BACKGROUND:The present paper revisits the 1977 paper by DW Cockcroft, RE Ruffin, the late J Dolovich and FE Hargreave entitled "Allergen-induced increase in nonallergic bronchial reactivity" (Clin Allergy 1977;7:503-13) that became a citation classic. Although clinical types of asthma were recognized at the time, there was a poor understanding regarding the role of allergic reactions in causing increases in airway hyperresponsiveness. The objective was to study formally Dr Altounyan's observation that patients with asthma showed increases in airway responsiveness at the times of natural allergen exposure during pollen season. Thirteen atopic patients with asthma were studied over two days, following inhalation of diluent (control) and following doubling amounts of an allergen solution at 10-min intervals until forced expiration volume in 1 s fell by 20%. Methacholine and histamine challenges were performed before, at 8 h, at 32 h and seven days following the inhalations. A significant reduction (reduction of at least one doubling concentration) in the provocative concentration that causes a 20% fall in forced expiration volume in 1 s occurred in seven of 13 patients, and more often in subjects with a late bronchoconstrictor response to allergen challenge.IMPORTANCE: The study showed that large changes in airway responsiveness could occur in patients with asthma and suggested that allergens could cause, rather than trigger, asthma. The study also led to the concept of asthma inducers and inciters -- inducers causing airway inflammation and inciters provoking bronchospasm. The results led to a series of observations that have now implicated immunoglobulin E-mediated airway inflammation as perhaps the most important cause of airway hyperresponsiveness in asthma.

Donald W Cockcroft

Allergen Induced Increase in Nonallergic Airway Responsiveness: A Citation Classic Revisited

BACKGROUND AND OBJECTIVE: The reported effects of asthma on gastroesophageal reflux (GER), effects of GER on asthma and the effects of antireflux therapy on asthma are conflicting. The purpose of this paper is to review the evidence for a relationship between the two conditions.DESIGN: A search of the MEDLINE 1966 to 1999 database, combining the terms GER and asthma, was used to identify studies of the effects of acid perfusion of the esophagus, the physiological equivalent of GER and the effects of both medical and surgical antireflux therapy on asthma. Bibliographies of the identified papers were also reviewed.MAIN RESULTS: The collected evidence suggests that GER causes asthma symptoms but has minimal effects on pulmonary function. Both medical and surgical antireflux therapy can improve asthma symptoms and asthma medication requirements without improving pulmonary function. The paradox of GER causing symptoms without affecting pulmonary function may be because of the retrosternal discomfort that accompanies GER increases minute ventilation and respiratory sensation.CONCLUSIONS: Despite an extensive body of literature, many questions remain about the relationship between GER and asthma. A review of the data suggests a strong association between the two conditions, and that GER worsens asthma symptoms without affecting pulmonary function. Asymptomatic GER does not worsen asthma. Antireflux therapy may have a role in asthma patients with symptomatic GER, possibly being most beneficial for those with reflux-associated respiratory symptoms. Unfortunately, many studies contain flaws such as a lack of controls and small sample sizes. Further properly designed controlled trials, including ones that measure the effects of GER and antireflux therapy on quality of life, are needed to understand better the role of GER in asthma.

Stephen K Field

Gastroesophageal Reflux and Asthma: Can the Paradox Be Explained?

