Indices of morbidity and control of asthma in adult patients exposed to environmental tobacco smoke

[Smoking cessation in asthmatic patients and its impact]

INTRODUCTION

The prevalence of smoking in asthmatic patients is similar to, or even higher than in the general population.

OBJECTIVES

This systematic review addresses (1) the effects of smoking on asthma, (2) smoking cessation strategies in asthmatic patients, and (3) the consequences of smoking cessation for people with asthma.

RESULTS

Active or passive smoking can promote the development of asthma. The few studies on smoking cessation in asthma confirm the efficacy of validated smoking cessation strategies in these patients (nicotine replacement therapy, varenicline, bupropion, cognitive and behavioural therapies). Smoking cessation in parents with asthmatic children is essential and is based on the same strategies. Electronic cigarettes may be a useful help to quit smoking in some patients. Smoking cessation is beneficial in asthmatic smokers and associated with (1) a reduction of asthma symptoms, acute exacerbations, bronchial hyperresponsiveness, and bronchial inflammation, (2) decreased use of rescue medications and in doses of inhaled corticosteroids, (3) improved asthma control, quality of life, and lung function.

CONCLUSION

In asthmatic patients, it is essential to assess smoking status and health professionals must assist them to quit smoking.

The effects of aflatoxin B1 on growth hormone regulated gene-1 and interaction between DNA and aflatoxin B1 in broiler chickens during hatching

Many types of aflatoxin cause problems for both public and animal health. Aflatoxin B₁ (AFB₁) is the most toxic and commonly encountered fungal toxin that appears in poultry feed and in feeds stored under unsuitable conditions. AFB₁ decreases feed quality, egg production and fertility of hatching eggs. Also, AFB₁ alters the development of embryos by infecting eggs. We investigated using sequence analysis the changes caused by different concentrations of AFB₁ on the promoter sequences of the growth hormone regulated gene-1 (GHRG-1) in chick embryo at 13, 17, 19 and 21 days incubation. DNA isolated from the liver of chick embryos treated with different concentrations of AFB₁ was separated using agarose gel electrophoresis to detect apoptosis, and DNA interaction with AFB₁ was investigated using plasmids to detect changes in electrophoretic mobility and their effects on DNA. Base changes of the promoter sequences of GHRG-1 in 5 ng/egg, 15 ng/egg and 40 ng/egg doses of AFB₁ were increased on day 19 compared to base changes of the same AFB₁ doses on day 13. We also found that AFB at different concentrations changed the mobility of DNA by binding to it, and that high doses of AFB1 destroyed DNA. The DNA interaction study using plasmid demonstrated that AFB₁ at high doses was bound to plasmid DNA, slowed its mobility and inhibited restriction cuts.

Annual average ambient particulate matter exposure estimates, measured home particulate matter, and hair nicotine are associated with respiratory outcomes in adults with asthma

BACKGROUND

While exposure to outdoor particulate matter (PM) has been associated with poor asthma outcomes, few studies have investigated the combined effects of outdoor and indoor PM (including secondhand tobacco smoke).

OBJECTIVE

To examine the associations between PM and asthma outcomes.

METHODS

We analyzed data from a cohort of adults with asthma and rhinitis (n=302; 82% both conditions; 13% asthma only; 5% rhinitis alone) including measures of home PM, tobacco smoke exposure (hair nicotine and self-report), ambient PM from regional monitoring, distance to roadway, and season (wet or dry). The outcomes of interest were frequent respiratory symptoms and forced expiratory volume in 1 second (FEV1) below the lower limit of normal (NHANES reference values). Multivariable regression analyses examined the associations (Odds Ratio [OR] and 95% Confidence Interval [95%CI]) between exposures and these outcomes, adjusted by sociodemographic characteristics.

RESULTS

In adjusted analyses of each exposure, the highest tertile of home PM and season of interview were associated with increased odds for more frequent respiratory symptoms (OR=1.64 95%CI: [1.00, 2.69] and OR=1.66 95%CI: [1.09, 2.51]). The highest tertile of hair nicotine was significantly associated with FEV1 below the lower limit of normal (OR=1.80 95%CI: [1.00, 3.25]). In a model including home PM, ambient PM, hair nicotine, and season, only two associations remained strong: hair nicotine with FEV1 below the lower limit of normal and season of measurement (dry, April-October) with increased respiratory symptoms (OR=1.85 95%CI: [1.00, 3.41] and OR=1.54 95%CI: [1.0, 2.37]). When that model was stratified by sex, the highest tertiles of ambient PM and hair nicotine were associated with FEV1 below the lower limit of normal among women (OR=2.23 95%CI: [1.08, 4.61] and OR=2.90 95%CI: [1.32, 6.38]), but not men. The highest tertile of hair nicotine was also associated with increased respiratory symptoms in women but not men (OR=2.38 95%CI: [1.26, 4.49]). When stratified by age, the middle quartile of ambient PM and the highest hair nicotine tertile were associated with increased respiratory symptoms (OR=2.07 95%CI: [1.01, 4.24] and OR=2.55 95%CI: [1.21, 5.36]) in those under 55 but not in the older stratum.

CONCLUSIONS

Exposure to PM from both home and ambient sources is associated with increased symptoms and lower lung function in adults with asthma, although these associations vary by type of PM, the respiratory outcome studied, sex and age.

