Study on arteriosclerosis among atomic bomb survivors

A total of 558 A-bomb survivors were entered onto this study, consisting of 213 exposed at ≤ 2000 m from the hypocenter (the exposed group) and 345 exposed at ≥ 3000 m or entering the city 9 days after bombing (the control group). Roentgenologic findings, such as the presence of calcification and the degree of tortuosity, were examined as indicators for arteriosclerosis. Blood levels of apoproteins and lipids were also determined. The presence of calcification and degree of tortuosity were associated with aging in the exposed and control groups. In the exposed group, A-bomb survivors aged 70 years or older had a significantly high tortuosity, as compard with those in the control group. An average blood level of apo-A I was significantly decreased when X-ray revealed calcification or high degree of tortuosity in the exposed group. In the control group, there was no correlation between blood levels of apo-A I and X-ray findings. In comparing the group with calcification and tortuosity (+) and that with calcification and tortuosity (-), blood levels of apo-B, total blood cholesterol, and HDL-cholesterol did not differ in the two groups, irrespective of exposure. Lower blood levels of apo-A I tended to be associated with calcification and tortuosity (+) in the exposed group. The incidence of higher apo-B/A I was similar in the exposed and control groups. The findings suggest that arteriosclerosis is likely to develop in older A-bomb survivors and that lipid metabolic abnormality may be involved in its development. (N.K.)