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Biomedical subjects

Stephen R Leeder

Publications and source records attributed to Stephen R Leeder.

At least 19 recordsLinked to original sources
PubMed2006

Prevention of asthma during the first 5 years of life: a randomized controlled trial.

BACKGROUND: Early life exposures may be important in the development of asthma and allergic disease. OBJECTIVE: To test house dust mite (HDM) avoidance and dietary fatty acid modification, implemented throughout the first 5 years of life, as interventions to prevent asthma and allergic disease. METHODS: We recruited newborns with a family history of asthma antenatally and randomized them, separately, to HDM avoidance or control and to dietary modification or control. At age 5 years, they were assessed for asthma and eczema and had skin prick tests for atopy. RESULTS: Of 616 children randomized, 516 (84%) were evaluated at age 5 years. The HDM avoidance intervention resulted in a 61% reduction in HDM allergen concentrations (microg/g dust) in the child's bed but no difference in the prevalence of asthma, wheeze, or atopy (P > .1). The prevalence of eczema was higher in the active HDM avoidance group (26% vs 19%; P = .06). The ratio of omega-6 to omega-3 fatty acids in plasma was lower in the active diet group (5.8 vs 7.4; P < .0001). However, the prevalence of asthma, wheezing, eczema, or atopy did not differ between the diet groups (P > .1). CONCLUSION: Further research is required to establish whether other interventions can be recommended for the prevention of asthma and allergic disease. CLINICAL IMPLICATIONS: House dust mite avoidance measures and dietary fatty acid modification, as implemented in this trial during infancy and early childhood, did not prevent the onset of asthma, eczema, or atopy in high-risk children.

Animals↗
PubMed2006

Proxy respondents reliably assessed the quality of life of elective cardiac surgery patients.

BACKGROUND AND OBJECTIVE: The level of agreement between index and proxy respondents on assessment of health status of clinical cohorts is variable. There is limited information regarding agreement between cardiac surgery patients and their proxies, and levels of agreement examined across repeated measures. This study examined the level of agreement between index and proxy respondents' perceptions of the patient's health status prior to and following cardiac surgery. METHODS: A prospective, paired-respondent, repeated measures observational study of elective cardiac surgical patients and their next of kin, from the cardiac surgical unit of a tertiary hospital in Sydney, Australia. Health status domains were examined using the15D and SF-36 instruments at three points: prior to surgery, at hospital discharge, and at 6 months post discharge. RESULTS: Moderate to good level of agreement was noted for physical function (physical functioning, role functioning-physical, mobility, breathing, speech, hearing, usual activities, sexual activities) and some psychosocial dimensions (role functioning-emotional, sleeping, depression, mental health). Agreement was highest for presurgery and 6 months post discharge. Differences in scores were not clinically important. CONCLUSION: Proxy respondents can reliably assess the quality of life of a cardiac surgical patient using 15D or SF-36, particularly for domains reflecting physical function.

Cardiac Surgical Procedures↗
PubMed2006

Consumption of 'extra' foods (energy-dense, nutrient-poor) among children aged 16-24 months from western Sydney, Australia.

OBJECTIVE: This study evaluates the contribution of energy-dense, nutrient-poor 'extra' foods to the diets of 16-24-month-old children from western Sydney, Australia. DESIGN: An analysis of cross-sectional data collected on participants in the Childhood Asthma Prevention Study (CAPS), a randomised trial investigating the primary prevention of asthma from birth to 5 years. We collected 3-day weighed food records, calculated nutrient intakes, classified recorded foods into major food groups, and further classified foods as either 'core' or 'extras' according to the Australian Guide to Healthy Eating. SETTING: Pregnant women, whose unborn child was at risk of developing asthma because of a family history, were recruited from all six hospitals in western Sydney, Australia. Data for this study were collected in clinic visits and at participants' homes at the 18-month assessment. PARTICIPANTS: Four hundred and twenty-nine children participating in the CAPS study; 80% of the total cohort. RESULTS: The mean consumption of 'extra' foods was approximately 150 g day(-1) and contributed 25-30% of the total energy, fat, carbohydrate and sodium to the diets of the study children. 'Extra' foods also contributed around 20% of fibre, 10% of protein and zinc, and about 5% of calcium. Children in the highest quintile of 'extra' foods intake had a slightly higher but not significantly different intake of energy from those in the lowest quintile. However, significant differences were evident for the percentage of energy provided by carbohydrate and sugars (higher) and protein and saturated fat (lower). The intake of most micronutrients was also significantly lower among children in the highest quintile of consumption. The intake of 'extra' foods was inversely associated with the intake of core foods. CONCLUSIONS: The high percentage of energy contributed by 'extra' foods and their negative association with nutrient density emphasise the need for dietary guidance for parents of children aged 1-2 years. These preliminary data on commonly consumed 'extra' foods and portion sizes may inform age-specific dietary assessment methods.

