+3 The results of institution of thyroid hormone therapy in September 1965 are of interest. The rationalefor its possible value in inhibiting the development of thyroid nodules appears to be ona firm basis. Bielschowsky** and Astwood and Cassidy*’ have reviewed the favorable effects of thyroid treatmentofpatients with nodules of the thyroid gland. The only experimental evidence found directly applicable to the Marshallese situation, however,is in 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 and unpublished data by Godwin*® demonstrating a reduced incidence of **'I-induced adenomasin rats treated with thyroid hormone.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 noevidence of thyroid carci- noma, experimental evidence strongly supports the belief that thyroid carcinoma maydevelop in this exposed population. This likelihood led to the performance of thyroidectomyonall children with thyroid nodules which hadfailed to disappear on suppressive therapy, even thoughearlier 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 treatment is successful, since there has been a spurt in growth in the two most dwarfed boysin the yearfollowinginstitution of the treatment. + AGING STUDIES 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 numberofcriteria have at one timeor another been regarded as being age dependent. These studies represent an effort to select criteria which could be used under the conditions of these examinations. The over-all objective has been to combine thescores of the variouscriteria into one “average age score’ for each individual and to compare scores in the exposed and unexposed groupsofsimilar age. An earlier attempt to quan- tify these aging criteria has been presentedin pre- vious publications.’'’° In this report several new criteria have been added, and further statistical treatmentof 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 numberofpeople involved, lack of vital statistics on the Marshallese people, the language barrier, and uncertainty as to the exact ages in some ofthe older people. In selecting the criteria to be used, these difficulties limited the ex- tent and usefulness of those tests which require motlvation and cooperationonthe part of the subject.* In this report 14 criteria of aging are presented: 4 involving the special sense organs(visual acuity, accommodation, arcus senilis, and hearing loss): + involving neurological or neuromuscular func- tion (vibratory sense, reaction time, rapidity of movement, and handstrength); 3 involving the integument(skin looseness, skin elasticity, and hair graying); one cardiovasculartest (systolic blood pressure); and 2 miscellaneous tests (serum cholesterol and body potassium). Two ofthe tests re- quired subjective evaluation on the part of the ex- aminer (hair grayness and arcus senilis): 7 required varying degrees of motivation and cooperation on the part of the subject (visual acuity, ac- commodation, hearing loss, vibratory sense, reaction time, neuromuscular function, and strength: and 5 tests involved direct measurements (skin looseness, skin elasticity, systolic blood pressure. body potassium, and serum cholesterol). integument. A special caliper with constant spring tension was devised for skin examinations.”-'°°"' (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 fold ofskin for *Several tests were tried and discarded for these reasons. including vital capacity and cardiovascuiar response to [wo-slep test. Also not included were several tests that were difficult to quanufy such as baldness and retinal and peripheral arterios ierosis. Other tests, such as serum folic acid and vitamin B, were eliminated because of poor correlation with aging. levels.