Power and pollutant exposure in the context of American Indian health and survival.

BACKGROUND: American Indians and Alaskan Natives (AI/AN) are a highly diverse group in terms of culture and language, but share a history of oppression and attempted extermination that has left many with a legacy of poverty and poor health. Cultural and biological survival are important issues for many AI/AN groups. METHODS: Using US criteria, AI/AN groups are more likely to be poor. The US National Center for Health Statistics reports that US AI/ANs have higher mortality and morbidity rates than the US population. While all groups racially defined by the US National Center for Health Statistics have been experiencing a decline in fertility since 1983, AI/ANs seem to be suffering a substantially greater and earlier decline in fertility. Given the importance of fertility in the survival of AI/AN communities, it is important to identify the source of this decline. RESULTS: A recent study of one AI/AN group living along the St. Lawrence River found that obesity and exposure to a particular group of polychlorinated biphenyls were the factors most highly associated with indicators of impaired fertility. Economic factors are often cited as reasons for fertility declines, however in this situation these other factors may have either primary or contributing roles. CONCLUSIONS: If the associations with obesity and toxicant exposure are confirmed, intervening on these factors might be important steps in stemming continued declines in fertility.

A partnership study of PCBs and the health of Mohawk youth: lessons from our past and guidelines for our future.

This paper describes a research partnership between the people of Akwesasne and researchers from the State University of New York at Albany for the study of polychlorinated biphenyls and the health of Mohawk youth. The study is distinctive because its goals have been set by the scientists and the community members and is being conducted jointly by these groups. The research partnership recognizes the history of relationships between native and nonnative peoples, particularly scientists, and seeks not only to fulfill certain scientific goals but to further community ones as well. The relationship is based on three principles: mutual respect, mutual equity, and mutual empowerment. These principles guided every aspect of the research process. The project goals were determined jointly to maximize data quality and minimize the intrusion of research activities into the lives of community members. Data collection is performed by research assistants who received extensive and ongoing training in data collection methods, and who are members of the community. Feedback procedures were designed by community members and scientists jointly to maximize understanding. Feedback regarding individuals' pollutant levels and assessments of growth and development are provided to each individual. Information about community pollutant levels are provided to the community. Hypothesis testing is carried out by research scientists, and the results presented first at a community meeting. Research conducted in this way--as a partnership--requires more communication, discussion, and travel, but the result is mutual satisfaction and growth.

Environmental pollution and child health in central and Eastern Europe.

For the last 50 years, the economic and industrial development of the nations of Central and Eastern Europe has been achieved at the cost of environmental degradation. The health risks posed by this pollution to children and the steps necessary to ameliorate such risks are only beginning to be investigated. At a recent conference in Poland, sponsored in part by the National Institute of Environmental Health Sciences, participants from 11 countries in the region, together with scientists from Western Europe and the United States, met to share information regarding pediatric environmental health in Central and Eastern Europe, to consider methodologic issues in the design and conduct of such studies, and to discuss preventive strategies. This report summarizes the deliberations, outlines problem areas such as heavy metals and air pollution, delineates research and training needs to help Central and Eastern Europeans deal more effectively with such problems, and recommends specific future actions and collaborative efforts.

Blood lead level, by year and season, among poor pregnant women.

The authors conducted a longitudinal study of poor pregnant women and their infants to examine the determinants of maternal and infant lead levels. To accurately depict these determinants, one must account for secular and seasonal variations in these levels. The women's lead levels declined over the 5-y period of study by approximately 20%/y, depending on when in the course of pregnancy measurements were made. After correction for secular trend, we found a periodic effect that differed from that typically seen in children (i.e., peak occurs in summer). In this study, lead levels in these women peaked during December-March. If the effects of lead are greatest in the youngest conceptus, early pregnancies that occur in the December-March period pose the largest prenatal risk.

Variation in blood lead and hematocrit levels during pregnancy in a socioeconomically disadvantaged population.

Lead is a long-recognized human toxicant that crosses the placenta. Fetal sensitivity to environmental agents can vary with stage of development; therefore, how maternal blood lead levels change during pregnancy and how fetal exposure is influenced provide useful knowledge. In this study, the authors describe longitudinal changes in blood lead levels during the course of pregnancy in a sample of socioeconomically disadvantaged pregnant women. The women were recruited early in pregnancy when they sought care at one of two obstetrics clinics in Albany, New York. Maternal blood lead levels changed between the 1st and 2nd trimesters, from 1.99 microg/dl to 1.69 microg/dl (hematocrit corrected, 1.70-1.62); between the 2nd and 3rd trimester from 1.78 microg/dl to 1.86 microg/dl (hematocrit corrected, 1.65-1.72); and between 3rd trimester and delivery from 1.80 microg/dl to 2.17 microg/dl (hematocrit corrected, 1.70-1.86). These changes were statistically significant and were corrected for secular trends. The rate of change per day in lead levels averaged -36.6% from trimester 1 to trimester 2, 18.3% from trimester 2 to trimester 3, and -40.8% from trimester 3 to delivery. The patterns in our study were consistent with the patterns reported in a few other longitudinal studies of change in lead level during pregnancy. Findings reveal significant associations between maternal blood lead levels and both hematocrit and trimester of pregnancy. Clinicians who interpret test results should take into account the dynamics of these variables when determining appropriate care for both mother and neonate.

