23 ranged from 20 to 26 months, with an average of 22.4 months. To determine whetheror not some pattern in physique characterized these children with retarded osseous development, several physical measurements(from the 1959 study) on them and on their sibs were compared (Table 13). These anthropometric data suggested two trends, First, the weight rankings correspondedto chronological age rankings and notto statural rankings. Second, the lack of synchrony in rankings of several meas- urements was noticeable in those children who my were shorter than their youngersibs. This con- trasted with the uniform ranking of all measurements in those whose statural ranking correspondedwith the chronological age ranking. It might be speculated from these limited observations that these children were exposedto radiation at a particularly vulnerable age andthatthe resulting retardation in osseous developmentled to failure in statural growth. On the other hand, it is not possible to exclude completely the possibility that some process unrelated to radiation damage was responsible for the retardation in skeletal development. ADULT ABNORMALITIES Table 14 is a compilation of the various physical abnormalities noted in the adult group during the 1959 and 1960 surveys. No abnormalities are included for 1960 in the unexposed group because this group was not examinedin the 1960 survey. This table does not show any significant differences between the abnormalities noted in the exposed and in the unexposed populations. Results of special examinationsare discussed below. CARDIOVASCULAR SURVEY malities, and in the older group 41%. Specific findings may be summarizedas follows. Electrocardiographic Findings 1. Rhythm. In the younger group of exposed subjects, all had normal rhythm. One abnormality of rhythm was seen in a memberof the younger unexposed group. In the older groups, arrhythmia occurred in 3 of 14 exposed individuals and in 4 of 29 unexposed. 2. Conduction Times. Few abnormalities were seen. No individual in either the exposed or the unexposed group had prolonged auriculoventricular conduction time (P-R interval) above normal. Several subjects had the shorter conduction time of 0.12 sec; this is considered normal. The intraventricular conduction time (QRSinterval) was prolonged in several subjects. In the younger unexposed group, the ORSinterval was 0.10 to 0.11 sec in one subject, sufficient to be considered right bundle branch block. In the exposed population the intraventricular conduction time was prolonged to 0.12 sec in only one individual, age 81, who had a marked degree of hypertensive and arteriosclerotic cardiovascular disease and cardiac enlargement. Among29 individuals in the older unexposed group, two showed intraventricuiar conduction times of 0.12 sec without the typical QRScomplex of bundle branch block. In all other subjects the intraventricular conduction time ranged from 0.06 to 0.09 sec in the younger groups and 0.08 to 0.09 in the older. 3. Electrical Axis Deviation and Electrical Position of the Heart. There were few variations. The Table 15 Electrocardiographic Abnormalities (Percent Incidence in Younger and Older Age Groups) Exposed The cardiovascular findings may be found in the table of physical abnormalities (Table 14). The incidence of various electrocardiographic ab- normalities is shown in Table 15. The population Abnormality Age 20-49 (24)* through 49, and an older group, aged > 50. In the Rhythm A-V I-V RST T wave 0 12 0 0 0 was divided into a younger group, aged 20 exposed population, the younger group of 24 people showed no major abnormalities, but of the 14 older people 29% showed one or more abnormalities. In the unexposed population, among the younger group 15% had one or more abnor- “Number examined. Unexposed Age 230 (14) Age 20-49 (55) Age 2 30 (29) 21 7 7 7 21 2 2 4 2 11 14 3 7 14 34

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