Effect on lipoprotein profile of replacing butter with margarine in a low fat diet: randomised crossover study with hypercholesterolaemic subjects
Alexandra Chisholm, Jim Mann, Wayne Sutherland, Ashley Duncan, Murray Skeaff, Christopher Frampton
Abstract
Objective - To examine the effect on lipid and lipoprotein concentrations when butter or an unsaturated margarine is used for cooking or spreading in a reduced fat diet.
Design - Randomised crossover study with two intervention periods of six weeks' duration separated by a five week washout.
Setting - Community setting in New Zealand.
Subjects - 49 volunteers with polygenic hypercholesterolaemia and baseline total cholesterol concentration in the range 5.5-7.9 mmol/l.
Main outcome measures - Concentrations of total and low density lipoprotein, Lp(a) lipoprotein, high density lipoprotein, apolipoprotein B 100, and apolipoprotein AI.
Results - Concentrations of low density lipoprotein cholesterol and apolipoprotein B were about 10% lower with margarine than with butter. Lp(a) lipoprotein and high density lipoprotein cholesterol concentrations were similar with the two diets.
Conclusion - Despite concerns about adverse effects on lipoproteins of trans fatty acids in margarines, the use of unsaturated margarine rather than butter by hypercholesterolaemic people is associated with a lipoprotein profile that would be expected to reduce cardiovascular risk.
Department of Human Nutrition University of Otago P0 Box 56 Dunedin New Zealand Alexandra Chisholm research dietitian Jim Mann professor of human nutrition Ashley Duncan senior technician Murray Skeaff lecturer in human nutrition
Department of Medicine University of Otago Wayne Sutherland research fellow
Centre for Computing and Biometrics Lincoln University Canterbury New Zealand Christopher Frampton lecturer
Correspondence to. Professor Mann.
Moshe S Weintraub, Itamar Grosskopf, Toby Rassin, Hylton Miller, Gideon Charach Heschi H Rotmensch, Meir Liron, Ardon Rubinstein, Adrian Iaina
Abstract
Objective - To test the hypothesis that subjects who clear chylomicron remnants slowly from plasma may be at higher risk of coronary artery disease than indicated by their fasting plasma lipid concentrations.
Design - Case control study over three years.
Setting - An 800 bed general municipal hospital.
Subjects - 85 normolipidaemic patients with coronary artery disease selected prospectively and matched with 85 normolipidaemic subjects with normal coronary arteries on angiography.
Interventions - All subjects were given a vitamin A fat loading test which specifically labels intestinal lipoproteins with retinyl palmitate.
Main outcome measure - Postprandial lipoprotein metabolism.
Results - The area below the chylomicron remnant retinyl palmitate curve was significantly increased in the coronary artery disease group as compared with the controls (mean 23.4 (SD 15.0) v 15.3 (8.9) mu mol/l.h; 95% confidence interval of difference 4.37 to 11.82).
Conclusions - Normolipidaemic patients with coronary artery disease had significantly higher concentrations of chylomicron remnants in plasma than normolipidaemic subjects with normal coronary vessels. This may explain the mechanism underlying the susceptibility to atherosclerosis of coronary artery disease patients with normal fasting lipid values. As diet and drugs can ameliorate the accumulation of postprandial lipoproteins in plasma, the concentration of chylomicron remnants should be measured in patients at high risk of coronary artery disease.
Tel Aviv-Sourasky Medical Center and Sackler Faculty of Medicine Tel Aviv University Tel Aviv Israel Moshe S Weintraub head, department of internal medicine C Itamar Grosskopf instructor, department of medicine C Toby Rassin instructor, department of medicine F Hylton Miller head, coronary catheterisation unit Gideon Charach instructor, department of medicine C Heschi H Rotmensch senior lecturer, department of medicine C Meir Liron head, department of medicine F Ardon Rubinstein head, unit of lipid metabolism Adrian Iaina head, department of nephrology
Correspondence and requests for reprints to: Dr Weintraub.
Genetic influences on osteoarthritis in women: a twin study
Tim D Spector, Flavia Cicuttini, Juliet Baker, John Loughlin, Deborah Hart
Abstract
Objectives - To assess the relative contribution of genetic and environmental factors to common forms of osteoarthritis of the hands and knees.
Design - Classic twin study with unselected twins who were screened radiologically for osteoarthritis.
Subjects - 130 identical and 120 non-identical female twins aged 48-70 recruited from a London based twin register and through a national media campaign.
