percent body fat: estimation and interpretation• slaughter et al. skinfold equations for...
TRANSCRIPT
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Percent Body Fat: Estimation and Interpretation
Michelle N. Kuperminc, MD Developmental and Behavioral Pediatrician
Naval Medical Center Portsmouth Portsmouth, Virginia
This presentation does not represent opinions or views of the US Government
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Overview
• Estimate percent body fat
– Slaughter method
– Gurka method
• Interpretation of percentages
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Rationale • Growth/nutritional status linked to health, participation, life
expectancy in individuals with CP
• Due to differences in body composition, simple anthropometric measures used in other populations not predictive of nutritional status in individuals with CP (weight/height, BMI, arm circumference, single skinfold measurement)
• Complex methods of body composition assessment not always feasible in clinical setting (underwater weighing, D2O dilution, DEXA, BIA)
• Additive skinfold equations developed to predict percent body fat Stevenson et al, 2006 Kuperminc et al, 2010
Brooks et al, 2012 Brooks et al, 2014
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Triceps skinfold
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Subscapular skinfold
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Slaughter Equations • Estimate percent body fat from skinfolds
• Prior equations by Lohman et al. not adequate for children (change in body composition over time and pubertal status)
• Developed from classic methods used to measure body composition (underwater weighing, D20 dilution method)
Slaughter et al, 1998
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Gurka Equations • Estimate percent body fat from skinfolds
• Slaughter equations underestimate percent body fat in children with CP
• Specific to individuals with CP
• Developed correction factors to Slaughter equations
• Based on DEXA
• Externally validated in ambulatory population
• May overestimate percent body fat in children with higher percent body fat
Kuperminc et. al, 2010 Gurka et al, 2010 Rieken et al, 2011
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Gurka Equations
Two skinfolds: subscapular and triceps
1. Slaughter method to calculate percent body
fat.
2. Correct for CP, gender, pubertal status,
severity of motor impairment (GMFCS 3-5)
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Example
• 11 year old prepubertal white male with CP GMFCS 4
• TSF=10
• SSF=11
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Percent body fat by Slaughter method
• TSF=10, SSSF=11
• %BF Slaughter=1.21 (TSF+SSSF)-.008 (TSF+SSSF)2-1.7
• %BF Slaughter=1.21 (21) – 0.008 (441) – 1.7
• %BF Slaughter= 25.42 – 3.528 - 1.7
• % BF Slaughter=23.6%
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Percent Body Fat by Gurka Method
• % BF Gurka =% BF Slaughter (corrected) • CP +12.2
• Male -5
• Level of motor impairment +5.1 • % BF Gurka =23.5 + 12.2 – 5 + 5.1
• % BF Gurka = 35.8%
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Interpretation
• Published, population based reference curves are descriptive rather than prescriptive
• Published, population based accepted cutoffs (may or may not be relevant
to children/adolescents with CP) are prescriptive
– Based on percentiles (random?)
– Based on health indicators (outcomes, metabolic studies)
• Emerging health indicators in population of individuals with CP
– Overall growth relationship with health and participation (Stevenson et al, 2006)
– Body weight relationship with mortality (Brooks et al, 2012)
– No published indicators linked to percent body fat in this population
McCarthy et al, 2006
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Reference Curve Percentiles for Percent Body Fat: US Boys Ages 5-19 NHANES IV
Laurson et al, 2011
Gurka
Slaughter
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Recommended cutoffs: UK Boys Ages 5-18
McCarthy et al, 2006
Gurka
Slaughter
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References • Brooks et al. Low weight, morbidity, and mortality in children with cerebral palsy: New clinical growth charts.
Pediatrics, 2011.
• Chumlea et al. Prediction of stature from knee height for black and white adults and children with application to mobility-impaired or handicapped persons. Juornal of the American Dietetic Association, 1994.
• Gurka et al. Assessment and correction of skinfolld thickness equations in estimating body fat in children with cerebral palsy, Developmental Medicine and Child Neurology, 2010.
• Kuperminc et al. Anthropometric measures: poor predictors for body fat in children with moderate to severe cerebral palsy, Developmental Medicine and Child Neurology, 2010.
• Laurson et al. Body Percentile Curves for US Adolescents and Children, American Journal of Preventative Medicine, 2011.
• Oeffinger et al. Accuracy of Skinfold and Bioelectrical Impedance assessments of body fat percentage in
ambulatory individuals with cerebral palsy. Developmental Medicine and Child Neurology, 2013.
• Rieken et al. Measuring body composition and energy expenditure in children with severe neurologic impairment
and intellectual disability. American Journal of Clinical Nutrition 2011.
• Slaughter et al. Skinfold equations for estimation of body fatness in children and youth. Human Biology, 1984
• Stevenson. Use of segmental measures to estimate stature in children with cerebral palsy. Archives of Pediatric and Adolescent Medicine, 1995.