CHANGES WITH AGING 



433 



Figure 8. Frequency distribution ot serum-cholesterol concentration in 

 middle-aged business men in Minnesota. It is estimated that above the cut- 

 ting line at 260 the risk of coronary heart disease within the following few- 

 years is of the order of foiu- times that for men below that line. Above the 

 cutting point 275, the risk is estimated to be around li\e times greater than 

 below. The broken curve is perfectly Gaussian. 



About 15 per cent of these men characteristically have cholesterol 

 levels of 275 or more. Judging from the follow-up studies previously 

 mentioned, these upper-level men carry a risk of early coronary heart 

 disease some five times greater than the rest of the men in the distribu- 

 tion. It seems reasonable to infer that they have an inherent tendency 

 toward h\percholesterolemia and therefore a built-in factor promoting 

 aging. 



At present there is no explanation for these individual differences 

 in cholesterol metabolism. We do know that the serum-cholesterol 

 levels of men who are inherently hypercholesterolemic show unusually 

 large responses to dietar\- changes, and these changes are quantita- 

 tively predictable, within limits. 



So it appears that both fatalistic and optimistic views about athero- 

 sclerosis and aging of the arteries must be admitted. Each individual 

 has distinguishing characteristics which we can modify but not oblit- 

 erate. Many of us believe that it is probable we can reduce the excess 

 risk of the man who, on a normal, average diet, has a cholesterol level 

 of 300. We know that we can, by dietary control, reduce the choles- 

 terol level and keep it reduced, though there is no proof as yet that we 



