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Biomedical subjects

E A Mitchell

Publications and source records attributed to E A Mitchell.

At least 163 records · Page 9Linked to original sources

Evaluation and outcome of the vision screening programme in south Auckland intermediate schools.

Four thousand, seven hundred and fifty-nine form 1 intermediate school children (aged 11 years) in the south Auckland health district were screened in 1987. There were 88 (1.8%) new visual defects detected (defined as a visual acuity (VA) of 6/12 or worse in one or both eyes), while 103 (2.2%) wore glasses and a further 22 (0.5%) did not have their glasses available at the time of the VA test. The total prevalence of screening visual defects was 4.5%. A survey was carried out of those pupils who failed the VA screening test in the previous year and those recorded as wearing glasses. Sixty-seven (76%) of 88 children with newly detected visual defects were interviewed. An abnormal VA test was confirmed in 59 (88%), of which 39 (66%) required treatment. Thirty were prescribed glasses, of which 27 purchased them, but at the time of interview nine did not have them available. Twenty-one (20%) of the 103 children tested with glasses failed the VA test. Twenty-two children had glasses but were not wearing them at the time of the VA test. Only three of these children had a VA better than 6/12 bilaterally. These results highlight the importance of the vision screening programme in this age group and the follow up of children with known visual defects.

Child↗

International trends in postneonatal mortality.

Trends in mortality in the age groups 1-5 and 6-11 months from 1966 to 1987 for Australia, Canada, England and Wales, New Zealand, and Sweden were examined. Mortality rates for ages 1-5 months differed appreciably between countries, with Sweden lower than all other countries examined. Rates have decreased in Australia, Canada, and England and Wales, but increased in New Zealand and Sweden. Mortality reported as due to the sudden death syndrome (SIDS) increased dramatically in all countries, although much of the increase was probably due to diagnostic transfer from respiratory diseases. Over 80% of SIDS deaths occurred in the age group 1-5 months and SIDS accounted for about half of all deaths in this age group. For developed countries total mortality in those aged 1-5 months was an indirect measure of SIDS mortality. A real increase in SIDS has thus occurred in Sweden and New Zealand and possibly in other countries as well. Mortality in the age group 6-11 months has approximately halved in all countries examined over the study period.

Australia↗

Why are hospital admission and mortality rates for childhood asthma higher in New Zealand than in the United Kingdom?

New Zealand has higher mortality and hospital admission rates for asthma than England and Wales. To determine the reasons for this the available data on asthma mortality and hospital admissions from the Auckland region of New Zealand were compared with data from the South West Thames Region of England for 1979-86 and data from previous surveys on prevalence of wheeze (Auckland 1985, Croydon 1978). In addition, a survey of general practitioners was carried out to determine their approach to the management of asthma, patient simulations being used. Asthma mortality in children of European descent aged 5-14 years was 2.5 times higher in Auckland than in South West Thames. The reported lifetime, 12 month, and one month prevalences of wheeze were also higher in Auckland (by 18.5%, 32.1%, and 87.5%). Unexpectedly, the hospital admission rate for asthma in children of European descent aged 5-14 years was 5% less in Auckland than in South West Thames. Comparative studies of hospital case notes and of the replies from general practitioners showed that in Auckland the duration of illness before admission was greater and that general practitioners were less likely to admit patients with acute asthma. The overall standard of general practitioner care in Auckland was, if anything, higher than in South West Thames but in both areas there was considerable variation. On balance it was concluded that the higher mortality rate in New Zealand is explained by higher levels of morbidity rather than relative deficiencies in care. Nevertheless, the implications of the lesser use of hospital care for acute asthma observed in Auckland need further consideration.

Acute Disease↗

The interrelationship among bronchial hyperresponsiveness, the diagnosis of asthma, and asthma symptoms.

Bronchial hyperresponsiveness (BHR) to inhaled histamine has often been cited as the gold standard in asthma diagnosis, but recently this has been questioned. This report assesses the relationship of BHR to asthma symptoms and asthma diagnosis in a large community-based sample of children. A total of 2,053 children 7 to 10 yr of age were randomly sampled from Auckland primary schools and assessed by a questionnaire and histamine inhalation challenge. In all, 14.3% had had asthma diagnosed, 29.6% reported having had one of the four respiratory symptoms in in the previous 12 months, and 15.9% had BHR (PD20 less than or equal to 7.8 mumol histamine). After a cumulative dose of 3.9 mumol histamine, the percent change in FEV1 from postsaline FEV1 was unimodally distributed, with those in whom asthma had been diagnosed dominating the severe end of the spectrum. However, 53% of those with BHR had no asthma diagnosis, and 41% had no current asthma symptoms. On the other hand, 48% of all subjects with diagnosed asthma and 42% of children with diagnosed asthma and current symptoms did not have BHR. Although severity of BHR tended to increase with wheezing frequency, all grades of severity (including no BHR) were found for any given frequency of wheeze. An existing diagnosis of asthma identified symptomatic children more accurately than did BHR, regardless of the criteria used for BHR or for "symptomatic" and irrespective of ethnic group. In conclusion, BHR is related to, but not identical to, clinical asthma. Bronchial challenge testing is an important tool of respiratory research, but cannot reliably or precisely separate asthmatics from nonasthmatics in the general community.

Asthma↗

Maori and nonMaori postneonatal mortality rates by domicile.

