Abstract  RAGS Part A is one of a three-part series: Part B addresses the development of risk-based preliminary remediation goals; and Part C addresses human health risk evaluations of remedial alternatives. RAGS Part A: Human Health Evaluation Manual provides guidance on the human health evaluation activities that are conducted during the baseline risk assessment - the first step of the Remedial Investigation/Feasibilty Study (RI/FS). The baseline risk assessment is an analysis of the potential adverse health effects (current or future) caused by hazardous substance releases from a site in the absence of any actions to control or mitigate these releases (i.e., under an assumption of no action). The baseline risk assessment contributes to the site characterization and subsequent development, evaluation, and selection of appropriate response alternatives. The results of the baseline risk assessment are used to help determine whether additional response action is necessary at the site, modify preliminary remediation goals, help support selection of the "no- action" remedial alternative, where appropriate, and document the magnitude of risk at a site, and the primary causes of that risk. Baseline risk assessments are site-specific and therefore may vary in both detail and the extent to which qualitative and quantitative analyses are used, depending on the complexity and particular circumstances of the site, as well as the availability of applicable or relevant and appropriate requirements (ARARs) and other criteria, advisories, and guidance. After an initial planning stage, there are four steps in the baseline risk assessment process: data collection and analysis; exposure assessment; toxicity assessment; and risk characterization. The potential users of Part A are the individuals actually conducting health risk assessments for sites, who frequently are contractors to the EPA, other federal agencies, states, or potentientially responsible parties. It is also targeted to EPA staff, including those responsible for review and oversight of risk assessments (e.g. technical staff in the regions) and those responsible for ensuring adequate evaluations of human health risks (i.e., RPMs).

Abstract  Precise age-specific average body weight estimates are necessary for deterministic risk assessments, and an accurate body weight distribution is equally important in probabilistic risk assessments. Age-specific body weight distributions for U.S. residents are estimated using NHANES (National Health and Nutrition Examination Survey) data collected in four surveys over the last 24 years. The weighted mean and standard deviation of natural log-transformed body weights are computed for single-year age groups and population age-specific weight patterns further described using piece-wise polynomial spline functions and nonparametric age-smoothed trend lines. These functions are used to compare distributional changes in age-specific body weight in the United States from the first NHANES survey in 1976?1980 to the most recent in 1999?2002. Analysis demonstrates that age- and sex-specific average body weight changes over this time period are not uniform. Use of these functions to compute body weight distributions for selected child-age categories is demonstrated.

Abstract  OBJECTIVES: The prevalence of childhood overweight in the United States has markedly increased over the last 30 years. We examined differences in the secular trends for BMI, weight, and height among white, black, and Mexican-American children.

RESEARCH METHODS AND PROCEDURES: Analyses were based on nationally representative data collected from 2 to 17 year olds in four examinations (1971-1974 through 1999-2002).

RESULTS: Overall, black children experienced much larger secular increases in BMI, weight, and height than did white children. For example, over the 30-year period, the prevalence of overweight increased approximately 3-fold (4% to 13%) among 6- to 11-year-old white children but 5-fold (4% to 20%) among black children. In most sex-age groups, Mexican-American children experienced increases in BMI and overweight that were between those experienced by blacks and whites. Race/ethnicity differences were less marked among 2 to 5 year olds, and in this age group, white children experienced the largest increase in overweight (from 4% to 9%). In 1999-2002, the prevalence of extreme BMI levels (> or =99th percentile) reached 6% to 7% among black girls and Mexican-American boys.

DISCUSSION: Because of the strong tracking of childhood BMI levels into adulthood, it is likely that the secular increases in childhood overweight will greatly increase the burden of adult disease. The further development of obesity interventions in different racial/ethnic groups should be emphasized.

Abstract  OBJECTIVES: This study describes the pattern of maternal weight gain in women with good pregnancy outcomes and provides data to fill in the provisional weight-gain charts published by the Institute of Medicine (IOM) in 1990.

METHODS: We selected 7002 women with good outcomes (defined by factors related to maternal and infant health) from the University of California, San Francisco, Perinatal Database. For each body mass index category, we compared percentiles of weight gain by trimester in women who achieved the IOM recommendations for total gain and those who did not.

RESULTS: Trimester rates of gain varied by body mass index category and exceeded IOM guidelines in all groups. Forty percent of these women with good outcomes had total gains within the guidelines and provided data to complete the IOM weight-gain charts.

CONCLUSIONS: Most women in this good-outcome sample would have been suspected of being at increased risk for poor outcome on the basis of their weight gain. This confirms the IOM recommendation that evaluation of the underlying causes of excessively high or low weight gain during pregnancy is necessary before appropriate interventions can be applied.

