Body mass index vs deuterium dilution method for establishing childhood obesity prevalence, Ghana, Kenya, Mauritius, Morocco, Namibia, Senegal, Tunisia and United Republic of Tanzania

Adama Diouf, Theodosia Adom, Abdel Aouidet, Asmaa El Hamdouchi, Noorjehan I Joonas, Cornelia U Loechl, Germana H Leyna, Dorcus Mbithe, Thabisile Moleah, Andries Monyeki, Hilde Liisa Nashandi, John J Reilly, Serge MA Somda

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Objective -- To compare the World Health Organization (WHO) body mass index (BMI)-for-age definition of obesity against measured body fatness in African children. Methods -- In a prospective multicentre study over 2013 to 2017, we recruited 1516 participants aged 8 to 11 years old from urban areas of eight countries (Ghana, Kenya, Mauritius, Morocco, Namibia, Senegal, Tunisia and United Republic of Tanzania). We measured height and weight and calculated BMI-for-age using WHO standards. We measured body fatness using the deuterium dilution method and defined excessive body fat percentage as > 25% in boys and > 30% in girls. We calculated the sensitivity and specificity of BMI z-score > +2.00 standard deviations (SD) and used receiver operating characteristic analysis and the Youden index to determine the optimal BMI z-score cut-off for classifying excessive fatness. Findings -- The prevalence of excessive fatness was over three times higher than BMI-for-age-defined obesity: 29.1% (95% CI: 26.8 to 31.4; 441 children) versus 8.8% (95% CI: 7.5 to 10.4; 134 children). The sensitivity of BMI z-score > +2.00 SD was low (29.7%, 95% CI: 25.5 to 34.2) and specificity was high (99.7%, 95% CI: 99.2 to 99.9). The receiver operating characteristic analysis found that a BMI z-score +0.58 SD would optimize sensitivity, and at this cut-off the area under the curve was 0.86, sensitivity 71.9% (95% CI: 67.4 to 76.0) and specificity 91.1% (95% CI: 89.2 to 92.7). Conclusion -- While BMI remains a practical tool for obesity surveillance, it underestimates excessive fatness and this should be considered when planning future African responses to the childhood obesity pandemic.
LanguageEnglish
Pages772-781
Number of pages10
JournalBulletin of the World Health Organization
Volume96
DOIs
Publication statusPublished - 1 Nov 2018

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Mauritius
Namibia
Morocco
Senegal
Tunisia
Ghana
Tanzania
Deuterium
Pediatric Obesity
Kenya
Body Mass Index
Obesity
ROC Curve
Pandemics
Multicenter Studies
Area Under Curve
Adipose Tissue
Prospective Studies
Weights and Measures
Sensitivity and Specificity

Keywords

  • World Health Organization
  • WHO
  • obsesity
  • public health
  • Ghana
  • Kenya
  • Mauritius
  • Moroco
  • Namibia
  • Senegal
  • Tunsia
  • Tanzania
  • body mass index
  • BMI
  • Africa
  • children
  • childhood obesity

Cite this

Diouf, Adama ; Adom, Theodosia ; Aouidet, Abdel ; El Hamdouchi, Asmaa ; Joonas, Noorjehan I ; Loechl, Cornelia U ; Leyna, Germana H ; Mbithe, Dorcus ; Moleah, Thabisile ; Monyeki, Andries ; Nashandi, Hilde Liisa ; Reilly, John J ; Somda, Serge MA. / Body mass index vs deuterium dilution method for establishing childhood obesity prevalence, Ghana, Kenya, Mauritius, Morocco, Namibia, Senegal, Tunisia and United Republic of Tanzania. In: Bulletin of the World Health Organization . 2018 ; Vol. 96. pp. 772-781.
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abstract = "Objective -- To compare the World Health Organization (WHO) body mass index (BMI)-for-age definition of obesity against measured body fatness in African children. Methods -- In a prospective multicentre study over 2013 to 2017, we recruited 1516 participants aged 8 to 11 years old from urban areas of eight countries (Ghana, Kenya, Mauritius, Morocco, Namibia, Senegal, Tunisia and United Republic of Tanzania). We measured height and weight and calculated BMI-for-age using WHO standards. We measured body fatness using the deuterium dilution method and defined excessive body fat percentage as > 25{\%} in boys and > 30{\%} in girls. We calculated the sensitivity and specificity of BMI z-score > +2.00 standard deviations (SD) and used receiver operating characteristic analysis and the Youden index to determine the optimal BMI z-score cut-off for classifying excessive fatness. Findings -- The prevalence of excessive fatness was over three times higher than BMI-for-age-defined obesity: 29.1{\%} (95{\%} CI: 26.8 to 31.4; 441 children) versus 8.8{\%} (95{\%} CI: 7.5 to 10.4; 134 children). The sensitivity of BMI z-score > +2.00 SD was low (29.7{\%}, 95{\%} CI: 25.5 to 34.2) and specificity was high (99.7{\%}, 95{\%} CI: 99.2 to 99.9). The receiver operating characteristic analysis found that a BMI z-score +0.58 SD would optimize sensitivity, and at this cut-off the area under the curve was 0.86, sensitivity 71.9{\%} (95{\%} CI: 67.4 to 76.0) and specificity 91.1{\%} (95{\%} CI: 89.2 to 92.7). Conclusion -- While BMI remains a practical tool for obesity surveillance, it underestimates excessive fatness and this should be considered when planning future African responses to the childhood obesity pandemic.",
keywords = "World Health Organization, WHO, obsesity, public health, Ghana, Kenya, Mauritius, Moroco, Namibia, Senegal, Tunsia, Tanzania, body mass index, BMI, Africa, children, childhood obesity",
author = "Adama Diouf and Theodosia Adom and Abdel Aouidet and {El Hamdouchi}, Asmaa and Joonas, {Noorjehan I} and Loechl, {Cornelia U} and Leyna, {Germana H} and Dorcus Mbithe and Thabisile Moleah and Andries Monyeki and Nashandi, {Hilde Liisa} and Reilly, {John J} and Somda, {Serge MA}",
year = "2018",
month = "11",
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language = "English",
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journal = "Bulletin of the World Health Organization",
issn = "0042-9686",

