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Biomedical subjects

P G Burney

Publications and source records attributed to P G Burney.

At least 19 recordsLinked to original sources
PubMed2005

Indoor nitrous acid and respiratory symptoms and lung function in adults.

BACKGROUND: Nitrogen dioxide (NO2) is an important pollutant of indoor and outdoor air, but epidemiological studies show inconsistent health effects. These inconsistencies may be due to failure to account for the health effects of nitrous acid (HONO) which is generated directly from gas combustion and indirectly from NO2. METHODS: Two hundred and seventy six adults provided information on respiratory symptoms and lung function and had home levels of NO2 and HONO measured as well as outdoor levels of NO2. The association of indoor HONO levels with symptoms and lung function was examined. RESULTS: The median indoor HONO level was 3.10 ppb (IQR 2.05-5.09), with higher levels in homes with gas hobs, gas ovens, and in those measured during the winter months. Non-significant increases in respiratory symptoms were observed in those living in homes with higher HONO levels. An increase of 1 ppb in indoor HONO was associated with a decrease in forced expiratory volume in 1 second (FEV1) percentage predicted (-0.96%; 95% CI -0.09 to -1.82) and a decrease in percentage FEV1/forced vital capacity (FVC) (-0.45%; 95% CI -0.06 to -0.83) after adjustment for relevant confounders. Measures of indoor NO2 were correlated with HONO (r = 0.77), but no significant association of indoor NO2 with symptoms or lung function was observed. After adjustment for NO2 measures, the association of HONO with low lung function persisted. CONCLUSION: Indoor HONO levels are associated with decrements in lung function and possibly with more respiratory symptoms. Inconsistencies between studies examining health effects of NO2 and use of gas appliances may be related to failure to account for this association.

Adult↗
PubMed2001

Dietary antioxidants and asthma in adults: population-based case-control study.

A protective role for dietary antioxidants in asthma has been proposed. However, epidemiological evidence to implicate antioxidant vitamins is weak, and data on the role of flavonoid-rich foods and antioxidant trace elements are lacking. We carried out a population-based case-control study in South London, UK, to investigate whether asthma is less common and less severe in adults who consume more dietary antioxidants. Participants were aged 16-50 yr and registered with 40 general practices. Asthma was defined by positive responses to a standard screening questionnaire in 1996, and complete information about usual diet was obtained by food frequency questionnaire from 607 cases and 864 controls in 1997. After controlling for potential confounding factors and total energy intake, apple consumption was negatively associated with asthma (odds ratio [OR] per increase in frequency group 0.89 [95% confidence interval [CI]: 0.82 to 0.97]; p = 0.006). Intake of selenium was also negatively associated with asthma (OR per quintile increase 0.84 [0.75 to 0.94]; p = 0.002). Red wine intake was negatively associated with asthma severity. The associations between apple and red wine consumption and asthma may indicate a protective effect of flavonoids. The findings for dietary selenium could have implications for health policy in Britain where intake has been declining.

Adolescent↗
PubMed2000

Frequent paracetamol use and asthma in adults.

BACKGROUND: The pulmonary antioxidant glutathione may limit airway inflammation in asthma. Since paracetamol (acetaminophen) depletes the lung of glutathione in animals, a study was undertaken to investigate whether frequent use in humans was associated with asthma. METHODS: Information was collected on the use of analgesics as part of a population based case-control study of dietary antioxidants and asthma in adults aged 16-49 years registered with 40 general practices in Greenwich, South London. The frequency of use of paracetamol and aspirin was compared in 664 individuals with asthma and in 910 without asthma. Asthma was defined by positive responses to questions about asthma attacks, asthma medication, or waking at night with shortness of breath. The association between analgesic use and severity of disease amongst asthma cases, as measured by a quality of life score, was also examined. RESULTS: Paracetamol use was positively associated with asthma. After controlling for potential confounding factors the odds ratio for asthma, compared with never users, was 1.06 (95% CI 0.77 to 1.45) in infrequent users (<monthly), 1.22 (0.87 to 1.72) in monthly users, 1. 79 (1.21 to 2.65) in weekly users, and 2.38 (1.22 to 4.64) in daily users (p (trend) = 0.0002). This association was present in users and non-users of aspirin and was stronger when cases with more severe disease were compared with controls; amongst cases increasing paracetamol use was associated with more severe disease. Frequency of aspirin use was not associated with asthma when cases as a whole were compared with controls, nor with severity of asthma amongst cases. Frequent paracetamol use was positively associated with rhinitis, but aspirin use was not. CONCLUSIONS: Frequent use of paracetamol may contribute to asthma morbidity and rhinitis in adults.

