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Biomedical subjects

A Dobson

Publications and source records attributed to A Dobson.

At least 19 recordsLinked to original sources
PubMed1999

Women drivers' behaviour, socio-demographic characteristics and accidents.

The purpose of this study was to examine factors which affect driving behaviour and accident rates in women in Australia. Two groups of women (aged 18-23 and 45-50 years) participating in the Australian Longitudinal Study on Women's Health, completed a mailed questionnaire on driver behaviour and road accidents. Self reported accident rates in the last 3 years were 1.87 per 100,000 km for the young drivers (n = 1199) and 0.59 per 100,000 km for the mid-age drivers (n = 1564); most accidents involved damage only, not injury. Mean scores for lapses obtained using the Driver Behaviour Questionnaire, were similar in the two age groups and similar to those found in other studies. In contrast, scores for errors and violations for the young women were higher than for the mid-age group and previous reports using the same instruments. Riskier driving behaviour among young women was associated with stress and habitual alcohol consumption. In the mid-age group, poorer driver behaviour scores were related to higher levels of education, feeling rushed, higher habitual alcohol consumption and lower life satisfaction scores. Accident rates in both groups were significantly related to lapses. Women born in non-English speaking countries had significantly higher risk of accidents compared to Australian-born women: relative risk = 3.40, 95% confidence interval (1.93, 5.98) for the young drivers; relative risk = 1.77, 95% confidence interval (1.11, 2.83) for mid-age drivers. These findings support the need for road safety campaigns targeted at young women to reduce dangerous driving practices, such as speeding, 'tail gating' and overtaking on the inside. There is also a need for further research to understand how lifestyle characteristics are associated with higher risk of accidents and to explore factors which might account for the higher risk for women drivers who were born overseas.

Accidents, Traffic↗
PubMed1999

Reducing coronary heart disease in the Australian Coalfields: evaluation of a 10-year community intervention.

Coronary heart disease is a leading cause of death in Australia with the Coalfields district of New South Wales having one of the country's highest rates. Identification of the Coalfields epidemic in the 1970's led to the formation of a community awareness program in the late 1980's (the healthy heart support group) followed by a more intense community action program in 1990, the Coalfields Healthy Heartbeat (CHHB). CHHB is a coalition of community members, local government officers, health workers and University researchers. We evaluate the CHHB program, examining both the nature and sustainability of heart health activities undertaken, as well as trends in risk factor levels and rates of coronary events in the Coalfields in comparison with nearby local government areas. Process data reveal difficulties mobilising the community as a whole; activities had to be selected for interested subgroups such as families of heart disease patients, school children, retired people and women concerned with family nutrition and body maintenance. Outcome data show a significantly larger reduction in case fatality for Coalfields men (although nonfatal heart attacks did not decline) while changes in risk factors levels were comparable with surrounding areas. We explain positive responses to the CHHB by schools, heart attack survivors and women interested in body maintenance in terms of the meaning these subgroups find in health promotion discourses based on their embodied experiences. When faced with a threat to one's identity, health discourse suddenly becomes meaningful along with the regimens for health improvement. General public disinterest in heart health promotion is examined in the context of historical patterns of outsiders criticising the lifestyle of miners, an orientation toward communal rather than individual responsibility for health (i.e. community 'owned' emergency services and hospitals) and anger about risks from environmental hazards imposed by industrialists.

Adult↗
PubMed1998

Teaching hospital costs: implications for academic missions in a competitive market.

