Enhancing Coordination Among the U.S. Preventive Services Task Force, Agency for Healthcare Research and Quality, and National Institutes of Health.

This paper focuses on the relationships among the U.S. Preventive Services Task Force (USPSTF); Agency for Healthcare Research and Quality (AHRQ); and NIH. After a brief description of the Task Force, AHRQ, NIH, and an example of how they interact, we describe the steps that have been taken recently by NIH to enhance their coordination. We also discuss several challenges that remain and consider potential remedies that NIH, AHRQ, and investigators can take to provide the USPSTF with the data it needs to make recommendations, particularly those pertaining to behavioral interventions.

Development of bioelectrical impedance analysis prediction equations for body composition with the use of a multicomponent model for use in epidemiologic surveys.

BACKGROUND: Previous studies to develop and validate bioelectrical impedance analysis (BIA) equations to predict body composition were limited by small sample sizes, sex specificity, and reliance on reference methods that use a 2-component model. OBJECTIVE: This study was designed to develop sex-specific BIA equations to predict total body water (TBW) and fat-free mass (FFM) with the use of a multicomponent model for children and adults. DESIGN: Data from 5 centers were pooled to create a sample of 1474 whites and 355 blacks aged 12-94 y. TBW was measured by dilution, and FFM was estimated with a multicomponent model based on densitometry, isotope dilution, and dual-energy X-ray absorptiometry. RESULTS: The final race-combined TBW prediction equations included stature(2)/resistance and body weight (R(2) = 0.84 and 0.79 and root mean square errors of 3.8 and 2.6 L for males and females, respectively; CV: 8%) and tended to underpredict TBW in black males (2.0 L) and females (1.4 L) and to overpredict TBW in white males (0.5 L) and females (0.3 L). The race-combined FFM prediction equations contained the same independent variables (R(2) = 0.90 and 0.83 and root mean square errors of 3.9 and 2.9 kg for males and females, respectively; CV: approximately 6%) and tended to underpredict FFM in black males (2.1 kg) and females (1.6 kg) and to overpredict FFM in white males (0.4 kg) and females (0.3 kg). CONCLUSION: These equations have excellent precision and are recommended for use in epidemiologic studies to describe normal levels of body composition.

Reference data for arm muscle and arm adipose tissue areas in Mexican Americans from the Hispanic Health and Nutrition Examination survey (HHANES 1982-1984): Comparisons with whites and blacks from NHANES II (1976-1980).

Data for arm muscle area (AMA) and arm adipose tissue area (AATA) from 3695 Mexican American children 6 months to 18 years of age included in HHANES (1982-1984) were used to obtain age-and gender-specific means and selected percentiles. These statistics were compared with those for non-Hispanic white and non-Hispanic black children from NHANES II (1976-1980). In comparison with non-Hispanic white and non-Hispanic black children, the Mexican American children tended to have smaller means and percentile values for AMA but larger values for AATA. There was considerable sexual dimorphism in AMA and AATA. Within each population, boys tended to have larger means and percentile values for AMA than girls, and girls tended to have larger values for AATA than boys. Within each population of boys, there was a prepubescent gain in AATA, followed by a midpubescent loss, and then an increase near the middle of the second decade. This "fat wave" pattern was not noticeable in girls. Population differences in age- and gender-specific mean values for AMA and AATA were small. Few statistically significant differences were observed; these were no more common than would occur by chance. Therefore, population-specific reference data for AMA and AATA may not be needed for the clinical evaluation of Mexican Americans, non-Hispanic blacks, and non-Hispanic whites. © 1996 Wiley-Liss, Inc.

Weight, stature, and body mass index data for Mexican Americans from the third national health and nutrition examination survey (NHANES III, 1988-1994).

Selected age- and sex-specific percentiles are presented for 4,054 Mexican American children ages 1-18 years who were included in the third National Health and Nutrition Examination Survey (NHANES III, 1988-1994). These percentile values are compared with corresponding percentiles for Mexican Americans from the Hispanic Health and Nutrition Examination Survey (HHANES, 1982-1984). In each sex, the weight and weight/stature(2) percentiles from NHANES III were significantly larger than those from HHANES. For weight, the NHANES III values tended to be clearly larger after 11 years in males and females, and they were larger for weight/stature(2) at the 50th and 90th percentiles in each sex after 6 years. For stature, the NHANES III values were significantly larger at the 90th percentile among females, but the differences were not significant for any other percentiles among females or males. In comparison with non-Hispanic White children, Mexican American children tend to be shorter and heavier, especially after the preschool period. The similarity of the findings for stature from NHANES III and HHANES indicates that the shorter statures of Mexican Americans are not cohort-specific. The tendency to larger values for weight/stature(2) in Mexican Americans has important public heath implications since this ratio tends to track after early childhood, and high ratios in adulthood constitute an important risk factor for common diseases such as diabetes mellitus and coronary heart disease. Am. J. Hum. Biol. 11:673-686, 1999. Copyright 1999 Wiley-Liss, Inc.

Statistical effects of varying sample sizes on the precision of percentile estimates.