Utilization of the National Health and Nutrition Examination (NHANES) Survey for Symptoms, Tests, and Diagnosis of Chronic Respiratory Diseases and Assessment of Second hand Smoke Exposure

BACKGROUND

Respiratory diseases encompass a number of complex disorders that constitute a major cause of both morbidity and mortality worldwide with a major burden to the afflicted as well as the health care systems that care for them. Although the prevalence of chronic respiratory diseases (CRDs) has been decreasing in industrialized countries due to a decreasing number of smokers and stricter laws aimed at reducing exposure to secondhand smoke (SHS), the burden of CRDs in developing world populations is expected to worsen due to communicable disease prevention programs, aging populations, environmental air pollution, and continued tobacco smoke exposure. Although tobacco smoking has been shown to be significantly associated with many CRDs, evidence linking SHS exposure to different CRDs is mixed, especially with low levels of SHS exposure.

METHODS

The National Health and Nutrition Examination Survey (NHANES) is a series of studies designed to assess the health and nutritional status of non-institutionalized adults and children in the United States (U.S.). In addition to being used to monitor the health of the U.S. population, NHANES data allow for research into prevalent health problems and their risk factors in the population, such with CRDs and SHS exposure. NHANES data can be utilized to explore a variety of issues related to the assessment of SHS exposure and its association to respiratory symptoms and illnesses.

RESULTS

First, we provide a brief review of NHANES including its strengths and limitations. We then provide a summary of the variables and publically available population based data that can be used to study associations between SHS exposure and CRD symptoms, testing and diagnoses.

CONCLUSION

Rich and cost effective, NHANES data provide a unique opportunity for research into the risk factors for CRDs in the U.S. population, particularly into the possible health effects of low levels of SHS exposure.

Differential diagnosis in allergy

The otolaryngic allergist must be able to distinguish between common nonallergic diagnoses that present very similarly to allergic conditions. This article describes a few of the vast myriad of conditions that must be ruled out before a diagnosis of allergy may be made. After reading this article clinicians will be able to identify various conditions, which will enhance their ability to appropriately make correct decisions for prompt and efficient management of their patients with allergic or nonallergic diseases of the head and neck.

Detrimental effects of environmental tobacco smoke in relation to asthma severity

BACKGROUND

Environmental tobacco smoke (ETS) has adverse effects on the health of asthmatics, however the harmful consequences of ETS in relation to asthma severity are unknown.

METHODS

In a multicenter study of severe asthma, we assessed the impact of ETS exposure on morbidity, health care utilization and lung functions; and activity of systemic superoxide dismutase (SOD), a potential oxidative target of ETS that is negatively associated with asthma severity.

FINDINGS

From 2002-2006, 654 asthmatics (non-severe 366, severe 288) were enrolled, among whom 109 non-severe and 67 severe asthmatics were routinely exposed to ETS as ascertained by history and validated by urine cotinine levels. ETS-exposure was associated with lower quality of life scores; greater rescue inhaler use; lower lung function; greater bronchodilator responsiveness; and greater risk for emergency room visits, hospitalization and intensive care unit admission. ETS-exposure was associated with lower levels of serum SOD activity, particularly in asthmatic women of African heritage.

INTERPRETATION

ETS-exposure of asthmatic individuals is associated with worse lung function, higher acuity of exacerbations, more health care utilization, and greater bronchial hyperreactivity. The association of diminished systemic SOD activity to ETS exposure provides for the first time a specific oxidant mechanism by which ETS may adversely affect patients with asthma.

Association of anti-smoking legislation with rates of hospital admission for cardiovascular and respiratory conditions

BACKGROUND

Few studies have examined the impact of anti-smoking legislation on respiratory or cardiovascular conditions other than acute myocardial infarction. We studied rates of hospital admission attributable to three cardiovascular conditions (acute myocardial infarction, angina, and stroke) and three respiratory conditions (asthma, chronic obstructive pulmonary disease, and pneumonia or bronchitis) after the implementation of smoking bans.

METHODS

We calculated crude rates of admission to hospital in Toronto, Ontario, from January 1996 (three years before the first phase of a smoking ban was implemented) to March 2006 (two years after the last phase was implemented. We used an autoregressive integrated moving-average (ARIMA) model to test for a relation between smoking bans and admission rates. We compared our results with similar data from two Ontario municipalities that did not have smoking bans and with conditions (acute cholecystitis, bowel obstruction and appendicitis) that are not known to be related to second-hand smoke.

RESULTS

Crude rates of admission to hospital because of cardiovascular conditions decreased by 39% (95% CI 38%-40%) and admissions because of respiratory conditions decreased by 33% (95% CI 32%-34%) during the ban period affecting restaurant settings. No consistent reductions in these rates were evident after smoking bans affecting other settings. No significant reductions were observed in control cities or for control conditions.

INTERPRETATION

Our results serve to expand the list of health outcomes that may be ameliorated by smoking bans. Further research is needed to establish the types of settings in which smoking bans are most effective. Our results lend legitimacy to efforts to further reduce public exposure to tobacco smoke.

Workplace secondhand smoke exposure in the U.S. trucking industry

BACKGROUND

Although the smoking rate in the United States is declining because of an increase of smoke-free laws, among blue-collar workers it remains higher than that among many other occupational groups.

OBJECTIVES

We evaluated the factors influencing workplace secondhand smoke (SHS) exposures in the U.S. unionized trucking industry.

METHODS

From 2003 through 2005, we measured workplace SHS exposure among 203 nonsmoking and 61 smoking workers in 25 trucking terminals. Workers in several job groups wore personal vapor-phase nicotine samplers on their lapels for two consecutive work shifts and completed a workplace SHS exposure questionnaire at the end of the personal sampling.

