Cholesterol screening is a regular part of lifestyle and well-personassessments in the workplace. But although it is recognised that raisedcholesterol levels lead to coronary heart disease, the benefits of randomscreening are still being questioned. By Vicki Madden The advantages of lowering cholesterol have already been demonstrated in twolandmark studies. The large scale secondary prevention clinical trial, theScandinavian Simvastatin Survival Study(4S)1, showed that patients with proven heartdisease and a raised total serum cholesterol in the range 5.5 to 8 mmols/litrebenefited from treatment with the lipid lowering drug, simvastatin. Compared with placebo, those in the treatment group had a 30 per centreduction in all cause mortality, and a 40 per cent reduction in CHD mortality.These survival benefits were also seen in men over 60 years of age and inwomen. The other large landmark study, the West of Scotland Coronary PreventionStudy (WOSCOPS) found that patients with raised cholesterol but no previoushistory of CHD also benefited from cholesterol lowering treatment. Results of the five-year study showed that those offered lipid loweringtherapy had a 31 per cent reduction in non-fatal heart attacks, compared withthose in the placebo group2. National diet Coronary heart disease rates in different countries reflect the serumcholesterol levels of their populations and these, in turn, are linked tonational diet. Countries where most energy is derived from carbohydrate have the lowestcholesterol levels and those, such as Britain, with the highest cholesterollevels consume a diet rich in fat. In Britain, the median cholesterol level from middle age onwards is 6 to 6.5mmols/litre, and while the levels are dropping among the young and moreaffluent, Britain still has one of the highest CHD rates in the world. Although different groups of cardiologists recommend slightly differentcholesterol levels at which diet and/or treatment should be initiated, all tendto be much lower than a few years ago. The most recent Joint British Recommendations on the Prevention of CHD inClinical Practice (1998) propose that for patients with established heartdisease, total cholesterol should be maintained at below 5.0 mmols/litre andthe “bad” low density lipoprotein (LDL) cholesterol should bemaintained at below 3.0 mmols/litre3. In practice, as so many people are above these levels, screening programmesare not recommended for everyone. Marilyn McDougall, health promotion nursing adviser at Glaxo Wellcome,screens patients who opt for a lifestyle assessment. “As part of theassessment we do a finger prick analysis for total serum cholesterol,” shesaid. “If anyone has a level over 6.5 mmols/l we recall them for a fastingcholesterol level and then send off their blood to the hospital for furtheranalysis. We also refer them to their GPs.” She adds, “Those with levels between 5.5 to 6.5 mmols/l are givenleaflets on cholesterol and advice on diet and exercise. In six years we havehad nine men and four women with levels over 6.5 mmols/l. When they wererecalled for their second assessment, we found all the men had cholesterollevels over 6.5 mmols/l, but only two women. Of the two women whose cholesterollevels had fallen, one had been put on hormone replacement therapy and theother had been put on lipid lowering therapy.” False negatives Although screening such as this is common in occupational health departmentsaround the country, epidemiologists such as Professor Nick Wald and Dr MalcolmLaw, from the Department of Epidemiology, St Bartholomew’s Hospital, London,still question the benefits. “Random testing like this will only pick uparound 11 per cent of those with raised cholesterol, and of these as many as 5per cent may be false negatives,” says Dr Law. “Unlike breast cancer screening, cholesterol screening is not asufficiently discriminating test. The difference between those at high risk andthose at low risk of developing CHD is small. “You cannot assume that people with cholesterol levels of 5.2mmols/lhave no risk of developing CHD. It’s like telling someone who smokes 30cigarettes a day that he has a higher risk of developing cancer than someonewho smokes 20 a day. The difference in their risk is, in fact,negligible.” However, Dr Law concedes that the mere fact of screening someone maymotivate them to change their way of life. “If they have a cholesteroltest they may then follow the health advice that will accompany the screeningtest. Graham Johnson, occupational health manager at MTL Medical Services, is alsosceptical about random cholesterol testing. He says it has just completed amajor contract with 750 personnel from Mersey Police. “The computer-aided lifestyle package that we used included a randomcholesterol test. During the course of the tests, this threw up a number ofindividuals with raised total serum cholesterol. As this gave no indication oftheir LDL/HDL ratio we had to refer them to their GP for further fastingcholesterol testing. “Inevitably, some individuals with raised totalcholesterol became unduly anxious.” Johnson recommends all those with high total serum cholesterol are alsogiven a fasting cholesterol check. Cholesterol should not be considered inisolation, he adds, and other CHD risk factors such as smoking, blood pressure,and the amount of exercise an individual does must be taken into account. “Whatever else it does, the cholesterol test can make individualsreflect on their lifestyles. It can only be to the good if that means that theytake more exercise and change their diet.” Vicki Madden is a freelance medical writer References 1 Randomised trial of cholesterol lowering in 4,444 patients with CHD: theScandinavian Simvastatin Survival Study(4S). Scandinavian Simvastatin Survivalgroup. Lancet 1994;344:1383-9. 2 Prevention of CHD with pravastatin in men with hypercholesterolaemia.Shepherd J, Cobbe SM, Ford I, et al for The West of Scotland CoronaryPrevention Study Group. New Engl J Med 1995;333: 1301-7 3 Prevention of CHD in clinical practice: recommendations of the jointsecond task force of the European and other societies on coronary prevention,Eur Heart J 1998;19: 1434-1503. LinksBritish Heart Foundation: www.bhf.org.ukBritish Heart Foundation Health Promotion Research: www.dphpc.ox.ac.ukSearching the Web: www.healthAtoZ.com Comments are closed. In good heartOn 1 May 2000 in Personnel Today Previous Article Next Article Related posts:No related photos.