CONTEXT: As the managed care environment demands lower prices and a greater focus on primary care, the high cost of teaching hospitals may adversely affect their ability to carry out academic missions. OBJECTIVE: To develop a national estimate of total inpatient hospital costs related to graduate medical education (GME). DESIGN: Using Medicare cost report data for fiscal year 1993, we developed a series of regression models to analyze the relationship between inpatient hospital costs per case and explanatory variables, such as case mix, wage levels, local market characteristics, and teaching intensity (the ratio of interns and residents to beds). SETTING AND PARTICIPANTS: A total of 4764 nonfederal, general acute care hospitals, including 1014 teaching hospitals. MAJOR OUTCOME MEASURES: Actual direct GME hospital costs and estimated indirect GME-related hospital costs based on the statistical relationship between teaching intensity and inpatient costs per case. RESULTS: In 1993, academic medical center (AMC) costs per case were 82.9% higher than those for urban nonteaching hospitals (actual cost per case, $9901 vs $5412, respectively). Non-AMC teaching hospital costs per case were 22.5% higher than those for nonteaching hospitals (actual cost per differences in case, $6630 vs $5412, respectively). After adjustment for case mix, wage levels, and direct GME costs, AMCs were 44% more expensive and other teaching hospitals were 14% more costly than nonteaching hospitals. The majority of this difference is explained by teaching intensity. Total estimated US direct and indirect GME-related costs were between $18.1 billion and $22.8 billion in 1997. These estimates include some indirect costs, not directly educational in nature, related to clinical research activities and specialized service capacity. CONCLUSIONS: The cost of teaching hospitals relative to their nonteaching counterparts justifies concern about the potential financial impact of competitive markets on academic missions. The 1997 GME-related cost estimates provide a starting point as public funding mechanisms for academic missions are debated. The efficiency of residency programs, their consistency with national health workforce needs, financial benefits provided to teaching hospitals, and ability of AMCs to maintain higher payment rates are also important considerations in determining future levels of public financial support.

Academic Medical Centers↗
PubMed1998

Outcome with calcium channel antagonists after myocardial infarction: a community-based study.

OBJECTIVES: We sought to estimate the risk of death and recurrent myocardial infarction associated with the use of calcium antagonists after myocardial infarction in a population-based cohort study. BACKGROUND: Calcium antagonists are commonly prescribed after myocardial infarction, but their long-term effects are not well established. METHODS: Patients 25 to 69 years old with a suspected myocardial infarction were identified and followed up through a community-based register of myocardial infarction and cardiac death (part of the World Health Organization Monitoring Trends and Determinants in Cardiovascular Disease [MONICA] Project in Newcastle, Australia). Data were collected by review of medical records, in-hospital interview and review of death certificates. RESULTS: From 1989 to 1993, 3,982 patients with a nonfatal suspected myocardial infarction were enrolled in the study. At hospital discharge, 1,001 patients were treated with beta-adrenergic blocking agents, 923 with calcium antagonists, 711 with both beta-blockers and calcium antagonists and 1,346 with neither drug. Compared with patients given beta-blockers, patients given calcium antagonists were more likely to suffer myocardial infarction or cardiac death (adjusted relative risk [RR] 1.4, 95% confidence interval [CI] 1.0 to 1.9), cardiac death (RR 1.6, 95% CI 1.0 to 2.7) and death from all causes (RR 1.7, 95% CI 1.1 to 2.6). Compared with patients given neither beta-blockers nor calcium antagonists, patients given calcium antagonists were not at increased risk of myocardial infarction or cardiac death (RR 1.0, 95% CI 0.8 to 1.3), cardiac death (RR 0.9, 95% CI 0.6 to 1.2) or death from all causes (RR 1.0, 95% CI 0.7 to 1.3). No excess in risk of myocardial infarction or cardiac death was observed among patients taking verapamil (RR 0.9, 95% CI 0.6 to 1.6), diltiazem (RR 1.1, 95% CI 0.8 to 1.4) or nifedipine (RR 1.3, 95% CI 0.7 to 2.2) compared with patients taking neither calcium antagonists nor beta-blockers. CONCLUSIONS: These results are consistent with randomized trial data showing benefit from beta-blockers after myocardial infarction and no effect on the risk of recurrent myocardial infarction and death with the use of calcium antagonists. Comparisons between beta-blockers and calcium antagonists favor beta-blockers because of the beneficial effects of beta-blockers and not because of adverse effects of calcium antagonists.

Adrenergic beta-Antagonists↗
PubMed1998

Anaesthesia and Prader-Willi syndrome.

