Atherosclerosis, serum cholesterol and the homocysteine theory: a study of 194 consecutive autopsies.

A retrospective study examined 194 consecutive autopsies to determine the proportion of cases of atherosclerosis without elevated serum cholesterol, diabetes mellitus, or hypertension. The study cases were classified into four groups, according to the cause of death and the degree of atherosclerosis. Cases in Group 1, in which death resulted from complications of severe atherosclerosis, have a mean serum cholesterol of 186.7 +/- 41.8 mg/dL, and the cholesterol is less than 200 in 65% and less than 250 in 92% of cases. Cases in Group 2, with severe atherosclerosis dying of other diseases, have a mean serum cholesterol of 174.6 +/- 60.4 mg/dL, and the cholesterol is less than 200 in 79% of cases and less than 250 in 89% of cases. Cases in Groups 3 and 4, with moderate and minimal atherosclerosis, respectively, have mean serum cholesterol values of 172.3 +/- 54.8 and 143.5 +/- 47.8 mg/dL, and the cholesterol is less than 200 in 71% and 92% and less than 250 in 92% and 96% of cases, respectively. Serum cholesterol is significantly associated with severity of atherosclerosis in the total sample (P = 0.01). Three fourths of all cases (147/194) have neither diabetes nor hypertension, and in 74% of these cases (109/147) the cholesterol is less than 200 and in 92% (135/147) the cholesterol is less than 250. In 66% (80/122) of the cases with severe atherosclerosis, the disease developed without evidence of elevated serum cholesterol, diabetes, or hypertension. Blood homocysteine, which has been shown by other studies to be an independent risk factor for atherosclerosis, is recommended for assessing prognosis in these cases.