Health care research in the developing world: a successful educational experiment.
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Developing Countries↗
Biomedical subjects
A J Dobson
Publications and source records attributed to A J Dobson.
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↗
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↗
Medical care and case fatality from myocardial infarction and coronary death in Newcastle and Perth.
Coronary mortality rates are significantly higher in Newcastle than Perth. In this paper we examine the extent to which this might be due to differences in medical treatment and case fatality. Population-based disease registers were used to identify all cases of non-fatal definite myocardial infarction (MI) and coronary death in people aged 25-64 years in the study populations between July 1988 and June 1990. Case fatality (at 28 days from onset of symptoms) was not significantly different between the centres. Thrombolytic therapy was used for one third of all hospitalised events in both centres. Other drugs of proven benefit were, however, used more often in Perth than in Newcastle. For example, during hospitalisation 74% of patients in Perth received beta-blockers compared with 41% in Newcastle (difference = 33%, 95% confidence interval (CI): 28%, 37%) and 85% of patients in Perth compared with 72% in Newcastle received aspirin (difference = 13%, 95% CI: 9%, 17%). Median lengths of stay in a coronary care unit (CCU) and total hospital stay were one day shorter in Perth. As case fatality was similar, the differences in mortality rates can be attributed mainly to differences in attack rates. Greater use of cardio-active drugs in Perth apparently did not result in improved short-term outcome although potential long-term benefits cannot be judged yet.
Adult↗
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↗
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↗
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↗
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↗
Tobacco smoking in response to cigarette advertising.
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Adolescent↗
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↗
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↗
Effect of processing time and storage on fibrinogen content of EDTA plasma assayed by radial immunodiffusion.
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Adult↗
Trends in ischaemic heart disease in the Hunter Region of New South Wales 1985-1989.
OBJECTIVE: To find out whether trends in rates of non-fatal myocardial infarction (MI) parallel trends in rates of coronary death. DESIGN: A population-based observational study involving continuous surveillance of all suspected heart attacks or coronary deaths from 1985 to 1989. STUDY POPULATION: Residents of the Hunter Region of New South Wales aged under 70 years. MAIN OUTCOME MEASURES: Rates of non-fatal definite or possible MI or fatal MI or coronary death, as defined by the diagnostic criteria of the WHO MONICA Project. RESULTS: For men, mortality rates declined by an average of 16.2 per 100,000 per year (95% confidence interval [CI]: -23.8, -8.7); rates of non-fatal definite MI declined by 16.2 per 100,000 (95% CI: -27.8, -4.6); rates of non-fatal possible MI increased initially and then stabilised. For women smaller changes occurred in the same directions. CONCLUSION: In this population trends in rates for non-fatal definite MI paralleled the declines in mortality rates. Rates for less severe non-fatal possible MI did not follow this pattern, perhaps reflecting increased medical attention to chest pain.
Adult↗
Mortality from coronary heart disease and incidence of acute myocardial infarction in Auckland, Newcastle and Perth.
OBJECTIVE: To confirm the existence of regional differences in coronary death rates in Australia and New Zealand and to determine whether or not these are associated with parallel differences in the incidence of acute myocardial infarction. DESIGN: Descriptive epidemiological study. SETTING: Community based study. SUBJECTS: Residents of Auckland, Newcastle and Perth aged 25-64 years admitted to hospital for acute myocardial infarction or dying from coronary heart disease between 1983 and 1987. MAIN OUTCOME MEASURES: Definite acute myocardial infarction or coronary death classified according to the criteria of the World Health Organization MONICA project. RESULTS: This study confirms the marked variation, evident from official statistics, in mortality rates from ischaemic heart disease between Newcastle (high), Auckland and Perth (low). A different pattern is observed for the incidence of acute myocardial infarction and there are also obvious differences between centres in the case fatality ratios for all acute coronary events combined. Newcastle has the highest rate for all coronary events, particularly in women. Auckland is characterised by substantially higher case fatality ratios compared with the two Australian cities. This is due especially to higher rates of coronary death outside hospital. Perth, which has the lowest mortality rates and case fatality ratios in both men and women, has rates for admission to hospital for acute myocardial infarction and all cases of ischaemic heart disease that are disproportionately high in relation to the corresponding mortality rates. CONCLUSION: The differences in case fatality ratios between these three centres are not readily explained by artefacts related to enumeration or classification. Rather, they are most likely related to differences in the natural history of ischaemic heart disease in the three populations. Differences in medical management may also contribute to the substantial variation in mortality rates.
Adult↗
Passive smoking and the risk of heart attack or coronary death.