A review of a case series of sixteen anaesthetics in eight cases was undertaken to determine whether children with Prader-Willi syndrome present particular problems to the anaesthetist. Children in an early stage of the condition who are below their centile for weight present no specific problems. Children who are heavier than 97th centile weight have problems associated with their obesity: difficult intravenous access and sleep apnoea. Scoliosis was noted in both groups and was not associated with problems after minor surgery.

Adolescent↗
PubMed1998

Accuracy of dilution techniques for access flow measurement during hemodialysis.

Access flow is now widely measured by creating artificial recirculation with the dialysis lines reversed and using dilution methods that sense either ultrasound velocity, electrical impedance, optical, or thermal changes. This study identifies and quantifies factors that influence the accuracy of access flow measurements and recommends ways to reduce these errors. Two major sources of access flow measurement error are identified, arising firstly from the second pass of the indicator by recirculation through the cardiopulmonary system (cardiopulmonary recirculation, CPR), and secondly from changes in venous line blood flow (Qb) and vascular access flow induced by the pressure of venous bolus injections. These errors are considered from theory, by direct measurement of access flow in a sheep model, and by analysis of clinical data. Two extremes for the venous introduction of indicator can be considered in access flow measurements, a slow infusion, which perturbs neither the venous line flow nor access flow but increases the error attributable to the second pass of the indicator by recirculation through cardiopulmonary system, or rapid injection, which eases separation of the second pass of the indicator signal but generates changes in the venous flow and access flow. If CPR is not eliminated, the area added to that of the first pass of indicator ranges up to 40%. Good time resolution could permit the separation of the areas generated by the first and second passage of the indicator. In sheep experiments, injections of 5 or 10 mL into a venous port close to the vascular access caused Qb to change by 20% to 40%. Both the animal experiments and analysis of raw data collected during routine clinical dialysis showed that moving the injection site sufficiently far from the patient, before or into the venous bubble trap, reduced the increase in Qb to only approximately 5% during the critical time when the concentration curve is changing for most tubing brands (Baxter, Belco, Gambro, Hospal, Medisystem, and National Medical Care). Because of the smaller volume of the venous bubble chamber in Cobe tubing (Cobe, Centrysystem 3), this brand showed approximately a 20% increase in Qb. Moving the site of bolus injections to before the bubble trap in the sheep experiments also eliminated the influence of changes in access flow. An additional error in access flow measurement of 20% or more arises from the use of flow reading taken from pump setting rather than a measured flow. The discrepancy between the real flow and pump setting is attributable to needle size, vascular access conditions, or pump calibration. The results show that problems can be minimized by using a dual sensor system that retains the precise timing necessary for separation of access recirculation from CPR; by accurate measurement of dialyzer blood flow; by moving the site of injection to before the venous bubble trap, sufficiently far from the patient, and correcting for any remaining deviations in flow in the venous line concurrent with the dilution curve.

Animals↗
PubMed1998

Rapid reduction in coronary risk for those who quit cigarette smoking.

The objective of this study was to determine the rate of the decline in risk of a major coronary event after quitting cigarette smoking. It was a population-based case-control study of men and women aged 35 to 69 years in Newcastle, Australia, and men and women aged 35 to 64 years in Auckland, New Zealand, between 1986 and 1994. Cases were 5,572 people identified in population registers of coronary events and controls were 6,268 participants in independent community-based risk factor prevalence surveys from the same study populations. There was a rapid reduction in risk after quitting cigarette smoking. The risk of suffering a major coronary event for men who were current cigarette smokers was 3.5 (95% CI 3.0-4.0) times higher than the risk for never smokers but this fell to 1.5 (95% CI 1.1-1.9) for men who had quit for 1-3 years. Women who were current cigarette smokers were 4.8 (95% CI 4.0-5.9) times more likely to suffer a major coronary event than never smokers and this fell to 1.6 (95% CI 1.0-2.5) for women who had quit for 1-3 years. Those who had quit cigarette smoking for 4-6 years or more had a similar risk to never smokers. These results reinforce the importance of smoking cessation. The public health message is that the benefit of giving up smoking occurs rapidly.

