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To determine whether increased fitness in natural populations is associated with heterozygosity, several studies have attempted to correlate heterozygosity at one or a few genetic loci with fitness-related quantitative traits. The results have been equivocal at best. Furthermore, data on fertility-related parameters and the extent of genetic polymorphism at a large number of loci in man are quite scanty. This report examines the association of four fertility-related parameters (number of pregnancies, number of livebirths, number of children surviving at least one year and number of children alive at the time of the survey) with heterozygosity at 17 polymorphic immunological and biochemical systems in the Aymara of Chile and Bolivia. Women 45 years of age and above, on whom complete fertility histories and phenotype data are available, were included in the study (n = 190). None of the fertility parameters seem to be correlated with heterozygosity, as measured by the proportion of polymorphic loci. For some individual loci, however, an association between heterozygous state and fertility parameters exists. Even in these cases, heterozygosity did not always confer higher fertility. To see whether these negative results are due to heterogeneity in the data, the total sample was divided according to altitude of residence and ethnicity. The conclusions remained the same, indicating that the lack of association of these fertility parameters with genetic polymorphism is not due to population heterogeneity alone. Reproductive fitness differentials, therefore, were not detectable in the Aymara by heterozygosity determined by the polymorphic genetic systems scored by serological and electrophoretic techniques.

The ethnic and geographic distributions of several common chronic diseases show distinct patterns that are consistent with the distribution of genes and genetic admixture. For example, diabetes and gallbladder disease occur most frequently among Amerindians, while those genetically admixed with them (such as Mexican-Americans) have intermediate rates, and lowest rates are found among Whites and Blacks. Because there will be heterogeneity from individual to individual in ancestral affinity within an admixed population, a method is developed for estimating each person's admixture probability. Results confirm that there is substantial heterogeneity of individual admixture among Mexican-Americans in Starr County, Texas, with a mean value indicating that 65% of genes in this population are Caucasian derived and 35% Amerindian derived. The individual estimates are shown to be unrelated to the probability of being diabetic and only marginally related to gallbladder disease, with those having the most Amerindian affinity being at increased risk. These results are a consequence of the independent assortment of loci and indicate that unless the markers employed are related (including linkage) to the disease of interest, the method will have limited utility. Individual admixture estimates will be useful, however, for examining aspects of population structure and will find increased utility for predicting disease and examining disease associations as more and more of the genome is represented by markers, a very probable prospect with the abundance of DNA polymorphism being identified by restriction enzymes.

Total glycosylated hemoglobin was measured from capillary blood specimens obtained from a sample of 1880 individuals of Mexican-American ancestry residing in Starr County, Texas, between January 1981 and February 1982, as part of an epidemiologic survey to assess the prevalence of noninsulin-dependent diabetes mellitus (Type II). No significant difference was found between males and females. Diabetics were found to have significantly higher levels of glycosylated hemoglobin than nondiabetics. However, among diabetics, there was no significant difference between newly diagnosed and known diabetics, and known diabetics taking medication did not differ significantly from those not taking medication. An analysis of the specificity and sensitivity of glycosylated hemoglobin, fasting blood glucose, and casual blood glucose determinations as screening devices in a survey of diabetes prevalence reveals that glycosylated hemoglobin is superior to casual blood glucose determination. The conditions under which various screening devices might be more effective are discussed.

This study dealt with approximately 2,000 children and their parents living in a hyperendemic goiter area in Central Brazil, which is bounded by the jungle to the north and by a large plain to the south. The determination of goiter was made according to the methods and classification adopted by WHO. Conspicuous forms of goiter were found in 41% of the children examined. Multiple linear regression analysis showed an increase with age in the frequency of goiter in both sexes. Although data from the literature show that Mulattoes and Negroes have statistically higher frequencies of goiter than do Whites, our multiple linear regression analysis revealed no evidence for an effect of race on the endemism. There was no significant association with socioeconomic level. The presence of goiter in parents was shown to be statistically associated with its occurrence in the children.

