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Biomedical subjects

William H Dietz

Publications and source records attributed to William H Dietz.

At least 19 recordsLinked to original sources
PubMed2007

Cardiovascular risk factors and excess adiposity among overweight children and adolescents: the Bogalusa Heart Study.

OBJECTIVE: To explore the accuracy of various body mass index (BMI) cutpoints in identifying children who have excess adiposity (based on skinfold thicknesses), adverse levels of lipids, insulin, and blood pressures, and a high risk for severe adult obesity. STUDY DESIGN: Cross-sectional (n = 10,099) and longitudinal (n = 2392) analyses were performed among subjects who participated in the Bogalusa Heart Study. RESULTS: Of children with a BMI > or =95th percentile (P) of the Centers for Disease Control (CDC) growth charts, 39% had at least two risk factors, 65% had excess adiposity, and 65% had an adult BMI of > or =35 kg/m(2). Of those with a BMI > or =99th P, 59% had at least two risk factors, 94% had excess adiposity, and 88% had an adult BMI of > or =35 kg/m(2). About 4% of children in the US now have a BMI > or =99th P. CONCLUSIONS: The 99th P of BMI-for-age may be appropriate for identifying children who are at very high risk for biochemical abnormalities and severe adult obesity. More aggressive weight control strategies may be warranted for this subgroup.

Adolescent↗
PubMed2006

Racial and ethnic differences in secular trends for childhood BMI, weight, and height.

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.

Adolescent↗
PubMed2005

Prevention and control of coronary heart disease and stroke--nomenclature for prevention approaches in public health: a statement for public health practice from the Centers for Disease Control and Prevention.

Successful prevention and control of coronary heart disease and stroke requires extensive collaboration and strategic partnerships with many health and non-health-related organizations and agencies in the voluntary, public, and private sectors. To assure a common language and purpose and to facilitate communication in these multiple settings, a simplified classification of prevention levels for public health practice is essential. This statement proposes three levels of prevention (health promotion, primary prevention, and secondary prevention) as a guide for public health practice. This statement is also intended to inform the design, implementation, and evaluation of programs and research initiatives that address the prevention and control of coronary heart disease and stroke, and to enhance communication and dialogue among health professionals, policymakers, and the public.

Centers for Disease Control and Prevention, U.S.↗
PubMed2005

Racial differences in the tracking of childhood BMI to adulthood.

OBJECTIVE: The possibility that there are racial differences in the patterns of BMI (kilograms per meter squared) change throughout life has not been examined. For example, the high prevalence of obesity among black women could result from a higher prevalence of obesity among black girls or because normal-weight black girls experience larger BMI increases in adolescence or adulthood than do their white counterparts. Therefore, we examined the tracking of childhood BMI into adulthood in a biracial (36% black) sample. RESEARCH METHODS AND PROCEDURES: Five- to 14-year-old children (2392) were followed for (mean) 17 years. Childhood overweight was defined as BMI > or = 95th percentile, and adult obesity was defined as BMI > or = 30 kg/m(2). RESULTS: The tracking of childhood BMI differed between whites and blacks. Among overweight children, 65% of white girls vs. 84% of black girls became obese adults, and predictive values among boys were 71% (whites) vs. 82% (blacks). These racial differences reflected contrasting patterns in the rate of BMI change. Although the initial BMI of black children was not higher than that of white children, BMI increases with age were larger among black girls and overweight black boys than among their white counterparts. In contrast, relatively thin (BMI < 50th percentile) white boys were more likely to become overweight adults than were their black counterparts. DISCUSSION: These findings emphasize the black/white differences in BMI changes with age. Because of the adult health consequences of childhood-onset obesity, early prevention should be given additional emphasis.

Adolescent↗
PubMed2005

Longitudinal changes in energy expenditure in girls from late childhood through midadolescence.

BACKGROUND: Longitudinal data on energy expenditure in children and adolescents are scarce. OBJECTIVE: The purpose of this study was to examine changes in energy expenditure and physical activity in girls from late childhood through midadolescence. DESIGN: We measured total energy expenditure (TEE) by doubly labeled water, resting metabolic rate (RMR) by indirect calorimetry, body composition by 18O dilution, and time spent in activity by an activity diary in 28 initially nonobese girls at approximately 10, approximately 12, and approximately 15 y of age. Changes with age in TEE, RMR, and activity energy expenditure (AEE), both in absolute terms and in adjusted analyses, and in physical activity level (PAL) and time spent sleeping, being sedentary, and in moderate and vigorous activity were evaluated by mixed-model repeated-measures analyses. RESULTS: Absolute TEE and AEE increased significantly from age 10 to age 15 y (P < 0.0001 for both). Absolute RMR at ages 12 and 15 y did not differ significantly, despite significant increases in fat-free mass and fat mass between the visits. PAL was significantly higher (P < 0.0001) at age 15 y than at age 10 or 12 y, whereas time spent being sedentary increased significantly from age 10 to age 15 y (P < 0.001), and AEE adjusted for fat-free mass appeared to decrease over the same interval. CONCLUSION: Conclusions drawn regarding changes with age in physical activity depend on the measure of physical activity assessed.

