 1 year were 36.5% and 33.6%. In univariate analysis, male gender, age (>50), higher number of cigarettes smoked, cardiovascular comorbidities, longer interval from the last cigarette and combined treatment of nortriptyline plus NRT were predictive of abstinence, while neuropsychiatric comorbidities and the answer “yes” to the question “Do you smoke more often during the first hours after waking” were correlated with failure. In a multivariate model, predictors of abstinence were neuropsychiatric comorbidities, the answer “yes” to the question “Do you smoke more often during the first hours after waking” and combined treatment of nortriptyline plus NRT. Male gender and a longer period from the last cigarette were correlated with lower abstinence rate. CONCLUSION: Satisfactory success rates were obtained in a teaching hospital. Factors such as age, daily cigarette consumption, number of pack‐years and dependency score were not reliable markers of abstinence. The combination nortriptyline+NRT was independently associated with higher abstinence rates.

Experimentation with and knowledge regarding water-pipe tobacco smoking among medical students at a major university in Brazil,

OBJECTIVE: Water-pipe tobacco smoking is becoming increasingly more common among young people. The objective of this study was to estimate the prevalence of the use of water pipes and other forms of tobacco use, including cigarette smoking, among medical students, as well as to examine the attitudes, beliefs, and knowledge of those students regarding this issue. METHODS: We administered a questionnaire to students enrolled in the University of São Paulo School of Medicine, in São Paulo, Brazil. The respondents were evaluated in their third and sixth years of medical school, between 2008 and 2013. Comparisons were drawn between the two years. RESULTS: We evaluated 586 completed questionnaires. Overall, the prevalence of current cigarette smokers was low, with a decline among males (9.78% vs. 5.26%) and an increase among females (1.43% vs. 2.65%) in the 3rd and 6th year, respectively. All respondents believed that health professionals should advise patients to quit smoking. However, few of the medical students who smoked received physician advice to quit. Experimentation with other forms of tobacco use was more common among males (p<0.0001). Despite their knowledge of its harmful effects, students experimented with water-pipe tobacco smoking in high proportions (47.32% and 46.75% of the third- and sixth-year students, respectively). CONCLUSIONS: The prevalence of experimentation with water-pipe tobacco smoking and other forms of tobacco use is high among aspiring physicians. Our findings highlight the need for better preventive education programs at medical schools, not only to protect the health of aspiring physicians but also to help them meet the challenge posed by this new epidemic.

An approach to using heart rate monitoring to estimate the ventilation and load of air pollution exposure

BACKGROUND The effects of air pollution on health are associated with the amount of pollutants inhaled which depends on the environmental concentration and the inhaled air volume. It has not been clear whether statistical models of the relationship between heart rate and ventilation obtained using laboratory cardiopulmonary exercise test (CPET) can be applied to an external group to estimate ventilation. OBJECTIVES To develop and evaluate a model to estimate respiratory ventilation based on heart rate for inhaled load of pollutant assessment in field studies. METHODS Sixty non-smoking men; 43 public street workers (public street group) and 17 employees of the Forest Institute (park group) performed a maximum cardiopulmonary exercise test (CPET). Regression equation models were constructed with the heart rate and natural logarithmic of minute ventilation data obtained on CPET. Ten individuals were chosen randomly (public street group) and were used for external validation of the models (test group). All subjects also underwent heart rate register, and particulate matter (PM2.5) monitoring for a 24-hour period. RESULTS For the public street group, the median difference between estimated and observed data was 0.5 (CI 95% -0.2 to 1.4) l/min and for the park group was 0.2 (CI 95% -0.2 to 1.2) l/min. In the test group, estimated values were smaller than the ones observed in the CPET, with a median difference of -2.4 (CI 95% -4.2 to -1.8) l/min. The mixed model estimated values suggest that this model is suitable for situations in which heart rate is around 120-140bpm. CONCLUSION The mixed effect model is suitable for ventilation estimate, with good accuracy when applied to homogeneous groups, suggesting that, in this case, the model could be used in field studies to estimate ventilation. A small but significant difference in the median of external validation estimates was observed, suggesting that the applicability of the model to external groups needs further evaluation.