Acheiropodia offers no special problem of a counseling nature. The genetic risk can be easily estimated since the anomaly is due to a rare autosomal recessive gene with complete penetrance and little variation in expression. However, considering that acheiropod individuals have a tremendous handicap (they are born without both hands and feet), it is remarkable how they overcome this difficulty and lead an almost 'normal' life. Several examples are given in this paper. The 'philosophy' of genetic counseling is briefly discussed; emphasis is placed upon the necessity for the geneticist to present the good perspectives, while preparing the consultand for the worst. Even in this last possibility, however, not everything is necessarily lost as the example of the acheiropods attests.

The physiological effect of chronic exposure to altitude hypoxia on the glycolytic intermediates, adenosine triphosphate and 2,3-diphosphoglyceric acid, and the hematologic parameters, hemoglobin, hematocrit, and mean cell hemoglobin concentration, has been examined in an indigenous population, the Aymara, of the Departamento de Arica, Chile. This population normally resides at three altitudes: the coast (0-500 m), the sierra (2,500-3,500 m), and the altiplano (above 4,200 m). After isolation of altitude from other environmental factors (age, sex, body build, ethnicity, smoking, and residential permanence), an increase in 2,3-diphosphoglycerate and a decrease in adenosine triphosphate was observed. Both hemoglobin and hematocrit increased as expected, but mean cell hemoglobin concentration declined. It is proposed that a decline in the activity of a single enzyme, pyruvate kinase, can account for these observed changes and suggests a pivotal role for pyruvate kinase in the physiological adaptation to altitude hypoxia.

While information on the toxic attributes of specific compounds is voluminous, most of it is inconclusive regarding the risks of reproductive problems. Observations that seem to suggest freedom from risk are often insufficient to conclude they are not due to chance, and when clinically outstanding effects are apparent, the number of observations is often so small that it is probable that their importance has been overestimated. This presentation focuses on the process rather than specific agents on the persons at risk, the types of exposures, the possible nature of the hazards, the factors which impinge on this risk, and finally, the additional information required to make risk estimation more precise. It seeks to identify strategies which will improve the quality of information routinely collected, address the mensurational problems associated with the estimation of exposures, and permit earlier recognition of the especially vulnerable.

An increasing body of evidence suggests that diabetes mellitus constitutes a major health burden among the Mexican-American population. For example, county-wide death rates in Texas attributable to diabetes from 1970-1981 range from 2.5-52.0 diabetes deaths per 1000 total deaths with the highest rates generally occurring in counties whose populations are more than 75% Spanish ancestry. To assess the prevalence and morbidity of noninsulin-dependent diabetes mellitus among Mexican Americans, 14% of the Starr County, Texas, population (97% Mexican-American) was randomly sampled. The reference population, sampling strategy, and screening results are described. Age-specific prevalences of diabetes for males ranged from 0% in males aged 15-24 years to 17.6% in those above 75 years of age. Rates for females ranged from 0.4% in those aged 15-24 years to a high of 19.0% in the 55- to 64-year age group. In both sexes, the rates are relatively low for persons under age 45 with a sharp increase in those aged 45-54 years and high rates prevailing in the older age groups. Comparisons of the rates in Starr County to those of the general US population indicate a two- to fivefold greater risk in Starr County. In terms of impact on this community, these results imply that over 50% of individuals older than 35 years are directly affected by diabetes by virtue of their having the disease or by being a first-degree relative of a diabetic.

