Search PubMed⌕ Search

Biomedical subjects

T W Meade

Publications and source records attributed to T W Meade.

At least 109 records · Page 6Linked to original sources
PubMed1991

Hormone replacement therapy in general practice: a survey of doctors in the MRC's general practice research framework.

OBJECTIVES: To survey current prescribing practice for hormone replacement therapy among general practitioners and to elicit their views on the role of hormone replacement therapy in the prevention of osteoporosis and cardiovascular disease; to determine whether they would participate in randomised controlled trials to evaluate the long term beneficial and adverse effects of hormone replacement therapy. DESIGN: Postal questionnaires to general practitioners throughout the United Kingdom. PARTICIPANTS: 1268 general practitioners in the Medical Research Council's general practice research framework. RESULTS: 1081 (85%) doctors in 220 (95%) practices responded. The doctors were currently prescribing hormone replacement therapy to an estimated 9% of their female patients aged 40 to 64, and 55% of doctors were prescribing opposed hormone replacement therapy (oestrogen plus progestogen) to more patients than a year previously. Over half the doctors would consider prescribing hormone replacement therapy for prevention of osteoporosis (670, 62%) and cardiovascular disease (611, 57%) to asymptomatic women. Overall, 79% of the doctors (851) would definitely or probably consider entering women who have had a hysterectomy into a randomised controlled trial comparing unopposed (oestrogen only) hormone replacement therapy with opposed hormone replacement therapy; 49% (524) would enter patients with a uterus into such a trial. Among a subsample, 85% (180/210) would consider entering patients without menopausal symptoms into a trial comparing hormone replacement therapy with no treatment (unopposed in patients who have had a hysterectomy, opposed in those with a uterus). CONCLUSION: There is considerable uncertainty among general practitioners as to the balance of beneficial and harmful effects of hormone replacement therapy in the long term, particularly relating to its use for prevention of osteoporosis and cardiovascular disease. Most of these doctors would be prepared to participate in randomised controlled trials to determine the long term effects of this increasingly widely used treatment.

Adult↗
PubMed1991

Variation in the promoter region of the beta fibrinogen gene is associated with plasma fibrinogen levels in smokers and non-smokers.

We investigated the association between fibrinogen levels and a HaeIII restriction fragment length polymorphism located at -453 bp from the start of transcription of the beta fibrinogen gene. 292 healthy men aged 45 to 69 years, recruited from general practices throughout Britain, were studied. None had a history of ischaemic heart disease. 41.1% (120) were smokers and fibrinogen levels were higher in this group. The frequency of the non-cutting allele (designated H2) was 0.19 and was the same in smokers and non-smokers. The H2 allele was associated with elevated levels of fibrinogen in both smokers and non-smokers and the effect of genotype was similar in both groups. After smoking, HaeIII genotype was the strongest predictor of fibrinogen levels and explained 3.1% of the variance in fibrinogen levels. These results confirm earlier studies that variation at the fibrinogen locus contributes to the between-individual differences in plasma fibrinogen level.

Base Sequence↗
PubMed1991

Plasma factor VII is activated by postprandial triglyceridaemia, irrespective of dietary fat composition.

Nine adults took two 7-day diets of standardised energy and total fat content, but with a dietary polyunsaturated/saturated fat ratio of less than 0.3 and greater than 3.0 respectively, while adhering to their daily routine. Blood was drawn on 6 occasions between 09.00 and 22.45 h on the final day of each dietary period for factor VII activity (VIIc), factor VII antigen (VIIag) and lipoprotein lipid concentrations. Diurnal variation was described for each variable in terms of its deviation from the individual's daily mean value at each time point across the day. Plasma triglyceride remained low until after the midday meal, whereafter a marked rise was sustained into the later evening. Plasma VIIc declined until early afternoon, but showed a marked rise in the late afternoon. Plasma VIIag showed no significant diurnal variation. Changes in plasma triglyceride concentration during the day were related positively to changes in VIIc about 160 min later, but not to VIIc at other time points. This effect of postprandial triglyceridaemia on VIIc persisted after allowance for the effect of VIIag on VIIc. Dietary fat composition did not influence VIIc or VIIag. The results suggested an acute but evanescent effect of triglyceride-rich lipoproteins on the reactivity of factor VII, irrespective of their lipid core composition.

