American journal of preventive medicine
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Body composition and fat distribution change dramatically during adolescence. Data based on longitudinal studies to describe these changes are limited. The aim of this study was to describe age-related changes in fat free-mass index (FFMI) and fat mass index (FMI), which are components of BMI, and waist circumference (WC) in participants of Project HeartBeat!, a longitudinal study of children. ⋯ The extent to which each component of BMI contributes to the changes in BMI depends on the gender, race, and age of the individual. Healthcare providers need to be aware that children who show upward deviation of BMI or BMI percentiles may have increases in their lean body mass rather than in adiposity.
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Users of smokeless tobacco (chew or snuff) in the U.S. are viewed demographically as being homogeneous. Prior studies have demonstrated such homogeneity in national survey data but have not utilized latent-variable methods. The objective of this study was to determine whether a single group or underlying subgroups best characterize users of smokeless tobacco. ⋯ While users of smokeless tobacco in the U.S. are predominantly white men, they are more heterogeneous with respect to education, occupation, and residency than commonly is perceived.
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Few investigations have examined whether associations between the apolipoprotein E genotype (apo E) and total cholesterol or LDL-C are modified or explained by other characteristics. The objective of this study was to explore effects of behavioral characteristics, physical growth, body composition, sexual maturation, and endocrine function on age trajectories of total cholesterol and LDL-C by apo E in adolescent girls. ⋯ Adolescent girls with epsilon3/3 and epsilon3/4 genotypes had higher total cholesterol and LDL-C and showed different patterns of change, compared to those with epsilon2/3 genotype. These apo E effects were independent of behavioral characteristics, physical growth, body composition, sexual maturation, and endocrine function. Girls with epsilon3/3 or epsilon3/4 genotypes may be at risk for elevated total cholesterol and LDL-C later in life.
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Systolic and fourth-phase and fifth-phase diastolic blood pressure (SBP, DBP4, DBP5) have appeared to differ in their patterns of age-related change, and SBP and DBP5 differ in their respective associations with anthropometric variables. Project HeartBeat! investigated trajectories of change in SBP, DBP4, and SBP5 with age and their relationships with indices of adiposity, controlling for energy intake, physical activity, and sexual maturation. ⋯ SBP, DBP4, and DBP5 are distinct in patterns of change with age, relationships to gender and race, and patterns of association with multiple anthropometric indices related to adiposity.
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Longitudinal data on the normal development of blood lipids and its relationships with body fatness in children and adolescents are limited. Objectives of the current analysis were to estimate trajectories related to age for four blood lipid components and to examine the impact of change in body fatness on blood lipid levels, comparing estimated effects among adiposity indices, in children and adolescents. ⋯ Patterns of change with age in blood lipid components vary significantly among gender and racial groups. Increase in body fatness among children is consistently associated with adverse change in blood lipids. Evaluation of blood lipid level should take into account variation by age, gender, and race. Intervention through body-fat control should help prevent adverse lipid levels in children and adolescents.