Does a high cholesterol level increase the risk of a heart attack? Medicine seems unable to come up with a definitive answer to this seemingly simple question, and two new studies do little to resolve the issue.

One study from Scandinavia indicates that high levels can lead to a heart attack and that the drug simvastatin will reduce cholesterol. But another, from Yale University, suggests that people over the age of 70 with high levels are not at any greater risk.

Perhaps the one conclusion that both studies could agree on is the old dictum of moderation in all things. The Yale study says that only older people with very high levels of cholesterol greater than 300 milligrams per deciliter or who already have a heart condition such as angina should consider taking drugs, whereas those with only moderately high levels, at around 240 milligrams, can better treat the condition through diet. The Scandinavian study, for its part, fails to draw a convincing case for the use of simvastatin among those with normal cholesterol levels.

Both papers in their way are significant. The Scandinavian one, prepared by the Scandinavian Simvastatin Survival Study, studied 4,444 patients with a heart condition and cholesterol levels from 200 milligrams upwards. About half the group was treated with simvastatin which, after a year, saw cholesterol levels fall below 200 milligrams. The group had a 42 per cent lower rate of fatal heart attack, and a 34 per cent reduction in heart disease than the placebo group (The Lancet, 19 November1994).

The Yale study is perhaps more radical because it questions the treatment of that sector of the population most likely to be bombarded with drugs, especially for lowering cholesterol. The report points out that, while cholesterol lowering drugs may reduce heart fatalities, patients tend to die of other causes. Also, the link between moderately high cholesterol levels and heart disease becomes less clear as people get older.

Instead, older people with moderately high levels should be encouraged to make changes to their diet, such as using more polyunsaturated fats, such as sunflower oil, or monosaturated fats, such as olive oil (see WDDTY vol 5 no 9). A change from animal to vegetable protein can often reduce cholesterol levels, although it is not recommended to go on a low fat diet

!AJAMA, 2 November 1994.