The urbanisation of Maori with the possible loss of family and cultural ties may in part account for the higher Maori postneonatal mortality rate compared with nonMaori. To examine this hypothesis rural and urban postneonatal mortality rates by region and ethnic group were compared. In the North Island regions there was no significant difference between the urban and rural rates of either ethnic group. In the South Island the rate for Maori in the rural areas (7.51/1000 live births) was lower (RR = 0.45, 95%CI = 0.17-1.17) than in the urban areas (16.83/1000).

Humans↗

Asthma costs.

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Asthma↗

Socioeconomic status in childhood asthma.

This study examines the relationship between socioeconomic status (SES) and asthma prevalence and the use of asthma medication. One thousand and fifty European children aged eight and nine years were studied by parent completed questionnaire and histamine inhalation challenge. After controlling for sex of the child and for smokers in the house there were significantly higher lifetime (P = 0.029) and current (P = 0.046) prevalence rates of wheeze in children in low SES groups. There was no relationship between SES and asthma diagnosis, bronchial hyperresponsiveness (BHR: PD20 less than 7.8 mumol), or any combination of BHR with symptoms or diagnosis. The use of bronchodilators and asthma prophylactic drugs was less frequent in the low SES groups of children with wheeze in the last 12 months both with concurrent BHR or irrespective of BHR than in those in high SES groups.

Asthma↗

Ethnic differences in prevalence of asthma symptoms and bronchial hyperresponsiveness in New Zealand schoolchildren.

Maoris and Pacific Islanders in New Zealand have a higher asthma mortality and hospital admission rates than Europeans. To determine whether difference in asthma prevalence is the major factor underlying these differences in mortality, 2053 Auckland children aged 7-10 years (European 1084, Maori 509, Pacific Islander 460) were randomly sampled from school classes in the Auckland Urban Area, and studied by questionnaire (completed by parents) and histamine inhalation challenge to assess the provocative dose of histamine causing a 20% fall in FEV1 (PD20). Maoris had the highest prevalence rates of respiratory symptoms, and Europeans had rates similar to Pacific Islanders. For "any current wheeze" for example, the prevalence in Maoris was 22.2% compared with 16.1% and 16.3% in the Europeans and Pacific Islanders. The prevalence of diagnosed asthma was similar in the three groups. When bronchial hyperresponsiveness (defined as a PD20 less than or equal to 7.8 mumol histamine) was considered, Europeans had the highest rates (20%), followed by Maoris (13%), and then Pacific Islanders (8.7%). These differences were not accounted for by differences in socioeconomic status, rates of smoking in the home, age, gender, or height. It is concluded that differences in asthma prevalence do not satisfactorily explain the mortality and admission rate differences, although the higher symptom prevalence in the Maoris could be relevant to the higher mortality rate. Maori and Pacific Island children with symptoms of asthma were less likely to be taking prophylactic medication than European children. It is proposed that differences in management are important factors relevant to the increased mortality and morbidity from asthma in Polynesians.

Asthma↗

Recent trends in asthma mortality, morbidity, and management in New Zealand.

Trends in mortality and hospital admission rates, prevalence, and drug sales, relating to asthma in New Zealand since 1960 were examined. Two epidemics of asthma death among people in the age range of 15-64 years occurred during this period with peak mortality rates more than four times pre-epidemic rates. Death from asthma was nevertheless rare compared with hospital admissions which have increased 20-fold in children and three- to fivefold in adults between 1960 and 1985. Asthma drug sales have also risen dramatically, particularly in the late 1970s when it is likely that a major change in the drug management of asthma occurred. Changes in asthma prevalence and severity may account in part for the increasing hospital admissions rates. However, the lack of any clear relationship between hospital admissions and death rates and the abrupt time course of the mortality epidemics suggest that changes in the management rather than in the disease itself may be responsible for the increased number of asthma deaths.

Adolescent↗

Why are hospital admissions of children with acute asthma increasing?

The hospital admission rate for asthma has increased in many countries. Particularly prominent has been the increase for children, especially male children under five yrs. The increased admission rate refers to increased number of individuals and to increased frequency per individual. The moderate increase in asthma prevalence does not account for the large increase in admissions. Various other factors are discussed here, such as changes in admission criteria, medical management, and/or clinical expression of the disease.

Asthma↗

Dry bed training.

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Behavior Therapy↗

Why are Polynesian children admitted to hospital for asthma more frequently than European children?

Polynesian children have higher hospital admission rates than European children. This study compared 156 Polynesian children with 199 European children admitted to hospital for asthma. After controlling for socioeconomic status Polynesian children were similar to European children for many variables, but there were a number of important differences. The number of previous hospital admissions for asthma was higher in Polynesians than Europeans (mean (SD), 3.9 (4.6) v 2.8 (3.8) respectively p = 0.028). Despite this, 33% of Polynesian children were not receiving any asthma drugs in the 24 hours prior to admission to hospital compared with 14% of Europeans (relative risk (RR) = 1.94, 95% confidence interval (CI) = 1.25-3.00) and fewer were taking sympathomimetics and cromoglycate. A similar trend in asthma drug usage was seen six months later. Polynesian children were less likely to be referred to hospital by a general practitioner than European children (42% v 64% respectively, RR = 0.72 95% CI = 0.58-0.89). The differences in hospital admission rates are not explained by genetic or socioeconomic factors but seem to be related more to patterns of medical management.

Adolescent↗