10 Dental Survey. Intra-oral examinations were conducted as part of the physical examination. All patients were examined with mouth mirror and explorer. Illumination was by standard operating hght. Salivary #H was taken by use ofpHydrion on all subjects who were not eating candy or any other foodstuff. Saliva samples were collected from these patients at the time #H determinations were made. Intra-oral radiograms were not available. Dental examinationswere carried out onthefollowing groups: 30 children at Majuro; all the adults and children at Rongelap whowerein the | physical examination group; and a numberof children at Utirik. Studies of Aging Criteria Although the exposed group has shown noout- ward evidence visible by gross observation of any accelerated aging effect of radiation, it was thought desirable to have available measurable criteria of possible age changes for use during normal physical examination. Therefore the over-all objective of this study was to establish tests to evaluate any possible radiation-induced senescence in the exposed group compared with the unexposed population living on the sameisland. However, the data (presented in a later section on results) collected during the 1959 survey (5 years after exposure) showed no apparent differences between the exposed and unexposed groups. Therefore the data from the two groups have been pooled with the objectives of presenting the methodology, indicating the trend of changes with age of the various agingcriteria chosen, and attempting to determinea biological age score for individuals anddifferent age groups. This study was hampered by the small number of people involved and the lack of vital statistics on the Marshallese people. Another difficulty has been the uncertainty of exact ages in some cases, particularly in older people. Table 1 Age Distribution in Rongelap Adult Population, 1959, Used in Aging Study Exposed Unexposed Age, yr M F M F 20-24 25-29 0 2 5 1 1 12 6 6 12 21 35-39 40-44 1 4 4 2 4 6 4 3 13 15 50-54 55-59 1 2 0 1 5 3 3 1 30-34 45-49 3 1 2 0 3 2 Total 5 3 13 6 11 7 60-64 0 6 5 3 14 70-74 1 2 0 0 3 1 2 0 5 65-69 75-79 >80 0 0 2 0° 1 2 0 3 0 3 ] 126 view toward ease of assessment during routine physical examination underfield conditions, time limitations, and language barrier. Therefore, unfortunately, tests of vigor and functional capacity were necessarily limited.* Of the 15 criteria selected, 9 were measured directly and 6 were estimated on a 0 through 4+ scale. Five tests involved the integument: (1) skin looseness, (2) skin elasticity (retraction time), (3) senile changesin the skin, (4) greying of the hair, and (5) baldness. Four tests involved the special sense organs: (1) accommodation, (2) visual acuity, (3) arcus senilis, and (4) hearing. The cardio- vascular system wastested by (1) systolic and (2) diastolic blood pressure recordings, (3) peripheral arteriosclerosis, and (4) retinal arteriosclerosis. adults 20 years of age and over. Of the 126 adults, There was one test of neuromuscularfunction. Vigor was measured by hand strength measurements. The test methods are described below. integument. A special skin caliper was designed for measuring skin looseness and elasticity the larger comparison population. Table 1 shows to any desired degree up to 5 cm on scale A by ad- Data on agingcriteria were recorded only on 42 werein the originally exposed group and84 in the age and sex distribution. The ages were reason- ably well distributed except for a smaller number of older people (>>60 yearsof age). The age criteria chosen were based on changes generally believed to be associated with physiological senescence and represent only a small number of the possible ones. They wereselected witha 906 1604 (Figure 8). The legs of the caliper can be opened justing screw B. The spring tension whenthecali- per is closed on a fold of skin results in a pressure of about 500 g. The inner andoutersurfaces of the legs are calibrated in millimeter markings (C). *Several tests, such as pulse and blood pressure response to a two-step test and vital capacity, were tried but not used because they proved unsatisfactory.