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Biomedical subjects

A J Dobson

Publications and source records attributed to A J Dobson.

At least 19 recordsLinked to original sources
PubMed1995

Success of cardiopulmonary resuscitation after heart attack in hospital and outside hospital.

OBJECTIVES: To determine factors associated with cardiopulmonary resuscitation being attempted after cardiac arrest from myocardial infarction, in or outside hospital, and estimate short term and long term survival rates. DESIGN: Descriptive cross sectional and cohort study. SETTING: Community based register of all suspected heart attacks and sudden cardiac deaths in Lower Hunter region of New South Wales, Australia. SUBJECTS: 4924 men and women aged 25-69. MAIN OUTCOME MEASURES: Rates of attempted cardiopulmonary resuscitation and survival after successful resuscitation. RESULTS: Cardiopulmonary resuscitation was attempted in 41% of cases of cardiac arrest after myocardial infarction outside hospital and 63% of cases in hospital. Survival rates at 28 days were 12% and 39% respectively. Among the survivors, although 41% had another myocardial infarction (or coronary death), 81% of both groups were still alive two years later. Younger and better educated people were more likely to receive cardiopulmonary resuscitation in either setting, and being married predicted cardiopulmonary resuscitation being attempted outside hospital. Younger age predicted better survival rates after attempted resuscitation in hospital. CONCLUSIONS: The reasons for better education to predict cardiopulmonary resuscitation being attempted need explanation. The higher survival rate after cardiopulmonary resuscitation in hospital compared with outside hospital and the good long term prognosis for survivors in both settings suggest that attempts to improve success of cardiopulmonary resuscitation outside hospital may be worth while.

Adult↗
PubMed1994

A randomised controlled trial of a dietary advice program for relatives of heart attack victims.

OBJECTIVE: To compare two interventions for reducing dietary fat intake in first degree relatives of recent heart attack victims. DESIGN: A randomised controlled trial comparing a low cost mail-out advice program; referral to a general practitioner (GP); and no intervention (control group). PARTICIPANTS: Adult children or siblings, aged less than 70 years, of survivors of definite or suspected heart attack who had been admitted to hospitals in the Lower Hunter Region of New South Wales. MAIN OUTCOME MEASURES: Dietary fat intake (evaluated with a validated short questionnaire) and measurement of blood cholesterol levels at six months. RESULTS: Of the 342 relatives who participated (36% of those invited), 109, 120 and 113, respectively, were randomly assigned to receive a mail-out intervention, advice from their GP or to be part of a control group. The six-month follow-up questionnaire was completed by only 59% of those in the mail-out intervention group compared with 71% of the GP group and 77% of the control group. Younger participants, cigarette smokers and children (compared with siblings) were less likely to return a follow-up questionnaire. The mail-out group showed a statistically significant 20% reduction in self-reported dietary fat intake, but this was not seen in either the GP group or the controls. The low response rate meant the study had insufficient power to detect hypothesised changes in blood cholesterol. CONCLUSION: Because of the poor response rate and possible biases from a differential response to follow-up, we conclude that this low intensity intervention for relatives of people with recent heart attack produces only a modest improvement in reported dietary fat intake. Alternative strategies may be more effective in reducing the risk of heart disease.

Adult↗
PubMed1994

Age-specific patterns of mortality from cardiovascular disease and other major causes, 1969 to 1990.

There were substantial reductions in mortality rates for all causes of death and for cardiovascular diseases in all age groups examined and both sexes during the period 1969 to 1990. Among young and middle-aged women, cardiovascular diseases were no longer the major cause of death; cancers were. In younger men, accidents, poisonings and violence (including suicides) were the leading cause of death. In middle-aged men, cardiovascular mortality dropped to about the same level as cancer mortality. Only in older people did cardiovascular mortality still dominate. Nevertheless, the proportion of all deaths due to cardiovascular disease remained high and there are opportunities for further reductions. The relative lack of improvement in mortality from cancers suggests that these will form increasing proportions of the burden of disease and treatment costs in the next decades.

Adult↗
PubMed1994

Relationship between risk factor trends and disease trends.

