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H W Blackburn

Publications and source records attributed to H W Blackburn.

10 recordsLinked to original sources
PubMed1998

Fruit and fish consumption: a possible explanation for population differences in COPD mortality (The Seven Countries Study).

OBJECTIVE: To investigate whether average intake of antioxidants, fruits, vegetables and fish may help to explain international differences in chronic obstructive pulmonary disease (COPD) mortality. DESIGN: Ecological analysis using information on baseline diet and the 25-year COPD mortality rate in the 16 cohorts of the Seven Countries Study. SETTING: Population-based cohorts. SUBJECTS: Men aged 40-59 years at baseline. METHODS: Dietary information was collected at baseline in small random samples of each cohort. In 1987 the reported foods were bought locally and analysed chemically. After 25 years of follow-up the underlying cause of death of those who died was established centrally. COPD mortality rate ratios were calculated, for a change equivalent to 10% of the overall mean consumption of a dietary factor. RESULTS: We observed independent inverse associations between 25-year COPD mortality and baseline consumption of fruits (rate ratio 0.49; 95% confidence interval 0.36-0.67) and fish (rate ratio, 0.97; 95% confidence interval 0.93-1.00), after adjustment for potential confounders. COPD mortality showed no statistically significant association with intake of antioxidants or vegetables. Fruit and fish consumption together explained about 67% of the variance in the COPD mortality rates of the cohorts. CONCLUSIONS: Fruit and fish consumption may partly explain population differences in COPD mortality. This is in accordance with suggestions for a relationship between fruit and fish consumption and COPD observed in studies in individuals.

Adult↗
PubMed1976

Duration of hospitalization in "uncomplicated completed acute myocardial infarction". An Ad Hoc Committee review.

The clinical and laboratory findings diagnostic of acute myocardial infarction include at least two of the following: (1) a history of pain consistent with myocardial ischemia, (2) electorcardiographic findings consistent with infarction, and (3) a rise in the serum level of specific cardiac enzymes. By the 4th or 5th day of illness, specific criteria can be applied to assign certain patients to a subset with "uncomplicated completed acute myocardial infarction." These criteria include the absence of evidence of (1) continuing cardiac ischemia, (2) left ventricular failure, (3) shock, (4) important cardiac arrhythmias, (5) conduction disturbances, and (6) other serious illnesses in patients with an established acute myocardial infarction. In terms of prognosis and management, patients in this subset should be regarded as substantively different from patients in other subsets. They should respond favorably to short periods of immobilization and hospitalization than those generally used. They may remain at bed rest (modified in regard to sitting and the use of a commode) for 4 days. Subsequently, mobilization with a program of progressive activity over the ensuing 5 to 10 days should reduce the duration of hospitalization to less than the current average of 17.5 to 20.8 days for patients with acute myocardial infarction. Nine to 14 days should suffice in most instances. Current and future trials may indicate that still earlier mobilization and shorter hospitalization periods can be applied to certain patient groups, but the evidence on this point is incomplete. For the individual patient, many factors will determine the optimal duration of bed rest and hospital stay. The patient's physician must consider the therapeutic benefits that may attend earlier mobilization and shorter hospitalization while weighing potential disadvantages. When the responsible physician does not regularly care for the patient, consultation with an experienced cardiologist is desirable. Patients whose condition is classified as "uncomplicated" may manifest deterioration during their illness and require assignment to a subset with a different prognosis and requiring different forms of treatment. For patients with uncomplicated acute myocardial infarction, as well as those in other subsets, absolute rules for therapy are unwise and application of broader principles by the alert physician is more likely to be beneficial.

Arrhythmias, Cardiac↗
PubMed1976

The concepts of sensitivity, specificity and accuracy in evaluation of electrocardiographic, vectorcardiographic and polarcardiographic criteria.

The concepts sensitivity and specificity are critically evaluated in the light of case studies drawn from electrocardiographic literature. These terms are often misused, and the meaning of these elementary statistical concepts is often misunderstood in studies on ECG, VCG and PCG criteria. Specificity figures reported in literature commonly refer to the fraction of true negatives with a negative test in normals. Limiting the test to two-group analysis and eliminating other disease categories tend to give overoptimistic values for specificity and diagnostic accuracy in general. It is pointed out that various performance indices for diagnostic accuracy depend heavily on the composition of the test groups and the fraction of test cases in each group. Sensitivity and specificity appear inadequate performance indices for evaluation of event detection schemes such as classification of ectopic beats. Alternative performance indices are considered, including the error ratio, association index, accuracy of positive test, accuracy of negative test, and overall diagnostic accuracy. Increased utilization of simple statistical tests for significance estimation in ECG criteria evaluation is suggested. The development and application of better diagnostic performance evaluation schemes based on concepts of cost of misclassification, entropy and information is encouraged.

Arrhythmias, Cardiac↗