Adolescent↗
PubMed2005

The relation of childhood BMI to adult adiposity: the Bogalusa Heart Study.

OBJECTIVE: Although many studies have found that childhood levels of body mass index (BMI; kg/m(2)) are associated with adult levels, it has been reported that childhood BMI is not associated with adult adiposity. We further examined these longitudinal associations. DESIGN: Cohort study based on examinations between 1973 and 1996. SETTING: Bogalusa, Louisiana. PARTICIPANTS: Children (2610; ages 2-17 years old) who were followed to ages 18 to 37 years; the mean follow-up was 17.6 years. MAIN OUTCOME MEASURES: BMI-for-age and triceps skinfold thickness (SF) were measured in childhood. Subscapular and triceps SFs were measured among adults, and the mean SF was used as an adiposity index. Adult obesity was defined as a BMI >or= 30 kg/m(2) and adult overfat as a mean SF in the upper (gender-specific) quartile. RESULTS: Childhood levels of both BMI and triceps SF were associated with adult levels of BMI and adiposity. The magnitude of these longitudinal associations increased with childhood age, but the BMI levels of even the youngest (ages 2-5 years) children were moderately associated (r = 0.33-0.41) with adult adiposity. Overweight (BMI-for-age >or= 95th centile) 2- to 5-year-olds were >4 times as likely to become overfat adults (15 of 23 [65%]), as were children with a BMI < 50th centile (30 of 201 [15%]). Even after accounting for the triceps SF of children, BMI-for-age provided additional information on adult adiposity. CONCLUSIONS: Childhood BMI is associated with adult adiposity, but it is possible that the magnitude of this association depends on the relative fatness of children.

Adolescent↗
PubMed2004

Height and adiposity among children.

OBJECTIVE: Although BMI (kilograms per meter squared) is widely used as a surrogate measure of adiposity, it is moderately associated (r approximately 0.3) with height among children. We examined whether the resulting preferential classification of taller children as overweight, based on a BMI > or = 95th percentile, is appropriate. RESEARCH METHODS AND PROCEDURES: We assessed the cross-sectional relation of height among 5- to 18-year-old subjects (n = 1180) to levels of BMI, the sum of 10 skinfold thicknesses, and percentage body fat as determined by DXA. RESULTS: The prevalence of a BMI level > or = 95th percentile was substantially higher among 5- to 11-year-old subjects who were relatively tall for their age than among shorter children. Among 5- to 8-year-old boys, for example, each SD increase in height-for-age was associated with a 4.6-fold increase in the prevalence of overweight (p < 0.001). Height not only was associated with BMI but also showed similar correlations with the skinfold sum and with percentage body fat; furthermore, the magnitudes of these associations decreased with age. We also found that the association between percentage body fat and BMI (r = 0.85 to 0.90) was close to the maximum correlation that can be achieved by any weight-height index. DISCUSSION: The use of BMI, which preferentially classifies taller young children as overweight, is appropriate because height and adiposity are correlated before the age of 12 years.

Absorptiometry, Photon↗
PubMed2004

Energy-dense snack food intake in adolescence: longitudinal relationship to weight and fatness.

OBJECTIVE: The longitudinal relationship between the consumption of energy-dense snack (EDS) foods and relative weight change during adolescence is uncertain. Using data from the Massachusetts Institute of Technology Growth and Development Study, the current analysis was undertaken to examine the longitudinal relationship of EDS food intake with relative weight status and percentage body fat and to examine how EDS food consumption is related to television viewing. RESEARCH METHODS AND PROCEDURES: One hundred ninety-six nonobese premenarcheal girls 8 to 12 years old were enrolled between 1990 and 1993 and followed until 4 years after menarche. At each annual follow-up visit, data were collected on percentage body fat (%BF), BMI z score, and dietary intake. Categories of EDS foods considered were baked goods, ice cream, chips, sugar-sweetened soda, and candy. RESULTS: At study entry, girls had a mean +/- SD BMI z score of -0.27 +/- 0.89, consumed 2.3 +/- 1.7 servings of EDS foods per day, and consumed 15.7 +/- 8.1% of daily calories from EDS foods. Linear mixed effects modeling indicated no relationship between BMI z score or %BF and total EDS food consumption. Soda was the only EDS food that was significantly related to BMI z score over the 10-year study period, but it was not related to %BF. In addition, a significant, positive relationship was observed between EDS food consumption and television viewing. DISCUSSION: In this cohort of initially nonobese girls, overall EDS food consumption does not seem to influence weight status or fatness change over the adolescent period.

