Background to discuss guidelines for control of plasma HDL cholesterol in Japan

A decrease in high density lipoprotein-cholesterol (hdl-c) is a strong risk factor for atherosclerotic disorders in japan,probably more important than an increase in low density lipoprotein-cholesterol (ldl-c). while there are rational grounds for the argument that elevation of hdl-c leads to decreased risk,there has as yet been no direct evidence of such an effect. if elevation of hdl-c decreases the risk,this effect is expected throughout the normal range of hdl-c or perhaps even higher than that. simulation based on epidemiological data indicated that it may eventually reduce the incidence of ischemic heart disease by 60-70% in japan. in the risk management guideline,low hdl-c is presently defined as 40 mg/dl or below. while there is no evidence that strongly urges a change in this definition,the results of epidemiological studies support the higher the hdl-c level,the lower the risk, even in the normal range. elevation of the hdl-c level may reduce the risk,probably at least up to 70 mg/dl; however,there are no supportive data for this effect still being obtained over 80 mg/dl. patients with homozygous cetp deficiency should be followed-up while controlling other risk factors,so as not to dismiss the possibility of a risk increase with an extremely elevated hdl-c level.