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Biomedical subjects

S Leeder

Publications and source records attributed to S Leeder.

At least 19 recordsLinked to original sources
PubMed2000

Acute effects of bushfires on peak expiratory flow rates in children with wheeze: a time series analysis.

OBJECTIVES: To determine the effects of the January 1994 Sydney bushfire on evening peak expiratory flow rates (PEFR) in children with wheeze. METHODS: Children with a history of wheeze were enrolled in the longitudinal study and completed a daily asthma diary. We obtained daily air pollution, meteorological, pollen and alternaria data. We then used generalised estimating equation techniques to determine associations between the bushfire period and particulate matter less than 10 microns (PM10) and PEFR. RESULTS: The maximum daily PM10 level peaked at 210 ug/m3, which was nearly seven times the usual PM10 level for the rest of January and February 1994. There was no significant association between mean PM10 and PEFR (beta-coefficient = -0.009, p = 0.86). Children without bronchial hyper-reactivity had a significant negative association between PEFR and PM10 (beta-coefficient = -0.1029, p = 0.03). The bushfire period was not significant in any of the models. CONCLUSIONS: We did not find an association between the bushfire period or PM10 and evening PEFR, although in a subgroup of children without bronchial hyper-reactivity, a significant negative association was present between PM10 and evening PEFR. IMPLICATIONS: We conclude that the high levels of particulate pollution caused by the Sydney bushfires did not lead to any clinically significant reductions in PEFR in symptomatic children. Our results have implications for community risk communication during future bushfires.

Air Pollution↗
PubMed1999

Validation of a predictive model for asthma admission in children: how accurate is it for predicting admissions?

We studied 364 index presentations to the Emergency Department of a children's hospital with a diagnosis of asthma. The admission rate for this group of children was about 31%. We developed a parsimonious multiple logistic regression model to predict asthma hospital admission based on asthma severity indicators. We then evaluated the model's predictive ability using two methods of cross-validation, using the same sample that was used for the predictive model, and using data from a split sample. The logistic regression model had a predictive accuracy of 90% (95% confidence interval 85-95%). The sensitivity and specificity were 86% and 88%, respectively. Cross-validation models confirmed that the predictive ability of the model was stable. In studies with limited sample sizes, it is possible to validate a model without setting aside a split sample for cross-validation.

Acute Disease↗
PubMed1999

Social capital and its relevance to health and family policy.

It is important to consider the global context in which we operate and in which the association between society and health is to be explored. We are in a democratic world, with an economy that emphasises the market and a post-modern culture. The ancient elements of state, market and community are discernible in avaricious combinations and, if we are seeking a just social order, it is important that we apply appropriate analytical methods to social understanding. While social capital is an arresting term, its ambiguity limits its broad applicability and even makes it dangerous. Sir Richard Doll and his colleague Richard Peto once described epidemiological insight as a boundary-setting exercise, delimiting territory within which basic and clinical science can explore mechanisms. When it comes to matters of social and personal well-being, the same approach may serve us well. Social capital, defined differently by everyone who uses it, must be given some stability and be subject to good quality epidemiological research, not too dissimilar to that which has underpinned epidemiology's immense success in public health over the decades. Despite social capital's complexity, there are growing efforts to measure it and relate it to desirable social functions, but the ability of social capital to capture fully the subtle interplay of individuals and society so essential for their health and happiness is questionable.

Community Participation↗
PubMed1998

Association between Der p 1 concentration and peak expiratory flow rate in children with wheeze: a longitudinal analysis.

BACKGROUND: House dust mite (HDM) allergen exposure has been well documented as an environmental cause of airway hyperresponsiveness (AHR) and asthma symptoms. The relationship between asthma morbidity and exposure to low concentrations of HDM allergen suggests that there may be no safe exposure threshold to HDM allergen. OBJECTIVE: We aimed to investigate the associations between Der p 1 in bedding and lung function in 30 children with a history of wheezing in a longitudinal study. METHODS: After a cross-sectional study of school children, which included histamine challenge for AHR and skin testing for dust mite atopy, we made repeated measurements of HDM allergens in children with a history of wheeze over a 12-month period. These children also kept a daily asthma diary in which they recorded their peak expiratory flow rates (PEFRs). We used a repeated measures model to determine the association between PEFR and HDM allergen concentration. RESULTS: There was a significant association between PEFRs and HDM allergen concentration (beta-coefficient = -14.17, P = .0024) in children with HDM atopy. An association was not found in children without HDM atopy. CONCLUSIONS: These findings support the hypothesis that HDM allergens have an adverse effect on the lung function of children with wheeze and highlight the importance of maintaining low dust mite allergen levels throughout the year in the home environment of children sensitized to HDMs.

Allergens↗
PubMed1998

Admission rates as an indicator of the prevalence of severe asthma in the community.

