Biomedical subjects
A M Fehily
Publications and source records attributed to A M Fehily.
Dietary magnesium and prediction of heart disease.
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Frequency of citation and outcome of cholesterol lowering trials.
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Coronary heart disease and dietary factors.
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Alcohol and platelet aggregation: the Caerphilly Prospective Heart Disease Study.
Intakes of alcohol and saturated fatty acids were determined through a dietary questionnaire from 1600 men (aged 49-66 y) in the Caerphilly Prospective Heart Disease Study. Platelet aggregation induced by thrombin adenosine disphosphate (ADP), and collagen was studied in subjects who had fasted and had not recently taken drugs affecting platelets. In subjects who drank alcohol, the odds ratio of a high response to aggregation was significantly reduced (primary ADP, P less than 0.05; secondary ADP, P less than 0.001; collagen, P less than 0.02). The significance was enhanced by adjusting for smoking and by including only the subjects with a high intake of saturated fatty acids or a low intake of polyunsaturated fatty acids. By contrast, the responsiveness to thrombin was slightly increased at all levels of alcohol consumption. We therefore suggest that part of the effects of alcohol on coronary heart disease may be mediated by a dose-dependent effect on certain platelet functions, modulated by the intake of dietary fat.
Factors affecting bone density in young adults.
A 14-y follow-up of 581 children who took part in a randomized controlled trial of the effect of a milk supplement on growth of children was conducted to investigate the supplement's effect on adult bone mineral content (BMC) and density (BMD). BMC and BMD of the nondominant forearm were measured by single-photon absorptiometry in 371 subjects (64%) aged 20-23 y, at a proximal site (shaft of radius and ulna) and at a distal site near the wrist. BMCs and BMDs tended to be higher in the intervention group (NS). Cross-sectionally, BMD was positively associated with body weight (P less than 0.01) in both sexes; inversely associated with alcohol consumption (P less than 0.05), and positively with manual occupation (NS) in men; positively associated with current intakes of calcium (P less than 0.05), vitamin D (P less than 0.01), and sports activity during adolescence (P less than 0.01), and inversely with parity (NS) in women. In multiple linear-regression analysis body weight and sports activity during adolescence were stronger determinants of female BMD than was diet.
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.
Long-term diet modification and platelet activity.
Platelet activity was assessed in a sub-sample of 56 participants in the MRC Diet and Reinfarction Trial (DART). Men whose diets contained a high ratio of polyunsaturated to saturated fatty acids (a P:S ratio of greater than 0.5) showed reduced secondary platelet aggregation to adenosine diphosphate (ADP) in platelet-rich plasma (PRP), and diminished platelet aggregation to ADP in whole blood. A trend of reduced secondary platelet aggregation to ADP with increasing dietary eicosapentaenoic acid was noted, but this was not statistically significant. The results of this study and the MRC Diet and Reinfarction Trial suggest a mediatory role for platelet activity in the relationship between diet and ischaemic heart disease.
Fatty fish and heart disease: a randomized controlled trial.
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The diets of men in four areas of the UK: the Caerphilly, Northern Ireland, Edinburgh and Speedwell studies.
Nutrient intakes in four areas of the UK were compared, 7-d weighed intake data were obtained for representative community samples of middle-aged men in Caerphilly (South Wales), Northern Ireland, Edinburgh and Bristol (Speedwell). Intakes of energy were higher in Edinburgh than in the other three areas, but following allowance for this, differences in nutrient intakes were very small. The exceptions were P/S ratio and alcohol consumption. The P/S ratio for Northern Ireland (0.38) was considerably higher than that for the other areas (0.30 to 0.32). The proportion of heavy drinkers was higher in Edinburgh (15 per cent) than in other areas (5-9 per cent) and the proportion of abstainers was highest in Northern Ireland (38 per cent). Differences in nutrient intakes did not parallel the differences in ischaemic heart disease (IHD) mortality rates between the areas.
Body fatness and frame size: the Caerphilly study.