RESULTS

Median nicotine level was 0.87 microg/m3 for nonsmokers and 5.96 microg/m3 for smokers. As expected, smokers experienced higher SHS exposure duration and intensity than did nonsmokers. For nonsmokers, multiple regression analyses indicated that self-reported exposure duration combined with intensity, lack of a smoking policy as reported by workers, having a nondriver job, and lower educational level were independently associated with elevated personal nicotine levels (model R2 = 0.52). Nondriver job and amount of active smoking were associated with elevated personal nicotine level in smokers, but self-reported exposure, lack of a smoking policy, and lower educational level were not.

CONCLUSIONS

Despite movements toward smoke-free laws, this population of blue-collar workers was still exposed to workplace SHS as recently as 2005. The perceived (reported by the workers), rather than the official (reported by the terminal managers), smoking policy was associated with measured SHS exposure levels among the nonsmokers. Job duties and educational level might also be important predictors of workplace SHS exposure.

Redox control of asthma: molecular mechanisms and therapeutic opportunities

An imbalance in reducing and oxidizing (redox) systems favoring a more oxidative environment is present in asthma and linked to the pathophysiology of the defining symptoms and signs including airflow limitation, hyper-reactivity, and airway remodeling. High levels of hydrogen peroxide, nitric oxide ((*)NO), and 15-F(2t)-isoprostane in exhaled breath, and excessive oxidative protein products in lung epithelial lining fluid, peripheral blood, and urine provide abundant evidence for pathologic oxidizing processes in asthma. Parallel studies document loss of reducing potential by nonenzymatic and enzymatic antioxidants. The essential first line antioxidant enzymes superoxide dismutases (SOD) and catalase are reduced in asthma as compared to healthy individuals, with lowest levels in those patients with the most severe asthma. Loss of SOD and catalase activity is related to oxidative modifications of the enzymes, while other antioxidant gene polymorphisms are linked to susceptibility to develop asthma. Monitoring of exhaled (*)NO has entered clinical practice because it is useful to optimize asthma care, and a wide array of other biochemical oxidative and nitrative biomarkers are currently being evaluated for asthma monitoring and phenotyping. Novel therapeutic strategies that target correction of redox abnormalities show promise for the treatment of asthma.

[Respiratory diseases related to passive smoking]

Passive smoking, measured in practice by using specific biomarkers, is a well known factor of morbidity and mortality. The main victims are children, often starting from conception, but adults are not spared. Many respiratory diseases are caused and/or worsened by passive smoking and environmental tobacco smoke (ETS) exposure can have serious health consequences that reduce life expectancy (sudden infant death, respiratory infections, asthma, chronic obstructive pulmonary diseases and lung cancer). Better knowledge of these risks has favourably influenced the legislation banning smoking in enclosed public places in France and in other countries. If one of the main objectives of this measure is to protect non-smokers as well as smokers, its rigorous application fits directly within the goals of prevention and treatment of tobacco dependency.

Passive smoking and adult asthma

Asthma is a common chronic health condition, affecting 5% of the United States adult population. In most developed countries, the prevalence of asthma and its severity continues to increase. Understanding the factors contributing to asthma morbidity and mortality has important clinical and public health implications. This article evaluates the evidence that secondhand smoke exposure is a risk factor for new-onset asthma among adults and exacerbates pre-existing adult asthma, resulting in greater symptom burden and morbidity.

Bronchial asthma: the Indian scene

PURPOSE OF REVIEW

Although asthma is a global disease, there are important differences in epidemiology, clinical spectrum and management practices in India. Some of these issues have been reviewed in this article.

RECENT FINDINGS

The prevalence of 'ever asthma' was reported in 2.4% in a population study on 73,605 individuals conducted simultaneously at four major centres in India with the use of a single definition and uniform methodology employing a validated questionnaire. Of the several risk factors which were found to be significant, exposure to environmental tobacco smoke during childhood alone or both during childhood and adulthood was important in the development of and in increasing morbidity from asthma. Many other triggers and risk factors which include local aeroallergens and air pollutants have been identified. Allergic bronchopulmonary aspergillosis is an important cause of difficult to treat asthma and almost half of these patients receive antitubercular treatment at some stage. Simplified consensus guidelines based on international guidelines and local practices have been developed for use at the primary and secondary levels of healthcare.

SUMMARY

The prevalence of asthma in India is somewhat similar to that seen in other Asian countries. Consensus management guidelines adapted from standard international guidelines adequately address the local concerns and issues.

Adequacy of outpatient management of asthma patients admitted to a state hospital in Argentina

OBJECTIVE

The aim of this study was to assess chronic outpatient management of adult patients admitted with asthma.

METHODOLOGY

A cross-sectional survey was conducted of 98 consecutive asthma admissions to a specialized pulmonary State Hospital in Buenos Aires, Argentina, over a 12-month period. Patients were surveyed, within 48 h of admission, with a previously validated questionnaire which deals with chronic outpatient management and measures taken by patients or physicians to treat symptoms during asthma exacerbations.

