Description of Child and Adolescent Beverage and Anthropometric Measures According to Adolescent Beverage Patterns

Associations between body mass index and body composition measures in a birth cohort

BACKGROUND

Associations among body composition measures have been limited to cross-sectional analyses of different subjects. We identified cross-sectional relationships between body mass index (BMI) and other body composition measures and predicted body composition measures from BMI throughout childhood and adolescence.

METHODS

BMI was calculated and % body fat (%BF), fat mass index (FMI), and fat-free mass index (FFMI) were measured using dual-energy x-ray absorptiometry at ages 5, 9, 11, 13, 15, and 17 years in a birth cohort (n = 629). Sex-specific body composition measures were calculated for BMI-for-age percentiles; associations between BMI and body composition measures were characterized; and body composition measures were predicted from BMI.

RESULTS

%BF, FMI, and FFMI generally increased with BMI-for-age percentiles at each age. Correlations between BMI and %BF or FMI were generally higher at BMI-for-age percentiles ≥95% than for lower BMI-for-age percentiles. Correlations between BMI and FFMI were generally higher for participants at very low and very high BMI-for-age percentiles than at moderate BMI-for-age percentiles. Age- and sex-specific predictions from BMI are provided for %BF, FM, and FFMI.

CONCLUSIONS

Sex-specific body composition measures throughout childhood and adolescence are presented. BMI is a better indicator of adiposity at higher than at lower BMI values.

IMPACT

Sex-specific body composition measures throughout childhood and adolescence are described. % BF, FMI, and FFMI generally increased with BMI-for-age percentiles for both sexes throughout childhood and adolescence. BMI is a better indicator of adiposity at higher BMI levels than at lower BMI values throughout childhood and adolescence.

Identification of and Associations among Low, Middle, and High Body Composition Trajectories from Age 5- to 17-Years

Our objective was to identify sex-specific age 5- to 17-year body composition (body mass index (BMI), % body fat, fat mass index, fat-free mass index) trajectories, compare trajectories assigned using age 5 (AGE5) data to those assigned using all available (ALL) data, and compare BMI assignments to other body composition assignments. Cluster analysis was used to identify low, medium, and high trajectories from body composition measures obtained from dual energy x-ray absorptiometry (DXA) scans at 5, 9, 11, 13, 15, and 17 years in a birth cohort followed longitudinally (n = 469). Moderate agreement was observed for comparisons between AGE5 data and ALL data cluster assignments for each body composition measure. Agreement between cluster assignments for BMI and other body composition measures was stronger using ALL data than using AGE5 data. Our results suggest that BMI, % body fat, fat mass index, and fat free mass index trajectories are established during early childhood, and that BMI is a reasonable predictor of body composition appropriate to track obesity in public health and clinical settings.

Perspective: Chaos in a Bottle-A Critical Evaluation of Beverage Categorization in Nutrition Research

Beverage consumption is an important contributor to total daily calorie intake among children and adolescents. While associations between excess calories from beverages and development of obesity are well established, a standardized approach for beverage categorization does not exist. As a result, there is marked heterogeneity in assessment and categorization of beverage intake across studies. The purpose of this article is to critically review beverage categorization in recent (published since 2010) observational studies that evaluated beverage intake in relation to weight/adiposity in US youth, and to put forth an initial proposal for a standardized beverage classification system. Standardized beverage classification is critical to ensure transparency in nutrition science research and facilitate comparison of findings across studies. A systematic literature search identified 37 eligible studies, across which beverage categorization varied considerably. The most heterogeneity was observed for categorization of "sugar-sweetened beverages" and the greatest consistency was observed for categorization of 100% juices. This review provides an evidence-based starting point for urgently needed, collaborative work to determine priorities for beverage categorization and leverage existing standards of identity in order to create and disseminate a standardized beverage classification system. A standardized approach will inform meaningful assessment of beverage consumption in research studies and facilitate impactful translation of research findings into public health nutrition policy.