IV. GROWTH AND DEVELOPMENT* A. Background The various anthropomorphic data on the Rongelap children have been tabulated periodically in previous annual reports (1,9-13), and ongoing analyses have also been published in the open literature (21,24,27,28). Interval skeletal age analyses were recorded in the 1963 and 1974 reports (10,1). Beginning several years after exposure it was noted that, for boys, the statural growth curve for the exposed group Lagged behind the curve for the unexposed group. This lag appeared to be due primarily to the slowed growth in the group of boys exposed at <5 years of age. It was first thought that the growth retardation might be a direct radiation effect (21), but subsequent findings established radiogenic hypofunction of the thyroid gland as its cause (20-year report) (1)._ Assessment of the pattern of growth and development of the individuals who were children (<18 years old) on March 1, 1954, has been a consistent component of the pediatric examinations of the Rongelap people. Data interpretation has been complicated by radiation injury to the thyroid gland, partial or total thyroidectomies in the children who developed thyroid abnormalities, and administration of TSH suppressive doses of thyroid hormone to the exposed Rongelap population since September 1965 (when the youngest exposed child was ll years old). Analyses presented in this report are limited to the population of Rongelap Atoll. B. Methods In 1957 the population repatriated to Rongelap included (in addition to the exposed returnees) a sizable number of children who had not been exposed to fallout radiation. Some were Rongelap natives who had been away at the time of fallout, and others were relatives of residents. Since these children were of the same stock (blood relations) and would live post-return under the same environmental conditions as the exposed population, they were selected as unexposed controls. During 1957, 1958, and 1959, the control population was carefully characterized. Its members are identified in Appendix 11 of ref. ll. The same examinations were conducted on these children as on the exposed population. From the very first examination, growth data have been recorded. During the first 3 years the measurements consisted of weight, standing height, sitting height, length of upper extremity, arm span, biacromial width, intercristal width, head circumference, abdominal circumference, and left calf circumference. In 1958 the battery of body measurements was standardized to include weight, stature, sitting height, head circumference, head width, head length, chest circumference, chest width, chest depth, buttock circumference, *Dr. W.W. Sutow (M.D. Anderson Hospital, Houston, TX) and Dr. R.A. Conard and Mr. K. Thompson (BNL). - 26 -