RESULTS

FEV1% predicted was 30.2 +/- 10.7. Mean admission rate and emergency department (ED) visits in the previous year were 0.7 +/- 1.2 and 4.6 +/- 5.1, respectively. A total of 96, 65 and 9% of the patients had been treated previously in the ED, admitted to hospital or mechanically ventilated, respectively. Only 62% had been prescribed inhaled corticosteroids (IC) by their physician; 38% had been prescribed nebulized beta agonists (Nbeta2) and 68% a metered dose inhaler (MDIbeta2). Inhaled beta2-agonist usage during acute exacerbations over the 24 h prior to admission was 14.4 +/- 7.4 puffs for MDIbeta2 and 8.6 +/- 5.4 occasions for Nbeta2. Only 11% of the patients were able to perform all the steps of the MDI inhalation technique correctly. An action plan had been provided by their physicians to 43% of patients, while 58% changed their medication on their own. Only three patients had a peak flow meter (PFM) prescribed. ED was used by 26% for their routine care. No health insurance coverage was available to 75.5% of the patients.

CONCLUSIONS

Underuse of IC, poor MDI inhalation technique, and low prescription of an action plan was common and a PFM was seldom prescribed. During exacerbations, many patients changed their medication spontaneously and MDIbeta2 underuse was observed.

Directly measured second hand smoke exposure and asthma health outcomes

BACKGROUND

Because they have chronic airway inflammation, adults with asthma could have symptomatic exacerbation after exposure to second hand smoke (SHS). Surprisingly, data on the effects of SHS exposure in adults with asthma are quite limited. Most previous epidemiological studies used self-reported SHS exposure which could be biased by inaccurate reporting. In a prospective cohort study of adult non-smokers recently admitted to hospital for asthma, the impact of SHS exposure on asthma health outcomes was examined.

METHODS

Recent SHS exposure during the previous 7 days was directly measured using a personal nicotine badge (n = 189) and exposure during the previous 3 months was estimated using hair nicotine and cotinine levels (n = 138). Asthma severity and health status were ascertained during telephone interviews, and subsequent admission to hospital for asthma was determined from computerised utilisation databases.

RESULTS

Most of the adults with asthma were exposed to SHS, with estimates ranging from 60% to 83% depending on the time frame and methodology. The highest level of recent SHS exposure, as measured by the personal nicotine badge, was related to greater asthma severity (mean score increment for highest tertile of nicotine level 1.56 points; 95% CI 0.18 to 2.95), controlling for sociodemographic covariates and previous smoking history. Moreover, the second and third tertiles of hair nicotine exposure during the previous month were associated with a greater baseline prospective risk of hospital admission for asthma (HR 3.73; 95% CI 1.04 to 13.30 and HR 3.61; 95% CI 1.0 to 12.9, respectively).

CONCLUSIONS

Directly measured SHS exposure appears to be associated with poorer asthma outcomes. In public health terms, these results support efforts to prohibit smoking in public places.

Impact of the home indoor environment on adult asthma and rhinitis

OBJECTIVE

We sought to study the combined effects of multiple home indoor environmental exposures in adult asthma and rhinitis.

METHODS

We studied 226 adults with asthma and rhinitis by structured interviews and home assessments. Environmental factors included dust allergen, endotoxin and glucan concentrations, and indoor air quality (IAQ) variables. Outcomes included forced expiratory volume in 1 second (FEV1) percent predicted, Severity of Asthma Score (SAS), Short-Form (SF)-12 Physical Component Scale (PCS), and asthma Quality of Life (QOL) score.

RESULTS

House dust-associated exposures together with limited IAQ variables were related to FEV1 % predicted (R = 0.24; P = 0.0001) and SAS (R = 0.18; P = 0.007). IAQ and limited dust variables were associated with SF-12 PCS (R = 0.15; P = 0.02), but not QOL (R = 0.13; P = 0.16).

CONCLUSIONS

The home environment is strongly linked to lung function, health status, and disease severity in adult asthma and rhinitis.

[Passive smoking]

INTRODUCTION

Environmental tobacco smoke is a recognized factor of morbidity and mortality. The first victims are children, sometimes starting from conception, but adults are not spared. In practice, evaluation of exposure to tobacco smoke can be achieved with more or less specific markers of tobacco smoke.

CURRENT KNOWLEDGE

Exposure of the fetus to maternal smoking and of the infant to environmental smoke can have a serious sometimes life-threatening impact. Such exposure increases the risk of spontaneous abortion, ectopic pregnancy, intrauterine growth retardation, premature membrane rupture, preterm birth, retroplacental hematoma, placenta praevia, and sudden infant death. Adult respiratory and cardiovascular disease are also influenced by environmental smoke. In France passive smoking causes premature death of 3000 persons per year.

PERSPECTIVES

Better knowledge of the risks of exposure to passive smoking can facilitate application of legislation with the objective of protecting non-smokers.

CONCLUSIONS

Rigorous application of current legislation is important to achieve the stated goals of prevention of smoking as well as assistance to cease smoking.