Australia↗
PubMed2006

The health system: what should our priorities be?

ISSUE ADDRESSED: The way the health system is organised is a critically important social determinant of health. Australia's current health system funding arrangements contain serious barriers to effective health promotion and chronic disease management. The consequences are most evident among disadvantaged people. Major health system reform is needed in Australia to rectify this problem. METHODS: This paper describes current mechanisms for funding health care in Australia and examines a recent reform experiment, the Co-ordinated Care Trials. It discusses why the trials were unsuccessful and identifies key criteria for future success. Three existing proposals for health system reform are assessed against these criteria - managed competition, a Commonwealth takeover of health and medical saving accounts. RESULTS: Successful reform of Australia's health system will need to ensure that more flexible services are delivered, changes are made on a large scale to affect demand and strong incentives to use cost-effective services are put in place. Of the models considered, managed competition best meets these criteria and is most likely to reduce health disparities and improve health promotion and disease prevention. A Commonwealth takeover of health funding is a less ambitious alternative but because of this, it is also likely to have less impact. It is doubtful whether medical savings accounts meet any of the criteria for success and they would also require a fundamental change in the values that underpin the Austrlian health system. CONCLUSION: Recent reforms of Australia's health system have been too small and have had little impact. Although radical reform of the health system is politically unpalatable and extremely rare, it may be the only way Australia will be able to meet the health challenges of the 21st Century.

Australia↗
PubMed2006

Regular aspirin use and retinal microvascular signs: the Blue Mountains Eye Study.

OBJECTIVE: Hypertension is closely related to microvascular abnormalities and there is increasing interest in agents that target the microvasculature. The effect of aspirin on the microvasculature has not been well studied. We examined the cross-sectional and longitudinal associations between regular aspirin use and retinal microvascular signs. DESIGN AND METHODS: We digitized retinal photographs from participants of the Blue Mountains Eye Study cohort (1992-1994, n = 3654, aged over 49 years, and 1997-1999, n = 2335) and used a computer-assisted method to measure average retinal arteriolar and venular diameters. Information on the frequency of aspirin use was collected, with regular aspirin use defined as weekly or daily. RESULTS: Regular aspirin users comprised 21.2% (n = 775) of the baseline population. At baseline and in individuals who were on one or more antihypertensive medication, regular aspirin use was found to be associated with retinal arterioles on average 3.6 mum (95% confidence interval 1.0, 6.2) wider than those of non-users or occasional aspirin users, after adjusting for age, blood pressure, smoking, diabetes, non-steroidal anti-inflammatory drug use and other variables. Increasing frequency of aspirin use was associated with increasing retinal arteriolar diameter (Ptrend < 0.01). At 5-year follow-up, regular users of aspirin and antihypertensive medication(s) had wider retinal arterioles than those who used aspirin less regularly. Neither antihypertensive medication use alone nor aspirin use alone was associated with wider retinal vessels. CONCLUSION: Our finding of a possible association between the combined use of aspirin and antihypertensive agent(s) and wider retinal arteriolar diameter warrants further investigation into the effects of aspirin on the microvasculature.

Aged↗
PubMed2005

A health policy for hearing impairment in older Australians: what should it include?

BACKGROUND: As in all western countries, Australia's older population experiences high levels of hearing impairment coupled with relatively low levels of hearing device usage. Poor hearing diminishes the quality of life of affected individuals and their families. This paper discusses how to improve Australian hearing health policies in order to better combat this impairment amongst older Australians. METHOD: We searched the databases Medline, Meditext and Web of Science to find articles that discussed strategies and innovations to assist the hearing health of older people, and related this material to observations made during the Blue Mountains Hearing Study in NSW between 1997 and 2003. RESULTS AND DISCUSSION: The literature search identified five areas for inclusion in a comprehensive hearing health policy in Australia. These are: early intervention; addressing of hearing aid expense; the use of assisted listening devices; hearing rehabilitation, and; screening and education. Further research in Australia is critical if we are to develop a strong approach to the increasing prevalence of age-related hearing loss. CONCLUSION: Australia needs to act now to address hearing impairment as it is a major cause of disability in those aged 55 and over. Federal and State governments should collaborate to construct a comprehensive hearing health policy that tackles poor levels of hearing health through early intervention, addressing hearing aid expense, encouraging the use of assisted listening devices, rehabilitation, screening and education. A good start would be to declare age related hearing impairment as a National Health Priority Area.