The present study evaluates the precision of outlying percentile estimates, with age- and sex-associated variations and facilitates decisions needed to revise the current NCHS 1977 Growth Charts with regard to 1) the inclusion of 3(rd) and 97(th) percentiles and 2) the selection of survey data for the construction of the revised growth charts. Simulation was performed to obtain data with distribution characteristics similar to those of The Third National Health and Nutritional Examination Survey (NHANES III) (1988-1991) data. NHANES III consists of a two-phase, 6-year, complex stratified multistage probability cluster, cross-sectional survey conducted from 1988 through 1994 to represent the US noninstitutionalized population. Phase I of the survey consisted of 679 boys and 622 girls in age groups 3, 8, 13, and 18 years. Weight and stature, the body mass index (BMI) (weight/stature(2); kg/m(2)) was calculated. The results show that 1) the precision of the percentile estimates is greater for stature than for weight and BMI, 2) percentiles during the pubertal period are less precise than those during the prepubertal and postpubertal periods for weight and BMI but there is little difference for stature, and 3) percentile estimates are more precise for girls than boys for weight and BMI, but not for stature. The present findings suggest that pooling of NHANES III and earlier National Center for Health Statistics (NCHS) survey data is necessary to achieve reasonable precision for the 3(rd) and 97(th) percentile estimates. Am. J. Hum. Biol. 12:64-74, 2000. Copyright 2000 Wiley-Liss, Inc.

Head circumference for Mexican American infants and young children from the Hispanic health and nutrition examination survey (HHANES 1982-1984): Comparisons with Whites and Blacks from NHANES II (1976-1980).

This study presents descriptive statistics for head circumference in Mexican American children 6 months to 7 years of age using data from the Hispanic Health and Nutrition Examination Survey (HHANES, 1982-1984) and compares these statistics with national estimates of head circumference for non-Hispanic White children and non-Hispanic Black children from the Second National Health and Nutrition Examination Survey (NHANES II, 1976-1980). Head circumference was measured in the same standardized fashion in the two surveys. The patterns of change with age in means and in empirical percentiles were similar for both genders and for all three ethnic groups. Values for head circumference increased with age, but the rate of increase became less as age advanced. Analyses indicated that at 1, 2, and 4 years of age, mean values for head circumferences for non-Hispanic White boys were significantly larger than those for Mexican American boys. The differences in mean values for head circumferences ranged from 0.7 to 1.1 cm. Because ethnic differences in head circumferences are small in magnitude, ethnic-specific sets of reference data for head circumference are not needed for clinical evaluation of Mexican Americans, non-Hispanic Whites, and non-Hispanic Blacks. Further analyses may be necessary when additional information from NHANES III allows the calculation of the 5th and 95th percentiles for Black and Mexican American children with small confidence limits. © 1995 Wiley-Liss, Inc.

Centers for Disease Control and Prevention 2000 growth charts for the United States: improvements to the 1977 National Center for Health Statistics version.

OBJECTIVE: To present a clinical version of the 2000 Centers for Disease Control and Prevention (CDC) growth charts and to compare them with the previous version, the 1977 National Center for Health Statistics (NCHS) growth charts. METHODS: The 2000 CDC percentile curves were developed in 2 stages. In the first stage, the empirical percentiles were smoothed by a variety of parametric and nonparametric procedures. To obtain corresponding percentiles and z scores, we approximated the smoothed percentiles using a modified LMS estimation procedure in the second stage. The charts include of a set of curves for infants, birth to 36 months of age, and a set for children and adolescents, 2 to 20 years of age. RESULTS: The charts represent a cross-section of children who live in the United States; breastfed infants are represented on the basis of their distribution in the US population. The 2000 CDC growth charts more closely match the national distribution of birth weights than did the 1977 NCHS growth charts, and the disjunction between weight-for-length and weight-for-stature or length-for-age and stature-for-age found in the 1977 charts has been corrected. Moreover, the 2000 CDC growth charts can be used to obtain both percentiles and z scores. Finally, body mass index-for-age charts are available for children and adolescents 2 to 20 years of age. CONCLUSION: The 2000 CDC growth charts are recommended for use in the United States. Pediatric clinics should make the transition from the 1977 NCHS to the 2000 CDC charts for routine monitoring of growth in infants, children, and adolescents.

2000 CDC Growth Charts for the United States: methods and development.

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.

Summary of the 2000 Surgeon General's listening session: toward a national action plan on overweight and obesity.

OBJECTIVE: To provide insight into discussions at the Surgeon General's Listening Session, "Toward a National Action Plan on Overweight and Obesity," and to complement The Surgeon General's Call to Action to Prevent and Decrease Overweight and Obesity. RESEARCH METHODS AND PROCEDURES: On December 7 and 8, 2000, representatives from federal, state, academic, and private sectors attended the Surgeon General's Listening Session and were given an opportunity to recommend what to include in a national plan to address overweight and obesity. The public was invited to comment during a corresponding public comment period. The Surgeon General's Listening Session was also broadcast on the Internet, allowing others to view the deliberations live or access the archived files. Significant discussion points from the Listening Session have been reviewed by representatives of the federal agencies and are the basis of this complementary document. RESULTS: Examples of issues, strategies, and barriers to change are discussed within five thematic areas: schools, health care, family and community, worksite, and media. Suggested cooperative or collaborative actions for preventing and decreasing overweight and obesity are described. An annotated list of some programmatic partnerships is included. DISCUSSION: The Surgeon General's Listening Session provided an opportunity for representatives from family and community groups, schools, the media, the health-care environment, and worksites to become partners and to unite around the common goal of preventing and decreasing overweight and obesity. The combination of approaches from these perspectives offers a rich resource of opportunity to combat the public health epidemic of overweight and obesity.