Effects of smoking cessation and reduction in asthmatics

The present study examined the effect of smoking reduction and cessation on asthma regulation and biomarkers of exposure to cigarette smoke. In a prospective open design, we allocated 220 asthmatics among three groups: (a) Smoking reduction (reducers), with the aim of smoking fewer than seven cigarettes per day, (b) complete smoking cessation (abstainers), or (c) continuation of usual smoking (continuing smokers). Subjects used nicotine chewing gum or an oral nicotine inhaler to promote reduction and cessation. We monitored changes in the biomarkers carbon monoxide, cotinine, and thiocyanate, and in peak flow, medicine use, bronchial reactivity, and asthma symptoms. The analysis used the three outcome groups, regardless of original allocation to treatment groups. At 4 months, analysis of abstainers (n = 27), reducers (n = 33), and continuing smokers (n = 50) showed marked, statistically significant decreases in expired carbon monoxide of 17 ppm (abstainers) and 15 ppm (reducers); in plasma cotinine of 124 ng/ml (abstainers) and 122 ng/ml (reducers); and in plasma thiocyanate of 5.03 ng/ml (abstainers) and 3.74 ng/m (reducers). For abstainers, we observed improvements in the asthma-specific quality-of-life score, and reductions in self-reported day and night use of rescue beta2-agonists, in doses of inhaled corticosteroids, in daytime asthma symptoms, and in bronchial hyperreactivity. For reducers, smaller improvements occurred for night use of rescue beta2-agonists, doses of inhaled corticosteroids, and bronchial hyperreactivity. Smoking cessation resulted in a marked decrease in three biomarkers of cigarette smoke inhalation and improved asthma regulation, whereas smoking reduction had a less pronounced effect on biomarkers and only a small effect on asthma regulation.

Causative and contributive factors to asthma severity and patterns of medication use in patients seeking specialized asthma care

STUDY OBJECTIVES

(1) To assess the prevalence of specific factors considered causative or contributive to asthma in a population of patients seen in a specialized asthma clinic, and to determine whether any of these factors were associated with more severe disease; and (2) to assess the utilization of inhaled steroids by asthma severity in this population and compare it with published guidelines of the National Heart, Lung, and Blood Institute (NHLBI). DESIGN, SETTING, AND PATIENT POPULATION: We conducted a retrospective chart review of new patients seen in a specialized asthma treatment center over a 2.5-year period and recorded the prevalence of 14 causative or contributive factors, the severity of asthma, and the intensity of treatment with inhaled corticosteroids in each patient. Patients were grouped as mild asthma vs moderate/severe asthma and compared by chi(2) analysis and stepwise logistic regression to determine whether certain factors were associated with more severe asthma.

MEASUREMENTS AND RESULTS

The average number of factors recorded was 2.9 +/- 1.8 in the mild group (+/- SD) and 3.5 +/- 1.6 in the moderate/severe asthma group. This difference was statistically significant (p = 0.014). Increasing age, male gender, symptomatic gastroesophageal reflux disease (GERD), and chronic sinusitis were independently associated with more severe asthma. Suboptimal use of inhaled corticosteroids was more common in patients with mild persistent asthma, but suboptimal dosing of inhaled corticosteroids was equally common in mild and moderate/severe asthma. No relationship was found between allergen sensitization combined with exposure to cats, dogs, dust mite, or molds and more severe asthma.

CONCLUSIONS

This study confirms earlier studies showing that symptomatic GERD and chronic sinusitis are important comorbid conditions in patients with asthma, both being associated with greater asthma severity. This study further shows that the doses of inhaled corticosteroids used for treatment of asthma fall short of NHLBI guidelines in the majority of patients regardless of asthma severity.

Respiratory health effects of exposure to environmental tobacco smoke

Tobacco smoke is a major component of indoor air pollution. Exposure to environmental tobacco smoke (ETS) is prevalent worldwide despite growing awareness of its adverse health effects on non-smokers. ETS contains the same toxic substances as identified in mainstream tobacco smoke. Cotinine (a metabolite of nicotine) can be measured in urine and serum of non-smokers exposed to ETS and reflects the degree of exposure. In children, exposure to ETS leads to reduced lung function, increased risk of lower respiratory tract illnesses, acute exacerbation of asthma resulting in hospitalization, increased prevalence of non-allergic bronchial hyperresponsiveness, increased risk for sudden infant death syndrome (SIDS) and possibly increased risk for asthma. Exposure to ETS is responsible for excess cost to the family's financial resources and demands on health services. In adults, exposure to ETS is associated with increased risk of lung cancer, particularly in those with high exposure and acute and chronic respiratory symptoms that improve after the cessation of exposure. Healthcare providers should advocate for non-smokers' rights in the community and support legislation to limit tobacco exposure.

Environmental tobacco smoke and adult asthma

The long-term health consequences of ETS exposure have been established over the past two decades. Consistent epidemiologic evidence links ETS exposure with serious chronic health effects, including lung cancer and cardiovascular disease [1, 48, 49]. In this article, the evidence suggests a causal relationship between ETS exposure and new-onset asthma and asthma exacerbation among adults. Despite the growing knowledge of ETS-related health effects, smoking is still permitted in many public locations and workplaces [50, 51]. Because asthma is a visible condition among the general public, the evidence that links ETS exposure with adverse asthma health outcomes should provide policymakers with additional impetus for regulating public smoking and creating smoke-free public environments.

Exposure to indoor combustion and adult asthma outcomes: environmental tobacco smoke, gas stoves, and woodsmoke

BACKGROUND

Because they have chronic airway inflammation, adults with asthma may be particularly susceptible to indoor air pollution. Despite widespread exposure to environmental tobacco smoke (ETS), gas stoves, and woodsmoke, the impact of these exposures on adult asthma has not been well characterised.

METHODS

Data were used from a prospective cohort study of 349 adults with asthma who underwent structured telephone interviews at baseline and 18 month follow up. The prospective impact of ETS, gas stove, and woodsmoke exposure on health outcomes was examined.