Culture, Urbanism and Changing Human Biology.

Anthropologists have long known that human activity driven by culture changes the environment. This is apparent in the archaeological record and through the study of the modern environment. Perhaps the largest change since the paleolithic era is the organization of human populations in cities. New environments can reshape human biology through evolution as shown by the evolution of the hominid lineage. Evolution is not the only process capable of reshaping our biology. Some changes in our human biology are adaptive and evolutionary while others are pathological. What changes in human biology may be wrought by the modern urban environment? One significant new change in the environment is the introduction of pollutants largely through urbanization. Pollutants can affect human biology in myriad ways. Evidence shows that human growth, reproduction, and cognitive functioning can be altered by some pollutants, and altered in different ways depending on the pollutant. Thus, pollutants have significance for human biologists and anthropologists generally. Further, they illustrate the bio-cultural interaction characterizing human change. Humans adapt by changing the environment, a cultural process, and then change biologically to adjust to that new environment. This ongoing, interactive process is a fundamental characteristic of human change over the millennia.

Using patterns of child growth and development to assess communitywide effects of low-level exposure to toxic materials.

Child growth is a low tech method for assessing a socially valued health outcome, and its assessment focuses attention on the early portion of the lifespan. It is easily measured and sensitive to a variety of influences including chemical ones. As summary measure of health, it does not signify that a particular chemical is present, but it is a response to a variety of them. When used in conjunction with other epidemiologic methods, child growth assessment constitutes a practical, socially meaningful and biologically reasonable tool to assess the impact on community health and well being of chronic low-level exposures to toxic materials.

Culture as a stressor: a revised model of biocultural interaction.

Contemporary urban societies display in high relief the action of social stratification on human biology. Recent studies of biological responses to urban environments and of socioeconomically disadvantaged people indicate that culture allocates risks disproportionately to some individuals and groups within society through its constituent values and related patterns of behavior. Although risk allocation is present in all societies, it is very clear in urban environments within stratified societies where high exposure to harmful materials is many times more likely for some segments of society. In urban environments, culture may be seen as adding stressors to the environment by concentrating naturally occurring materials to levels that are toxic to humans and through the creation of new toxic materials. In stratified societies the risk of exposure to these new stressors is focused on the socioeconomically disadvantaged. This exposure has consequences that increase the likelihood of more exposure and more socioeconomic disadvantage, thereby increasing social stratification. This suggests that models of biocultural interaction include a feedback relationship in which biological factors influence the sociocultural system in addition to the usual action of the sociocultural system on biological features and responses. This model strongly reinforces the view that stressors can originate from cultural arrangements.

Environmental noise and human prenatal growth.

To determine whether chronic exposure to relatively loud noise has demonstrable biological effects in humans, a study was conducted on the effect of mother's exposure to airport noise while pregnant, and of social and biological characteristics of the family upon birthweight and gestation length. The sample of births was drawn from a community located adjacent to an international airport in the U.S., where noise levels had been measured previously. Mother's noise exposure was based upon noise levels near her residence in the community while she was pregnant. Data from 115 births were used, these being from mothers whose noise exposure history was most complete throughout the pregnancy. Using multivariate analysis to correct for family characteristics, the partial correlation coefficient for noise exposure and gestation length was negative, large, and significant in girls (r = -0.49, p less than 0.001). In boys the partial correlation coefficient was also negative but was smaller and did not quite reach statistical significance. Partial correlations with birthweight were smaller in both boys and girls and not significant. These results agree best with previous studies that suggest that noise may reduce prenatal growth. The size of the observed effects may be related to a conservative research design biased towards underestimation, as well as to the real effects of noise upon human prenatal growth.

Airport noise exposure and the postnatal growth of children.