Antigens↗
PubMed1990

Low back pain of mechanical origin: randomised comparison of chiropractic and hospital outpatient treatment.

OBJECTIVE: To compare chiropractic and hospital outpatient treatment for managing low back pain of mechanical origin. DESIGN: Randomised controlled trial. Allocation to chiropractic or hospital management by minimisation to establish groups for analysis of results according to initial referral clinic, length of current episode, history, and severity of back pain. Patients were followed up for up two years. SETTING: Chiropractic and hospital outpatient clinics in 11 centres. PATIENTS: 741 Patients aged 18-65 who had no contraindications to manipulation and who had not been treated within the past month. INTERVENTIONS: Treatment at the discretion of the chiropractors, who used chiropractic manipulation in most patients, or of the hospital staff, who most commonly used Maitland mobilisation or manipulation, or both. MAIN OUTCOME MEASURES: Changes in the score on the Oswestry pain disability questionnaire and in the results of tests of straight leg raising and lumbar flexion. RESULTS: Chiropractic treatment was more effective than hospital outpatient management, mainly for patients with chronic or severe back pain. A benefit of about 7% points on the Oswestry scale was seen at two years. The benefit of chiropractic treatment became more evident throughout the follow up period. Secondary outcome measures also showed that chiropractic was more beneficial. CONCLUSIONS: For patients with low back pain in whom manipulation is not contraindicated chiropractic almost certainly confers worthwhile, long term benefit in comparison with hospital outpatient management. The benefit is seen mainly in those with chronic or severe pain. Introducing chiropractic into NHS practice should be considered.

Adolescent↗
PubMed1990

Low-dose warfarin and low-dose aspirin in the primary prevention of ischemic heart disease.

The thrombotic component in ischemic heart disease (IHD) is now universally recognized. It is therefore logical to consider modifying both fibrin formation and platelet function in primary (as well as secondary) prevention. The scientific case for evaluating lower-dose warfarin in primary prevention rests on the implications of the secondary prevention trials, increasing evidence of an association between the level of factor VII coagulant activity, VIIc, and the incidence of IHD, and the results of short-term lower-dose trials for the prevention of venous thrombosis and thromboembolism. The general case for considering aspirin in primary prevention is well known, but the potential value of low-dose aspirin in men at high risk needs to be established. Currently available evidence suggests that the combination of lower doses of both warfarin and aspirin in primary prevention may be effective and safe. The objective of the factorial Thrombosis Prevention Trial is to demonstrate a reduction in the incidence of IHD in men at high risk attributable to low-dose warfarin or low-dose aspirin, or both, with 1 group receiving both active treatments. The feasibility of this trial has been demonstrated. An International Normalized Ratio of about 1.5, achieved with an average daily dose of 4.6 mg warfarin, has resulted in no increase in the number of men ever reporting minor bleeding episodes, although rectal bleeding occurs more frequently in those men who do report this symptom.

Aspirin↗
PubMed1990

Antithrombin III and procoagulant activity: sex differences and effects of the menopause.

Among participants in the Northwick Park Heart Study, antithrombin III activity was lower in pre-menopausal women than in men of the same age. In the women, however, the menopause was associated with a significant increase in antithrombin III, mean levels in these older women then exceeding levels in men of the same age. The occurrence of the menopause was also accompanied by large increases in factor VII coagulant activity, VIIc, and in plasma fibrinogen, these increases being greater in those experiencing a natural menopause than in those whose menopause was artificial. Sex differences in antithrombin III may form part of the explanation for the observed differences between men and women in their experience of ischaemic heart disease (IHD) and also for the contrasting effects of oral contraceptives and of hormone replacement therapy on the risk of thromboembolic disease.