Previous investigations have established that the Mexican-American community of south Texas has a three- to five-fold elevated risk for non-insulin dependent diabetes mellitus when compared to the US population as a whole. In addition, evidence points to similarly increased risks of the related disorders, hypertension and obesity. In this paper, age- and sex-specific rates of borderline and definite hypertension among 1931 Mexican-Americans aged 15 years and above based on a single, at-home blood pressure determination are reported. Observed rates of definite hypertension are uniformly lower than the US population while borderline hypertension is correspondingly higher for all age and sex strata yielding overall prevalences of hypertension which are not significantly different. The Starr sample, however, has one and one-third times as many individuals taking hypertensive medications so that the true rate of hypertension is likely to be higher. Examining sources of blood pressure variability using analyses of covariance indicate that age has the most significant effect. A direct measure of body size was not available, but classification based on simple silhouettes representing body form is shown to be the next most significant effect. Furthermore, the silhouettes appear to provide nearly an equivalent amount of information as does the body mass index as an empirical predictor of blood pressure variability. Diabetic classification is a significant effect for systolic blood pressure in females, but not for males or for diastolic pressure in either.

We examined the contributions of genetic factors and the family environment to human fatness in a sample of 540 adult Danish adoptees who were selected from a population of 3580 and divided into four weight classes: thin, median weight, overweight, and obese. There was a strong relation between the weight class of the adoptees and the body-mass index of their biologic parents - for the mothers, P less than 0.0001; for the fathers, P less than 0.02. There was no relation between the weight class of the adoptees and the body-mass index of their adoptive parents. Cumulative distributions of the body-mass index of parents showed similar results; there was a strong relation between the body-mass index of biologic parents and adoptee weight class and no relation between the index of adoptive parents and adoptee weight class. Furthermore, the relation between biologic parents and adoptees was not confined to the obesity weight class, but was present across the whole range of body fatness - from very thin to very fat. We conclude that genetic influences have an important role in determining human fatness in adults, whereas the family environment alone has no apparent effect.

Red cell haemoglobin (Hb), haematocrit (Ht), 2,3-diphosphoglycerate (DPG), and adenosine triphosphate (ATP) levels were measured in 876 individuals from six villages at two altitude levels (altiplano and coast) of the Departmento de Arica of Northern Chile. Of these, data on 761 individuals are subjected to analysis to search for the evidence of genetic adaptation to a hypoxic environment at a high altitude. Total phenotypic variance for each of the variables is higher at the altiplano as compared to their counterparts at the coastal level. Data on 1127 pairs of relatives of six degrees of relationships are used to determine the genetic component of variation in each of these four traits. To a certain extent the larger familial correlations as well as higher variances at altiplano are explained by the apparent assortative mating (which may again be due to their restricted population size) at the higher elevation. Yet, at least in three variables (Hb, Ht, and DPG) no reduction in the additive genetic component of variation is noticed at the higher altitude. ATP seems to have the highest degree of genetic component of variance, particularly at the coastal level. Some implications of these results are discussed in the light of their roles in the glycolytic pathway.

The assessment of obesity by anthropometry or body composition in studies of chronic disease epidemiology is not always feasible. In this paper we test the accuracy and validity of two alternative methods: body silhouettes and reported weights and heights in a sample of Mexican American adults (n = 166) participating in the Diabetes Alert Study. The body silhouettes were those developed by A. Stunkard and colleagues. We compared the silhouettes obtained independently by three different observers, one with minimal experience in assessing obesity, the other two skilled in anthropometry. Correlations between the expert observers were 0.89-0.90. Those between the expert and less skilled observers were lower (0.64 to 0.85) and were better for female than male subjects. Results suggest an acceptable level of precision for persons with some training in obesity assessment. Body silhouettes compared well with the body mass index (r = 0.85 to 0.92 for the expert vs r = 0.65 to 0.84 for the less skilled observer), being higher for female subjects. The body silhouettes are thus useful for categorizing normal, overweight and obese individuals. The poorer performance on male subjects may relate to the female-like obesity depicted in both sexes in this particular set of silhouettes. A substantial proportion of subjects could not recall their weight or height. For those who could recall their measurements, accuracy was good but measurement error higher than that for measured variables. These problems of recall in this sample from rural Texas point to the potential usefulness of the body silhouette method when actual height and weight measurements cannot be made.

The fit to Hardy-Weinberg equilibrium is improved if an atypical B allele is assumed to exist along with the A1, Aint, A2, B, and O genes in the ABO system. This atypical B allele accounts for 37% or so of the total B gene frequency in both Brazilian whites and blacks.