Adult↗
PubMed1997

Population versus clinical view of case fatality from acute coronary heart disease: results from the WHO MONICA Project 1985-1990. Multinational MONItoring of Trends and Determinants in CArdiovascular Disease.

BACKGROUND: The clinical view of case fatality (CF) from acute myocardial infarction (AMI) in those reaching the hospital alive is different from the population view. Registration of both hospitalized AMI cases and out-of-hospital coronary heart disease (CHD) deaths in the WHO MONICA Project allows both views to be reconciled. The WHO MONICA Project provides the largest data set worldwide to explore the relationship between CHD CF and age, sex, coronary event rate, and first versus recurrent event. METHODS AND RESULTS: All 79,669 events of definite AMI or possible coronary death, occurring from 1985 to 90 among 5,725,762 people, 35 to 64 years of age, in 29 MONICA populations are the basis for CF calculations. Age-adjusted CF (percentage of CHD events that were fatal) was calculated across populations, stratified for different time periods, and related to age, sex, and CHD event rate. Median 28-day population CF was 49% (range, 35% to 60%) in men and 51% (range, 34% to 70%) in women and was particularly higher in women than men in populations in which CHD event rates were low. Median 28-day CF for hospitalized events was much lower: in men 22% (range, 15% to 36%) and in women 27% (range, 19% to 46%). Among hospitalized events CF was twice as high for recurrent as for first events. CONCLUSIONS: Overall 28-day CF is halved for hospitalized events compared with all events and again nearly halved for hospitalized 24-hour survivors. Because approximately two thirds of 28-day CHD deaths in men and women occurred before reaching the hospital, opportunities for reducing CF through improved care in the acute event are limited. Major emphasis should be on primary and secondary prevention.

Acute Disease↗
PubMed1997

Mild myocardial infarction--a classification problem in epidemiologic studies. WHO MONICA Project.

In studies assessing the trends in coronary events, such as the World Health Organization (WHO) MONICA Project (multinational MONItoring of trends and determinants of CArdiovascular disease), the main emphasis has been on coronary deaths and non-fatal definite myocardial infarctions (MI). It is, however, possible that the proportion of milder MIs may be increasing because of improvements in treatment and reductions in levels of risk factors. We used the MI register data of the WHO MONICA Project to investigate several definitions for mild non-fatal MIs that would be applicable in various settings and could be used to assess trends in milder coronary events. Of 38 populations participating in the WHO MONICA MI register study, more than half registered a sufficiently wide spectrum of events that it was possible to identify subsets of milder cases. The event rates and case-fatality rates of MI are clearly dependent on the spectrum of non-fatal MIs, which are included. On clinical grounds we propose that the original MONICA category "non-fatal possible MI" could be divided into two groups: "non-fatal probable MI" and "prolonged chest pain." Non-fatal probable MIs are cases, which in addition to "typical symptoms" have electrocardiogram (ECG) or enzyme changes suggesting cardiac ischemia, but not severe enough to fulfil the criteria for non-fatal definite MI. In more than half of the MONICA Collaborating Centers, the registration of MI covers these milder events reasonably well. Proportions of non-fatal probable MIs vary less between populations than do proportions of non-fatal possible MIs. Also rates of non-fatal probable MI are somewhat more highly correlated with rates of fatal events and non-fatal definite MI. These findings support the validity of the category of non-fatal probable MI. In each center the increase in event rates and the decrease in case-fatality due to the inclusion of non-fatal probable MI was larger for women than men. For the WHO MONICA Project and other epidemiological studies the proposed category of non-fatal probable MIs can be used for assessing trends in rates of milder MI.

Adult↗
PubMed1997

Dietary trends: estimates from food supply and survey data.