To what extent can trends in risk factor levels in populations explain trends in disease rates? Some methodological difficulties in answering this question include weaknesses of ecological studies, small sample size, time lags and multiple sources of variability. Two possible approaches are to apply predictive equations derived from longitudinal studies of individuals to average data for populations, or to use results from overviews of randomized, controlled trials and cohort studies to estimate the magnitude of effects achievable through various risk factor changes. These methods are illustrated with Australian data on trends in mortality from ischaemic heart disease and cigarette smoking, blood pressure and cholesterol during the 1980s. If it is assumed that time lags are short between reductions in risk factor levels and reductions in risk, then both methods suggest that about half the mortality decline in men, and less in women, may be related to changes in these three well-established risk factors. Improvements in population levels of blood pressure and, for men, reductions in smoking appear to be the main contributors. It is argued that such ecological analyses can provide valid results as long as care is taken to avoid various epidemiological pitfalls.

Adult↗
PubMed1994

Can the increasing weight of Australians be explained by the decreasing prevalence of cigarette smoking?

In Australia there has been a recent increase in the body mass index (BMI) of the population and a decrease in smoking prevalence. Data from the three risk factor prevalence surveys conducted by the National Heart Foundation of Australia in 1980, 1983 and 1989 were analysed to determine if the increase in BMI could be explained by the decrease in smoking. For men in all age groups and for women aged 50 years or over, there were parallel increases in mean BMI for current smokers, ex-smokers and never smokers. For women under 50 years, the pattern of increasing BMI over time was less clear. Mean BMI increased over time within each five-year age group and in age 'cohorts' and the pattern was independent of smoking status. For men and for both groups of women there were similar changes in mean BMI over time for most categories of employment status, education and physical activity. Thus the increase in body weight cannot be explained by the decrease in smoking rate, or by the other factors investigated in this paper.

Adult↗
PubMed1993

Smoking and the incidence of coronary heart disease in an Australian population.

OBJECTIVE: To estimate the impact of smoking on the incidence of coronary heart disease in Australia. Data collected for the WHO MONICA Project were used. DESIGN: Combined data from a community-based register of all suspected coronary events and a survey of risk factor prevalence in a random sample of the same population. SETTING AND PARTICIPANTS: All residents of the Hunter Region of New South Wales aged 35-69 years who had a first acute myocardial infarction or fatal heart attack (without a history of coronary heart disease) between 1 January 1986 and 31 December 1990. MAIN OUTCOME MEASURES: Acute myocardial infarction or coronary death, as defined by the WHO MONICA Project. RESULTS: Men who are current smokers are 2.9 times (95% CI, 2.7-3.1) more likely than non-smokers to have a first myocardial infarction or fatal heart attack, and for women the equivalent figure is 3.5 times (95% CI, 3.2-3.8), after adjusting for age. Current male smokers with a history of hypertension are 4.5 times more likely to have a coronary event (7.9 times in women) than are non-smokers without a history of hypertension. The age-adjusted excess rate was 566 per 100,000 per year in men and 373 per 100,000 per year in women. Smoking is a stronger predictor of coronary heart disease incidence than a history of hypertension (relative risk [RR] = 1.6 for men and 1.9 for women) or a known history of hypercholesterolaemia (RR not significantly different from 1). CONCLUSIONS: Cigarette smoking plays a more important role in the causation of a first myocardial infarction or fatal heart attack and appears to have more influence on the incidence of coronary heart disease in Australia than hypertension.

Adult↗
PubMed1993

Secondary prevention after acute myocardial infarction.

The hypothesis that 6 months after acute myocardial infarction, adoption of secondary prevention activities would be higher, quality of life better, and blood cholesterol lower in patients randomly allocated to a mail-out intervention program than in those receiving usual care was tested. Patients were aged < 70 years, admitted to hospitals in and around Newcastle, Australia with a suspected heart attack and discharged alive from the hospital. Cluster randomization, based on the patient's family practitioner, was used to allocate consenting patients to an intervention or usual care group. A low-cost mail-out program was designed to help patients reduce dietary fat, obtain regular exercise by walking and (for smokers only) to quit smoking. Supplementary telephone contact was also used. In addition, a letter was sent to the family doctor regarding the benefit of aspirin and beta blockers for secondary prevention. Of eligible patients, 71% participated, and 79% of the 213 intervention subjects and 87% of the 237 usual care ones returned a 6-month follow-up questionnaire. Self-reported fat intake was significantly lower, an "emotional" score obtained from a quality-of-life questionnaire was significantly higher in the intervention than in the usual care group, and "physical" and "social" scores for quality of life were slightly higher. Blood cholesterol level and other variables were not different between the groups at 6 months. Simple low-cost programs providing support and advice on lifestyle change may be beneficial, particularly in improving patients' perceived quality of life.