Abstract  The appropriate interpretation of monitored fetal growth throughout pregnancy in individual patients and populations is dependent upon the availability of adequate standards. There is no adequate standard of fetal weight throughout pregnancy that is suitable for patients in the U.S.A. To determine such a standard for infants delivered at about sea level the 10th, 25th, 50th, 75th, and 90th percentiles of fetal weight for each menstrual week of gestation were calculated from 430 fetuses at 8 to 20 menstrual weeks' gestation aborted with prostaglandins and from 30,772 liveborn infants delivered of patients at 21 to 44 menstrual weeks' gestation. Median fetal crown-to-rump lengths and crown-to-heel lengths were derived from measurements of 496 aborted fetuses of 8 to 21 weeks' gestation. Fetal weight correction factors for parity, race (socioeconomic status), and fetal sex were calculated. The derived fetal growth curves are useful for clinical, public health, and investigational purposes.

Abstract  Water ingestion estimates are important for the assessment of risk to human populations of exposure to water-borne pollutants. This paper reports mean and percentile estimates of the distributions of daily average per capita water ingestion for a number of age range groups. The age ranges, based on guidance from the US EPA's Risk Assessment Forum, are narrow for younger ages when development is rapid and wider for older ages when the rate of development decreases. Estimates are based on data from the United States Department of Agriculture's (USDA's) 1994-1996 and 1998 Continuing Survey of Food Intake by Individuals (CSFII). Water ingestion estimates include water ingested directly as a beverage and water added to foods and beverages during preparation at home or in local establishments. Water occurring naturally in foods or added by manufacturers to commercial products (beverage or food) is not included. Estimates are reported in milliliters (ml/person/day) and milliliters per kilogram of body weight (ml/kg/day). As a by-product of constructing estimates in terms of body weight of respondents, distributions of self-reported body weights based on the CSFII were estimated and are also reported here.

Abstract  The United States Environmental Protection Agency (U.S. EPA) generated the estimates in this report in response to legislative mandates in the Safe Drinking Water Act Amendments of 1996. These mandates require up-to-date information on water ingestion to identify subpopulations at elevated risk of health effects from exposure to contaminants in drinking water. The estimates also support characterization of health risks to sensitive populations from contaminants in drinking water. The estimates in this document characterize the empirical distributions of 2-day average per capita ingestion of water for specific subpopulations. Subpopulation estimates apply to demographic categories, but do not distinguish individuals with a history of serious illness or with lifestyles that effect water ingestion.

Abstract  This report presents trends in national estimates of mean weight, height, and body mass index (BMI) from the National Health Examination and the National Health and Nutrition Examination Surveys between 1960 and 2002. The tables included in this report present data for adults by sex, race/ethnicity, and age group and for children by sex and year of age. Mean weight and BMI have increased for both sexes, all race/ethnic groups, and all ages. Among adults, mean weight increased more than 24 pounds. Although not as dramatically, mean height has also increased for most ages and for both males and females.

Abstract  Based on results reported from the NHANES II Survey (the National Health and Nutrition Examination Survey II) for people living in the United States during 1976-1980, we use exploratory data analysis, probability plots, and the method of maximum likelihood to fit lognormal distributions to percentiles of body weight for males and females as a function of age from 6 months through 74 years. The results are immediately useful in probabilistic (and deterministic) risk assessments.

Abstract  The third report reviews the dietary and nutritional status of the U.S. population, as well as the factors that determine status, based on the data available through the National Nutrition Monitoring and Related Research Program (NNMRRP) by June 1994. The NNMRRP includes surveys, surveillance systems, and other monitoring activities that provide information about the dietary, nutritional, and nutrition-related health status of Americans; the relationship between diet and health; and the factors that influence dietary and nutritional status. The program was established by the U.S. Congress in the National Nutrition Monitoring and Related Research Act of 1990 (Public Law 101-445). The act specified that the U.S. Department of Health and Human Services (HHS) and the U.S. Department of Agriculture (USDA) jointly implement and coordinate the activities of the NNMRRP. The legislation further specified that the agencies 'contract with a scientific body, such as the National Academy of Sciences or the Federation of American Societies for Experimental Biology, to interpret available data analyses, and publish ... a report on the dietary, nutritional, and health-related status of the people of the United States and the nutritional quality (including the nutritive and nonnutritive content) of food consumed in the United States ... at least once every five years.'

Abstract  OBJECTIVES: This report provides detailed information on how the 2000 Centers for Disease Control and Prevention (CDC) growth charts for the United States were developed, expanding upon the report that accompanied the initial release of the charts in 2000.

METHODS: The growth charts were developed with data from five national health examination surveys and limited supplemental data. Smoothed percentile curves were developed in two stages. In the first stage, selected empirical percentiles were smoothed with a variety of parametric and nonparametric procedures. In the second stage, parameters were created to obtain the final curves, additional percentiles and z-scores. The revised charts were evaluated using statistical and graphical measures.

