Roger Buchdahl, Alison Parker, Tabitha Stebbings, Abdel Babiker
Abstract
Objective - To examine the association between the air pollutants ozone, sulphur dioxide, and nitrogen dioxide and the incidence of acute childhood wheezy episodes.
Design - Prospective observational study over one year.
Setting - District general hospital.
Subject - 1,025 children attending the accident and emergency department with acute wheezy episodes; 4285 children with other conditions as the control group.
Main outcome measures - Daily incidence of acute wheezy episodes.
Results - After seasonal adjustment, day to day variations in daily average concentrations of ozone and sulphur dioxide were found to have significant associations with the incidence of acute wheezy episodes. The strongest association was with ozone, for which a non-linear U shaped relation was seen. In terms of the incidence rate ratio (1 at a mean 24 hour ozone concentration of 40 mu g/m(to power 3) (SD equals 19.1)), children were more likely to attend when the concentration was two standard deviations below the mean (incidence rate ratio equals 3.01; 95% confidence interval 2.17 to 4.18) or two standard deviations above the mean (1.34; l.09 to 1.66). Sulphur dioxide had a weaker log - linear relation with incidence (1.12; l.05 to 1.19 for each standard deviation (14.1) increase in sulphur dioxide concentration). Further adjustment for temperature and wind speed did not significantly alter these associations.
Conclusions - Independent of season, temperature, and wind speed, fluctuations in concentrations of atmospheric ozone and sulphur dioxide are strongly associated with patterns of attendance at accident and emergency departments for acute childhood wheezy episodes. A critical ozone concentration seems to exist in the atmosphere above or below which children are more likely to develop symptoms.
Hillingdon Hospital Middlesex UB8 3NN Roger Buchdahl consultant paediatrician Alison Parker paediatric respiratory nurse
Environmental Protection Unit London Borough of Hillingdon Uxbridge Middlesex UB8 1UN Tabitha Stebbings senior environmental health officer
MRC HIV Clinical Trials Centre University College of London Medical School London WC1E 6AU Abdel Babiker senior lecturer in epidemiology
Correspondence to: Dr Buchdahl. rbuc@easynet.co.uk
Air pollution and daily mortality in London: 1987 - 92
H Ross Anderson, Antonio Ponce de Leon, I Martin Bland, Jonathan S Bower, David P Strachan
Abstract
Objective - To investigate whether outdoor air pollution levels in London influence daily mortality.
Design - Poisson regression analysis of daily counts of deaths, with adjustment for effects of secular trend, seasonal and other cyclical factors, day of the week, holidays, influenza epidemic, temperature, humidity, and autocorrelation, from April 1987 to March 1992. Pollution variables were particles (black smoke), sulphur dioxide, ozone, and nitrogen dioxide, lagged 0-3 days.
Setting - Greater London.
Outcome measures - Relative risk of death from all causes (excluding accidents), respiratory disease, and cardiovascular disease.
Results - Ozone levels (same day) were associated with a significant increase in all cause, cardiovascular, and respiratory mortality; the effects were greater in the warm season (April to September) and were independent of the effects of other pollutants. In the warm season an increase of the eight hour ozone concentration from the 10th to the 90th centile of the seasonal range (7-36 ppb) was associated with an increase of 3.5% (95% confidence interval 1.7 to 5.3), 3.6% (1.04 to 6.1), and 5.4% (0.4 to 10.7) in all cause, cardiovascular, and respiratory mortality respectively. Black smoke concentrations on the previous day were significantly associated with all cause mortality, and this effect was also greater in the warm season and was independent of the effects of other pollutants. For black smoke an increase from the 10th to 90th centile in the warm season (7-19 mu g/m[power3]) was associated with an increase of 2.5% (0.9 to 4.1) in all cause mortality. Significant but smaller and less consistent effects were also observed for nitrogen dioxide and sulphur dioxide.
Conclusion - Daily variations in air pollution within the range currently occurring in London may have an adverse effect on daily mortality.
Department of Public Health Sciences St George's Hospital Medical School London SW17 0RE H Rosa Anderson professor of epidemiology and public health Antonio Ponce de Leon research fellow J Martin Bland professor of medical statistics David P Strachan reader in epidemiology
AEA Technology National Environmental Technology Centre Culham Abingdon Oxfordshire Jonathan S Bower section leader, air pollution monitoring
Correspondence to: Professor Anderson.
Health care rationing: the public's debate
Ann Bowling
Abstract
Objective - To elicit the views of a large nationally representative sample of adults on priorities for health services.
Design - An interview survey based on a random sample of people aged 16 and over in Great Britain taken by the Office of Population Censuses and Surveys.
Subjects - The response rate to the survey was 75%, and the total number of adults interviewed was 2,005.
Main outcome measures - A priority ranking exercise of health services supplemented with attitude questions about priorities, who should set priorities, and budget allocation.