Immunoglobulin (Gm and Km) allotype and haplotype frequencies are presented for 1707 individuals from Northern Chile and Western Bolivia, subdividing them by ethnicity and altitude of residence. The haplotype distribution of Gm as well as Km loci in these populations suggest that in almost all of the ethnicity x altitude subdivisions of this population considerable admixture of Amerindian and Caucasian genes have occurred. The haplotype frequency heterogeneity and the analysis of departure from Hardy-Weinberg expectations demonstrate that while some local variation in haplotype frequencies at the Gm and Km loci exists in this region, there is no clear evidence suggesting that the pattern of variation is due to an adaptation to the hypoxia of altitude. We conclude that such differences in haplotype frequencies are probably due to random genetic drift and differential admixture of Amerindian and Caucasian genes that have occurred in the past.

Studies of lung function in high altitude populations have suggested the influence of hypoxic environment on the development of this characteristic independent of confounding variables such as ethnicity and habitual exercise. However, often the effect of altitude on vital capacity is greater in children than adults, suggesting that more than developmental adaptation is operative. Also selective migration could account for the similarity of migrants and permanent residents at a destination altitude. To explore these problems we studied the lung function (FVC, FEV1, PFR) of 377 individuals who had migrated between altitudes in northern Chile. Migrant measurements were adjusted to those of permanent residents of appropriate age, sex and height at the altitudes of origin and destination. The measurements were then related to ethnicity (Spanish-Aymara ancestry), occupation and permanence, the latter combining information on both age at migration to and length of stay at a destination altitude. Upward migration was associated with increased chest depth, FVC and FEV1, but not height or other chest measurements. Downward migration had no significant effect. The flow-dependent test PFR was so sensitive to observer variability and occupation that it was difficult to establish its relationship to permanence. Unlike the body measurements, lung function measurements (especially PFR) tended to deviate from permanent controls at the origin altitude in a direction suggestive of selective migration, nor was permanence itself independent of ethnicity and occupation. Because of these difficulties the question of developmental adaptation in lung function may not be answerable in cross-sectional studies like the present and previous efforts, but rather in longitudinal investigations in which the control is the individual him/herself.

Phenotype and gene frequencies are presented for eight polymorphic systems among the Nubians of South Egypt, namely, acid phosphatase, glucose-6-phosphate dehydrogenase, adenylate kinase, 6-phosphogluconate dehydrogenase, esterase D, phosphoglucomutase I, peptidase A, and haptoglobin. Eleven systems, namely, albumin, ceruloplasmin, hemoglobin, lactate dehydrogenase, isocitrate dehydrogenase, phosphohexose isomerase, malate dehydrogenase, peptidase B and C, phosphoglucomutase II, and transferrin were found to be monomorphic. A single electrophoretic variant of phosphohexose isomerase were observed.

Data are presented on four indicators of genetic effects from studies of children born to survivors of the atomic bombings of Hiroshima and Nagasaki. The indicators are frequency of untoward pregnancy outcomes (stillbirth, major congenital defect, death during the first postnatal weak); occurrence of death in live-born children, through an average of life expectancy of 17 years; frequency of children with sex chromosome aneuploidy; and frequency of children with mutation resulting in an eletrophoretic variant. In no instance is there a statistically significant effect of parental exposure; but for all indicators the observed effect is in the direction suggested by the hypothesis that genetic damage resulted from the exposure. On the basis of assumptions concerning the contribution that spontaneous mutation in the preceding generation makes to the indicators in question, it is possible to estimate the genetic doubling dose for radiation for the first three indicators (the data base is still too small for the fourth). The average of these estimates is 156 rems. This is some four times higher than the results from experimental studies on the mouse with comparable radiation sources, which have been the principal guide to the presumed human sensitivities. The relevance of these data in setting permissible limits for human exposures is discussed briefly.

