Dataset Information

Tri-Ponderal Mass Index vs Body Mass Index in Estimating Body Fat During Adolescence.

ABSTRACT:

Importance

Body mass index (BMI) is used to diagnose obesity in adolescents worldwide, despite evidence that weight does not scale with height squared in adolescents. To account for this, health care providers diagnose obesity using BMI percentiles for each age (BMI z scores), but this does not ensure that BMI is accurate in adolescents.

Objective

To compare the accuracy of BMI vs other body fat indices of the form body mass divided by heightn in estimating body fat levels in adolescents.

Design, setting, and participants

Cross-sectional data from the 1999 to 2006 US National Health and Nutrition Examination Survey were analyzed between September 2015 and December 2016.

Main outcomes and measures

Dual-energy x-ray absorptiometry and anthropometric data were used to determine changes in body fat levels, body proportions, and the scaling relationships among body mass, height, and percent body fat. To assess the merits of each adiposity index, 3 criteria were used: stability with age, accuracy in estimating percent body fat, and accuracy in classifying adolescents as overweight vs normal weight.

Results

Participants included 2285 non-Hispanic white participants aged 8 to 29 years. Percent body fat varied with both age and height during adolescence, invalidating the standard weight-to-height regression as the way of finding the optimal body fat index. Because the correct regression model (percent body fat is proportional to mass divided by heightn) suggested that percent body fat scales to height with an exponent closer to 3, we therefore focused on the tri-ponderal mass index (TMI; mass divided by height cubed) as an alternative to BMI z scores. For ages 8 to 17 years, TMI yielded greater stability with age and estimated percent body fat better than BMI (R2?=?0.64 vs 0.38 in boys and R2?=?0.72 vs 0.66 in girls). Moreover, TMI misclassified adolescents as overweight vs normal weight less often than BMI z scores (TMI, 8.4%; 95% CI, 7.3%-9.5% vs BMI, 19.4%; 95% CI, 17.8%-20.0%; P?Conclusions and relevanceThe tri-ponderal mass index estimates body fat levels more accurately than BMI in non-Hispanic white adolescents aged 8 to 17 years. Moreover, TMI diagnoses adolescents as overweight more accurately than BMI z scores and equally as well as updated BMI percentiles but is much simpler to use than either because it does not involve complicated percentiles. Taken together, it is worth considering replacing BMI z scores with TMI to estimate body fat levels in adolescents.

SUBMITTER: Peterson CM

PROVIDER: S-EPMC5710345 | biostudies-literature | 2017 Jul

REPOSITORIES: biostudies-literature

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Publications

Tri-Ponderal Mass Index vs Body Mass Index in Estimating Body Fat During Adolescence.

Peterson Courtney M CM Su Haiyan H Thomas Diana M DM Heo Moonseong M Golnabi Amir H AH Pietrobelli Angelo A Heymsfield Steven B SB

JAMA pediatrics 20170701 7

<h4>Importance</h4>Body mass index (BMI) is used to diagnose obesity in adolescents worldwide, despite evidence that weight does not scale with height squared in adolescents. To account for this, health care providers diagnose obesity using BMI percentiles for each age (BMI z scores), but this does not ensure that BMI is accurate in adolescents.<h4>Objective</h4>To compare the accuracy of BMI vs other body fat indices of the form body mass divided by heightn in estimating body fat levels in adol ...[more]

PMID: 28505241

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Project description:Background/objectiveThe evidence that maternal non-nutritive sweetener (NNS) intake during pregnancy increases childhood obesity risk is conflicting. A potential reason for this is that all prior studies examined childhood body mass index (BMI) at only one timepoint and at different ages. We examined the extent to which NNS intake during pregnancy is associated with offspring BMI z-score and body fat longitudinally from birth to 18 years.SubjectsA total of 1683 children from Project Viva, a prospective pre-birth cohort, were recruited from 1999 to 2002 in Massachusetts.MethodsWe assessed maternal NNS intake in the first and second trimesters of pregnancy using a semiquantitative food frequency questionnaire. Our outcomes were offspring BMI z-score, (at birth, infancy (median 6.3 months), early childhood (3.2 years), mid-childhood (7.7 years), and early adolescence (12.9 years)), sum of skinfolds (SS), fat mass index (FMI) measured by dual x-ray absorptiometry, and BMI z-score trajectory from birth to 18 years. We adjusted models for maternal pre-pregnancy BMI, age, race/ethnicity, education, parity, pre-pregnancy physical activity, smoking, and paternal BMI and education.ResultsA total of 70% of mothers were white and pre-pregnancy BMI was 24.6 ± 5.2 kg/m2. The highest quartile of NNS intake (Q4: 0.98 ± 0.91 servings/day) was associated with higher BMI z-score in infancy (β 0.20 units; 95% CI 0.02, 0.38), early childhood (0.21; 0.05, 0.37), mid-childhood (0.21; 0.02, 0.40), and early adolescence (0.14; -0.07, 0.35) compared with Q1 intake (Q1: 0.00 ± 0.00 servings/day). Q4 was also associated with higher SS in early childhood (1.17 mm; 0.47, 1.88), mid-childhood (2.33 mm; 0.80, 3.87), and early adolescence (2.27 mm; -0.06, 4.60) and higher FMI in mid-childhood (0.26 kg/m2; -0.07, 0.59). Associations of maternal NNS intake with offspring BMI z-score became stronger with increasing age from 3 to 18 years (Pinteraction < 0.0001).ConclusionsMaternal NNS intake during pregnancy is associated with increased childhood BMI z-score and body fat from birth to teenage years. This is relevant given the escalating obesity epidemic, and popularity of NNS.

