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Biomedical subjects

M L Burr

Publications and source records attributed to M L Burr.

At least 19 recordsLinked to original sources
PubMed1992

Haematological prognostic indices after myocardial infarction: evidence from the diet and reinfarction trial (DART).

Data from the Diet and Reinfarction Trial were examined to check the prognostic effects of plasma fibrinogen, plasma viscosity, white blood cell count, haemoglobin and mean platelet volume in 92 deaths among 1755 men who had recently recovered from acute myocardial infarction. All these variables were significantly associated with all-cause mortality over the following 18 months (haemoglobin negatively, the others positively). Those who gave up smoking following their infarct had a lower mortality than those who continued to smoke (4.1% and 7.9% respectively), and this effect appeared to be mediated by fibrinogen levels. Smoking habit accounted for only part of the prognostic effect of fibrinogen and white blood cell count. Haematological variables have an important prognostic significance after myocardial infarction. Cessation of smoking after myocardial infarction is worthwhile and has a favourable effect on plasma fibrinogen.

Blood Viscosity↗
PubMed1992

Fish food, fish oil and cardiovascular disease.

During recent years there has been growing interest in the possibility that dietary fish confers some protection against ischaemic heart disease. In four prospective studies, people who ate moderate amounts of fish tend to have a lower mortality from heart disease than persons who ate little or no fish. A randomized controlled trial showed that mortality after myocardial infarction was less among men who were advised to increase their intake of fatty fish than in a control group. Studies of fish oil administered to volunteers suggest that it is the omega-3 fatty acids which are responsible. The effects of fish oil include a reduction in serum triglyceride concentration, a reduction in platelet activity, a reduction in blood pressure, and (in animals) prevention of arrhythmias. Some of these effects require doses much larger than those that would normally be supplied by dietary fish.

Animals↗
PubMed1991

Influence of platelet size on outcome after myocardial infarction.

Although platelet characteristics have an important influence on ischaemic heart disease, the nature of the association of platelet size and platelet count with death and reinfarction after an index heart attack is unknown. Mean platelet volume (MPV), a determinant of platelet reactivity, was measured in 1716 men six months after myocardial infarction (MI). Deaths and recurrent ischaemic heart disease events were then assessed at two years. MPV was greater in 126 men who had a further ischaemic event (fatal or non-fatal) than in the 1590 men who had no further MI (p less than 0.001). In addition, the MPV was larger in men who died than in those who did not (p less than 0.001). There was no difference in platelet count between these groups. When analysed by quartiles, consistent trends of increasing age-adjusted relative odds of death and recurrent ischaemic events were noted for MPV. MPV did not correlate with known ischaemic heart disease risk factors such as blood pressure, blood lipids, fibrinogen, white cell count, or plasma viscosity. We believe that MPV is a further independent risk factor for recurrent MI.

Aged↗
PubMed1991

Helicobacter pylori infection rates in relation to age and social class in a population of Welsh men.

The seroprevalence of IgG antibodies to Helicobacter pylori was determined using a standard enzyme linked immunosorbent assay in a population of 749 randomly selected men, aged 30-75 years, from Caerphilly, South Wales. The overall prevalence of H pylori was 56.9%, increasing sharply in middle age from 29.8% in those aged 30-34 to over 59% in those aged 45 or older (p less than 0.0001). Age standardised seroprevalence rates were lowest in combined social class categories I and II (49.2%), intermediate in categories IIIN and M (57.5%), and highest in categories IV and V (62.2%) (p = 0.01). In those aged 30-34 years, the prevalence rate for those in combined social class categories IV and V was 57.9% - double the rate for social class categories IIIM and N (28.3%) and five times the prevalence rate in those in social class categories I and II (11.1%). These differences in the infection patterns of H pylori by social class are consistent with patterns of peptic ulcer disease and gastric cancer.

Adult↗
PubMed1991

Prevalence of asthma among 12 year old children in New Zealand and South Wales: a comparative survey.

A survey of 12 year old schoolchildren was carried out in New Zealand and South Wales, the same questionnaire and exercise provocation test being used. The prevalence of a history of asthma at any time was higher in New Zealand (147/873, 17%) than in South Wales (116/965, 12%). The New Zealand children were also more likely than the Welsh children to have a history of "wheeze ever" (27% versus 22%), and wheeze brought on by running (15% versus 10.5%). The sex ratio of asthmatic and wheezy children was very similar in the two countries. A history of hospital admission for chest trouble was twice as common in New Zealand as in South Wales. An exercise test produced a fall in peak expiratory flow rate of 15% or more in more New Zealand children (12.2%) than Welsh children (7.7%). These results suggest that the prevalence of childhood asthma is higher in New Zealand than in South Wales.

Animals↗
PubMed1991

Epidemiology of childhood asthma.

There is considerable concern in several countries that the death-rate for asthma is rising among children. Hospital admission-rates have been rising steeply in England and Wales, as in other countries; the rise does not seem to be attributable to the admission of less severe cases. The possibility of increasing prevalence is difficult to assess because of the lack of a clear-cut definition of asthma and the consequent uncertainty as to whether children are now labelled as asthmatic who formerly would not have been. Repeat surveys using identical methodology are needed to provide reliable information. In 1973 a survey was conducted in South Wales among 12-year old children, and repeated in the same area in 1988. An increase has occurred in reported asthma, in relevant symptoms, and in exercise-induced bronchospasm. Data from Sweden, Finland, New Zealand and elsewhere suggest that the rise in asthma is a worldwide phenomenon, and is associated with some environmental factors in the developed countries. The cause of the increase is a matter of speculation.

Adolescent↗
PubMed1989

Effects of changes in fat, fish, and fibre intakes on death and myocardial reinfarction: diet and reinfarction trial (DART).

