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This study examined the associations of moderate-to-vigorous intensity physical activity (MVPA) trajectories in adolescence through young adulthood with adiposity in young adults. Participants from The Iowa Bone Development Study cohort were longitudinally assessed (N = 297; 57% female). Accelerometry-measured MVPA (min/day) at ages 15 through 23 years, and fat mass and visceral adipose tissue mass indices (kg/m.sup.2, g/m.sup.2) derived from dual-energy X-ray absorptiometry scans at age 23 years were analyzed. Latent trajectory analyses classified MVPA into two patterns. Multivariable linear regression analyses showed that being in the high MVPA trajectory group was associated with lower fat mass index z-scores. Individuals who were consistently active with high MVPA (vs. moderately active with decreasing MVPA) during adolescence up until early young adulthood had less accumulation of total body adiposity in young adulthood. This study suggests that adopting a consistently active lifestyle throughout adolescence can result in healthier body composition in young adulthood., Author(s): Minsuk Oh [sup.1] , Dong Zhang [sup.2] , Kara M. Whitaker [sup.1] [sup.3] , Elena M. Letuchy [sup.3] , Kathleen F. Janz [sup.1] [sup.3] , Steven M. Levy [sup.3] [...]

Purpose: Most pediatric physical activity and bone health research has focused on the period immediately around puberty; few have addressed bone structural strength outcomes. This study assessed the magnitude and consistency of the longitudinal relationships between device-measured vigorous-intensity physical activity (VPA) and structural bone strength outcomes across adolescence to emerging adulthood. Methods: Participants with 3 to 5 bone scans between the age of 11 and 19 years were studied (N = 439, 220 females, 1838 records). Dual-energy X-ray absorptiometry scans of the hip (hip structural analysis) and peripheral quantitative computed tomography scans of the tibia were obtained. Outcomes included femoral neck section modulus, femoral neck cross-sectional area, tibial Bone Strength Index, and tibial torsion strength (polar Strength Strain Index). Sex-specific bone mixed growth models were developed using biological age (chronological age − age at peak height velocity) as the time variable, and height, weight, and device-measured VPA as time-varying covariates. Models also included the VPA–biological age interaction. Results: Individual-centered VPA and the VPA–biological age interaction were significantly, positively associated (P <.05) with Bone Strength Index, polar Strength Strain Index, section modulus, and cross-sectional area in males and females, indicating accumulative effects of VPA throughout maturation and beyond. Conclusion: Bone remains responsive to the mechanical loading of physical activity throughout adolescence and into emerging adulthood. Attention should be placed on promoting bone-strengthening physical activity after the prepubertal years when adult exercise patterns are likely formed. [ABSTRACT FROM AUTHOR]

In this paper, the authors present reliability and validity information for the Netherlands (Health Education Project) Physical Activity Questionnaire (NPAQ), a global proxy report of children's everyday activity preferences (Montoye, Kemper, Saris, & Washburn, 1996). In this study, the authors examined the measurement properties of a global proxy report of young children's physical activity. Children (N= 204) and their parents were participants in the Iowa Bone Development Study (Janz et al., 2004). The children, 91 boys and 113 girls, were between ages 4 and 7 years (M age = 5.7 years, SD = 0.5). Children's height was (M = 112 cm, SD = 5) and weight was (M = 21 kg, SD = 3). Generalized estimating equations using unstructured covariance were used to simultaneously examine mean group differences over time for repeat measures and differences in measures between boys and girls, including a Gender x Time interaction. The results suggest moderate to good evidence for test-retest reliability of the NPAQ and low to moderate evidence for concurrent validity. Using trilogistic regression, the authors have shown that the NPAQ can be used to classify children into low and high activity groups approximately 70% of the time. The authors also examined the measurement properties of a proxy recall for TV viewing. Findings suggest moderate to good reliability for these measures and some support for validity.

Objectives: This article reports on estimated daily fluoride intake from water, other beverages and selected foods, dentifrice, and dietary fluoride supplements by both individual sources, and all sources combined, among 787 children participating in the Iowa Fluoride Study (IFS) from 6 to 17 years of age. Methods: Total daily fluoride intake (mg F) and fluoride intake per kilogram bodyweight (mg F/kg bw) were estimated using responses to questionnaires sent every 3–6 months. Dietary assessments included frequencies and amounts of beverage intake for the previous week from water, milk, ready‐to‐drink beverages, beverages made by adding water to concentrate or powder, and selected foods with substantial water content. Descriptive statistics and bivariate and multivariable analyses with linear mixed models were used to assess associations with each of mg F and mg F/kg bw. Results: Mean combined dietary fluoride (mg F) from all sources examined in the study increased slightly with age, whereas the fluoride intake per kg bw decreased with age. Age, sex, and socioeconomic status were significantly associated with fluoride intake (mg F and mg F/kg bw). Each year increase in age was associated with a 0.02‐mg increase in fluoride consumption, on average, after adjusting for the effects of covariates. Conclusions: Daily mean fluoride intakes from single and combined sources were relatively stable, while the intake of fluoride per kg bw decreased from 6 to 17 years of age. Fluoridated water was the major source of ingested fluoride, contributing over 50% of total daily intake at all ages. [ABSTRACT FROM AUTHOR]

Although genetics affects early childhood caries (ECC) risk, few studies have focused on finding its specific genetic determinants. Here, we performed genome-wide association studies (GWAS) in five cohorts of children (aged up to 5 years, total N = 2974, cohorts: Center for Oral Health Research in Appalachia cohorts one and two [COHRA1, COHRA2], Iowa Fluoride Study, Iowa Head Start, Avon Longitudinal Study of Parents and Children [ALSPAC]) aiming to identify genes with potential roles in ECC biology. We meta-analyzed the GWASs testing ~3.9 million genetic variants and found suggestive evidence for association at genetic regions previously associated with caries in primary and permanent dentition, including the β-defensin anti-microbial proteins. We then integrated the meta-analysis results with gene expression data in a transcriptome-wide association study (TWAS). This approach identified four genes whose genetically predicted expression was associated with ECC (p-values < 3.09 × 10−6; CDH17, TAS2R43, SMIM10L1, TAS2R14). Some of the strongest associations were with genes encoding members of the bitter taste receptor family (TAS2R); other members of this family have previously been associated with caries. Of note, we identified the receptor encoded by TAS2R14, which stimulates innate immunity and anti-microbial defense in response to molecules released by the cariogenic bacteria, Streptococcus mutans and Staphylococcus aureus. These findings provide insight into ECC genetic architecture, underscore the importance of host-microbial interaction in caries risk, and identify novel risk genes. [ABSTRACT FROM AUTHOR]