The distribution of the number of exclusions to be expected in paternity testing is derived, and the calculation of the mean and variance of this distribution is indicated.

Census areas in Detroit were ranked for their stress scores based on instability (e.g., crime, marital break up) and socioeconomic status. Four areas were selected for detailed study: 1) high stress, population predominantly black, 2) white, 3) low stress, population predominantly black, 4) white. A sample was drawn from each area of persons of the predominant race, 25-60 years old, married and living with spouse, and having relatives in the Detroit Area. Nurses interviewed such persons; three blood pressure readings were taken during the first half-hour of medical history, and skin color was rated. Results show that darker skin color, for black males especially, is related to higher pressure, independently of nine control variables (e.g., age, weight, socioeconomic status, etc.). However, younger black males (25-39 years of age) in high stress areas had higher pressure than counterparts in low stress areas, regardless of skin color and relative weight; for older black males (40-59 years of age) darker skin color was correlated with higher pressure, regardless of relative weight or stress area. For 35 blacks whose fathers were from the West Indies, pressures were higher than those with American-born fathers. These findings suggest that varied gene mixtures may be related to blood pressure levels and that skin color, an indicator of possible metabolic significance, combines with socially induced stress to induce higher blood pressures in lower class American blacks.

A continuing study of mortality rates among children born to survivors of the atomic bombings and a suitable group of controls has been updated; the average interval between birth and verification of death or survival is 17 years. The mortality experience is now based on 18,946 children liveborn to parents one or both of whom were proximally exposed, receiving jointly an estimated dose of 117 rem; 16,516 children born to distally exposed parents receiving essentially no radiation; and 17,263 children born to parents not in Hiroshima or Nagasaki at the time of the bombings. No clearly significant effect of parental exposure on child's survival can be demonstrated either by a contingency chi(2) type of analysis or regression analysis. On the basis of the regression data, the minimal gametic doubling dose of radiation of this type for mutations resulting in death during (on the average) the first 17 years of life among liveborn infants conceived 0-13 years after parental exposure is estimated at 46 rem for fathers and 125 rem for mothers. On the basis of experimental data, the gametic doubling dose for chronic, low-level radiation would be expected to be three to four times this value for males and as much as 1000 rem for females.

The association between body fat distribution patterns and cardiovascular disease risk variables (high density lipoprotein (HDL) cholesterol, total cholesterol, diastolic and systolic blood pressures, and fasting blood glucose levels) was sought in a sample of Mexican American adults who were studied during 1981-1983 in Starr County, Texas. In the sample, all diabetics were excluded to see whether centralized obesity carried any risk for cardiovascular disease independent of diabetes. A component of centralized body fat distribution was identified through the use of principal components analysis of five skinfold measurements, which included the upper and lower extremities and trunk areas. The centralized obese were compared with generalized (peripheral) obese and nonobese controls in four subgroups of the population: younger and older adult males and females. The means of all cardiovascular risk variables were in a direction indicating that the centralized obese were significantly at greater risk than nonobese controls (in particular, HDL cholesterol, total cholesterol, and blood glucose levels). The generalized obese differed from the centralized obese in having significantly lower blood glucose levels, and tended to be intermediate between centralized obese and nonobese controls in the other variables. The data confirm that centralized obesity as defined by a linear combination of skinfold measures works in the same way as the waist-to-hip circumference ratio in describing a body build factor which heightens the risk of cardiovascular disease in the obese independent of the clinical diabetic state.

History of adult weight gain and fat patterning is compared in Mexican American diabetics and age and sex matched non-diabetics. Diabetics differed little from non-diabetics in overall body fatness at the time of the examination. However, history of adult weight gain and current fat patterning were very different. Diabetics were heavier than non-diabetics at age 18. They subsequently gained weight faster and attained a substantially higher weight, at an earlier age, than non-diabetics. Discriminant function analysis was used to test for differences in patterning. Diabetics tend to have more trunk fat, as reflected particularly in the subscapular skinfold, and less lower extremity (leg) fat. Fat patterning in this population does not appear to be influenced by age when weight gain occurred, but is related to diabetic status, especially in women.