To determine whether chronic exposure to airport noise affects children, a study was conducted of the physical growth of children, aged 5-13 years, from two communities, one exposed to airport noise (n = 148) and another, not exposed (n = 102). Ten standard anthropometric measurements were made according to U.S. Health Examination Survey guidelines, and information on the social and biological characteristics of each family was collected in interviews. Hotelling's T2-tests were performed comparing the noise-exposed and nonnoise-exposed samples. There was no significant difference between the sample for measurements of social and biological characteristics of the families (including socioeconomic status and maternal reproductive history). Parental anthropometrics differed significantly (T2 = 24.32, P = 0.0001) as did child anthropometrics (T2 = 21.01, P = 0.032). For the child anthropometrics, noise-exposed children's slightly smaller measures of body bulk, together with their larger facial breadths, contributed to the significant T2. When the entire sample (n = 250) was analyzed by multiple linear regression, noise exposure was a significant predictor only of male triceps and subscapular skinfolds. For these two variables, and most other anthropometrics, however, the beta coefficients were negative for both sexes. In order to include information on the covariance structure among all variables, a canonical correlation analysis was performed. Noise exposure loaded negatively on the third canonical variate and was paired with positively loaded measures of body bulk. Taken together, the three analyses suggest that while there is some evidence for a slight effect of airport noise on measures of body bulk for males in this sample, most measures of postnatal growth for both males and females were unaffected by the noise levels experienced.

Longitudinal study of growth status and airport noise exposure.

A study of children living adjacent to an international airport was conducted to learn whether noise exposure affected physical growth. Prenatal and postnatal noise exposures were estimated for each subject based on noise levels at their residences during jetplane takeoffs. Subjects' birthweights were standardized for sex and parity, and their postnatal heights and weights were standardized for sex and age (range 6-11 years). The difference between standardized birthweight score and postnatal height score, and between birthweight score and postnatal weight score, represent a change in growth status of a more or less permanent nature, respectively. After adjusting for confounding factors, children from the exposed community (n = 103) had a significantly smaller mean of status change by height (p less than 0.05), and a somewhat smaller mean of status change by weight (0.10 less than p less than 0.05) in comparison to children from an unexposed community (n = 94). A dose-response curve was then expected in the exposed community. However, in multiple regression analyses of the exposed children, noise exposure was not related to either change in growth status variable. This second result is inconsistent with the differences between communities and suggest that they are a result of factors other than noise exposure. We conclude that the moderate to severe noise levels of the areas surrounding most subjects' homes did not adversely affect postnatal growth. Further studies of noise and growth should concentrate observations on people exposed to even more severe noise levels than those experienced by most subjects in this study.

Variation in size at birth and cigarette smoking during pregnancy.

The influence of cigarette smoking during pregnancy and other familial factors on size at birth and gestation length is investigated among 458 births to 227 mothers living in a suburban community in the U.S. In this sample, 56% of the births were to mothers who reported not smoking during the pregnancy and 35% were to mothers who reported smoking 20 cigarettes or less. Multiple stepwise regression analysis was employed to examine the influence of cigarette smoking after statistical adjustment for such social and biological characteristics of the family as parents' sizes, education, income, and aspects of mother's reproductive history. After correction for significant social and biological characteristics, smoking status was a significant contributor to birth weight variation. In fact, cigarette smoking had the next-largest partial correlation coefficient (r = -0.26) second to gestation length. Birth length is also negatively associated with cigarette smoking, though not so strongly as is birth weight. The reduction in birth lengths can be attributed to the reduction in birth weights. Gestation length was not associated with cigarette smoking in this sample. The analysis of collinearity between smoking status and the other independent variables indicates that the effect of smoking appears to be independent of interrelationships among the independent variables.

Neonatal size of low socio-economic status Black and White term births in Albany County, NYS.

Birth weight has long been a focus of study by epidemiologists and human biologists, because it reflects the quality of the intrauterine environment and may be used as a predictor of future growth and development. Comparisons of Black and White neonates in the USA have consistently shown differences in birth weight. Confounding variables are a major problem in any such investigation, especially socio-economic status which is highly correlated with race in the USA. This study was distinctive in the sampling of one socio-economic stratum (low income), and the use of five anthropometric measures in addition to birth weight. The goals of this study were as follows: to determine if there were differences in body size and body composition at birth in Black and White neonates of low socio-economic status (SES), and to investigate what variables might account for any observed variability. The sample consisted of full term Black and White neonates of low SES (n = 323) born in Albany, NY (1986-1997). Birth weight, length, head and arm circumference, and subscapular and triceps skinfolds were compared. Race was determined through maternal self-identification. White neonates were significantly larger than Black neonates in birth weight, length and head circumference. Among female neonates none of the anthropometric dimensions differed between Blacks and Whites. Among male neonates, Whites were significantly larger than Blacks in birth weight, length, head and arm circumferences. Principal components analysis reduced the six anthropometric dimensions to two summary measures: body size and composition. When controlling for social and biological variables, race and sex were significant predictors of body composition, but not body size. Interpretation of results and possible causal relationships are discussed.

The relationship of body fat weight, determined densitometrically, to relative weight and triceps skinfold in American youths, 12-17 years of age.

