Effect of intervention was sustained

EDITOR,—The two papers on the cost effectiveness of health checks in the Oxcheck study emphasise the importance of the duration of the effect after the intervention.1 2 The principal benefit resulting from the health checks, which had the largest effect on reducing the risk of coronary heart disease, was the lowering of serum total cholesterol concentrations.3 The economic predictions were that health checks would become cost effective if the benefit was sustained for at least five years. The Oxcheck study group (of which …