This brief communication reports the results of 24-ambulatory cardiac monitoring of a Bering Strait Eskimo population and compares the findings with 3 other populations. Similar heart rate rhythmicity and almost identical acrophases are found in the Eskimo, Aymara Indian and French populations. However, the Alaskan Eskimo and Aymara Indian 24-h means vary by approximately 15 beats/min, with the American population between these two. The mesor displays most radical differences.

Recent studies of the effects of hypoxia on human growth and adult size have focused mainly on the variability of single measurements. In this paper we explore changes with altitude and ethnicity (Spanish-Aymara ancestry) in body proportions of permanent residents of an altitudinal gradient (0-4000 meters) in northern Chile. Body proportion or shape is assessed by anthropometric indices and principal components of 14 bone measurements. Ethnicity independent of altitude had its major effect on proportions and a lesser effect on size. Aymara had larger relative sitting heights, broader builds and prominent facial development as compared to non-Aymara (Spanish). Altitude also affected head and chest proportions during growth. On the whole, the effects of altitude and Aymara ancestry on the measurements and indices were independent (not necessarily of similar direction or magnitude), in spite of a correlation of ethnicity and altitude in Andean populations.

In 1972 a multidisciplinary study sought to assess the health status of the indigenous peoples of the Department of Arica in northern Chile, the Aymara, and to relate disease, morphological, physiological and biochemical variation, to the wide changes in altitude of the region. Presented here are the morphological changes which accompany age, altitude and ethnicity amoung 1047 children and adults, permanent residents of the coast, sierra and altiplano. At comparable ages, high-altitude residents were shorter, lighter and leaner but with more expansive and rounder chests than sea-level controls. None of these effects was systematically related to ethnicity (Spanish-Aymara surname), although when stature was held constant, children with greater Aymara ancestry had largest chest circumferences and longer bones. These results suggest that (1) altitude confers allometric growth changes (expensive growth of the chest and diminished growth of the structures less related to oxygen transport); and (2) size changes associated with altitude are acquired during development while shape changes may be under genetic control. Altitude appears to account for less of the variation in growth in this relatively homogeneous Chilean sample than has been reported for other Andean samples, suggesting other concomitants confounding the effects of hypoxia in Andean South America.

A Monte Carlo simulation is performed to study the distribution of the family set estimators of heritability and to compare their performance with that of some conventional estimators used in human genetics. Comparisons of statistical properties among the two family set estimators (one based on the partial regression coefficients of the index's values on those of sib and cousin, respectively, and one based on the variances of the differences between the phenotypic values of index and cousin and of index and sib) and the three conventional estimators (one based on regression of index value on midparental value, another based on the sib-sib correlation, and the last one based on the index-cousin correlation) are also made under two genetic models.

An analysis of the dose response within the low-dose range (as here defined, doses of less than 50 cGy (50 rad) was conducted among A-bomb survivors in the ABCC-RERF cohort in an attempt to detect the phenomenon of radiation hormesis, if it is present. These studies include as endpoints cancer mortality, cancer incidence, the frequency of cells with chromosomal aberrations, the phytohemagglutinin response of peripheral lymphocytes and the frequency of mental retardation among survivors exposed in utero. In general, the dose response for these indices of radiation damage varied among comparison groups within the low-dose range, but failed to suggest the existence of radiation hormesis.

Panama's black citizens are culturally and historically divisible into two groups, the Spanish-speaking coloniales and the English-speaking anglos or afro-antillanos. Until recently these groups have been geographically as well as culturally isolated one from the other, although both are predominantly of West and Southwest African origin. Assessment of the genetic diversity within-villages and within language groups reveals as much, possibly somewhat more, diversity in 15 inherited biochemical markers within villages and language groups as that which obtains between villages and language groups. A number of rare variants at the 6-phosphogluconate dehydrogenase, lactate dehydrogenase, and esterase D loci were encountered and are described.