Adult↗
PubMed1989

Risk factors for stroke and myocardial infarction in women in the United Kingdom as assessed in general practice: a case-control study.

Data available in the United Kingdom through the Medical Research Council's General Practice Research Framework were recorded in a study of 603 women aged 45-69 with confirmed diagnoses of stroke or myocardial infarction, each matched by age with two controls. Current cigarette smoking and a family history of myocardial infarction were both strongly associated with the risk of stroke and myocardial infarction, with relative risks of 2.47 (95% confidence interval 1.89 to 3.23) and 1.93 (95% confidence interval 1.52 to 2.44) respectively. The relative risks associated with past smoking decreased according to the length of time since stopping smoking. A family history of stroke was not significantly related to the risk of stroke or myocardial infarction. Single women had a lower risk of stroke and myocardial infarction than married women (relative risk 0.49), but parity, past use of oral contraceptives, and menopausal state were not significantly related to the risk of stroke and myocardial infarction in this study. Other characteristics that were identified as risk factors either for subsequent stroke or for myocardial infarction included not only hypertension, diabetes, and past histories of stroke and myocardial infarction, but also past histories of gynaecological cancer and of venous thrombosis. The association with venous thrombosis may indicate the importance of the haemostatic system in a common pathogenesis of venous thrombosis and myocardial infarction.

Aged↗
PubMed1989

The use of hormonal replacement therapy and the risk of stroke and myocardial infarction in women.

STUDY OBJECTIVE: To determine whether there is an association between the use of hormonal replacement therapy (HRT) and the risk of stroke and myocardial infarction (MI). DESIGN: A case-control study of women with stroke or MI was undertaken. SETTING: The cases were notified from 83 general practices to the coordinating centre at Northwick Park Hospital, where the diagnoses were independently confirmed. SUBJECTS: The cases, 603 white women aged 45-69, were each matched to two controls for age and general practitioner. Of the controls, 79% were the first eligible, 15% the second eligible and 6% were obtained at the third or more attempt. MEASUREMENTS AND MAIN RESULTS: A research nurse completed a questionnaire for each case and both controls, which included information obtained from the medical notes on the prescriptions of HRT. An independent quality control check on the selection of controls and on the abstraction of information from the medical notes was made. More than one HRT prescription had been given to 109 cases (18%) and 174 controls (14%), showing a weak association between the risk of stroke and MI and the past use of HRT (relative risk [RR] 1.36, 95% confidence interval [CI] 1.01-1.81). There was a stronger association with preparations contained progestogen alone (RR 1.90, 95% CI 1.11-3.25). On average, HRT had been used 9 years before recruitment to the study and for 15 months. However, the observed gradients of risk according to the duration of HRT use and time since HRT use do not support a causal interpretation. Also, the estimated relative risks were reduced when allowance was made for other cardiovascular risk factors. CONCLUSIONS: There is no evidence that the use of HRT as recently prescribed in the UK constitutes a major cardiovascular risk or benefit.

Aged↗
PubMed1989

Skinfold thickness, body mass index and ischaemic heart disease.

STUDY OBJECTIVE: To determine the relationship between obesity and subsequent incidence of ischaemic heart disease (IHD). DESIGN: Prospective cohort survey. SETTING: Study of three occupational groups, with follow up examinations. SUBJECTS: 3500 people recruited between 1972 and 1978 (80% response rate), and followed up between 1978 and 1984. This report is based on subgroup of 1511 white men aged 40-64 at entry. MEASUREMENTS AND MAIN RESULTS: Information was obtained on smoking and family history of IHD. Blood pressure, weight, height, skinfold thickness at four sites, fibrinogen, factor VII activity and cholesterol were measured during follow up. Body mass index (BMI) was used as an index of obesity. BMI was found to be more strongly correlated with IHD than any of the skinfold measurements, none of which was significantly associated with IHD when BMI was allowed for. Increase in BMI by 1 SD (approximately 8 kg) was associated with a 44% increase in the risk of IHD. Of the four skinfolds, subscapular was the most closely associated with risk, confirming the relevance of central obesity. The association between obesity and IHD remained when possible mechanisms for its effects were taken into account, and its strength may increase with time: for 1 SD increase in BMI, risk of events within 5 years was increased by 28%, while risk of events after longer than 5 years was increased by 65%. CONCLUSIONS: Preventive strategies for IHD should include avoidance of obesity.