Tabagismo: o que tem sido abordado em periódicos brasileiros

The topic of tobacco smoking, in its several aspects, has been receiving increasing attention among researchers over the past few years, which has been reflected in more data and more solid scientific literature on the subject in national journals. This article aims to review the studies that focused on smoking published between January 2010 and June 2012, in Arquivos Brasileiros de Cardiologia (Brazilian Archives of Cardiology), Brazilian Journal of Medical and Biological Research, Clinics (Sao Paulo), Jornal Brasileiro de Pneumologia (Brazilian Journal of Pulmonology), Revista da Associação Médica Brasileira (Journal of the Brazilian Medical Association) and Revista Brasileira de Cirurgia Cardiovascular (Brazilian Journal of Cardiovascular Surgery). During the aforementioned period 58 articles were published, 52 of which were original ones, addressing several aspects of smoking, such as effects on health, epidemiology, cessation and experimental studies.

Effective tobacco control measures: agreement among medical students

ABSTRACTObjective: To determine the level of agreement with effective tobacco control measures recommended by the World Health Organization and to assess the attitudes toward, knowledge of, and beliefs regarding smoking among third-year medical students at University of Sao Paulo School of Medicine, located in the city of Sao Paulo, Brazil. Methods: Between 2008 and 2012, all third-year medical students were invited to complete a self-administered questionnaire based on the Global Health Professionals Student Survey and its additional modules. Results: The study sample comprised 556 students. The level of agreement with the World Health Organization recommendations was high, except for the components “received smoking cessation training” and “raising taxes is effective to reduce the prevalence of smoking”. Most of the students reported that they agree with banning tobacco product sales to minors (95%), believe that physicians are role models to their patients (84%), and believe that they should advise their patients to quit cigarette smoking (96%) and using other tobacco products (94%). Regarding smoking cessation methods, most of the students were found to know more about nicotine replacement therapy than about non-nicotine therapies (93% vs. 53%). Only 37% of the respondents were aware of the importance of educational antismoking materials, and only 31% reported that they believe in the effectiveness of encouraging their patients, during medical visits. In our sample, the prevalence of current cigarette smoking was 5.23%; however, 43.82% of the respondents reported having experimented with water-pipe tobacco smoking.

Reply from the author: erratum and discussion on anti-oxidant enzymes.

In the letter published by Kamal and Malik, two inaccuracies were pointed out in the references from Prado et al. (2012) article. The drop in erythrocyte antioxidant enzymes described in elderly subjects exposed to traffic-related outdoor pollution was actually published by Delfino et al. (2009). Regarding the sentence,“This phenomenon may also be explained by epigenetic changes in the genes encoding GST and transcription factors, which could occur as the result of chronic inflammation and exposure to the genotoxic components of pollution, such as polycyclic aromatic hydrocarbons, aldehydes, black carbon and gases (Madrigano et al., 2011),” the editing process of the original manuscript, aiming for conciseness, accidentally omitted two citations: epigenetic changes induced by PAH exposure were described by Pavanello et al. (2010), as well as epigenomic responses to long-term low-dose formaldehyde exposure were published by Liu et al. (2011). Therefore, the correct version of that sentence is: “This phenomenon may also be explained by epigenetic changes (...) which could occur as the result of chronic inflammation and exposure to the genotoxic components of pollution, such as polycyclic aromatic hydrocarbons (Pavanello et al., 2010), aldehydes (Liu et al., 2011), and black carbon and gases (Madrigano et al., 2011).” Concerning the effect of air pollution exposure on the activity of antioxidant enzymes, our study demonstrated a statistically significant reduction (according to regression analysis by linearmixed effects model, adjusted for age and body mass index) in the activities of glutathione peroxidase, glutathione S-transferase, catalase, and glutathione reductase. The hypotheses to explain such unusual decremental effects of these adaptive responses have been postulated in our paper as a possible direct inhibition of the enzymes by some components of air pollution, epigenetic changes in antioxidant response protein genes by particulate and gaseous compounds, and inhibition of transcription and translation of antioxidant agents. Another possible explanation for the reduced activity of antioxidant enzymes in volunteers exposed to air pollution from biomass burning is the direct cytotoxicity of ultrafine particles. The direct translocation into the intracellular spaces, and especially to the interior of the mitochondria (Li et al., 2003, Nel et al., 2006), may lead to mitochondrial perturbation and release of pro-apoptotic factors, resulting in cell death (Li et al., 2003) and consequent reduction of anti-reservation oxidants. Moreover, specifically regarding the reduction of catalase activity, an enzyme particularly recognized for its so-called “catalytic perfection”,