We have already reported from our epidemiological studies that serum total cholesterol is a negative risk factor of cerebral hemorrhage and is a positive risk factor of coronary heart disease.
In this study, we tried to find the optimal serum total cholesterol level preventing both cerebral hemorrhage and coronary heart disease.
To find the lower limit of optimal serum total cholesterol level, we saw the relationship between serum total cholesterol level and cerebral hemorrhage incidence in our Akita cohort. As the result, the incidence of cerebral hemorrhage was markedly higher in those whose serum total cholesterol was less than 140mg/dl compared with those whose cholesterol levels were higher than that.
On the other hand, we also saw the relationship between serum total cholesterol and coronary heart disease in our Osaka cohort of employees in order to find the upper limit of optimal serum total cholesterol level. From this study, we have found that the incidence of coronary heart disease was markedly higher in those whose serum total cholesterol levels were more than 200mg/dl than in those of cholesterol level less than that.
From these results, we conclude that the optimal level of serum total cholesterol is 140-200mg/dl for the prevention of both cerebral hemorrhage and coronary heart disease.