43 Theresults of institution of thyroid hormone therapy in September 1965 are of interest. The rationale for its possible value in inhibiting the development of thyroid nodules appears to be ona firm basis. Bielschowskv*? and Astwood and Cassidy”’ have reviewed the favorable effects of -- aee thyroid treatment of patients with nodulesof the thyroid gland. The only experimental evidence found directly applicable to the Marshallese situ- ation, however, isin a paper by Nichols et al.**. and unpublished data by Godwin** demonstrating a reduced incidence of '*'I-induced adenomasin rats treated with thyroid hormone. Although the children with thyroid nodules have thus far shown no evidence of thyroid carcinoma, experimental evidence strongly supports the belief that thyroid carcinoma may develop in this exposed population. This likelihood led to the performanceof thyroidectomyonall children with thyroid nodules which had failed to disappear on suppressive therapy, even though earlier operative specimens had revealed only adenomatous changes. Since total thyroidectomy was not performed except in a few cases, even the operated patients will haveto be followed closely for the possible development of new nodules, and the suppressive effect of thyroid hormone replacement therapy may be important even in them. The results of the treatment of children with thyroid hormonewill also test the thesis of hypothyroid etiology of growth retardation. Early indi- cations are that the treatmentis successful, since there has been a spurt in growth in the two most dwarfed boys in the year following institution of the treatment. During physical examinations, aging effects are usually referred to in a general qualitative sense. In order to evaluate possible aging effects better, a more quantitative approach was indicated. A large number of criteria have at one time or an- other been regarded as being age dependent. These studies represent an effort to select criteria which could be used underthe conditionsof these examinations. The over-all objective has been to combine the scoresof the variouscriteria into one “average age score’ for each individual and to compare scores in the exposed and unexposed groups of similar age. An earlier attempt to quan- 900832) ce eee tee criteria. have been added, andfurtherstatistical treatment of the data has been undertaken. Methods The aging criteria to be presented were recorded only in adults (20 years of age and older). Data were recorded on 91 adults, 36 in the Rongelap and Ailingnae exposed groups and 55 in the larger comparison population. The ages were reasonably well distributed except for the small numberof people >60 years of age. The study was hampered by the small numberof people involved, lack of vital statistics on the Marshallese people, the language barrier, and uncertainty as to the exact ages in someofthe older people. In selecting the criteria to be used, these difficulties limited the extent and usefulness of those tests which require moti- vation and cooperation on thepart ofthe subject.* In this report 14 criteria of aging are presented: 4 involving the special sense organs(visual acuity, accommodation, arcus senilis, and hearing loss); 4 involving neurological or neuromuscular function (vibratory sense, reaction time, rapidity of movement, and handstrength); 3 involving the integument(skin looseness, skin elasticity, and hair graying); one cardiovascular test (systolic blood pressure); and 2 miscellaneous tests (serum choles- . terol and body potassium). Two of the tests required subjective evaluation on the part of the ex- aminer (hair grayness and arcus senilis); 7 re- quired varving degrees of motivation and cooperation on the part of the subject (visual acuity, ac- commodation, hearingloss, vibratory sense, reac- tion time, neuromuscular function, and strength); and 5 tests involved direct measurements (skin looseness, skin elasticity, systolic blood pressure, AGING STUDIES re er eee - tifv these aging criteria has been presented in previous publications.**° In this report several new 7 -- - body potassium, and serum cholesterol). integument. A special caliper with constant spring tension was devised for skin examinations.7°"! (1) Skin Looseness. The skin fold at the junction of the chin and neck was measured in millimeters as described previously. (2) Skin Elas- ticity. This was measured on the back of the hand by allowing the caliper to pinch a foid of skin for *Several tests were tried and discarded for these reasons, including vital capacity and cardiovascular response to two-step test. Also not included were several tests that were difficult to quantify such as baldness and retinal and peripheralarterioscierosis. Other tests. such as serum folic acid and vitamin B,. levels, were eliminated because of poor correlation with aging.