OBJECTIVE: To illustrate methodological issues involved in estimating dietary trends in populations using data obtained from various sources in Australia in the 1980s and 1990s. METHODS: Estimates of absolute and relative change in consumption of selected food items were calculated using national data published annually on the national food supply for 1982-83 to 1992-93 and responses to food frequency questions in two population based risk factor surveys in 1983 and 1994 in the Hunter Region of New South Wales, Australia. The validity of estimated food quantities obtained from these inexpensive sources at the beginning of the period was assessed by comparison with data from a national dietary survey conducted in 1983 using 24 h recall. RESULTS: Trend estimates from the food supply data and risk factor survey data were in good agreement for increases in consumption of fresh fruit, vegetables and breakfast food and decreases in butter, margarine, sugar and alcohol. Estimates for trends in milk, eggs and bread consumption, however, were inconsistent. CONCLUSIONS: Both data sources can be used for monitoring progress towards national nutrition goals based on selected food items provided that some limitations are recognized. While data collection methods should be consistent over time they also need to allow for changes in the food supply (for example the introduction of new varieties such as low-fat dairy products). From time to time the trends derived from these inexpensive data sources should be compared with data derived from more detailed and quantitative estimates of dietary intake.

Adult↗
PubMed1997

Blood pressure levels in the 41 populations of the WHO MONICA Project.

In the early to mid 1980s, the WHO MONICA Project conducted cardiovascular risk factor surveys in 41 study populations in 22 countries. Study populations aged 35-64 years comprised 32,422 men and 32,554 women. Blood pressures (BP) and body mass index (BMI) were measured according to a standard protocol. Participants were asked about antihypertensive medication. In men, the average age-standardized BPs ranged among the populations from 124 to 148 mm Hg for systolic (SBP) and from 75 to 93 mm Hg for diastolic (DBP). The corresponding values in women were 118-145 mm Hg for SBP and 74-90 mm Hg for DBP. In all populations, women had lower SBP than men in the age group 35-44. However, SBP in women rose more steeply with age so that in 34 of 41 populations women had higher SBP than men in the age group 55-64. The proportion of participants with untreated major elevation of BP ranged from 4.5% to 33.7% in men and from 1.9% to 22.3% in women. The proportions of participants receiving antihypertensive medication were 4.3-17.7% for men and 6.0-22.0% for women. These proportions were not correlated with the prevalence of untreated hypertensives. Age-adjusted BMI was associated with SBP and accounted for 14% of the SBP variance in men and 32% in women. We found a large difference in SBP among the MONICA study populations and conclude that the results represent a valid estimate of the public health problem posed by elevated BP. We also have shown that almost universally the problem of elevated BP is more prevalent in women than in men, especially in the older age groups.

Adult↗
PubMed1997

Validation in the sheep of an ultrasound velocity dilution technique for haemodialysis graft flow.

BACKGROUND: A simple, rapid, inexpensive method for measuring the flow in a patient's vascular access would permit routine monitoring during haemodialysis, and hence provide information of access graft deterioration sufficiently early to increase the success of minimally invasive remedial procedures. This paper reports the validation of such a method in animals. METHODS: A PTFE graft was implanted in sheep between the carotid artery and the jugular vein. While the sheep was under general anaesthesia and on an haemodialysis circuit, ultrasound velocity in its blood was perturbed by the injection of a 5-10 ml bolus of isotonic NaCl. The pump tubing flow was measured by a transit-time blood flow meter. This flow was combined with the areas of perturbation generated by the injection before and after mixing in the access flow to estimate graft flow. The calculated graft flow was compared to flow measured directly by a transit-time probe on the same carotid artery. RESULTS: Over a 10-fold range, 120-1260 ml/min, graft flow measured by ultrasound velocity dilution agreed well with graft flow measured directly with a scatter of 76 ml/min about the regression line. CONCLUSION: Ultrasound velocity dilution provides a method for measuring flow in the graft accurate enough for clinical evaluation of patients on dialysis.

Animals↗
PubMed1997

Whose diet has changed?

The same questions about diet were asked in two community-based surveys conducted in the Hunter Region of New South Wales in 1983 and 1994. There were substantial changes in diet over the period; for example, the proportion of respondents who reported using low-fat or skim milk increased from 25 per cent to 51 per cent, the proportion eating meat fewer than five times a week doubled from 21 per cent to 42 per cent and the proportion eating fewer than three eggs per week increased from 55 per cent to 80 per cent. In both surveys, women reported eating a healthier diet than men, and older people and those of higher socioeconomic status reported better diets than younger people or people with less education or lower status occupations. The surprising finding was that over the 11-year period the changes in patterns of food consumption were remarkably similar across all strata of the population. The conclusions are that wide-spread dietary change is possible. However, the changes in the last decade related mainly to reducing the risk of cardiovascular disease; similar behavioural changes to reduce the risk of diet-related cancer are required.

