Margarine does not adversely affect lipids and lipoproteins
Trans fatty acids increase concentrations of total and low density lipoprotein cholesterol, decrease high density lipoprotein, and may increase Lp(a) lipoprotein. Most "unsaturated margarines" contain trans fatty acids, and it has been suggested that the potential benefit of these spreads conferred by the reduced saturated fat content might be outweighed by the untoward effects of the trans fatty acids. On p 931 Chisholm et al compare the effects of butter and margarine when used as a major source of cooking or spreading fat in the context of an overall fat reduced diet. Use of margarine instead of butter was associated with a reduction of total and low density lipoprotein cholesterol and no adverse effects on high density lipoprotein cholesterol or lipoprotein concentrations. These findings suggest that unsaturated margarines are a suitable substitute for high saturated fat products.
Chylomicron remnants clear more slowly in atherosclerosis
Discovering new factors that play a part in coronary artery disease challenges researchers. Hyperlipidaemia is an established risk factor that traditionally relates to fasting concentrations of lipids and lipoproteins. New importance could be assigned to hyperlipidaemia if it was related to postprandial lipid and lipoprotein values, as humans usually exist in a postprandial state. Blood vessels are continuously exposed to postprandial lipoproteins, which are assumed to be atherogenic, and this holds true even for people whose fasting lipid values are normal. On p 935 Weintraub et al report finding a significant accumulation of postprandial lipoproteins in a large group of normolipidaemic patients with coronary artery disease. This, they say, suggests that postprandial lipids play a part in coronary heart disease. As the accumulation of postprandial lipoproteins can be ameliorated by diet and drugs, the authors believe that this "new" risk factor should be sought, especially in patients at high risk of coronary artery disease.
General practitioners differ in the things that make them change prescribing practices
Almost as important as finding a sound basis for individual medical interventions is persuading doctors to change their clinical behaviour to adopt evidence based practices. On p 949 Armstrong et al describe a qualitative survey aimed at discovering what prompted 18 general practitioners in south London to change their prescribing habits over the previous six months. The most common change related to using fluoxetine, angiotensin converting enzyme inhibitors, and antibiotic treatment of Helicobacter pylori. The authors identified three main patterns of change: accumulation, in which evidence to change gradually built up; challenge, in which a dramatic clinical event prompted the change; and continuity, in which a willingness to change was converted into action by a specific event. The lessons are that individual doctors respond to different types of cues; engineering a challenge may help; and that the change needs reinforcement.
Osteoarthritis is a genetic condition
Osteoarthritis is one of the commonest causes of disability in developed countries. Doctors are largely ignorant of the disease processes and have little to offer as treatment other than joint replacement. Traditionally, it has been viewed as an inevitable consequence of wear and tear in old age. Spector et al (p 940) studied 500 middle aged female twins and found that genetic factors accounted for up to 65% of radiological signs of the disease in the hands and knees. They argue that there may be important gene-environment interactions that determine who will be affected. Finding the genes concerned could have important consequences in screening for and treating this disease.
Quality of intensive care for severe head injury varies widely
The quality of intensive care of severe head injury has an important influence on outcome. Jeevaratnam and Menon (p 944) conducted a structured telephone survey of senior nursing staff in intensive care units in 39 neurosurgical referral centres in the United Kingdom. They found wide variations in the intensive care of severely head injured patients, with only half the centres surveyed routinely monitoring intracranial pressure in comatose patients. Moderate hyperventilation and treatment with corticosteroids were still used by several centres despite increasing evidence of their lack of efficacy and potential for causing harm. The authors call for the establishment of national minimum standards of care.