Acetaminophen↗
PubMed2000

Paracetamol sales and atopic disease in children and adults: an ecological analysis.

The authors recently observed that frequent paracetamol use was positively associated with asthma and rhinitis in young adults. Therefore, an ecological analysis was performed to measure international associations between paracetamol sales and atopic disease prevalences in children and adults. Published data from the International Study of Asthma and Allergies in Childhood (ISAAC) on the prevalence of four atopic symptoms in 13-14-yr-olds (112 centres) and 67-yr-olds (66 centres) in 1994/1995, and European Community Respiratory Health Survey (ECRHS) data on the prevalence of asthma symptoms, diagnosed asthma and rhinitis (44 centres), prevalence of atopy, mean bronchial responsiveness and mean total immunoglobulin E levels (34 centres) in young adults in 1991/1992, were used. Their associations with national 1994/1995 per capita paracetamol sales were measured using linear regression. Paracetamol sales were high in English-speaking countries, and were positively associated with asthma symptoms, eczema and allergic rhinoconjunctivitis in 13-14-yr-olds, and with wheeze, diagnosed asthma, rhinitis and bronchial responsiveness in adults. The prevalence of wheeze increased by 0.52% in 13-14-yr-olds and by 0.26% in adults (p<0.0005) for each gram increase in per capita paracetamol sales. These ecological findings require cautious interpretation, but raise the possibility that variation in paracetamol usage may explain some of the variation in atopic disease prevalence between countries.

Acetaminophen↗
PubMed1999

Clustered randomised trial of an intervention to improve the management of asthma: Greenwich asthma study.

OBJECTIVES: To evaluate the effectiveness of an asthma resource centre in improving treatment and quality of life for asthmatic patients. DESIGN: Community based randomised controlled trial. SETTING: 41 general practices in Greenwich with a practice nurse. SUBJECTS: All registered patients aged 15-50 years. INTERVENTION: Nurse specialists in asthma who educated and supported practice nurses, who in turn educated patients in the management of asthma according to the British Thoracic Society's guidelines. MAIN OUTCOME MEASURES: Quality of life of asthmatic patients, attendance at accident and emergency departments, admissions to local hospitals, and steroid prescribing by general practitioners. RESULTS: Of 24 400 patients randomly selected and surveyed in 1993, 12 238 replied; 1621 were asthmatic of whom 1291 were sent a repeat questionnaire in 1996 and 780 replied. Of 24 400 patients newly surveyed in 1996, 10 783 (1616 asthmatic) replied. No evidence was found for an improvement in asthma related quality of life among newly surveyed patients in intervention practices compared with control practices. Neither was there evidence of an improvement in other measures of the quality of asthma care. Weak evidence was found for an improvement in quality of life in intervention practices among asthmatics registered with study practices in 1993 and followed up in 1996. Neither attendances at accident and emergency departments nor admissions for asthma showed any tendency to diverge in intervention and control practices over the study period. Steroid prescribing rates rose steadily during the study period. The average annual increase in steroid prescribing was 3% per year higher in intervention than control practices (95% confidence interval -1% to 6%, P=0.10). CONCLUSIONS: This model of service delivery is not effective in improving the outcome of asthma in the community. Further development is required if cost effective management of asthma is to be introduced.

Adolescent↗
PubMed1999

Risk factors for death from asthma, chronic obstructive pulmonary disease, and cardiovascular disease after a hospital admission for asthma.

BACKGROUND: Patients with asthma have an increased risk of death from causes other than asthma. A study was undertaken to identify whether severity of asthma, its treatment, or associated co-morbidity were associated with increased risk of death from other causes. METHODS: Eighty five deaths from all causes occurring within three years of discharge from hospital in a cohort of 2242 subjects aged 16-64 years admitted for asthma were compared with a random sample of 61 controls aged <45 years and 61 aged >/=45 years from the same cohort. RESULTS: Deaths from asthma were associated with a history of clinically severe asthma (OR 6.29 (95% CI 1.84 to 21.52)), chest pain (OR 3.78 (95% CI 1.06 to 13.5)), biochemical or haematological abnormalities at admission (OR 4.12 (95% CI 1.36 to 12.49)), prescription of ipratropium bromide (OR 4.04 (95% CI 1.47 to 11.13)), and failure to prescribe inhaled steroids on discharge (OR 3.45 (95% CI 1.35 to 9.10)). Deaths from chronic obstructive pulmonary disease (COPD) were associated with lower peak expiratory flow rates (OR 2.56 (95% CI 1.52 to 4.35) for each 50 l/min change), a history of smoking (OR 5.03 (95% CI 1.17 to 21.58)), prescription of ipratropium bromide (OR 7.75 (95% CI 2.21 to 27.14)), and failure to prescribe inhaled steroids on discharge (OR 3.33 (95% CI 0.95 to 11.10)). Cardiovascular deaths were more common among those prescribed ipratropium bromide on discharge (OR 3.55 (95% CI 1.05 to 11.94)) and less likely in those admitted after an upper respiratory tract infection (OR 0.21 (95% CI 0.05 to 0.95)). Treatment with ipratropium bromide at discharge was associated with an increased risk of death from asthma even after adjusting for peak flow, COPD and cardiovascular co-morbidity, ever having smoked, and age at onset of asthma. CONCLUSIONS: Prescription of inhaled steroids on discharge is important even for those patients with co-existent COPD and asthma. Treatment with ipratropium at discharge is associated with increased risk of death from asthma even after adjustment for a range of markers of COPD. These results need to be tested in larger studies.

