Microscopic morphometry of abdominal aorta from men in New Orleans and Guatemala.

Morphometric light microscope measurements were made on 154 abdominal aortas from 77 Guatemalan Indian-white (ladinos) men and from 77 new Orleans white men, aged 15 to 54 years. In each case, means were derived from 12 points measured independently. A progressive increase in intimal lipid with increasing age was observed in men from both countries. Extracellular intimal lipid was consistently higher in men from New Orleans than in those from Guatemala, although not always significantly so. Intimal thickness followed a similar pattern to intimal lipid regarding age and geographic location. Foam cells and leukocytes (mainly monocytes) did not follow a consistent pattern. The smooth muscle cell count was the only variable that was significantly greater in New Orleans men than in Guatemalans aged 15 to 34 years. Morphometric microscopic measurements were significantly correlated with unaided visual estimates of atherosclerotic lesions and with chemical determinations of lipid fractions in the arterial intima. All three methods, gross grading, microscopy, and chemistry, agree in revealing little or nor measureable difference between new Orleans men and Guatemalans younger than 35 years, but an accelerated divergence of the populations over age 35.