Results - The results of the main priority ranking exercise of 12 health services showed that the highest priority (rank 1) was accorded to "treatments for children with life threatening illness," the next highest priority (rank 2) was accorded to "special care and pain relief for people who are dying." The lowest priorities (11 and 12) were given to "treatment for infertility" and "treatment for people aged 75 and over with life threatening illness." Most respondents thought that surveys like this one should be used in the planning of health services.
Conclusions - The public prioritise treatments specifically for younger rather than older people. There is some public support for people with self inflicted conditions (for example, through tobacco smoking) receiving lower priority for care, which raises ethical issues.
Centre for Health Informatics and Multiprofessional Education (CHIME) University College London Medical School Whittington Hospital London N19 5NF Ann Bowling reader in health services research
Control of hydatid disease in Wales
S R Palmer, A H Biffin, P S Craig, TM Walters
Abstract
Objectives - To evaluate the success of the south Powys hydatid control programme by analysis of trends in cystic disease in humans and sheep and dog infestation.
Design - A review of hospital admissions for human hydatid disease in 1984 - 90, abattoir prevalence surveys of hydatid cysts in adult sheep, arecoline acetarsol and coproantigen surveys of prevalence of Echinococcus infestation in dogs.
Setting - All hospitals in England and Wales, three abattoirs, and dog populations in mid and south east Wales.
Subjects - Residents of England and Wales admitted to hospital between 1984 and 1990 with a new diagnosis of human hydatid disease (International Classification of Diseases (ICD), ninth revision, code 122) acquired in the United Kingdom.
Results - The average annual incidence of human hydatid disease in Powys, mid-Wales, fell from 3.9x10 [to the -5] in 1974-83 to 2.3x10 [to the -5] in 1984-90. Age specific incidence rates in Wales declined over this period only in children, and no cases occurred in children (under 15 years) in Powys. Two Welsh children who lived in Gwent and mid - Glamorgan were infected. Prevalence of hydatid cysts in old sheep from south Wales declined during the control period, but in 1993 prevalence of cysts was 13%. Prevalence of E granulosus infestation was zero in the control area in 1993, but it was 2.4% in Powys dogs outside the control area in 1989 and 9.2% in dogs in Gwent in 1991.
Conclusions - Human hydatid disease has been successfully controlled in south Powys but cystic echinococcosis is still endemic in sheep in mid-Wales, and there is a focus of infection in humans, sheep, and dogs in the bordering areas of Gwent and mid-Glamorgan. There is considerable potential for an upsurge in human cases if control measures are relaxed.
Public Health Laboratory Service Communicable Disease Surveillance Centre (Welsh Unit) Abton House Roath Cardiff CF4 3QX S R Palmer regional epidemiologist A H Biffin principal scientist
Department of Biological Sciences University of Salford Salford M5 4WT PS Craig professor
Powys Health Promotion Health Promotion Unit Mansion House Bronllys Brecon Powys LD3 0LS T M Walters hydatid disease campaign coordinator
Correspondence to: Professor Palmer.
I P O'Hare, A Hopper, C Madhaven, M Charny, T S Purewal, B Harney, I Griffiths
Abstract
Objective - To evaluate whether adding retinal photography improved community screening for diabetic retinopathy.
Setting - Mobile screening unit at rural and urban general practices in south west England.
Subjects - 1,010 diabetic patients from primary care.
Design - Prospective study; patients were examined by ophthalmoscopy by general practitioners or opticians without fundal photographs and again with photographs, and assessments were compared to those of an ophthalmologist.
Main outcome measures - Whether fundal photography improved the sensitivity of detection of retinopathy and referrable diabetic retinopathy, and whether this sensitivity could be improved by including a review of the films by the specialist.
Results - Diabetic retinopathy was detected by the ophthalmologist in 205 patients (20.5%) and referrable retinopathy in 49 (4.9%). The sensitivity of the general practitioners and opticians for referrable retinopathy with opthalmoscopy was 65% and improved to 84% with retinal photographs. General practitioners' sensitivity in detecting background retinopathy improved with photographs from 22% to 65%; opticians' sensitivity in detecting background retinopathy improved from 43% to 71%. The sensitivity of detecting referrable retinopathy by general practitioners improved from 56% to 80% with photographs; for opticians it improved from 75% to 88%.
Conclusion - Combining modalities of screening by providing photography with specialist review of all films in addition to direct ophthalmoscopy through dilated pupils improves assessment and referral for diabetic retinopathy by general practitioners and opticians. With further training and experience, primary care screeners should be able to achieve a sensitivity that will achieve an effective, acceptable, and economical community based screening programme for this condition.
Department of Medicine Royal United Hospital Combe Park Bath BA1 3NG J P O'Hare consultant physician A Hopper senior medical photographer T S Purewal senior registrar
Department of Ophthalmology Royal United Hospital C Madhaven staff grade ophthalmologist B Harney consultant ophthalmologist J Griffiths consultant ophthalmologist
Wiltshire and Bath Health Commission Devizes Wiltshire SN1O 5EQ M Charny director of public health
Correspondence to: Dr O'Hare.