The prevalence of asthma and respiratory symptoms among young adults: is it increasing in Australia?

The objective of this study was to determine the prevalence of self-reported asthma and respiratory symptoms among young adults and whether there had been any change since a previous survey. A cross-sectional postal community survey was conducted in three parliamentary electorates in the inner South East region of Melbourne, Australia. A total of 4500 individuals aged between 20 and 44 years were randomly selected from the electoral roll. After three mailings and telephone follow-up, an adjusted response rate of 79% was achieved. No intervention was performed. Self-reported asthma and respiratory symptoms were recorded from the European Community Respiratory Health Survey screening questionnaire. Respondents were most likely to report nasal allergies (41%), nocturnal cough (28.6%), and wheeze in the last 12 months (28.1%). Nocturnal cough was more common in females than males. The prevalence of wheeze, nocturnal chest tightness, and use of asthma medications decreased with age. An attack of asthma in the last 12 months was reported by 9.7% of young adults, and this fell to 8.2% after correction for nonresponse bias. The prevalence of current asthma had not increased significantly since a previous postal survey in 1990. However the prevalence of nocturnal chest tightness, nocturnal cough, and use of asthma medications had increased significantly over a 2-year period. Further research is required to investigate why asthma is so prevalent in Australia and why some features are increasing in prevalence.

Allergies, upper respiratory tract infections, and asthma

The aims of this study were (1) to quantify the prevalence of aeroallergen hypersensitivity in presentations for emergency treatment of asthma and (2) to determine the strength of association between viral upper respiratory tract infections (URTIs) and admission for treatment of asthma. A series of 209 asthmatic patients presenting to the Emergency Department (ED) of the Alfred Hospital over 6 months underwent skin prick testing and venipuncture for serum IgE and rye grass pollen (RGP) RAST. A case-control study of 38 asthmatic inpatients and 90 controls admitted for road trauma or endoscopy underwent nasopharyngeal aspiration for viral culture and immunofluorescence (IF). Eighty-four percent of ED asthmatic patients had one or more positive skin tests to common aeroallergens, 57% had a positive skin test, and 45% had a positive RAST to RGP. Viral cultures or IF studies were positive in 8 asthmatic patients and 2 controls. Asthmatic inpatients were 6 times more likely to have a viral URTI than were controls. It is concluded that aeroallergen hypersensitivity is present in most asthmatic patients presenting to the ED, and that there is a strong association between viral URTIs and admission for asthma.

A placebo-controlled study of three clonidine doses for smoking cessation

BACKGROUND AND OBJECTIVE

Clonidine in doses of 150 to 450 micrograms per day has been reported to reduce symptoms of craving associated with tobacco withdrawal and, in some cases, to improve long-term abstinence rates of smoking cessation programs. However, subjects frequently experienced symptoms of dry mouth and drowsiness. This study investigated the lower end of the effective dose range of clonidine for smoking cessation to identify the lowest useful dose and thus minimize the adverse effects of the drug.

METHODS

A randomized, double-blind, four-way crossover design compared the effects of clonidine doses or placebo within individual subjects for 4 consecutive weeks. Smokers who were highly nicotine dependent were randomly assigned to different sequences of placebo and 300, 200, and 100 micrograms clonidine per day. Subjects were treated for 4 days of each treatment week and began smoking cessation from the end of day 2. Smokers recorded withdrawal symptoms on multiple visual analog scales during days 3 and 4 before resuming normal smoking until the next period of smoking cessation.

RESULTS

A statistically significant dose-response effect was found for craving scores (dose-response gradient, -3.8/100 micrograms; 95% confidence interval [CI], -6.2 to -1.5; p = 0.002) but not for pooled tobacco withdrawal scores. The dose of 300 micrograms per day reduced mean craving scores significantly (-16%; 95% CI, -31% to -1%). Dosing with 200 micrograms approached statistical significance (-14%; 95% CI -30% to 1%) but dosing with 100 micrograms did not (-6%; 95% CI, -22% to 9%). Troublesome adverse experiences were reported by more than 67% of subjects during 200 and 300 micrograms dosing.

CONCLUSIONS

This study showed a statistically significant dose-response effect of clonidine on tobacco withdrawal craving and a reduction in mean craving scores of 16% during 300 micrograms dosing. However, its clinical usefulness is doubtful because of frequently reported adverse experiences.

The prevalence of asthma in Victorian adults

To determine the prevalence of asthma in Victorian adults, we carried out a cross-sectional postal survey utilising a new screening questionnaire which gathered data on self reported respiratory symptoms, whether asthma had been diagnosed and, if so, how it had been treated. Questionnaires were returned by 2198 (72%) of 3095 adults selected randomly from the Victorian electoral roll, an adequate response rate. The reported prevalences of individual asthmatic symptoms in the last 12 months ranged from 8% for nocturnal wheeze to 22% for current wheeze. Thirteen per cent of respondents had ever had asthma, 7% had experienced an attack within the last 12 months and 6% were currently taking medication. The high prevalence of asthma revealed by our study has major implications for the planning of health services.