Adult↗
PubMed1997

Food habits of young and middle-aged women living outside the capital cities of Australia.

Young (18-22 years) and middle-aged (45-49 years) women living in urban and rural areas of New South Wales completed a brief food frequency questionnaire as part of a wider health survey. Urban women in both age groups consumed meat less frequently than women in rural areas, and women in the less populated rural areas were more likely to eat green and yellow vegetables and least likely to eat dried beans. There were few other geographic differences in food habits. Middle-aged women consumed reduced-fat milk, fruit, vegetables, fish, biscuits and cakes significantly more frequently, and rice, pasta, full-cream milk, fried food and take-away food less frequently than younger women. Smokers in both age groups consumed fresh fruit, vegetables and breakfast cereals significantly less frequently than non-smokers, and women with low levels of habitual physical activity consumed fresh fruit and cereals less frequently than more active women. The findings suggest that strategies aimed at changing eating behaviours should be age-group-specific and targeted specifically to smokers and less active women.

Adolescent↗
PubMed1997

Working and living conditions of construction workers: comparison between large and small construction sites in northeastern Thailand.

This study examined differences in working and living conditions of construction workers in large and small construction sites in Northeastern Thailand. Data were collected by questionnaires, through observation and interviewing. A total of 812 construction workers from 20 large sites and 24 small sites were studied. Working and living conditions among the construction workers were generally poor. However, they were better at the large sites than the small ones. The data suggest an urgent need to improve sanitation and safety conditions on the construction sites and camp sites, including personal protective devices and improved welfare for the workers and their families.

Adolescent↗
PubMed1996

Relations of changes in coronary disease rates and changes in risk factor levels: methodological issues and a practical example.

One of the main hypotheses of the World Health Organization (WHO) MONICA Project is that trends in the major coronary disease risk factors are related to trends in rates of fatal and non-fatal coronary disease events. The units of study are populations rather than individuals. The WHO MONICA Project involves continuous monitoring of all coronary disease events in the populations over a 10-year period and periodic risk factor surveys in random samples of the same populations. Estimation of associations between average annual changes in mortality and risk factor levels is illustrated with the use of data from a subset of MONICA centers. Crude estimates of regression coefficients are compared with estimates obtained by weighting for standard errors in both the outcome and explanatory variables. The results show that the strength of association may be either underestimated or overestimated if these errors are not taken into account.

Adult↗
PubMed1996

Physical medicine and rehabilitation workforce study: the supply of and demand for physiatrists.

OBJECTIVE: Analysis, results, and implications of a supply and demand workforce model for physical medicine and rehabilitation. Explicit issues addressed include: (1) the supply implications of maintaining current (1994-1995) output of physiatrists from residency programs; (2) the implications of continued growth in managed care on the demand for the services of physiatrists; (3) likely future supply and demand conditions; and (4) strategies to adapt to future conditions. DESIGN: A workforce model of the supply and demand for physiatrists was developed. Parameters of the model are estimated using econometric models and by applying the judgments of a consensus panel. The model evaluated several different scenarios regarding managed care growth, competition from other providers and other factors. RESULTS: Based on the analysis, physiatrists will continue to be in excess demand through the year 2000. More aggressive growth in managed care can affect this result. CONCLUSIONS: Based on an overall assessment of supply and demand conditions, and under the assumption that the supply of new entrants each year remains in the range of 1994-1995 levels, demand for physiatrists will continue to exceed supply, on average, through the year 2000. Excess supply has, and will, emerge in selected geographic areas. If the profession is successful in informing the market regarding the advantages of physiatry, the profession can continue to grow without experiencing excess supply, in the aggregate, for the foreseeable future.

Forecasting↗