RESULTS

ETS exposure at baseline interview was associated with impaired health status at longitudinal follow up. Compared with respondents with no baseline self-reported exposure to ETS, higher level exposure (>/=7 hours/week) was associated with worse severity of asthma scores at follow up, controlling for baseline asthma severity, age, sex, race, income, and educational attainment (mean score increment 1.5 points; 95% CI 0.4 to 2.6). Higher level baseline exposure to ETS was also related to poorer physical health status (mean decrement -4.9 points; 95% CI -8.4 to -1.3) and asthma specific quality of life (mean increase 4.4 points; 95% CI -0.2 to 9.0) at longitudinal follow up. Higher level baseline ETS exposure was associated with a greater risk of emergency department visits (OR 3.4; 95% CI 1.1 to 10.3) and hospital admissions for asthma at prospective follow up (OR 12.2; 95% CI 1.5 to 102). There was no clear relationship between gas stove use or woodstove exposure and asthma health outcomes.

CONCLUSION

Although gas stove and woodstove exposure do not appear negatively to affect adults with asthma, ETS is associated with a clear impairment in health status.

Assessment of diurnal variability of peak expiratory flow in stable asthmatics

Five daily readings of peak expiratory flow (PEF) were obtained for three days on 100 patients with chronic stable asthma. The variability of PEF was calculated as the amplitude percent mean (A%M) from the readings obtained on the third day, and compared to previously reported data from 152 healthy Indian adults. Patients with severe asthma exhibited significantly higher A%M than patients with both mild and moderate asthma (p < 0.05), but there was considerable overlap across disease categories. The area under the receiver operating characteristic curve plotted to assess the performance of PEF variability as a discriminator in diagnosing asthma was 0.826, with best discrimination at a value of 12.5 (sensitivity 0.640, specificity 0.941). Using a cut-off value of 16.5 (as proposed earlier by us) improved specificity to 0.987 but reduced sensitivity to 0.510. Using a traditional cut-off of 20, specificity remained almost unchanged (0.993), but sensitivity dropped further to 0.440. Thus A%M>16.5 is a useful marker of bronchial asthma in epidemiological studies in India. However, its use in population screening, clinical diagnosis, or in the assessment of the severity of asthma in individual patients has serious limitations because of poor sensitivity.

Pulmonary effects of passive smoking: the Indian experience

There are only a few studies done on pulmonary effects of passive smoking from India, which are summarized in this paper. Several vernacular tobacco products are used in India, bidis (beedis) being the commonest form of these. Bidis contain a higher concentration of nicotine and other tobacco alkaloids compared to the standard cigarettes (e.g., the sum of total nicotine and minor tobacco alkaloids was 37.5 mg in bidi compared to 14–16 mg in Indian or American cigarettes in one study). A large study performed on 9090 adolescent school children demonstrated environmental tobacco smoke (ETS) exposure to be associated with an increased risk of asthma. The odds ratio for being asthmatic in ETS-exposed as compared to ETS-unexposed children was 1.78 (95% CI: 1.33–2.31). Nearly one third of the children in this study reported non-specific respiratory symptoms and the ETS exposure was found to be positively associated with the prevalence of each symptom. Passive smoking was also shown to increase morbidity and to worsen the control of asthma among adults. Another study demonstrated exposure to ETS was a significant trigger for acute exacerbation of asthma. Increased bronchial hyper-responsiveness was also demonstrated among the healthy nonsmoking adult women exposed to ETS. Passive smoking leads to subtle changes in airflow mechanics. In a study among 50 healthy nonsmoking women passively exposed to tobacco smoke and matched for age with 50 unexposed women, forced expiratory volume in first second (FEV1) and peak expiratory flow (PEF) were marginally lower among the passive smokers (mean difference 0.13 L and 0.20 L-1, respectively), but maximal mid expiratory flow (FEF25–75%), airway resistance (Raw) and specific conductance (sGaw) were significantly impaired. An association between passive smoking and lung cancer has also been described. In a study conducted in association with the International Agency for Research on Cancer, the exposure to ETS during childhood was strongly associated with an enhanced incidence of lung cancer (OR = 3.9, 95% CI 1.9–8.2). In conclusions several adverse pulmonary effects of passive smoking, similar to those described from the western and developed countries, have been described from India.

Exposure to environmental tobacco smoke: association with personal characteristics and self reported health conditions

STUDY OBJECTIVE

To examine the association between exposure to environmental tobacco smoke (ETS) and demographic, lifestyle, occupational characteristics and self reported health conditions.

DESIGN

Cross sectional study, using data from multiphasic health checkups between 1979 and 1985.

SETTING

Large health plan in Northern California, USA.

PARTICIPANTS

16 524 men aged 15-89 years and 26 197 women aged 15-105 years who never smoked.

RESULTS

Sixty eight per cent of men and 64 per cent of women reported any current ETS exposure (at home, in small spaces other than home or in large indoor areas). The exposure time from all three sources of ETS exposure correlated negatively with age. Men and women reporting high level ETS exposure were more likely to be black and never married or separated/divorced, to have no college or partial college education, to consume three alcoholic drink/day or more and to report exposure to several occupational hazards. Consistent independent relations across sexes were found between any current exposure to ETS and a positive history of hay fever/asthma (odds ratio (OR)=1.22 in men, 1.14 in women), hearing loss (OR=1.30 in men, 1.27 in women), severe headache (OR=1.22 in men, 1.17 in women), and cold/flu symptoms (OR=1.52 in men, 1.57 in women). Any current ETS exposure was also associated with chronic cough (OR=1.22) in men and with heart disease (OR=1.10) in women. Self reported stroke was inversely associated with any current ETS exposure in men (OR=0.27). No associations were noted for cancer or tumour and for migraine.