Adipose Tissue↗
PubMed2004

Relation of body mass index and body fatness to energy expenditure: longitudinal changes from preadolescence through adolescence.

BACKGROUND: Although it is widely accepted that weight gain results when energy intake exceeds energy expenditure (EE), how reduced EE contributes to the development of obesity remains unclear. OBJECTIVE: We tested the hypothesis that reduced EE in the premenarcheal period in girls constitutes a risk factor for an increase in relative weight [body mass index (BMI) z score] and percentage of body fat (%BF) during adolescence. DESIGN: We measured EE at study entry in 196 premenarcheal nonobese girls. Resting metabolic rate (RMR) was measured by indirect calorimetry. Total energy expenditure (TEE) was measured by the doubly labeled water method. Activity energy expenditure (AEE) was calculated from RMR and TEE. After the baseline study, girls were followed annually until 4 y after menarche (x+/- SD: 7.1 +/- 2.6 y). At each visit, height, weight, and %BF by bioelectrical impedance were measured. Girls also completed annual food-frequency and activity questionnaires. Linear mixed effects modeling was used to evaluate the longitudinal relation between BMI z score and %BF and measures of baseline EE. RESULTS: We found no significant relation in change in %BF with RMR, AEE, or TEE. We observed a small positive relation between BMI z score and AEE and TEE (P < 0.05) but no significant relation with RMR. When we stratified by parental overweight, the findings were unchanged for RMR. TEE and AEE were positively related to BMI z score in girls of overweight parents. CONCLUSIONS: Our findings suggest that EE in the premenarcheal period is not a risk factor for increases in %BF or BMI z score in girls during adolescence.

Adipose Tissue↗
PubMed2004

Shifts in percentiles of growth during early childhood: analysis of longitudinal data from the California Child Health and Development Study.

OBJECTIVE: To document growth-velocity changes across major percentiles during the preschool years. DESIGN: Analyses of longitudinal data using height-for-age, weight-for-age, weight-for-height, and body mass index (BMI)-for-age percentiles were performed to examine crossing of major percentiles of the Centers for Disease Control and Prevention 2000 growth charts. The 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentiles were defined as the major percentiles. SETTING: Data from the California Child Health and Development Study were used. SUBJECTS: A total of 10,844 children up to 60 months of age, with 44,296 height and weight measurements, were included in our final analysis. RESULTS: For height-for-age, 32% of children between birth and 6 months of age, 13% to 15% of children between 6 and 24 months of age, and 2% to 10% of children between 24 and 60 months of age crossed 2 major percentiles. For weight-for-age, 39% of children between birth and 6 months of age, 6% to 15% of children between 6 and 24 months of age, and 1% to 5% of children between 24 and 60 months of age crossed 2 major percentiles. In contrast, for weight-for-height, 62% of children between birth and 6 months of age, 20% to 27% of children between 6 and 24 months of age, and 6% to 15% of children between 24 to 60 months of age crossed 2 major percentiles. Similar to the pattern observed for weight-for-height, 8% to 15% of children between 24 and 60 months of age crossed 2 major BMI-for-age percentiles. During the preschool years, weight-for-height had the highest percentages of children who crossed 2 major percentiles, and weight-for-age had the lowest percentages of children who crossed 2 major percentiles among these 3 indices. CONCLUSIONS: Shifts in growth rates were very common for children from birth to 6 months of age, somewhat less common for children 6 to 24 months of age, and least common for children 24 to 60 months of age. Shifts in weight-for-height occurred more frequently than did other growth changes. Pediatricians must consider the prevalence of growth rate shifts during infancy and early childhood before they counsel parents regarding growth or refer children for additional evaluations of growth.

Body Height↗
PubMed2003

Law as a tool for preventing chronic diseases: expanding the range of effective public health strategies.

Law, which is a fundamental element of effective public health policy and practice, played a crucial role in many of public health's greatest achievements of the 20th century. Still, conceptual legal frameworks for the systematic application of law to chronic disease prevention and control have not been fully recognized and used to address public health needs. Development and implementation of legal frameworks could broaden the range of effective public health strategies and provide valuable tools for the public health workforce, especially for state and local health department program managers and state and national policy makers. In an effort to expand the range of effective public health interventions, the Centers for Disease Control and Prevention will work with its partners to explore the development of systematic legal frameworks as a tool for preventing chronic diseases and addressing the growing epidemic of obesity, heart disease, stroke, and other chronic diseases and their risk factors.

Chronic Disease↗