Journal Article↗
PubMed2005

Low hemoglobin, chronic kidney disease, and risk for coronary heart disease-related death: the Blue Mountains Eye Study.

A recent report found that chronic kidney disease (CKD) increased the risk for coronary heart disease (CHD) events in people with anemia but not in those without anemia. This study aimed to verify these findings in the Blue Mountains Eye Study cohort, a prospective Australian population-based study of 3654 residents aged 49 to 97 yr. Fasting blood samples were obtained at baseline and confirmed CHD-related deaths over 9 yr with the Australian National Death Index. "Low hemoglobin" was defined as levels in the lowest quintile of the cohort. Body surface area-adjusted GFR was estimated using a variety of methods (Cockcroft-Gault, abbreviated Modification of Diet in Renal Disease, and Bjornsson equations). People with CKD (GFR <60 ml/min per 1.73 m2 as estimated using the Cockcroft-Gault equation) and low hemoglobin (mean 13.2 g/dl; range 7.6 to 14.6 g/dl) had an increased risk for CHD-related death (multivariable-adjusted hazard risk ratio 1.49; 95% confidence interval 1.08 to 2.06) compared with people with CKD but in higher hemoglobin quintiles. This effect was not evident in people without CKD. The interaction between GFR and hemoglobin was significant (P = 0.05) when GFR was estimated using either the Cockcroft-Gault or Bjornsson equations or when serum creatinine instead of GFR was used in the analyses but not when GFR was estimated using the abbreviated Modification of Diet in Renal Disease equation. In conclusion, this study found that low hemoglobin, even within the normal range, together with CKD increased the risk for CHD-related death.

Aged↗
PubMed2005

Health care safety: what needs to be done?

Recent MJA editorials assert that Australian hospitals are no safer than they were when the first hospital safety report was published in 1995. Despite many recommendations by several committees and much activity to improve safety over the past decade, we lack concrete evidence that safety and quality of health care have improved. Efforts to promote hospital safety in the United States and the United Kingdom also remain unevaluated. Incentives for safer care have been implemented locally, but not applied to entire health systems. A recent review in Australia has recommended replacing the current Australian Council for Safety and Quality in Health Care with a smaller Commission on Safety and Quality in Health Care. The Commission will link all national safety activity and report annually to Australian health ministers on hospital safety. We need a system that measures quality and safety, and provides financial incentives for safer care. Implementing the national framework for education about patient safety would develop teamwork skills and skills in techniques of continuous improvement. Linked to this, adequate financial support should be available to make safety changes in the health care environment.

Australia↗
PubMed2005

Beyond reproduction: women's health in today's developing world.

BACKGROUND: The concept of women's health is tethered strongly to reproductive health. At present, international attention and resources are focused on obstetric events and, recently, HIV/AIDS because of the significance of these problems in the least developed nations. This limited concept of women's health, however, is decreasingly relevant to the global community, and needs to be revisited in the light of decreasing fertility and increasing life expectancy in many countries where it was previously applicable. It should be expanded to embrace the full spectrum of health experienced by women, and preventive and remedial approaches to the major conditions that afflict women. Allocation of health service resources should be aligned with the epidemiological realities of these threats to women's health. METHODS: Cause of death data for women aged 15-34 years and 35-44 years were examined for nine less developed countries. Deaths associated with pregnancy and child birth, and HIV were compared with deaths due to three chronic disease categories (cancer, cardiovascular disease, and diabetes). The women's health research literature for developing countries appearing in the American Journal of Public Health and British Medical Journal was also examined. RESULTS: In seven out of the nine countries, among women aged 15-34 years, chronic diseases caused over 20% of deaths, while reproductive causes and HIV together accounted for approximately 10% of deaths, in all countries except in India. Among women aged 35-44 years, in all but India, chronic diseases accounted for over four times the deaths attributable to reproductive causes and HIV. The causes of death were not related to the level of development in these countries as measured by GNI PPP. Papers pertaining to women's health published in public health and medical research journals focused principally on reproduction. CONCLUSIONS: Extending the definition of women's health to include a concern for chronic diseases is critical if the needs of women in less developed nations are to be met. In less developed countries, chronic disease is the most important cause of female death even during childbearing years and for women with young families. Development agencies and private philanthropy must begin to fund the studies that will further refine our understanding of the role of chronic diseases in women's health in the developing world.

Adolescent↗
PubMed2004

Retinal arteriolar narrowing is associated with 5-year incident severe hypertension: the Blue Mountains Eye Study.