Adrenergic beta-Antagonists↗
PubMed1993

A self-administered quality-of-life questionnaire after acute myocardial infarction.

A slightly modified version of the Quality-of-Life after Myocardial Infarction (QLMI) questionnaire developed by Oldridge and colleagues was applied in a self-administered mode to patients with suspected acute myocardial infarction (AMI) in a randomized controlled trial of secondary prevention. Acceptability of the questionnaire was good, with 93% of responders answering all items. Factor analysis suggested three quality-of-life (QL) dimensions which we called "emotional", "physical" and "social". These differed somewhat from the dimensions proposed by Oldridge and colleagues. However, a sensitivity analysis showed relative invariance of results to weighting schemes. Scores on our three dimensions were responsive to differences between the treatment groups, and demonstrated construct validity based on associations between the measured QL and variables expected to affect QL. We conclude that the QLMI questionnaire has good potential as an instrument for assessing QL in post-AMI patients and that it can be successfully self-administered.

Factor Analysis, Statistical↗
PubMed1993

Seasons, temperature and coronary disease.

Using data from a community-based register of heart disease (the WHO MONICA Project) associations between daily temperature, rainfall and other seasonal effects were investigated in relation to fatal coronary events and non-fatal definite myocardial infarctions in an Australian population. Coronary events, both fatal and non-fatal, were 20-40% more likely to occur in winter and spring than at other times of the year. Coronary deaths were more likely to occur on days of low temperature (and to a much lesser extent, on days of high temperature). No differences were found between patterns of sudden and non-sudden deaths (those occurring later after the onset of symptoms) associated with weather conditions. Statistical models allowing simultaneously for longer-term seasonal effects and daily temperature effects suggested that both exist. These results suggest that avoiding temperature stress could lead to reductions in the annual peaks in coronary events.

Aged↗
PubMed1993

Short fat questionnaire: a self-administered measure of fat-intake behaviour.

A brief questionnaire has been developed to measure behaviour related to dietary fat intake. It is self-administered and self-coded. Mean completion time is about three minutes. Criterion validity was assessed by comparison with a well-established food frequency questionnaire using 124 adults from Newcastle and Sydney. The correlations with the questionnaire scores were: r = 0.55 for total fat as a percentage of total energy, r = 0.67 for saturated fat as a percentage of total energy, and r = 0.44 for polyunsaturated to saturated fat ratio. Reproducibility was assessed by re-use by 25 subjects after seven to nine months (r = 0.85). When used in a community survey of other 300 randomly chosen people in the Hunter Region, the mean scores for men and for women and among different age groups were significantly different. The questionnaire was strongly associated with other scales measuring attitudes, behaviour and knowledge related to low-fat diets. The questionnaire appears suitable for rapid self-assessment by subjects, and as it directs their attention to aspects of their diet which might need improvement, it could be used for health education. It might also be used for epidemiological studies to rank subjects broadly according to their fat-intake behaviour.

Adolescent↗
PubMed1993

Community worry about heart disease: a needs survey in the Coalfields and Newcastle areas of the Hunter region.

A needs survey was administered by mail in the Coalfields area of the Hunter region (a lower socioeconomic area around Cessnock) and in a higher socioeconomic area of Newcastle. The purpose was to assist planning for Coalfields Healthy Heartbeat--a community-action heart disease prevention program. Response rates from random samples of residents were 435/897 (49 per cent) for the Coalfields and 565/875 (65 per cent) for Newcastle. In both study areas heart attack was ranked eleventh from a list of 17 potential community worries, well below drugs, crime, road safety, the environment, cancer and 'loss of health'. Coalfields respondents were more worried about all issues on the list than were the residents in Newcastle and were less likely to have heard about recent health promotion campaigns. Coalfields respondents felt that heart disease prevention was the responsibility of the individual, the family, and the medical profession, in that order, and much less the responsibility of local community groups. Results suggest that health promotion strategies incorporating values, language and symbols that are meaningful to distinct subgroups may be more successful than disease-specific programs aimed at the general population.

Adult↗
PubMed1993

Coronary artery stenosis in an Australian population.

