FOR THE past five years we have been engaged in an intensive study of lipid metabolism. The data in this series were derived from studying 500 subjects aged 13 to 100 years, in an attempt to determine which laboratory and clinical criteria are definitive in diagnosing atherosclerosis and which means are useful in its management. X-ray films of 1000 persons aged 50 to 100 years, including 335 patients 80 to 100 years of age, were reviewed. In this series were 100 normal subjects 80 to 100 years old in whom detailed lipid metabolic studies were made. These elderly persons, who were institutionalized for custodial care, had no previous history of coronary, metabolic, endocrine, or venereal disease and were considered to be "normal."
METHODS OF STUDY
Blood chemistry examinations were performed for creatinine, nonprotein nitrogen, and serum lipid partitions such as total cholesterol, phospholipid, neutral fats, and total lipids. Serum lipoprotein