Adolescent↗
PubMed1998

Serum eosinophil cationic protein: distribution and reproducibility in a randomly selected sample of men living in rural Norfolk, UK.

BACKGROUND: It has been proposed that serum levels of eosinophil cationic protein (ECP) may be a clinically useful measure in allergic illness. The aim of this report is to describe the distribution and reproducibility of serum ECP levels in a population sample and to examine its relationship with other markers of disease. METHODS: The study was conducted in rural areas of Norfolk, UK in a random sample of men aged 20-44 years enriched with subjects drawn from general practice 'asthma registers'. Asthma symptoms were assessed using the EC Respiratory Health Survey questionnaire. Atopy was measured by skin prick tests and serum IgE. Airway hyperresponsiveness (AHR) was tested by methacholine challenge test. Serum IgE and ECP was measured by fluoroimmunoassay using the Pharmacia CAP system. Reference equations were derived in subjects from the random sample who did not have symptoms of asthma, abnormal lung function or AHR. The relation of serum ECP with various clinical characteristics was examined in the whole study population. Reproducibility of serum ECP measurement was assessed in 57 subjects 4 weeks after the initial test. RESULTS: The study population comprised 311 from the random sample and 58 from the asthma sample. The reference equation for serum ECP for healthy men was log10 ECP = 1.3966 - [(age - 20) x 0.0057]. The estimated mean serum ECP for a 20-year-old man was 25 microg/L. Current smokers have higher serum ECP levels that non-smokers (P = 0.014). ECP levels were not related to the skin prick test reactivity, serum IgE, a questionnaire-based diagnosis of asthma, or impaired lung function (all P > 0.05). Levels were higher in subjects with AHR (P = 0.003) and those who reported wheeze (P = 0.017) but there was no clinically useful separation in ECP levels between subjects classified by these criteria. The test was moderately reproducible over a 4-week period (intraclass correlation coefficient = 0.62). DISCUSSION: Serum ECP levels were higher in this rural English population than reported in a comparable population in Sweden. Serum ECP is a reproducible test but cross-sectionally does not relate in any clinically useful way to markers of asthma. The meaning of between- subject differences in ECP levels requires further exploration.

Adult↗
PubMed1997

A reliable method to retrieve accident & emergency data stored on a free-text basis.

Accident & Emergency (A & E) data on asthma-related attendances are useful for studies on the effectiveness of asthma interventions, and to determine the relationship of environmental factors to asthma and asthma epidemics. The final diagnoses made in the A & E departments are not usually coded when entered into hospital databases in the U.K., although the "presenting complaint' can be retrieved from the computerized Hospital Information & Support Systems (HISS), from a free-text attendance diagnosis field entered by the reception clerk when the patient arrives at the A & E department. The validity of this as an indication of the final diagnosis is unevaluated. The aim of this study was to measure the validity of the string "asth' in the A & E attendance diagnosis field for identifying patients attending the A & E departments of two hospitals for asthma-related conditions. A list of patients who attended the A & E department of two hospitals was retrieved from the HISS along with the attendance diagnosis field. If the attendance diagnosis field contained the text string "asth', mentioned wheeze or breathing problems, or the patients were referred by their GP without any diagnostic information entered on HISS, the records were selected for evaluation. The remaining attendances, which were not evaluated further, were attributed to another diagnosis based on the evidence of the recorded attendance diagnosis. The results indicated that the string "asth' in the attendance diagnosis field had a sensitivity of 80.3% (95% CI 75.1-85.5%) and a specificity of 96.7% (95% CI 95.6-97.8%) for a final diagnosis of asthma. It is concluded that free-text attendance diagnosis fields in hospital databases can be searched with suitable strings to obtain reliable data on attendance with asthma. As part of another investigation, the present authors attempted to retrieve a list of the attendances with asthma at the same two A & E departments at a time that was reportedly associated with an epidemic of asthma following a thunderstorm. On this occasion, the string "asth' proved to be significantly less sensitive. The possible reasons for this and the implications for using this method for identifying cases are discussed.

