6 tion must be exercised in evaluating the results of these studies on genetically inherited character- istics because of the small number of samples tested. The data do seem to indicate relative homogeneity of the population andclosest kinship with people of Southeast Asia. These dataalso may beuseful as a base line should genetic changes appearin later generations, possibly related to radiation exposure. Results of other laboratory studies included the following: Serum protein levels were generally on the high side of normal; electrophoretic patterns showed theincrease in proteins was largely due to an increase in the gammaglobulin fraction. The reasonfor this is not apparent. Numerouschronic infections may be an explanation. — Sodium levels in the urine and food indicated about the same consumption of NaCi as in Americans. The generally lower incidence of hypertension in the Marshallese might be related to the fact that the formernative diet was probabhy lower in salt content than the present, more westernized diet. It will be interesting to see whetherthe incidence of hypertension will later increase. Serum cholesterol levels (1957, 1959) were some- cases with eosinophilia showed no helminthic infectionsat all suggests that other factors besides parasitic infections must be responsible. The eosinophilia maybe related to chronic fungus and other infections, particularly of the skin. Complementfixation studies for parainfluenza1, 2, and 3, respiratory syncitial, psittacosis, and fever showedantibodiesto all groups of viruses except that for Asian influenza, which probably had not vet seriously involved the people of the Marshall Islands. The antibody titers appeared to be somewhat lowerin the exposed people. DIFFICULTIES ASSOCIATED WITH THE EXAMINATIONS As mentioned in previous reports, several difficulties were associated with carrying out the examinations as well as interpreting the findings. 1. The language barrier made examinations difficult, since very little English is spoken bythe Marshallese. However, there were sufficient English-speaking Marshallese to assist the medical team in most instances. Serum creatinine levels (1937) were in the normal 2. The lack of vital statistics or demographic data on the Marshallese imposed a serious difficulty in interpretation and evaluation of the medical data. Recorcls of births, deaths. etc.. have been made bythe health aides or magistrates of the villages and supposedly forwarded to the district ad- Serum vitamin B,, concentrations (1958, 1959) complete or lost in most instances, and vitalstatis- what lowerin the exposed population thanin the comparison of Utirik populations, but were in the low normal range. No abnorally lowreadings were noted. — range with no abnormallevels noted. were generally significantly higher than American levels. The possibility of contamination of the samples with bacteria producing vitamin B,, must be considered, since myeloproliferative and liverdis- eases were not seen. Serum protein bound iodine levels (1957, 1959) were generally slightly elevated. Evidence for thyroid dysfunction was not apparentin the people. Glucosuria and elevated blood sugar were foundin 4 unexposed individuals, which indicated a rather high incidence of diabetes. A survey for intestinal parasites (1958) showed 73% of the people to be infected with various types. For the three major pathogens found, the over- all infection rates were, for Entamoeba histolytica, 18.2%; for hookworm, 5.5%; and for Trichurts trichtura, 34.3%. Eosinophilia >5% has consistently been noted in about half the people. The fact that half the ministrator; however, such records have been in- tics are therefore inadequate. Trust Territory officials are now attemptingto assemble such data. 3. There is uncertainty on the part of some of the Marshallese as to their exact ages, particularly amongthe older group. This imposes certain difficulties in interpreting someof the studies to be outlined. COMPARISON POPULATIONS During the first 2 years, two separate groups of Marshallese people were used for comparison, each of comparable size to the exposed Rongelap group and matched for age and sex. However,this population was found to be unstable, with a large attrition rate over the 2 years, which madeit un- satisfactory. At the time of the 3-year survey,it was found that during the preceding 12 months the Rongelap population at Majuro Atoll had

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