The purpose of this study was to examine the extent and severity of coronary stenosis in an Australian population. The subjects were autopsy cases among people aged 20-69 yrs dying in and out of hospital in the Newcastle area of New South Wales in 1985-86. Three groups were compared: coronary deaths, deaths from other natural causes and deaths due to external causes. Cross-sectional luminal narrowing in each major subepicardial artery was measured by stereological point counting. Stenosis was found, as expected, to be more severe in males than in females, increased with age and was greatest in those who died from coronary disease. Even in non-coronary deaths mean percentage luminal narrowing in the narrowest segments ranged from about 40% in people aged 20-29 yrs to over 60% in those aged 60-69 yrs. Narrowing was more pronounced in the left anterior descending artery and least in the left circumflex artery. To the extent that results from this autopsy study can be generalized to the whole population, these findings illustrate that, despite declining mortality from ischemic heart disease in Australia, coronary atherosclerosis remains a widespread problem.

Adult↗
PubMed1992

Changes in drug treatment and case fatality of patients with acute myocardial infarction. Observations from the Newcastle MONICA Project, 1984/1985 to 1988/1990.

OBJECTIVE: To describe changes in medications administered to patients with acute myocardial infarction between 1984/1985 and 1988/1990 and changes in case fatality. DESIGN: Descriptive study from the Newcastle MONICA Project, which monitors all heart attacks in men and women aged 25 to 69 years in the Lower Hunter Region of New South Wales. SUBJECTS: All patients admitted to hospital with a "definite" acute myocardial infarction who survived at least 28 days during periods in 1984/1985 (513 events) and 1988/1990 (790 events). MAIN OUTCOME MEASURES: Changes in drugs being taken immediately before the onset of the myocardial infarction, prescribed during hospitalisation and on discharge from hospital, and changes in case fatality rates. RESULTS: From the first time period to the second there were significant increases in the use of aspirin, calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors and hypolipidaemic agents, and significant reductions in the use of diuretics. In 1988/1990, 34% of patients with a definite myocardial infarction received thrombolytic therapy compared with fewer than 1% in 1984/1985. Among those patients who survived at least one hour from onset of symptoms, the case fatality rate declined from 13.5% to 7.9% (change -5.6%; 95% confidence limits, -8.9%, -2.2%). CONCLUSION: Large changes in drug treatment of patients with acute myocardial infarction have occurred in the second half of the 1980s. These may be responsible for the reduction in case fatality. Nevertheless, use of drugs of proven effectiveness in acute care and for secondary prevention is surprisingly low in this population.

Adult↗
PubMed1992

Predicting the prevalence of a disease in a cohort at risk.

A non-homogeneous Markov chain model is used to describe the evolution of a progressive chronic disease. Transition probabilities are estimated from data on coronary heart disease in Australia. By varying the transition probabilities, the effects of changes in medical management or in the natural history of the disease are examined. For reducing rates of fatal and non-fatal acute myocardial infarction a multifaceted strategy of primary and secondary prevention and improved acute care is found most effective. Primary prevention reducing the risk of early stages of the disease has the potential to yield the highest proportion of disease-free people. By contrast, intensive medical treatment of acute disease would reduce mortality but increase the total burden of disease in the population.

Adult↗
PubMed1992

Cigarette smoking and sick leave in an industrial population in Shanghai, China.

A study of cigarette smoking and sick leave was conducted at a large petrochemical complex in Shanghai, China in 1988. Among a random sample of 1856 men the smoking prevalence was 80% with the highest rate (84%) occurring in the age group 25-34 years. Only 53% of smokers and 76% of nonsmokers said they believed smoking was harmful to health and knowledge of which diseases were associated with smoking was poor. Retrospective data were also collected on sick leave in 1986 and 1987. In 1986 13% of men took sick leave and in 1987 12%; the mean duration of sick leave was 3 days per year. In 1986 the odds ratios (OR) for taking sick leave were 2.37 for heavy smokers and 1.45 for light smokers compared to unity for nonsmokers; the corresponding OR for 1987 were 1.70 and 1.28 for heavy and light smokers compared with nonsmokers. Smoking was positively associated with sick leave even after adjustment for age, consumption of alcohol and exposure to chemicals; OR = 1.56 (95% confidence interval (Cl): 1.06-2.31) in 1986 and OR = 1.32 (95% Cl: 0.90-1.95) in 1987. Demonstration of this association even in a young population with low sick leave rates illustrates yet again the adverse effects of smoking on health and the urgent need to reduce the very high prevalence of smoking in China.

Absenteeism↗