Asthma↗
PubMed1997

Variation in nebulizer aerosol output and weight output from the Mefar dosimeter: implications for multicentre studies.

The active aerosol component of nebulizers is less than 100% of output by weight, and may vary between nebulizers in different batches from the same manufacturer. A measure of bronchial responsiveness to methacholine, which can overcome this problem, is required. One hundred and sixty nebulizers from 21 centres in the European Community Respiratory Health Survey (ECRHS) were calibrated for aerosol and weight output. Methacholine challenge data were obtained for 1,021 subjects in three English centres of the ECRHS. The dose producing a 20% fall in forced expiratory volume in one second (PD20), and log-slope, the regression slope of percentage decline in FEV1 with log (dose), were calculated, with and without calibration of nebulizers by weight. Within-centre variation in nebulizer percentage aerosol output had a coefficient of variation of less than 10%. Unlike PD20, log-slope is unaffected by constant percentage overestimation of nebulizer output. Variation in output by weight of nebulizers of 10% had little affect on log-slope. It is, however, affected by the scheduled range of doses. Log-slope shows advantages in analysis, and is less affected by variation in nebulizer output. It can be used for multicentre comparisons, with restriction to a common dose protocol.

Aerosols↗
PubMed1997

Asthma in Greenwich, UK: impact of the disease and current management practices.

A great deal of the care of patients with asthma takes place in general practices. The aim of the present study was to describe the impact of asthma in the community and to identify current asthma self-management practices. A two-part questionnaire survey was conducted in a random sample (23%; n=24,398) of persons aged 16-50 yrs, registered with one of the 41 general practices in Greenwich, London, UK. The two parts were: a screening questionnaire identifying persons with current asthma (defined as waking with shortness of breath in the last 12 months, attack of asthma in the last 12 months, or currently taking treatment for asthma); and an asthma questionnaire (completed by those with asthma) assessing quality of life, frequency of asthma symptoms, possession and use of self-management tools, and action in the event of an exacerbation of asthma. The crude response rate was 51%, but this may be an underestimate due to errors in the sampling frame. The prevalences of wheeze and asthma in the past 12 months were 26% and 14%, respectively. Among asthma patients: 43% reported symptoms occurring three or more times per week, and 20% were woken by asthma symptoms on three or more nights per week; most had asthma with a mild impact on quality of life; 26% used inhaled steroids on most days in the preceding month; 16% had a peak flow meter at home; and 7% had oral steroids available. Of the 44% of subjects with asthma, who could identify an exacerbation of asthma in the preceding 6 months: 19% had used a peak flow meter during the episode; 19% had changed their treatment without first being told to do so by a doctor; and 50% had sought urgent medical help. Smokers used less appropriate asthma management and subjects whose asthma had a severe impact on quality of life used more treatment and peak flow monitoring. In conclusion, the prevalence of asthma among adults in Greenwich, UK, has increased since a similar survey in 1986. Many people have fairly mild asthma and a smaller number have severe disease. Much remains to be done to promote appropriate strategies for self-management of asthma exacerbations.

Adolescent↗
PubMed1996

Measuring atopy in a multi-centre epidemiological study.

Skin prick tests are used as a measure of atopy in epidemiological studies, but results may be influenced by the fieldworker performing the test. In a multi-centre epidemiological study the method of reporting the results should consider the need for comparability of findings from different centres. Data on over 1000 subjects from three English centres of the European Community Respiratory Health Survey were analysed to determine whether allergen wheal should be adjusted for histamine wheal, and what cutoff diameter gave the most comparable results. No consistent relation between allergen wheal diameter and histamine wheal diameter was found for any fieldworker or allergen. A cutoff of > 0 mm for a positive result gave a more consistent relation with the corresponding specific IgE value between fieldworkers than either a cutoff of > or = 3 mm or the use of the mean wheal diameter. While this result is not immediately generalisable to studies using different skin prick test reagents, the method of analysis to determine the appropriate criterion of reporting can be used in other epidemiological studies.

Adult↗
PubMed1996

Accuracy of recording of deaths from asthma in the UK: the false negative rate.