CONCLUSION

ETS exposure correlated with several personal characteristics potentially associated with adverse health outcomes. Although the study design precluded causal inference, ETS exposure was associated with several self reported acute and chronic medical conditions.

Prevalence of bronchial asthma and association with environmental tobacco smoke exposure in adolescent school children in Chandigarh, north India

Prevalence of asthma and its association with environmental tobacco smoke (ETS) exposure were examined among adolescent schoolchildren in Chandigarh, India. Using a previously standardized questionnaire, data from 9090 students in the 9- to 20-year age range were analyzed. There were 4367 (48%) boys, in whom the observed prevalence of asthma was 2.6%. Among 4723 (52%) girls, asthma was present in 90 (1.9%) students. Presence of one or more respiratory symptoms was reported by 31% students. More students with asthma had either parents or other family members smoking at home as compared to nonasthmatics (41% vs. 28%, p<0.0001). The odds ratio for being asthmatic for patients exposed to ETS compared to those not exposed to ETS was 1.78 (95% confidence interval 1.33-2.31). ETS was also positively associated with prevalence of all the respiratory symptoms, with odds ratios varying between 1.6 and 2.25.

Discharge of the asthmatic patient

Asthma continues to be a challenging disease to treat in both the inpatient and outpatient settings. The growing database on therapeutic interventions at the time of transition from the acute to chronic phase of this disease is encouraging. Glucocorticoids and inhaled beta-agonists clearly reduce readmission and relapse. Other medications and educational interventions also appear effective. Still, no true discharge guidelines have been established. Multiple statements by consensus panels have recommended using FEV1 or PEFR as indicators of readiness for discharge, but this has not been prospectively validated from either the emergency department or inpatient setting. In contrast, some studies argue that pulmonary functions do not accurately predict relapse and readmission, so the usefulness of these discharge recommendations is debatable. Large studies, especially in the adult asthmatic population, are needed to validate these recommendation.

Prior exposure to aged and diluted sidestream cigarette smoke impairs bronchiolar injury and repair

The bronchiolar injury/repair response to naphthalene (NA) in mice includes acute distal airway epithelial injury that is followed by epithelial proliferation and redifferentiation, which result in repair of the epithelium within 14 days. To test whether prior exposure to aged and diluted sidestream cigarette smoke (TS) would alter the injury/repair response of the airway epithelium, adult mice were exposed to either filtered air (FA) or smoke for 5 days before injection with either corn oil carrier (CO) or naphthalene. Mice were killed 1 and 14 days after naphthalene injury. Lung and lobar bronchus were examined and measured using high-resolution epoxyresin sections. The control group (FACOFA) that was exposed to filtered air/corn oil/filtered air contained airway epithelium similar to untreated controls at all airway levels. The group exposed to tobacco smoke/corn oil/filtered air (TSCOFA) contained some rounded cells in the small airways and some expansion of the lateral intercellular space in the larger airways. Necrotic or vacuolated cells were not observed. As expected, the epithelium in the group exposed to filtered air/naphthalene/filtered air (FANAFA) contained many light-staining vacuolated Clara cells and squamated ciliated cells within distal bronchioles during the acute injury phase. Repair (including redifferentiation of epithelial cells and restoration of epithelial thickness) was nearly complete 14 days after injury. The extent of Clara cell injury, as assessed in lobar bronchi, was not different between the four groups. Although the FANAFA group contained greater initial injury in the distal airways at 1 day, the group exposed to tobacco smoke/naphthalene/filtered air (TSNAFA) had the least amount of epithelial repair at 14 days after naphthalene treatment; many terminal bronchioles contained abundant squamated undifferentiated epithelium. We conclude that tobacco smoke exposure prior to injury (1) does not change the target site or target cell type of naphthalene injury, since Clara cells in terminal bronchioles are still selectively injured; (2) results in slightly diminished acute injury from naphthalene in distal bronchioles; and (3) delays bronchiolar epithelial repair.

Association of environmental tobacco smoke at work and forced expiratory lung function among never smoking asthmatics and non-asthmatics. The SAPALDIA-Team. Swiss Study on Air Pollution and Lung Disease in Adults

Inconsistencies across studies on the association of environmental tobacco smoke (ETS) and pulmonary function may be clarified addressing potentially susceptible subgroups. We determined the association of ETS exposure at work with FVC, FEV1, and FEF25-75% in life-time never smokers (N = 3534) of the SAPALDIA random population sample (age 18-60). We considered sex, bronchial reactivity, and asthma status as a priori indicators to identify susceptible riskgroups. The multivariate regression models adjusted for height, age, education, dust/aerosol exposure, region, and ETS at home. Overall, ETS was not significantly associated with FVC (0.7%; -0.4 to +1.8), FEV1 (-0.1%; 95% CI: -1.3 to +1.1) or FEF25-75% (-1.9%; -4.2 to +0.5). Effects were observed among asthmatics (n = 325), FEV1 (-4.8%; 0 to -9.2); FEF25-75% (-12.4%; -3.7 to -20.4); FVC: (-1.7%; +2.1 to -5.5), particularly in asthmatic women (n = 183): FVC -4.4% (-9.6 to +1.1); FEV1: -8.7% (-14.5 to -2.5); FEF25-75%: -20.8% (-32 to -7.6), where duration of ETS exposure at work was associated with lung function (FEV1 -6% per hour of ETS exposure at work (p = 0.01); FEF25-75%: -3.4%/h (p < 0.05). In non-asthmatic women (n = 1963) and in men no significant effect was observed. The size of the observed effect among susceptible subgroups has to be considered clinically relevant. However, due to inherent limitations of this cross-sectional analysis, selection or information biases may not be fully controlled. For example, asthmatic women reported higher ETS exposure at work than asthmatic men. Given the public health importance to identify susceptible subgroups, these results ought to be replicated.