Main outcome measures - Similarity in identical compared with non-identical twin pairs for radiographic changes at the interphalangeal and first carpometacarpal joints of the hands and the tibiofemoral joint and patellofemoral joint of the knee expressed as intraclass correlations.
Results - The intraclass correlations of radiographic osteophytes and narrowing at most sites and the presence of Heberden's nodes and knee pain were higher in the identical pairs. The intraclass correlation of the total radiographic osteoarthritis score m identical pairs (rMZ) was 0.64 (SE 0.05) compared with 0.38 (0.08) in non-identical pairs. The proportion of genetic variance of total osteoarthritis score (osteophytes and narrowing) with modelling techniques was estimated at 0.54 (95% confidence interval 0.43 to 0.65) and ranged from 0.39 to 0.65 for different sites and features (P less than 0.001) after adjustment for age and weight.
Conclusions - These results demonstrate for the first time a clear genetic effect for radiographic osteoarthritis of the hand and knee in women, with a genetic influence ranging from 39-65%, independent of known environmental or demographic confounders. The results of this study should lead to further work on isolating the gene or genes involved in the pathogenesis of this common disabling disease.
Department of Rheumatology St Thomas's Hospital London SE1 7EH Tim D Spector consultant rheumatologist Flavia Cicuttini research fellow Juliet Baker research nurse Deborah Hart research therapist
Collagen Genetics Unit Institute of Molecular Medicine Oxford John Loughlin research scientist
Correspondence to: Dr Spector.
Survey of intensive care of severely head injured patients in the United Kingdom
D R Jeevaratnam, D K Menon
Abstract
Objectives - To study practice in intensive care of patients with severe head injury in neurosurgical referral centres in United Kingdom.
Design - Structured telephone interview of senior nursing staff in intensive care unit of adult neurosurgical referral centre.
Setting - 39 intensive care units in hospitals that accepted acute head injuries for specialist neurosurgical management, identified from Medical Directory and information from professional bodies.
Main outcome measures - Details of organisation and administration of intensive care and patterns of monitoring and treatment for patients admitted with severe head injury.
Results - Patients were managed in specialist neurosurgical intensive care units in 21 of the centres and in general intensive care units in 18. Their intensive care was coordinated by an anaesthetist in 25 units and by a neurosurgeon in 12. Annual caseload varied between units: 20 received more than 100 patients, 12 received 50-100, and seven received 25-49. Monitoring and treatment varied considerably between centres. Invasive arterial pressure monitoring was used routinely in 36 units, but central venous pressure monitoring was routinely used in 24 and intracranial pressure was routinely monitored in only 19. Corticosteroids were used to treat intracranial hypertension in 19 units. Seventeen units routinely aimed for arterial carbon dioxide pressure of 3.3-4.0 kPa, and one unit still used severe hyperventilation to a pressure of under 3.3 kPa.
Conclusion - The intensive care of patients with acute head injuries varied widely between the centres surveyed. Rationalisation of the intensive care of severe head injury with the production of widely accepted guidelines ought to improve the quality of care.
Department of Anaesthesia University of Cambridge Clinical School Addenbrooke's Hospital Cambridge CB2 2QQ D R Jeevaratnam senior registrar D K Menon lecturer and honorary consultant
Correspondence to: Dr Menon.
A study of general practitioners' reasons for changing their prescribing behaviour
David Armstrong, Hugh Reyburn, Roger Jones
Abstract
Objectives - To explore gene?al practitioners' reasons for recent changes in their prescribing behaviour.
Design - Qualitative analysis of semistructured interviews.
Setting - General practice in south east London.
Subjects - A heterogeneous sample of 18 general practitioners.
Results - Interviewees were able to identify between two and five specific changes that had occurred in their prescribing in the preceding six months. The most frequently mentioned changes related to fluoxetine, angiotensin converting enzyme inhibitors, and the antibiotic treatment of Helicobacter pylon. Three models of change were identified: an accumulation model, in which the volume and authority of evidence were important; a challenge model, in which behaviour change followed a dramatic or conflictual clinical event; and a continuity model, in which change took place against a background of willingness to change, modulated by other factors such as cost pressures and the comprehensible therapeutic action of a drug. Behaviour change was reinforced and sustained by experiences with individual patients.
Conclusions - Multiple factors are involved in general practitioners' decisions to change their prescribing habits. Three models of change can be identified which have important implications for the design and evaluation of interventions aimed at behaviour change.
Department of General Practice United Medical and Dental School of Guy's and St Thomas's London SE11 6SP David Armstrong reader in sociology as applied to medicine Hugh Reyburn research fellow Roger Jones Wolfson professor of general practice
Correspondence to: Professor Jones.