Data on a total of 7,593 persons in Hiroshima who were in 2,518 wooden Japanese houses and exposed to A-bomb within 1.6 km from the hypocenter have been used to estimate the LD50/60. The effect of radiation shielding for these people in particularly well-characterized in the new dosimetry system DS86. A range of values emerge, varying slightly with the method of estimation used. This range, derived from DS86 marrow doses, and based on a linear fit to equally weighted estimates of the probabilities of death at various doses, is 2.3-2.6 Gy. A linear estimate in which the probabilities of death at the various doses are weighted by the inverse of their variances is somewhat lower, 2.2 Gy. These values may be underestimates of actual LD50/60 because of inclusion of deaths in the first day, and the severely injured (burns, trauma) who survived the first day but succumbed later to their injuries.

The ratios of circumferences (waist/hip, waist/thigh) have been proposed in lieu of skinfold measurements for studies of obesity and body fat distribution. The purpose of this paper is to present our experience in measuring a series of body circumferences and skinfolds in an obese population, and seek the relationship between these two kinds of variables as indicators of fatness and body fat distribution using canonical correlation analysis. With this method, weighted vectors of circumferences on the one hand and skinfolds on the other, are formed in such a way that the correlation between the two sets of variables is maximized. The weights (regression coefficients) and their signs help us select the best combination of circumferences which describe a component of centralized obesity. Our experience showed that 21 percent of women would have been excluded from this multivariate analysis due to skinfolds what could not be measured (mainly due to poor fold definition). Few men were so excluded (6 per cent), and almost all circumferences could be measured in both sexes. A first canonical correlation was substantial (0.84 in women, 0.89 in men) and appeared to relate to level of fatness. A second canonical correlation was moderate (0.59 in women, 0.42 in men) and statistically significant (P less than 0.01) in both sexes. Only in women was it independent of age, but in both sexes it reflected differences in central and peripheral (especially lower limb) fat. The simple waist/thigh ratio correlated well with the second canonical variate (0.79 in women, 0.67 in men).(ABSTRACT TRUNCATED AT 250 WORDS)

Tape monitoring of the electrocardiogram among ambulant individuals with and without cardiac disease has been practicable for some years now. It has, however, found greater acceptance and utilization in diagnosis, early detection of silent ischemic heart disease (17), and the evaluation of the effectiveness of different dysrhythmia treatment modalities than as a means to examine differences in cardiovascular response to environmentally stressful situations. This study illustrates its practicability under field conditions substantially more rigorous than in most prior uses, and its applicability to our further understanding of the cardiovascular changes associated with adaptation to the hypoxia of altitude.

We have examined the risk for cancer (incidence) over a period of 40 years, 1945-1984, among 1829 persons exposed in utero to the atomic bombing of Hiroshima and Nagasaki. This report adds eight years of follow-up to a previous report which was confined to mortality. Only two cases of childhood cancer were observed among these survivors in the first 14 years of life; both had been heavily exposed. Subsequent cancers have all been of the adult type. Not only did these latter cancers occur earlier in persons exposed to greater than 0.30 Gy than in unexposed (0 Gy) but the incidence continues to increase, and the crude cumulative incidence rate 40 years after the bombing is 3.9-fold greater in persons exposed to greater than 0.30 Gy. In the observation period 1950-1984, the relative risk for cancer at 1 Gy, based on the absorbed dose to the mother's uterus as estimated by the Dosimetry System 1986 (DS86), is 3.77 with a 95% confidence interval of 1.14-13.48. For all persons exposed to greater than 0.01 Gy, the average excess risk per 10(4) person-year-Gy is 6.57 (0.07-14.49), and the estimated attributable risk is 40.9% (2.9-90.2%). These results, when viewed in the perspective of fetal doses, suggest that susceptibility to radiation-induced cancers is higher in survivors exposed prenatally than in those exposed postnatally (at least, those exposed as adults). However, definitive conclusions must await further follow-up studies.