Reformulation of BMI and percent body fat to remove the height bias in 8-year-olds

Dick TELFORD, Ross Cunningham

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

BMI and percent body fat (%BF) are both related to height (Ht) in prepubertal children, so may misrepresent childhood adiposity, especially in tall or short children. We sought to construct replacement functions for BMI and %BF that are independent of Ht. Fat mass (FM) was measured using dual‐energy X‐ray absorptiometry, together with Ht and body mass (BM) in 746 healthy boys and girls aged 8 years (0.34 s.d.). Relationships between BM, FM, and Ht were measured and values of p and q derived such that the functions BM. Ht−p and FM.BM−q were unrelated to Ht. BM was not directly proportional to Ht2, BMI being significantly related to Ht in both boys and girls (P < 0.001). BM was proportional to Ht3, BM. Ht−3 being independent of Ht. Similarly, FM was not directly proportional to BM and %BF was significantly related to Ht (P < 0.001). While FM was proportional to BM2, FM.BM−1.5 was the function found to be independent of Ht. Using the 85th and 95th percentiles as the cutoffs for overweight and obesity respectively, 6.4% of the boys and 6.8% of the girls were classified differently by BMI and the Ht independent measure BM. Ht−3. Similarly, 10.1% boys and 13.7% girls were classified differently by %BF and the Ht independent measure FM.BM−1.5. We propose that improved diagnostic accuracy of body composition in 8‐year‐olds is provided by the BM function (BMF, BM. Ht−3) and FM function (FMF, FM.BM−1.5) replacing BMI and %BF, which both overestimate the adiposity of taller children and underestimate it in shorter children
Original languageEnglish
Pages (from-to)2175-2181
Number of pages7
JournalObesity
Volume16
Issue number9
DOIs
Publication statusPublished - 2008
Externally publishedYes

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Adipose Tissue
Fats
Body Height
Adiposity
Body Weights and Measures
Body Composition
Obesity
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TELFORD, Dick ; Cunningham, Ross. / Reformulation of BMI and percent body fat to remove the height bias in 8-year-olds. In: Obesity. 2008 ; Vol. 16, No. 9. pp. 2175-2181.
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abstract = "BMI and percent body fat ({\%}BF) are both related to height (Ht) in prepubertal children, so may misrepresent childhood adiposity, especially in tall or short children. We sought to construct replacement functions for BMI and {\%}BF that are independent of Ht. Fat mass (FM) was measured using dual‐energy X‐ray absorptiometry, together with Ht and body mass (BM) in 746 healthy boys and girls aged 8 years (0.34 s.d.). Relationships between BM, FM, and Ht were measured and values of p and q derived such that the functions BM. Ht−p and FM.BM−q were unrelated to Ht. BM was not directly proportional to Ht2, BMI being significantly related to Ht in both boys and girls (P < 0.001). BM was proportional to Ht3, BM. Ht−3 being independent of Ht. Similarly, FM was not directly proportional to BM and {\%}BF was significantly related to Ht (P < 0.001). While FM was proportional to BM2, FM.BM−1.5 was the function found to be independent of Ht. Using the 85th and 95th percentiles as the cutoffs for overweight and obesity respectively, 6.4{\%} of the boys and 6.8{\%} of the girls were classified differently by BMI and the Ht independent measure BM. Ht−3. Similarly, 10.1{\%} boys and 13.7{\%} girls were classified differently by {\%}BF and the Ht independent measure FM.BM−1.5. We propose that improved diagnostic accuracy of body composition in 8‐year‐olds is provided by the BM function (BMF, BM. Ht−3) and FM function (FMF, FM.BM−1.5) replacing BMI and {\%}BF, which both overestimate the adiposity of taller children and underestimate it in shorter children",
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Reformulation of BMI and percent body fat to remove the height bias in 8-year-olds. / TELFORD, Dick; Cunningham, Ross.

In: Obesity, Vol. 16, No. 9, 2008, p. 2175-2181.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Reformulation of BMI and percent body fat to remove the height bias in 8-year-olds

AU - TELFORD, Dick

AU - Cunningham, Ross

PY - 2008

Y1 - 2008

N2 - BMI and percent body fat (%BF) are both related to height (Ht) in prepubertal children, so may misrepresent childhood adiposity, especially in tall or short children. We sought to construct replacement functions for BMI and %BF that are independent of Ht. Fat mass (FM) was measured using dual‐energy X‐ray absorptiometry, together with Ht and body mass (BM) in 746 healthy boys and girls aged 8 years (0.34 s.d.). Relationships between BM, FM, and Ht were measured and values of p and q derived such that the functions BM. Ht−p and FM.BM−q were unrelated to Ht. BM was not directly proportional to Ht2, BMI being significantly related to Ht in both boys and girls (P < 0.001). BM was proportional to Ht3, BM. Ht−3 being independent of Ht. Similarly, FM was not directly proportional to BM and %BF was significantly related to Ht (P < 0.001). While FM was proportional to BM2, FM.BM−1.5 was the function found to be independent of Ht. Using the 85th and 95th percentiles as the cutoffs for overweight and obesity respectively, 6.4% of the boys and 6.8% of the girls were classified differently by BMI and the Ht independent measure BM. Ht−3. Similarly, 10.1% boys and 13.7% girls were classified differently by %BF and the Ht independent measure FM.BM−1.5. We propose that improved diagnostic accuracy of body composition in 8‐year‐olds is provided by the BM function (BMF, BM. Ht−3) and FM function (FMF, FM.BM−1.5) replacing BMI and %BF, which both overestimate the adiposity of taller children and underestimate it in shorter children

AB - BMI and percent body fat (%BF) are both related to height (Ht) in prepubertal children, so may misrepresent childhood adiposity, especially in tall or short children. We sought to construct replacement functions for BMI and %BF that are independent of Ht. Fat mass (FM) was measured using dual‐energy X‐ray absorptiometry, together with Ht and body mass (BM) in 746 healthy boys and girls aged 8 years (0.34 s.d.). Relationships between BM, FM, and Ht were measured and values of p and q derived such that the functions BM. Ht−p and FM.BM−q were unrelated to Ht. BM was not directly proportional to Ht2, BMI being significantly related to Ht in both boys and girls (P < 0.001). BM was proportional to Ht3, BM. Ht−3 being independent of Ht. Similarly, FM was not directly proportional to BM and %BF was significantly related to Ht (P < 0.001). While FM was proportional to BM2, FM.BM−1.5 was the function found to be independent of Ht. Using the 85th and 95th percentiles as the cutoffs for overweight and obesity respectively, 6.4% of the boys and 6.8% of the girls were classified differently by BMI and the Ht independent measure BM. Ht−3. Similarly, 10.1% boys and 13.7% girls were classified differently by %BF and the Ht independent measure FM.BM−1.5. We propose that improved diagnostic accuracy of body composition in 8‐year‐olds is provided by the BM function (BMF, BM. Ht−3) and FM function (FMF, FM.BM−1.5) replacing BMI and %BF, which both overestimate the adiposity of taller children and underestimate it in shorter children

KW - adipose tissue

KW - article

KW - body composition

KW - body height

KW - body mass

KW - body weight

U2 - 10.1038/oby.2008.332

DO - 10.1038/oby.2008.332

M3 - Article

VL - 16

SP - 2175

EP - 2181

JO - Obesity Research

JF - Obesity Research

SN - 1071-7323

IS - 9

ER -