The effect of adjusting height-weight indices for frame size on the prediction of body fatness was investigated in a community sample of 2512 men aged 45-59 years. Body fatness was assessed from skinfold thickness measurements at four sites: triceps, biceps, subscapular and supra-iliac. Body diameters (biacromial, bi-iliocristal, wrist or knee) were used as estimates of frame size. Body diameters were not independent of body fatness, wrist diameter showing the lowest association with skinfold thickness measurements. Adjustment of weight/height2 (W/H2) for frame size had little effect on the prediction of body fatness, the correlation coefficient for body fatness with W/H2 (r = 0.76) being almost identical to that for W/H2 adjusted for wrist diameter (r = 0.74).
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.
Cigarettes and heart disease.
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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.
Type A behaviour, eating pattern and nutrient intake: the Caerphilly Study.
Relationships between type A behaviour and eating pattern and nutrient intake were investigated in a representative sample of 532 employed men aged 45-59 years drawn from the Caerphilly study. Eating pattern and nutrient intake were assessed by 7-day weighed dietary records. A change in Framingham type A scores from the lower third to the upper third was associated with a 9% reduction in meal size and a 6% increase in meal frequency. No trends with type A were found for nutrient intake in absolute terms. For means of nutrient intake as a percentage of energy, however, higher values for sugar and lower values for starch and polyunsaturated fat were observed with higher type A scores. In multiple regression analysis, after control for the effects of age, height, social class and smoking, significant associations with type A were found only for meal size, dietary fibre per MJ and sugar as a percentage of energy. It is concluded that diet is unlikely to be an explanation of the relationship between type A and ischaemic heart disease.
Infant feeding and allergy.
The effect of withholding cows' milk was examined in 487 infants at high risk of allergic disease. Before birth they were randomly allocated either to a control group, most of whom received cows' milk preparations, or to an intervention group, who were offered a soya based substitute. Eczema and wheezing occurred to a similar extent in the two groups during the first year of life, although napkin rash, diarrhoea, and oral thrush were commoner in the intervention group, especially during the first three months. Breast feeding for any length of time was associated with a reduced incidence of wheezing and diarrhoea.
Dietary determinants of plasma lipids and lipoproteins: the Caerphilly Study.
Associations between nutrient intakes and plasma lipids were examined in a representative sample of 653 middle-aged men in Caerphilly, South Wales. Nutrient intakes were calculated from 7-d weighed intake records and were expressed both as g/d and as a percentage of total energy intake. In multivariate analyses, after taking the effects of potential confounding factors (age, body mass index and smoking habit) into account, the percentage of variance in the plasma lipid concentrations which could be explained solely by the dietary variables was very small, ranging from 1 to 7 per cent. Associations which were statistically significant included a positive association between saturated fat intake and both total cholesterol and low density lipoprotein cholesterol; a negative association between carbohydrate intake and both total cholesterol and high density lipoprotein cholesterol (HDL-C); a positive association between magnesium intake and an HDL-C subfraction (HDL2-C); a positive association between alcohol intake and each of the following: HDL-C, its subfractions and triglyceride.
Nutritional determinants of haemostatic factors in the Caerphilly Study.
A study of possible nutritional determinants of certain haemostatic factors (heparin-neutralizing activity, fibrinogen and antithrombin III) was conducted in the Caerphilly cohort of 2512 men. Data on diet were obtained in a sub-sample of 665 men by a 7-d weighed dietary inventory and in the complete cohort by questionnaire. All the associations between major nutrients and haemostatic factors were weak and few achieved statistical significance. There were significant associations between two of the blood tests and total energy intake which suggests that, in general, relationships between nutritional variables and thrombosis-related factors should be standardized for total energy intake. Negative associations between alcohol, fibrinogen and antithrombin III and positive associations between fibre, polyunsaturated fat and antithrombin III are of possible clinical or public health importance. However, nutritional factors appear to explain only about 3 per cent of the variance in the distributions of the haemostatic factors examined. The extent to which uncertainties in the measurement of dietary intake will have led to the underestimate of the true association is, of course, unknown. At the same time it is of relevance that in similar studies of dietary determinants of plasma cholesterol only about 3 per cent of the variance of cholesterol levels can be explained.