BACKGROUND: Asthma is one of the most frequent causes of preventable hospital admissions among children.OBJECTIVES: To identify preventable risk factors for future hospital admissions. Some of the environmental and patient characteristics of children who were hospitalized more than once with an acute asthma attack were investigated.DESIGN, SETTING AND PATIENTS: An analysis was performed of 140 children with asthma, aged three to 15 years, admitted to the Department of Pediatrics at Dicle University Hospital, Diyarbakir, Turkey, over three years, followed for a maximum of 48 months. Associations between hospital admissions and probable predictors (clinical findings, laboratory studies and a detailed case history) were analyzed.RESULTS: The asthma admissions were higher in boys than in girls (male to female ratio 1.86). Of 140 children, 30 (21.4%) had multiple admissions, defined as a mean of more than one admission per year during the follow-up period. The following factors were associated significantly with the frequency of hospital admission for asthma attacks when analyzed using a X2 test: indoor cigarette smoking (odds ratio [OR] 2.55), maternal smoking (OR 4.05), symptoms of dermal atopy (OR 2.96), symptoms of allergic conjunctivitis (OR 2.68), age less than five years (OR 5.12) and use of inhaled corticosteroids during the follow-up (OR 0.37). With multivariate logistic regression analysis, among other factors, only maternal smoking (r=0.29, P=0.017) and age less than five years (r=-0.32, P=0.012) were significant effective factors for the multiple hospital admissions. No significant association with the frequency of hospital admission was found for sex, serum total immunoglobulin E, history of frequent upper respiratory tract infections or number of family members.CONCLUSIONS: Prevention of indoor smoking, especially maternal smoking, may be effective in decreasing hospital admissions in children with asthma. Children less than five years of age are more likely to be hospitalized than are children five years of age or greater.

Fuat Gürkan

Aydin Ece

Kenan Haspolat

Orhan Derman

Mehmet Bosnak

Predictors for Multiple Hospital Admissions in Children with Asthma

OBJECTIVE: To compare cases of tuberculosis (TB) diagnosed among aboriginal persons with a random sample of nonaboriginal persons diagnosed with TB, and evaluate the trends in rates of disease between both groups during the same period.DESIGN: A case-control study.SETTING: A provincial TB control program.PATIENTS AND METHODS: All patients with TB diagnosed among aboriginal persons in British Columbia between 1992 and 1996 were compared with control patients diagnosed during the same period. For each patient a control patient was identified.INTERVENTION: The demographic details, type of disease, bacteriology, risk factors for TB, therapy received as well as mode of administration were documented. The number of contacts identified for each patient as well as the number of patients completing chemoprophylaxis were identified. The rates of disease during the same period were also documented.RESULTS: During the study, 202 patients with TB were diagnosed among aboriginal persons and 201 controls were chosen. Apart from age at diagnosis (35.1±20 years versus 45.7±19.7), differences in the prevalence of lymphadenopathy (5.9% versus 16.4%, P=0.0008) and pleural disease (21.3% versus 16.4%, P=0.00008), there were no differences in presentation between aboriginal and nonaboriginal people. Aboriginal people were more likely to have a  history of contact with a patient with TB (53% versus 17.9%, P&#xc3;0.05), to have received directly observed therapy (55% versus 33.8%, P=0.00002) and to have contacts who were purified protein derivative (PPD) positive (4±9 versus 2±3, P=0.002). These contacts were more likely to start isoniazid (2±3 versus 1±1, P=0.002). Overall, there was a significant decline in rates of TB among aboriginal persons compared with the general population, but there was a small increase in rates among all subjects in the final year of the study.CONCLUSIONS: In the present study, significant variations in rates of TB among different population groups in British Columbia were found. During the study period, there was a greater decline in the rates of TB among aboriginal persons. A greater use of directly observed therapy and greater use of chemoprophylaxis occurred among aboriginal persons, which may have contributed to this decline, or alternatively, it simply reflects the natural evolution of the TB epidemic.

L Wang

K Noertjojo

RK Elwood

J Mark FitzGerald

Tuberculosis among Aboriginal and Nonaboriginal Persons in British Columbia

Endemic tuberculosis (TB) was almost certainly present in Canadian aboriginal people (aboriginal Canadians denotes status Indians, Inuit, nonstatus Indians and metis as reported by Statistics Canada) before the Old World traders arrived. However, the social changes that resulted from contact with these traders created the conditions that converted endemic TB into epidemic TB. The incidence of TB varied inversely with the time interval from this cultural collision, which began on the east coast in the 16th century and ended in the Northern Territories in the 20th century. This relatively recent epidemic explains why the disease is more frequent in aboriginal children than in Canadian-born nonaboriginal people. Treatment plans must account for the socioeconomic conditions and cultural characteristics of the aboriginal people, especially healing models and language. Prevention includes bacillus Calmette-Guerin vaccination and chemoprophylaxis, and must account for community conditions, such as rates of suicide, which have exceeded the rate of TB. The control of TB requires a centralized program with specifically directed funding. It must include a program that works in partnership with aboriginal communities.