RESULTS: The 1977 National Center for Health Statistics (NCHS) growth charts were revised for infants (birth to 36 months) and older children (2 to 20 years). New body mass index-for-age (BMI-for-age) charts were created. Use of national data improved the transition from the infant charts to those for older children. The evaluation of the charts found no large or systematic differences between the smoothed percentiles and the empirical data.

CONCLUSION: The 2000 CDC growth charts were developed with improved data and statistical procedures. Health care providers now have an instrument for growth screening that better represents the racial-ethnic diversity and combination of breast- and formula-feeding in the United States. It is recommended that these charts replace the 1977 NCHS charts when assessing the size and growth patterns of infants, children, and adolescents.

Abstract  This report provides a set of early-life stage age groups for U.S. Environmental Protection Agency (EPA, or the Agency) scientists to consider when assessing children's exposure to environmental contaminants and the resultant potential dose. These recommended age groups are based on current understanding of differences in behavior and physiology that may impact exposures in children. A consistent set of early-life age groups, supported by an underlying scientific rationale, is expected to improve Agency exposure and risk assessments for children by increasing the consistency and comparability of risk assessments across the Agency, improving accuracy and transparency in assessments for those cases where current practice might too broadly combine behaviorally and physiologically disparate age groups, and fostering a consistent approach to future exposure surveys and monitoring efforts to generate improved exposure factors for children.

Abstract  Most previously published tables of birth weight percentiles as a function of gestational age have been derived from neonates with imprecise gestational dating. In order to improve the accuracy of neonatal birth weight percentiles, we developed a birth weight table based on measurements from a group of neonates who had accurate gestational dating by prenatal first trimester ultrasonography. By matching a database of obstetrical ultrasonograms over a 5 year period to birth records at our institution, 3718 newborn infants with gestational dating by first trimester ultrasonography were identified. Statistical smoothing and regression techniques were applied to gestational age at birth and birth weight data to develop a table for the 10th, 50th, 90th, and other weight percentiles for 25 weeks of gestation onward. The weight table developed from our population has lower 50th and 90th percentile weights, and narrower 10th to 90th percentile ranges, at 25 to 35 weeks than in prior tables. At 39 to 43 weeks, our 10th, 50th, and 90th percentile weights are higher than those in previous tables. Our weight table for newborn infants, based on measurements from neonates with accurate dating, permits improved assignment of weight percentiles for gestational age and more accurate diagnosis of growth disorders in fetuses and neonates.

Abstract  OBJECTIVES: This report presents 2005 data on U.S. births according to a wide variety of characteristics. Data are presented for maternal demographic characteristics including age, live-birth order, race, Hispanic origin, marital status, and educational attainment; maternal lifestyle and health characteristics (medical risk factors, weight gain, and tobacco use); medical care utilization by pregnant women (prenatal care, obstetric procedures, characteristics of labor and/or delivery, attendant at birth, and method of delivery); and infant characteristics (period of gestation, birthweight, Apgar score, congenital anomalies, and multiple births). Also presented are birth and fertility rates by age, live-birth order, race, Hispanic origin, and marital status. Selected data by mother's state of residence are shown, as well as data on month and day of birth, sex ratio, and age of father. Trends in fertility patterns and maternal and infant characteristics are described and interpreted.

METHODS: Descriptive tabulations of data reported on the birth certificates of the 4.1 million births that occurred in 2005 are presented. Denominators for population-based rates are postcensal estimates derived from the U.S. 2000 census.

RESULTS: In 2005, 4,138,349 births were registered in the United States, 1 percent more than in 2004. The 2005 crude birth rate was 14.0, unchanged from the previous year; the general fertility rate increased slightly to 66.7. Teenage childbearing continued to decline, dropping to the lowest levels recorded. Rates for women aged 20-29 were fairly stable, whereas childbearing among women 30 years of age and older increased. All measures of unmarried childbearing rose substantially in 2005. Smoking during pregnancy continued to decline. No improvement was seen in the timely initiation of prenatal care. The cesarean delivery rate climbed to more than 30 percent of all births, another all-time high. Preterm and low birthweight rates also continued to rise; the twin birth rate was unchanged and the rate of triplet and higher order multiple births declined for the 7th consecutive year.

Abstract  For the U.S. population, we fit bivariate distributions to estimated numbers of men and women aged 18-74 years in cells representing 1 in. intervals in height and 10 lb intervals in weight. For each sex separately, the marginal histogram of height is well fit by a normal distribution. For men and women, respectively, the marginal histogram of weight is well fit and satisfactorily fit by a lognormal distribution. For men, the bivariate histogram is satisfactorily fit by a normal distribution between the height and the natural logarithm of weight. For women, the bivariate histogram is satisfactorily fit by two superposed normal distributions between the height and the natural logarithm of weight. The resulting distributions are suitable for use in public health risk assessments.