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Project description:ImportanceThe American Academy of Pediatrics currently recommends weight for length (WFL) for assessment of weight status in children younger than 2 years but body mass index (BMI) for children older than 2 years. However, the clinical implications of using WFL vs BMI in children younger than 2 years as an indicator of future health outcomes remains understudied.ObjectiveTo compare associations of overweight based on WFL vs BMI in children younger than 2 years with cardiometabolic outcomes during early adolescence.Design, setting, and participantsThis prospective study of birth cohorts in the United States (Project Viva) and Belarus (Promotion of Breastfeeding Intervention Trial [PROBIT]) performed from June 1, 1996, to November 31, 2002, included 13 666 children younger than 2 years.Main exposuresOverweight defined as Centers for Disease Control and Prevention (CDC) WFL in the 95th percentile or greater, World Health Organization (WHO) WFL in the 97.7th percentile or greater, or WHO BMI in the 97.7th percentile or greater at 6, 12, 18, or 24 months of age.Main outcomes and measuresPrimary outcomes were fat mass index, insulin resistance, metabolic risk score, and obesity during early adolescence. Secondary outcomes were height and BMI z scores, sum of skinfolds, waist circumference, and systolic blood pressure during early adolescence.ResultsThe study included 919 children (mean [SD] age, 12.9 [0.9] years; 460 [50.1%] male; and 598 [65.1%] white) from Project Viva and 12 747 children (mean [SD] age, 11.5 [0.5] years; 6204 [48.7%] male; and 12 747 [100%] white) from PROBIT. During 6 to 24 months of age, in Project Viva, 206 children (22.4%) were overweight at any of the 4 times points according to the CDC WFL, 160 (17.4%) according to WHO WFL, and 161 (17.5%) according to WHO BMI cut points. In PROBIT, 3715 children (29.1%) were overweight at any of the 4 time points according to the CDC WFL, 3069 (24.1%) according to WHO WFL, and 3125 (24.5%) according to WHO BMI cut points. After maternal and child characteristics were adjusted for, being ever overweight (vs never overweight) during 6 to 24 months of age was associated with higher likelihood of adverse cardiometabolic risk markers during early adolescence, but associations did not differ substantially across WFL and BMI cut points in either cohort. For example, for fat mass index in Project Viva, β = 0.9 (95% CI, 0.5-1.4) for the CDC WFL, β = 1.1 (95% CI, 0.6-1.6) for WHO WFL, and β = 1.4 (95% CI, 0.9-1.9) for WHO BMI. For PROBIT, β = 0.5 (95% CI, 0.4-0.6) for the CDC WFL, β = 0.6 (95% CI, 0.5-0.7) for WHO WFL, and β = 0.6 (95% CI, 0.5-0.6) for WHO BMI. Neither growth metric in infancy was superior over the others based on F statistics (Project Viva: 17.1-17.8; PROBIT: 87.1-88.7). Findings were similar for insulin resistance, metabolic risk score, obesity, and secondary outcomes.Conclusions and relevanceChoice of WFL vs BMI to define overweight during the first 2 years of life may not greatly affect the association with cardiometabolic outcomes during early adolescence. The findings appear to have important implications for investigators seeking to use BMI as a growth metric for epidemiologic research and for practitioners monitoring the weight status of children younger than 2 years.

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Dataset Information

Tri-Ponderal Mass Index vs Body Mass Index in Estimating Body Fat During Adolescence.

Importance

Objective

Design, setting, and participants

Main outcomes and measures

Results

Publications

Tri-Ponderal Mass Index vs Body Mass Index in Estimating Body Fat During Adolescence.

Similar Datasets

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