BACKGROUND: A reliable indicator of the prevalence of severe asthma in the community is needed to monitor population-based asthma control strategies. We examined the potential use of asthma admissions to hospital as such an indicator. METHODS: We recruited subjects from the Emergency Department (ED) of a children's hospital. The attending doctor completed the 'physician questionnaire' which included questions on the patient's asthma severity and interval severity/chronicity of asthma. The parent/guardian completed the 'parent questionnaire'. It included questions on demography, asthma knowledge and attitudes, asthma history and social support. We performed univariate and multiple logistic regression to determine predictors for hospital admission. RESULTS: Interval severity of asthma, pre-treatment severity of wheeze and low post-treatment pulse oximetry best predicted whether children presenting with asthma were admitted. Demographic variables, factors associated with access to health services and factors related to the asthma history and management were not significant predictors of admission. DISCUSSION: At the population level, it may be possible to utilise routine hospital admission rates as an indicator of the prevalence of severe asthma in the community, especially within the context of monitoring trends in asthma prevalence. Our study was conducted in a metropolitan tertiary paediatric hospital. The reliability of hospital admission rates as indicators of the prevalence of severe asthma in other hospital settings, in different population groups and over time remains to be established.

Adolescent↗
PubMed1997

Selection bias from sampling frames: telephone directory and electoral roll compared with door-to-door population census: results from the Blue Mountains Eye Study.

Many Australian public health research studies use the telephone directory or the electoral roll as a sampling frame from which to draw study subjects. The sociodemographic, disease-state and risk-factor characteristics of subjects who could be recruited using only the telephone directory or only the electoral roll sampling frames were compared with the characteristics of subjects who would have been missed using only these sampling frames, respectively. In the first phase of the Blue Mountains Eye Study we interviewed and examined 2557 people aged 49 and over living in a defined postcode area, recruited from a door-to-door census. This represented a participation rate of 80.9 per cent and a response rate of 87.9 per cent. The telephone directory was searched for each subject's telephone number and the electoral roll was searched for each subject. Subject characteristics for those who were present in each of these sampling frames were compared with the characteristics of those subjects not included in the sampling frames. The telephone directory listed 2102 (82.2 per cent) of the subjects, and 115 (4.5 per cent) had no telephone connected. The electoral roll contained 2156 (84.3 per cent) of the subjects, and 141 subjects (5.5 per cent) could not be found in either the electoral roll or the telephone directory. Younger subjects, subjects who did not own their own homes and subjects born outside of Australia were significantly less likely to be included in either of these sampling frames. The telephone directory was also more likely to exclude subjects with higher occupational prestige, while the electoral roll was more likely to exclude unmarried persons and males. Researchers using the telephone directory and electoral roll to select subjects for study should be aware of the potential selection bias these sampling frames incur and need to take care when generalising their findings to the wider community.

Aged↗
PubMed1997

Re:Public health.

Explore the source record for details and available documents.

Australia↗
PubMed1997

Female sterilization in New South Wales, 1981 to 1994-1995.

This paper investigates and confirms the dramatic decline in female sterilization in New South Wales over the past decade, a period when male sterilization has remained fairly constant. The most significant decline occurred among women under 30 years of age, which resulted in a rise in the mean age at sterilization. In 1994-1995, 70% of sterilization operations were performed for contraceptive management only, 11% were concurrent with Caesarean section, and 9% with abortion. Incidental findings were an increase in Caesarean section and the proportion of women having concurrent sterilization, and a large decline in intrauterine device removals, more than half of which were accompanied with sterilization in 1994-1995. Currently-married women accounted for 80% of sterilization cases. Immigrant women generally had lower incidence of sterilization compared to the Australian-born.

Adult↗
PubMed1996

Logic, hermeneutics, and informed consent.

A belief in the validity of informed consent is one of the most important consequences of the doctrine of autonomy in medical ethics. Truly informed consent requires full disclosure of all relevant information by the doctor, competence of the patient to appreciate what the information signifies, understanding of the facts and issues by the patient, a voluntary choice by the patient and an autonomous authorisation for treatment or entry into a trial. Each of these conditions is hard to fulfil. In particular, full autonomy cannot exist in illness, and this is acknowledged by the act of consultation. The issue is further complicated by the stochastic nature of biological systems and the responses to illness and treatment. Disclosure of likely outcomes is, of necessity, unsatisfactory when a patient seeks surety when entering the clinical process with a serious and life threatening disease. Neither strict logic nor the law provide answers to this problem. The legal and moral issues have become confused. This is unfortunate, because the legal concern often centres on avoidance of actions in law rather than on the more fundamental issue of benefit to the patient. There is a need to teach doctors that discussion is a necessary part of the doctor-patient relationship, that fully informed consent is seldom-if ever-possible, and that skill in understanding what the patient is seeking is more important than the development of rigid and legally "complete" consent forms.

Communication↗