We assessed whether retinal arteriolar narrowing and structural abnormalities independently predicted 5-year incident severe (grade 2 or 3) hypertension in an older population-based cohort. The Blue Mountains Eye Study baseline (1992 to 1994) examined 3654 residents aged 49 and older in 2 postal code areas, west of Sydney. Of the 2335 participants (75.1% of survivors) who returned at the 5-year examinations, 1319 were normotensive or had mild (grade 1) hypertension at baseline. Baseline retinal photographs were graded for focal retinal vessel wall signs and vessel diameters were measured. Participants were classified as having normal, high-normal blood pressure [BP] (systolic BP 121 to 139 mm Hg and/or diastolic BP 81 to 89 mm Hg), mild hypertension (systolic BP 140 to 159 mm Hg and/or diastolic BP 90 to 99 mm Hg), or severe hypertension if they had a previous diagnosis of hypertension and were receiving antihypertensive medications or had systolic BP > or =160 mm Hg and/or diastolic BP > or =100 mm Hg at examination. Incident severe hypertension was defined in persons who were free of severe hypertension at baseline but classified as having severe hypertension at the 5-year examinations. Of the 1319 baseline subjects at risk, 390 (29.6%) developed severe hypertension. After adjusting for age, sex, body mass index, smoking, glucose, and total cholesterol, generalized retinal arteriolar narrowing at baseline was associated with increased risk of incident severe hypertension (odds ratio 2.6; 95% confidence interval, 1.7 to 3.9) when comparing the narrowest versus widest quintile. This association remained significant after further adjustment for baseline mean arterial BP or BP status. Our findings support the hypothesis that small vessel structural changes may precede the development of severe hypertension.

Aged↗
PubMed2004

Three-year outcomes of dietary fatty acid modification and house dust mite reduction in the Childhood Asthma Prevention Study.

BACKGROUND: Two factors thought to influence the risk of asthma are the promoting effect of sensitization to house dust mites and the preventive effect of increased omega-3 fatty acids. Although house dust mite allergen avoidance has been used as a preventive strategy in several trials, the effect of omega-3 fatty acid supplementation in the primary prevention of asthma and allergic disease is not known. OBJECTIVE: To measure the effects of dietary supplementation with omega-3 fatty acids and house dust mite allergen avoidance in children with a family history of asthma. METHODS: A total of 616 children at high risk of asthma were enrolled antenatally in a randomized controlled trial, and 526 children remained in the trial at age 3 years. The outcomes were symptoms of allergic disease and allergen sensitization. RESULTS: There was a significant 10.0% (95% CI, 3.7-16.4) reduction in the prevalence of cough in atopic children in the active diet group ( P=.003; number needed to treat, 10) but a negligible 1.1% (95% CI, -7.1 to 9.5) reduction cough among nonatopic children. There was a 7.2% (95% CI, 10.11-14.3) reduction in sensitization to house dust mite in the active allergen avoidance group ( P=.05; number needed to treat, 14). No significant differences in wheeze were found with either intervention. CONCLUSION: These results suggest that our interventions, designed to be used in simple public health campaigns, may have a role in preventing the development of allergic sensitization and airways disease in early childhood. This offers the prospect of reducing allergic disease in later life.

Adult↗
PubMed2004

Acute effects of urban ambient air pollution on respiratory symptoms, asthma medication use, and doctor visits for asthma in a cohort of Australian children.

We enrolled a cohort of primary school children with a history of wheeze (n=148) in an 11-month longitudinal study to examine the relationship between ambient air pollution and respiratory morbidity. We obtained daily air pollution (ozone, particulate matter less than 10 microm, and nitrogen dioxide), meteorological, and pollen data. One hundred twenty-five children remained in the final analysis. We used logistic regression models to determine associations between air pollution and respiratory symptoms, asthma medication use, and doctor visits for asthma. There were no associations between ambient ozone concentrations and respiratory symptoms, asthma medication use, and doctor visits for asthma. There was, however, an association between PM(10) concentrations and doctor visits for asthma (RR=1.11, 95% CI=1.04-1.19) and between NO(2) concentration and wet cough (RR=1.05, 95% CI=1.003-1.10) in single-pollutant models. The associations remained significant in multipollutant models. There was no consistent evidence that children with wheeze, positive histamine challenge, and doctor diagnosis of asthma reacted differently to air pollution from children with wheeze and doctor diagnosis of asthma and children with wheeze only. There were significant associations between PM(10) levels and doctor visits for asthma and an association between NO(2) levels and the prevalence of wet cough. We were, however, unable to demonstrate that current levels of ambient air pollution in western Sydney have a coherent range of adverse health effects on children with a history of wheezing.

Air Pollution↗