BACKGROUND: A study was carried out to determine the extent to which asthma deaths are wrongly attributed to another cause on UK death certificates. METHODS: Deaths from all causes occurring anywhere in the UK were identified amongst 2382 subjects aged 16-64 years within three years of discharge following hospital treatment for asthma (ICD9 493) in hospitals in the South East Thames region. The deaths were reviewed by an expert panel to assess the proportion of asthma deaths identified by the panel which were attributed to another cause of death on the death certificate (false negatives). RESULTS: Eighty five deaths from all causes were identified in a mean follow up period of two years and three months. In 61 cases (72%) there was sufficient information for the expert panel to be confident about the cause of death. The panel identified 22 deaths from asthma, four of which were certified as non-asthma deaths (two as deaths from chronic obstructive pulmonary disease (COPD) and two as deaths from cardiovascular disease). The proportion of false negative death certificates was four of 22 (18%, 95% confidence interval (CI) 5 to 40). CONCLUSIONS: There is evidence that asthma deaths in the UK are wrongly certified as deaths from both chronic obstructive pulmonary disease and diseases of the cardiovascular system.

Adolescent↗
PubMed1996

Validation of the U.K. diagnostic criteria for atopic dermatitis in a population setting. U.K. Diagnostic Criteria for Atopic Dermatitis Working Party.

One reason why so little is known about the epidemiology of atopic dermatitis (AD) is lack of suitable diagnostic criteria. A simple list of diagnostic criteria for AD for use in epidemiological studies has recently been developed by a U.K. working party. These have performed well in hospital validation studies of subjects with skin diseases. This study sought to validate the newly proposed criteria for AD in a population setting by conducting a cross-sectional survey of 695 schoolchildren aged 3-11 years in three randomly selected primary schools in West Lambeth, London. As a point prevalence measure, the U.K. criteria had a sensitivity of 70%, a specificity of 93%, and a positive predictive value of 47% when compared with a dermatologist's examination findings. Subsequent analysis suggested that most children classified as false positives had suffered from AD in the last year, but were inactive at the time of examination. When adjusted for these cases, the sensitivity and specificity increased to 80 and 97%, respectively, corresponding to positive and negative predictive values of 80 and 97%, respectively. The U.K. diagnostic criteria for AD appear to work well as a 1-year period prevalence measure in London schoolchildren. Further validation in adults and other countries are needed.

Child↗
PubMed1995

London-born black Caribbean children are at increased risk of atopic dermatitis.

BACKGROUND: Previous reports suggest that atopic dermatitis is more common in black Caribbean children born in the United Kingdom than in white children. It is unclear whether these differences are caused by selection bias or variations in the use of the word "eczema" in the groups studied. OBJECTIVE: Our objective was to explore ethnic group differences in the prevalence of atopic dermatitis in London schoolchildren. METHODS: A cross-sectional prevalence survey of 693 junior school children in three schools was performed. Atopic dermatitis was defined in three ways: (1) by a dermatologist, (2) by visible flexural dermatitis as recorded by an independent observer, and (3) by a history of flexural dermatitis according to the child's parents. RESULTS: The prevalence of atopic dermatitis according to examination by a dermatologist was 16.3% in black Caribbean children and 8.7% in white children. This increased risk was present for different methods of defining of a atopic dermatitis and persisted after adjustment for potential confounders. CONCLUSION: London-born black Caribbean children appear to be at an increased risk of having atopic dermatitis.

Black or African American↗
PubMed1995

Adjustment of reported prevalence of respiratory symptoms for non-response in a multi-centre health survey.

BACKGROUND: Estimation of non-response bias by modelling prevalence as a function of the number of mailings required to achieve a response, or of the cumulative response, has been advocated, but the models have not incorporated age and sex, differential response rates by age and sex, or season of response. METHODS: The effect on age-sex standardized prevalence of estimating non-response bias using a variety of models was investigated using data on nine symptom and medication questions from 13,007 subjects in the three English centres of the European Community Respiratory Health Survey. Comparison was made of goodness of fit and the prediction of responses in a 25% follow-up sample with the observed values. RESULTS: Despite low response rates in Cambridge and significant decreases in prevalence with additional mailings or increasing cumulative response in Norwich, there were only small effects on estimated age-sex standardized prevalences. No model was consistently better for any centre or question. CONCLUSIONS: The models are useful for exploring the sensitivity of estimated prevalence to non-response bias, but should be used with caution to adjust estimates. Ideally first mailings should be staggered over the whole year so that mailing and season are not confounded, and sufficient mailings or other contacts carried out for the whole sample to ensure a high response rate.

Adult↗