Adult↗
PubMed1989

Arterial disease risk factors and angiographic evidence of atheroma of the carotid artery.

We conducted a prospective study of serial intravenous digital subtraction angiography to determine the relation of arterial disease risk factors and hemostatic variables with the presence of visible atheroma at the carotid bifurcation. Of the 492 patients with cerebrovascular disease or ischemic heart disease who entered the study, 354 had hematologic studies, including platelet aggregation in 230. Abnormal angiograms were associated with greater age, treated hypertension, current smoking, and lower hemoglobin levels but with higher uric acid, factor VIII, and fibrinogen concentrations. In patients presenting with isolated transient ischemic attacks, abnormal angiograms were also associated with higher levels of cholesterol and triglycerides. To study atheroma progression, the 230 patients with complete data at entry were recalled 2 years later. Repeat angiography in 209 patients showed progression of visible bifurcation disease in 13.4%. There was some evidence that progression was linked to higher age, hypertension, and more severe disease at entry, but further analysis was hampered by the small number of patients showing increased plaque size. The possible role of risk factors and hemostatic variables, especially fibrinogen, is discussed. Factors that did not correlate with progression of angiographically visible disease may also influence clinical end points by other mechanisms, such as thrombogenesis.

Aging↗
PubMed1988

Risks and mechanisms of cardiovascular events in users of oral contraceptives.

Three large British studies on the vascular effects of oral contraceptives have established that the risk of thromboembolic episodes, both venous and arterial, rises with increasing estrogen dose. Two of these studies have also demonstrated a dose-dependent relationship between the progestogenic component of oral contraceptives and the risk of arterial disease, though not of venous events. In men, high levels of factor VII coagulant activity, VIIC, and plasma fibrinogen are associated with an increased risk for ischemic heart disease. In view of the dose-dependent relationship between estrogen and these two clotting factors, especially VIIC, it is likely that the effects of oral contraceptive usage on the risk for thromboembolism are mediated substantially through the level of coagulability. The relationship between the progestogenic component of oral contraceptives and the risk for arterial disease is probably related, at least in part, to the effects of progestogens on blood pressure.

Antigens↗
PubMed1988

Dietary and other characteristics relevant for coronary heart disease in men of Indian, West Indian and European descent in London.

The origins of the high standardized mortality ratio (SMR) for coronary heart disease (CHD) among Indians in Britain, and the low SMR for West Indian immigrants, have been explored by a community survey in London. Serum lipoproteins, plasma glucose, haemostatic factors and other putative risk characteristics were measured in 75 Indian, 64 European and 24 West Indian men aged 45-54 years. These represented 81% of men registered with a general practice and resident within a defined area. In 51 men, diet was assessed by 5-day weighed inventory. Plasma phospholipid fatty acids (PFA) were measured in 18 Indians and 19 Europeans with dietary records. The relatively high HDL and HDL2-cholesterol concentrations, low LDL-cholesterol concentration, reduced fat intake, increased ratio of dietary polyunsaturated/saturated fat, relatively frequent use of alcohol, and lack of obesity in West Indians accorded with their low SMR from CHD. By contrast, only the relatively low HDL and HDL2-cholesterol concentrations, infrequency of alcohol consumption, and lower proportion of PFA as n-3 fatty acids of marine origin afforded explanations for the high SMR of Indians. Hyperglycaemia appeared similarly prevalent in Indians and West Indians, but less common in Europeans. Of the haemostatic factors, West Indians had a relatively low VIIc (not statistically significant), while Indians had an increased platelet count and reduced platelet volume. Improved understanding of these ethnic differences in CHD mortality may depend upon elucidation of the contrasts in HDL-cholesterol concentration.

Blood Coagulation Tests↗