The relationship between fat weight, measured densitometrically, and the triceps skinfold and Quetelet's Index has been analyzed by means of linear regression analysis of 235 American youths, 12-17 years of age; 48 males and 41 females were from Minneapolis and 121 males and 25 females from the Greater Philadelphia area. Validation was accomplished by using the results of 10 separate regression analysis, each on 90% of the sample, the remaining 10% serving in each instance as the validation group; this is known as the Jackknife Method. When the Minneapolis and Philadelphia components were pooled, suitable regression models were derived with standard deviations of the errors of prediction of 3.330 kg in males and 2.056 in females. When the sample was subdivided by city the SD's remained essentially the same, but the mean errors were larger. It is concluded that the linear regression models can be used on closely similar populations to estimate fat weight for groups, but estimates for individuals may be expected to have an error of +/- 5-6 kg (i.e., 2 SD's) and are therefore not likely to be suitably accurate for use. The regression weights indicate a greater contribution of the triceps skinfold to fat weight than of Quetelet's Index in males. In females the reverse was found. This may affect sex differences in prevalence rates of obesity, if the diagnosis is based upon a single anthropometric indicator.

Directional asymmetry of body dimensions among white adolescents.

Asymmetry of paired dimensions has been recognized as a methodological problem in anthropometry and more recently as an indicator of environmental stress. This study seeks to determine the extent of directional asymmetry for some of the measurements commonly made in anthropometry. Upper arm circumference, biepicondylar breadth, triceps and subscapular skinfolds, bicondylar breadth of the femur, and calf circumference were measured on right and left sides among 135 white adolescents from suburban Philadelphia. Handedness (right or nonright) was subject-assessed. Body composition was estimated through underwater weighing. Asymmetry was evaluated using a paired t test. Arm measurements are significantly asymmetric in favor of the right side; subscapular skinfolds and leg measurements are not significantly asymmetric. Among the sample of right-handed subjects (n = 116), upper arm circumference and biepicondylar breadth were significantly larger on the right side, and, among the males of this subsample, triceps was as well. The nonright-handed subjects (n = 19) did not show statistically significant asymmetry. Asymmetry was negatively but weakly related to body composition. These results are consistent with an explanation in terms of preferred use of one side of the body and consequent muscle hypertrophy, but an adequate test of this explanation requires hypothesis testing in larger samples of nonright-handed subjects.

Critical weight at menarche. Critique of a hypothesis.

The critical weight hypothesis in relation to menarche, which is known as the Frisch-Revelle model, has been examined. Since, in eight samples, girls reached menarche at weights spanning a 71.4-kg (157-lb) range, Frisch and Revelle's concept of a critical weight of 47 to 48 kg (104 to 106 lb) cannot be applied meaningfully to individuals. Neither can the suggestion of an invariant mean weight be accepted, because significant differences occur among the mean menarcheal weights for several samples of normal white girls. Finally, when stature is held constant, there is some evidence that girls who reach menarche at younger ages are heavier than those who begin menstruating at older ages. Apparent reductions in variability when the estimated amount of total body water is used instead of body weight may result from statistical artifacts associated with regression analysis.

Social support and adverse pregnancy outcome in a high-risk population.

Low birth weight is a significant health problem in the United States, particularly among poor women. By combining traditional predictors of birth weight with social support indicators, we were able to substantially improve the discrimination between the highest birth weight quartile from the lowest among high-risk gravidae receiving first time prenatal care at the Albany, New York, County Department of Health. The impact of traditional predictors and social support indicators varied considerably between African-American and white women. Providers of care to poor women can utilize this information to maximize the likelihood of a good birth outcome.

Distribution of albumin variants Naskapi amd Mexico among Aleuts, Frobisher Bay Eskimos, and Micmac, Naskapi, Mohawk, Omaha, and Apache Indians.

In order to help define the boundaries of the distribution of the albumin variants Naskapi and Mexico which are polymorphic among several American Indian groups, we examined sera from Micmac, Mohawk, Northwest River Naskapi, Omaha and Apache Indians, and from Aleuts and Eskimos. Sera from a total of 1,524 individuals were examined. Using a cellulose acetate membrane electrophoretic system with Tris-Citric acid at pH 5.4 we were able to distinguish normal albumin and both variants in the same run. Naskapi and Mexico variants were absent from Aleut, Eskimo, Micmac, Mohawk and Omaha samples. The albumin Naskapi variant was present in an allele frequency of 0.03 in the Naskapi Indian sample. Albumin variants Naskapi and Mexico were found in the Apache sample at frequencies of 0.016 and 0.037, respectively. This report supersedes that previously published by Schell and Agarwal ('76). Generally, within an area there is a correspondence between changes in the frequency of albumin variants and changes in the ethnic background and history of the area's populations. At the same time, when viewing widely separated areas, relationships between distant groups based on linguistic and cultural similarities are paralleled on a biologic level by the distribution of normal albumin and variant albumins.