OBJECTIVES: To estimate the prevalence of passive smoking in an Australian population, the magnitude of risk of myocardial infarction or coronary death associated with passive smoking and the extent to which fibrinogen concentrations might be affected by passive smoking. DESIGN: A population-based case-control study of myocardial infarction or coronary death and passive smoking, and measurement of fibrinogen in a random sample from the same population. SETTING AND PARTICIPANTS: Residents of the Lower Hunter Region of New South Wales aged 35-69 years in 1988-1989. Case subjects were all those who suffered myocardial infarction or coronary death. Control subjects were participants in a risk factor prevalence survey. OUTCOME MEASURES: Myocardial infarction or coronary death, defined by criteria of the WHO MONICA Project, and fibrinogen concentration (measured in controls only). RESULTS: Prevalence of passive smoking at home was 20% for male case subjects, 13% for male control subjects, 29% for female case subjects and 19% for female control subjects. The corresponding prevalence rates for passive smoking at work were 40%, 44%, 41% and 37%. Odds ratios of myocardial infarction or coronary death for active smokers compared with non-smokers were 4.70 (95% confidence interval [CI], 3.35-6.58) in women and 2.71 (95% CI, 2.07-3.53) in men. For women the odds ratios of myocardial infarction or coronary death for those exposed to passive smoking at home were 2.46 (95% CI, 1.47-4.13) among non-smokers and 1.48 (95% CI, 0.67-3.30) among ex-smokers. For men the odds ratios for passive smoking at home were 0.97 (95% CI, 0.50-1.86) for non-smokers and 1.78 (95% CI, 1.13-2.79) for ex-smokers. The odds ratios for passive smoking at work did not suggest increased risk. Fibrinogen concentrations were generally higher among people exposed to passive smoking at home or work compared with those not exposed but were not as high as concentrations in active smokers. CONCLUSIONS: Passive smoking increases the risk of coronary heart disease and increased fibrinogen concentration provides a marker of its effect.
Adult↗
Lipid and apolipoprotein levels in an Australian community.
Serum levels of total and high density lipoprotein (HDL) cholesterol and apolipoproteins A1 and B were measured in over 600 men and women aged 30-69 years who were selected at random from an Australian community. Total cholesterol and apolipoprotein A1 and B levels increased with age, with this effect being most pronounced for total cholesterol and apolipoprotein B in women. Body mass index and waist-to-hip ratio were positively correlated with apolipoprotein B and total cholesterol levels, and negatively correlated with apolipoprotein A1 and HDL cholesterol levels. All lipid and apolipoprotein A1 levels increased with the quantity of alcohol consumed. After adjusting for age, body mass index and smoking, the association with alcohol was strongest for apolipoprotein A1 and HDL cholesterol levels in men (P = 0.0001), and for apolipoprotein A1 levels in women (P = 0.01). Levels of apolipoprotein A1 and HDL cholesterol were lower, and of apolipoprotein B and total cholesterol were higher, in current cigarette smokers than non-smokers, with significant associations for apolipoprotein B (P = 0.004) and HDL cholesterol levels (P = 0.04) in men. In general, the associations between apolipoprotein A1 levels and the other variables were weaker than those for HDL cholesterol levels, whereas the associations with apolipoprotein B levels were stronger than those for total cholesterol levels (except for alcohol consumption). Thus, obesity, alcohol consumption and cigarette smoking should be considered when interpreting apolipoprotein levels.
Adult↗
Confidence intervals for weighted sums of Poisson parameters.
Directly standardized mortality rates are examples of weighted sums of Poisson rate parameters. If the numbers of events are large then normal approximations can be used to calculate confidence intervals, but these are inadequate if the numbers are small. We present a method for obtaining approximate confidence limits for the weighted sum of Poisson parameters as linear functions of the confidence limits for a single Poisson parameter, the unweighted sum. The location and length of the proposed interval depend on the method used to obtain confidence limits for the single parameter. Therefore several methods for obtaining confidence intervals for a single Poisson parameter are compared. For single parameters and for weighted sums of parameters, simulation suggests that the coverage of the proposed intervals is close to the nominal confidence levels. The method is illustrated using data on rates of myocardial infarction obtained as part of the WHO MONICA Project in Augsburg, Federal Republic of Germany.
Adult↗
How soon after quitting smoking does risk of heart attack decline?
A population-based case-control study (involving 1282 cases and 2068 controls) was conducted to examine the risk of myocardial infarction or coronary death after cigarette smokers quit smoking. The odds ratios for current smokers were significantly elevated compared to non-smokers (OR = 2.7 for men and OR = 4.7 for women). For ex-smokers odds ratios declined rapidly after quitting and after about 3 years they were not significantly different from unity. Fibrinogen concentrations measured in the controls only were higher in current smokers and ex-smokers up to 2 years after quitting than in non-smokers and after that time were similar to levels in non-smokers; however, most of the differences among categories of smokers were not statistically significant. These results support the hypothesis that risk of a coronary event in ex-smokers declines rapidly after quitting and within 2-3 years is similar to the risk for non-smokers.
Adult↗