Vernon H Hoeppner

Darcy D Marciniuk

Tuberculosis in Aboriginal Canadians

Patients with chronic obstructive pulmonary disease (COPD - chronic bronchitis, emphysema, asthma) are often  limited in their capacity to exercise, mainly because they experience shortness of breath or muscle fatigue. The reasons  for shortness of breath are dealt with in another patient page (Can Respir J 2000;7(1):35-36), and include  narrowing of the airways, poor lung function leading to falls in the amount of oxygen carried in the blood and weak  muscles for breathing. Easy fatiguability may be because of muscle weakness or changes in muscle function, related  to inactivity and ageing. Other less common factors include heart problems associated with COPD, and other coexisting  health problems, such as anemia and arthritis.

Norman L Jones

Number 2: Chronic Obstructive Pulmonary Disease: The Importance of Exercise

May 6 to 10, 2000 is a great time for the Canadian respiratory community. It is the 100th anniversary of our Lung Association, and it is our chance to host the respiratory world at the American Lung Association, American Thoracic Society International Conference and the Canadian Thoracic Society Annual Meeting.     The name Toronto comes from a Mohawk word meaning 'meeting place'. The rivers that run into Lake Ontario were traditional gathering places for the aboriginal peoples that lived in this area before the coming of the European settlers. My ancestors include both Mohawks and the Mississaugas of the Credit, the native tribe that occupied the Toronto area as its traditional territory until the late 18th century.

Malcolm King

Welcome to Toronto. Welcome to the CIHR

I sometimes feel that I am so dominated by circumstances  and coincidences that I have little free choice, for example,  when approaching an editorial. A case in point was a few  days last month during which I attended a well-sponsored  meeting of the Ontario Lung Association, reviewed a couple  of papers reporting drug trials, read of the threats of litigation  made by pharmaceutical companies to two Ontario researchers,  heard of a public apology made by the New England  Journal of Medicine regarding reviewers' conflicts of  interest and received a critical letter from Dr Rob McFadden,  an associate editor of the Canadian Respiratory Journal,  about a sponsored publication that accompanied the last issue  of 1999. All this I suppose reflects our rather ambivalent relationship  with the pharmaceutical industry that supports many  professional and academic programs but clearly expects  some returns in addition to corporate tax benefits. We are  now dependent on the industry's financial backing for academic  and professional meetings that have become so large  that they require large and expensive venues. But then the industry  has the right to expect some return on its "investment"  in such meetings.

Dangerous Liaisons?

With the editorial staff of the Canadian Respiratory Journal, I extend our best wishes for the New Year, and heartfelt thanks to everyone who has helped the Journal establish itself in the competitive field of quality, peer-reviewed publications in chest medicine. It may seem odd to start the new millennium with an editorial eulogizing the past, but even in these 'postmodern' days of chaos, complexity and ordered unpredictability, the past can be seen to have a huge influence on the present and the future. The importance of looking back on work that has influenced our present views on chest medicine, and why, was the main reason for the series inaugurated in the present issue - 'Modern Classics Revisited' (pages 71-76).

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Canadian Respiratory Journal provides a multidisciplinary forum for research in all areas of respiratory medicine. The journal publishes research related to asthma, allergy, COPD, non-invasive ventilation, therapeutic intervention etc.

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Chief Editor, Dr Alice M Turner, is based at the University of Birmingham, UK. Her main research interests are the clinical aspects of alpha 1 antitrypsin deficiency and chronic obstructive pulmonary disease.

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Canadian Respiratory Journal - Table of contents 2000

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Canadian Respiratory Journal provides a multidisciplinary forum for research in all areas of respiratory medicine. The journal publishes research related to asthma, allergy, COPD, non-invasive ventilation, therapeutic intervention etc.

Canadian Respiratory Journal