Epidemiologic basis for an occupational and environmental policy on environmental tobacco smoke

ETS contains numerous toxins. Robust epidemiologic evidence implicates ETS as a cause of lung cancer and as a primary cause and source of exacerbation of excess respiratory disease. There is also increasing evidence that ETS may be associated with other outcomes, including heart disease. There is currently little doubt that ETS is an important and avoidable health hazard. Unfortunately, ETS is frequently encountered in the workplace--where it is no safer than in other environments and where it presents hazards to exposed workers and to others. A unique aspect of workplace ETS is that exposure is rarely an outcome of essential manufacturing, extraction, or service delivery processes. Moreover, ETS exposure, with its growing list of known hazards, is preventable by engineering or policy means. Implementation of policies to prevent workplace ETS can be highly effective while entailing low costs and yielding primary and secondary benefits to employers and employees. ACOEM strongly supports an increase in the scope and effectiveness of policies and efforts that protect against exposure to ETS in the workplace and elsewhere. To that end, ACOEM supports voluntary, regulatory, and legislative initiatives to eliminate ETS from the workplace, including public spaces such as bars, casinos, restaurants, schools, day-care centers, and public transportation. ACOEM also encourages employers to provide employee training concerning the health hazards of ETS and voluntary personal smoking-cessation programs.

Unlimited opportunities for environmental interventions with inner-city asthmatics

The purpose of this study was to identify the asthmatics living in the Lower West Side (LWS) of Buffalo, New York, and then explore the relationship between urban asthmatic and nonasthmatic exposures to many common household aeroallergens. Eight hundred twenty-eight households were visited and 167 asthmatics and 161 nonasthmatics were identified for comparison. Specific self-reported household exposure prevalences were identified for environmental tobacco smoke, sources of molds, household pets, rats, cockroaches, and sources of dust. Sources of molds, pets, and cockroaches were more likely to be found in the homes of asthmatics compared to nonasthmatics (p < 0.05). Other aeroallergens studied, although highly prevalent, were not more likely to be found in either asthmatic or nonasthmatic homes.

Environmental tobacco smoke and adult asthma. The impact of changing exposure status on health outcomes

The effect of environmental tobacco smoke (ETS) exposure on adults with asthma has not been well characterized. In a prospective cohort study of 451 nonsmoking adults with asthma, we evaluated the impact of ETS exposure on asthma severity, health status, and health care utilization over 18 mo. There were 129 subjects (29%; 95% CI, 25-33%) who reported regular ETS exposure, falling into three categories: exposure at baseline but none at follow-up (n = 43, 10%), no baseline exposure and new exposure at follow-up (n = 56, 12%), and exposure at both baseline and follow-up (n = 30, 7%). In cross-sectional analyses, subjects with baseline ETS exposure had greater severity-of-asthma scores (score difference, 1.7; 95% CI, 0. 2-3.1), worse asthma-specific quality of life scores (score difference, 3.5; 95% CI, 0.03-7.0), and worse scores on the Medical Outcomes Study SF-36 physical component summary (score difference, 3. 0; 95% CI, 0-6.0) than unexposed subjects. They also had greater odds of emergency department visits (odds ratio [OR] = 2.1; 95% CI, 1.2-3.5), urgent physician visits (OR = 1.9; 95% CI, 1.1-3.3), and hospitalizations (OR = 1.9; 95% CI, 1.02-3.6). In longitudinal follow-up, subjects reporting ETS cessation showed improvement in severity-of-asthma scores (score reduction, -3.2; 95% CI, -4.4 to -2. 0) and physical component summary scores (score increase, 5.3; 95% CI, 2.6-8.1). Environmental tobacco smoke cessation decreased the odds of emergency department visits (OR = 0.4; 95% CI, 0.2-0.97) and hospitalizations (OR = 0.2; 95% CI, 0.04-0.97) after adjustment for covariates. Environmental tobacco smoke initiation was associated with greater asthma severity only in subjects with high-level (>= 3 h/wk) exposure (score increase, 1.4; 95% CI, 0.03-2.7). In conclusion, self-reported ETS exposure is associated with greater asthma severity, worse health status, and increased health care utilization in adults with asthma.

Epidemiology of Asthma

Epidemiology of asthma is discussed in terms of the prevalence, risk factors associated with increasing morbidity and mortality, impact on life-style, long-term prognosis, and economic impact. Those most at risk for development of asthma are young children, African Americans, and those in lower economic status and inner-city communities. The primary contributing factor to increasing morbidity and mortality is undertreatment. Contributing factors may be restricted access to continuing medical care, unstable family situations, cultural and language barriers, failure to recognize severity of the disease, and inability to afford care.

[Epidemiology of severe asthma]

Prevalence of severe acute asthma can be evaluated through mortality statistics, hospitalization rates and epidemiological studies. Risk factors include personnal characteristics (age, socio-economic status, disease denial, depression, medical features associated with increased severity), environment factors as life events and exposure to specific (allergens) and as non-specific factors (viral or microbial infections, passive smoking, air polluants) and the health care system (care delivery, quality of medical management). Such factors are inter-related. Their knowledge should allow a better management leading to a lower incidence of severe acute asthma attacks.