29 (adult) statures and weights, measured at age 21 or older, of subjects exposed to radiation at age ' £17 indicated that those exposed in Hiroshima attained a mean height markedly lower than normal and that the degree of retardation diminished with increasing age at exposure, being greatest in those exposed at age <5. The effect was more prominent in boys. The preliminary tabulations of growth data in the Marshallese children26-45 showed similar trends. Subsequently, the extent of the thyroid injury documented in the Marshallese children provided the basis for the present assumption that growth retardation reflected primarily the results of impaired thyroid function.It is anticipated that when adult (final) anthropometric measurements becomeavailable, further evalua- tion of the growth pattern of the Marshallese chil- dren (including further assessment of the effect of thyroid hormone administration) will be possible. G. DEGENERATIVE DISEASES dividuals >40 vears old have revealed the cardiac changes expected with aging: arteriosclerosis heart disease with occasional cardiac decompensation. Auricular fibrillation has been noted in a few people; rheumatic heart disease in only two. Peripheral vascular diseases (thrombophlebitis, peripheral venous disease, hemorrhoids) appear to be less common than in Americans. Oscillometric studies showed peripheral pulses to be exceptionally good, even in older people andin diabetics (see below). No luetic, metabolic, or nutritional form of heart disease has been seen. 2. Arthritis Many Marshallese >40 years of age complain of joint symptomsin the arms and legs and to a lesser extent in the lower back. Many,particularly the older ones, have complained also of vague muscle pains in the arms and legs. Some older women develop marked kyphosis in the lower thoracic-lumbar region which may be related partly to the squatting or stooping position neces- therefore, in these studies careful consideration has sary for cooking over open fires. X rays show many of the above complaints to be associated with osteoarthritic changes; but many people with complaintsdo not have definite bone changes. Arthritis seems no more commonin the exposed than in the of cardiovascular diseases, arthritis, and other de- does notdiffer greatly from that among Ameri- The aging process is accompanied by an increased incidence of degenerative diseases, and irradiated animals have shownincreases both in general aging phenomenaandin such diseases; been given to signs of aging andto the incidence unexposed population, and its general incidence generative diseases. cans. Rheumatoid arthritis has rarely been seen. 1. Cardiovascular Diseases gave positive results in only a few cases (3 of 184 Cardiovascular diseases appear to be no more prevalent among the Marshailese than in Ameri- cans or other populations, and no difference was found betweentheir incidences in the exposed and unexposed groups. Hypertension appears to be somewhatless prevalent among the Marshallese than among Americans. Blood pressures > 140/90 have been recorded in only about 9% of the people, and the increasing percentage of older people in the study groups does not seem to haveraised the incidence of hypertension. Manyof the younger people, particularly females, have notably lower blood pressures (90-100/55-65). The generally lower blood pressures in the Marshallese have been thought to be related to lower dietary salt intake,7.46 but the gradually increasing use of im- ported foods of greatersalt content has caused no apparentincrease in hypertension. Serum sodium and potassium levels have usually been in the nor- mal range. Routine chest x rays and ECG’s on in- S0Cb I 2b Examination of the sera for “rheumatic factor” tested in 1959).8 3. Nephroscierosis Primary kidney disease has not been notedfre- quently, but nephrosclerosis has occasionally been seen complicating cardiovascular disease. 4. Aging Radiation in sublethal doses may reduce longev- ity in animals and man, [nduction of malignant transformation is weil documented and accounts for most of the early deaths. However, develop- ment of premature senescence with associated degenerative diseases and immunodeficiency, as a late effect of exposure,is also believed to accountfor some degree oflife shortening in animals.*7-49 For humans,definite proof of such effects is lacking, the only documentedlife-shortening effect being related to malignancies.59-5! In the Japanese bomb survivors, the correlation of life-shortening with