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 prominentin boys. The preliminary tabulations of growth data in the Marshallese children16-45 showedsimilar trends. Subsequently, the extent of the thyroid injury documented in the Marshailese children providedthe 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 become available, further evaluation of the growth pattern of the Marshallese children (including further assessmentof the effect of thyroid hormone administration) will be possible. G. DEGENERATIVE DISEASES The aging process is accompanied by an increased incidence of degenerative diseases, and irradiated animals have shown increases both in general aging phenomenaand in such diseases; therefore, in these studies careful consideration has been givento signs of aging andto the incidence of cardiovascular diseases, arthritis, and other de- generative diseases. 1. Cardiovascular Diseases dividuals >40 years old have revealed the cardiac changes ex ith aging: arteriosclerosisheart disease withootasionaltatdiac de Auricutaryg ation. lay has -beerSoeditbe people; rheumatic“heart ditease j Eneiro. Peripheral vasctlar diseases (thrdmBophtEBitis, peripheral venous disease, hemorrhoids) appear te be less commonthan in Americans. Oscillonmetaft studies showed peripheral: pulses to be éxieptionally good, even in older people andin diabetics (see below). No luetic, metabolic, or nutritional ~ form of heart disease has beenen seen. co, i$. 2. Arthritis Med war = Many Marfhaliése,>40 yeats of age-complain ofjoint symptoms in the arms and legs and toa lesser extent in the lower back=Many,particularly the older anes, Have compl@ined also of vague muscige-]pains in the arms and legs.*Someolder women develop marked. kyphosis in*ghe tower thoracic-lumb cegign—vchich maybaggelated partly to the bagegiee dFffooping position necessary for cooking over openfires. X rays show many of the above complaints to be associated with osteoarthritic changes; but many people with complaints do not have definite bone changes. Arthritis seems no more commonin the exposed than tn the unexposed population, and its general incidence does not differ greatly from that among Americans. Rheumatoid arthritis has rarely been seen. tefacter” Examination of sheserttiog, gave positive results in only a cages{3 of 184 Cardiovascular diseases appear to be no more prevalent among the Marshallese than in Americans or other populations, and no difference was found between their incidences in the exposed and unexposed groups. Hypertension appears to be somewhatless prevalent among the Marshallese than among Americans. Blood pressures > 140/90 tested in 1959).8 and the increasing percentage of older people in Radiation in sublethal doses may reduce longe¥ ity in animals and man. Induction of malignant transformationis well documented and accounts for most of the early deaths. However, déevelopment 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.5°-5! In the Japanese bomb survivors, the correlation oflife-shortening with have been recordedin only about 9% of the people, the study groups does not seem to have raised 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 imported foods of greater salt content has caused no apparentincrease in hypertension. Serum sodium and potassium levels have usually been in the normal range. Routine chest x rays and ECG’s on in- Be Ae. ~ 1 rugs 3. Nephrosclerosis 0 Sees Primary kidney disease has noibeen noted fré: quently, but nephrosclerosis has occasionally|been seen complicating cardiovascular disease. 4. Aging = 3