A randomised controlled trial with a factorial design was done to examine the effects of dietary intervention in the secondary prevention of myocardial infarction (MI). 2033 men who had recovered from MI were allocated to receive or not to receive advice on each of three dietary factors: a reduction in fat intake and an increase in the ratio of polyunsaturated to saturated fat, an increase in fatty fish intake, and an increase in cereal fibre intake. The advice on fat was not associated with any difference in mortality, perhaps because it produced only a small reduction (3-4%) in serum cholesterol. The subjects advised to eat fatty fish had a 29% reduction in 2 year all-cause mortality compared with those not so advised. This effect, which was significant, was not altered by adjusting for ten potential confounding factors. Subjects given fibre advice had a slightly higher mortality than other subjects (not significant). The 2 year incidence of reinfarction plus death from ischaemic heart disease was not significantly affected by any of the dietary regimens. A modest intake of fatty fish (two or three portions per week) may reduce mortality in men who have recovered from MI.

Actuarial Analysis↗
PubMed1989

Diet and reinfarction trial (DART): design, recruitment, and compliance.

A randomized controlled trial has been set up to examine the effect of diet on the secondary prevention of myocardial infarction, involving 2033 men. The trial has a factorial design, subjects being randomized independently to receive advice or no advice regarding three dietary factors: 1. a reduction in total fat and an increase in polyunsaturated fat intake; 2. an increase in fatty fish intake; 3. an increase in cereal fibre intake. Nearly half the men under 70 years of age who survived myocardial infarction during the recruitment period entered the trial, the commonest reason for exclusion being that the subject was already eating (or intended to eat) a diet which included one or more of the regimens being investigated. Detailed dietary questionnaires were completed by each subject after 6 months in the trial. The results suggest that compliance with the advice is reasonably good. The differences between the diets of the groups given and not given advice on fish and fibre were substantial; the difference attributable to advice on fat has been somewhat less than anticipated, partly because of failure to comply with advice and partly because of spontaneous changes in the diets of control subjects.

Animals↗
PubMed1989

Changes in asthma prevalence: two surveys 15 years apart.

In 1973 a survey was conducted among 12 year old children living in a defined area of South Wales. In 1988 the survey was repeated in the same area, again among 12 year old children. Questionnaires were completed for all 965 children in the population sample; peak expiratory flow rates were performed on them all, and repeated (except for five children) after an exercise provocation test. The prevalence of a history of wheeze at any time had increased from 17% to 22%, while that of a history of asthma at any time had increased from 6% to 12%. Current asthma had increased from 4% to 9%, but wheezing in the past year not attributed to asthma had remained at 6%. The exercise provocation tests suggested that both mild and severe asthma had become more common. Increases had also occurred in the frequencies of a history of eczema (from 5% to 16%) and of hay fever (from 9% to 15%). It seems that the prevalence of asthma has risen, and that this cannot be wholly explained by a greater readiness to diagnose the disease.

Asthma↗
PubMed1989

Environmental factors and symptoms in infants at high risk of allergy.

STUDY OBJECTIVE: To identify environmental determinants of six symptoms associated with allergic disease in infancy. DESIGN: Infants were participants in a prospective randomised controlled trial of feeding practices in families with a history of atopy. SETTING: Infants were recruited in two maternity hospitals in S Wales and followed up in the community for 1 year. PARTICIPANTS: Mothers of 519 infants agreed to participate, but 36 were excluded (mainly for moving home or failing to attend for follow-up), leaving 483 in the study (253 male, 230 female). Infants were followed up and examined for evidence of allergic disease at 3, 6, and 12 months. MEASUREMENTS AND MAIN RESULTS: At each examination, mothers were questioned about episodes of illness in the infant, and the data presented relate to (reported and observed) eczema and nasal discharge, and (reported) wheeze, prolonged colds, diarrhoea and vomiting. Mothers kept a diary with details of feeding for the first 6 months. All homes were visited by a nurse who took samples of dust for dust mite antigen analysis. Extensive socio-demographic data were collected. None of the factors studied showed a convincing relationship with eczema. In a multiple logistic regression analysis breast feeding appeared to protect against wheeze, nasal discharge, colds, vomiting and diarrhoea. Having more siblings increased the likelihood of prolonged colds, and (together with overcrowding) of wheeze and nasal discharge. Maternal smoking and low social class were associated with wheeze, and house dust antigen with prolonged colds. Respiratory symptoms were associated with some aspects of housing but these could not be distinguished clearly from other social factors. Babies born in Autumn were at increased risk of wheeze, vomiting and diarrhoea. CONCLUSIONS: Environmental factors play an important part in determining risk of symptoms in potentially atopic babies. These factors are in principle open to manipulation.

Allergens↗
PubMed1989

Coffee, blood pressure and plasma lipids: a randomized controlled trial.

A randomized controlled trial was conducted to examine the effects of coffee (as commonly drunk in Britain) on blood pressure and plasma lipids in healthy subjects. Fifty-four subjects followed three regimens successively, the order being randomized according to a Latin square design: five or more cups of coffee daily for 4 weeks; five or more cups of decaffeinated coffee daily for 4 weeks but no ordinary coffee; no coffee for 4 weeks. Coffee appeared to cause a small rise (of 3 mm Hg) in recumbent systolic blood pressure; this effect was less than, and obscured by, changes induced by posture and mild stress. No consistent changes attributable to coffee were found in diastolic blood pressure or pulse rate. Small changes in the expected directions occurred in plasma high density lipoprotein (HDL) cholesterol and apolipoprotein AI (decrease), and in total cholesterol, non-HDL cholesterol and apolipoprotein B (increase), but none of these were statistically significant. The effect of coffee on risk of heart disease in Britain is probably small.

Adolescent↗