}

Body mass index vs deuterium dilution method for establishing childhood obesity prevalence, Ghana, Kenya, Mauritius, Morocco, Namibia, Senegal, Tunisia and United Republic of Tanzania. / Diouf, Adama; Adom, Theodosia; Aouidet, Abdel; El Hamdouchi, Asmaa ; Joonas, Noorjehan I ; Loechl, Cornelia U ; Leyna, Germana H ; Mbithe, Dorcus; Moleah, Thabisile; Monyeki, Andries; Nashandi, Hilde Liisa ; Reilly, John J; Somda, Serge MA.

In: Bulletin of the World Health Organization , Vol. 96, 01.11.2018, p. 772-781.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Body mass index vs deuterium dilution method for establishing childhood obesity prevalence, Ghana, Kenya, Mauritius, Morocco, Namibia, Senegal, Tunisia and United Republic of Tanzania

AU - Diouf, Adama

AU - Adom, Theodosia

AU - Aouidet, Abdel

AU - El Hamdouchi, Asmaa

AU - Joonas, Noorjehan I

AU - Loechl, Cornelia U

AU - Leyna, Germana H

AU - Mbithe, Dorcus

AU - Moleah, Thabisile

AU - Monyeki, Andries

AU - Nashandi, Hilde Liisa

AU - Reilly, John J

AU - Somda, Serge MA

PY - 2018/11/1

Y1 - 2018/11/1

N2 - Objective -- To compare the World Health Organization (WHO) body mass index (BMI)-for-age definition of obesity against measured body fatness in African children. Methods -- In a prospective multicentre study over 2013 to 2017, we recruited 1516 participants aged 8 to 11 years old from urban areas of eight countries (Ghana, Kenya, Mauritius, Morocco, Namibia, Senegal, Tunisia and United Republic of Tanzania). We measured height and weight and calculated BMI-for-age using WHO standards. We measured body fatness using the deuterium dilution method and defined excessive body fat percentage as > 25% in boys and > 30% in girls. We calculated the sensitivity and specificity of BMI z-score > +2.00 standard deviations (SD) and used receiver operating characteristic analysis and the Youden index to determine the optimal BMI z-score cut-off for classifying excessive fatness. Findings -- The prevalence of excessive fatness was over three times higher than BMI-for-age-defined obesity: 29.1% (95% CI: 26.8 to 31.4; 441 children) versus 8.8% (95% CI: 7.5 to 10.4; 134 children). The sensitivity of BMI z-score > +2.00 SD was low (29.7%, 95% CI: 25.5 to 34.2) and specificity was high (99.7%, 95% CI: 99.2 to 99.9). The receiver operating characteristic analysis found that a BMI z-score +0.58 SD would optimize sensitivity, and at this cut-off the area under the curve was 0.86, sensitivity 71.9% (95% CI: 67.4 to 76.0) and specificity 91.1% (95% CI: 89.2 to 92.7). Conclusion -- While BMI remains a practical tool for obesity surveillance, it underestimates excessive fatness and this should be considered when planning future African responses to the childhood obesity pandemic.

AB - Objective -- To compare the World Health Organization (WHO) body mass index (BMI)-for-age definition of obesity against measured body fatness in African children. Methods -- In a prospective multicentre study over 2013 to 2017, we recruited 1516 participants aged 8 to 11 years old from urban areas of eight countries (Ghana, Kenya, Mauritius, Morocco, Namibia, Senegal, Tunisia and United Republic of Tanzania). We measured height and weight and calculated BMI-for-age using WHO standards. We measured body fatness using the deuterium dilution method and defined excessive body fat percentage as > 25% in boys and > 30% in girls. We calculated the sensitivity and specificity of BMI z-score > +2.00 standard deviations (SD) and used receiver operating characteristic analysis and the Youden index to determine the optimal BMI z-score cut-off for classifying excessive fatness. Findings -- The prevalence of excessive fatness was over three times higher than BMI-for-age-defined obesity: 29.1% (95% CI: 26.8 to 31.4; 441 children) versus 8.8% (95% CI: 7.5 to 10.4; 134 children). The sensitivity of BMI z-score > +2.00 SD was low (29.7%, 95% CI: 25.5 to 34.2) and specificity was high (99.7%, 95% CI: 99.2 to 99.9). The receiver operating characteristic analysis found that a BMI z-score +0.58 SD would optimize sensitivity, and at this cut-off the area under the curve was 0.86, sensitivity 71.9% (95% CI: 67.4 to 76.0) and specificity 91.1% (95% CI: 89.2 to 92.7). Conclusion -- While BMI remains a practical tool for obesity surveillance, it underestimates excessive fatness and this should be considered when planning future African responses to the childhood obesity pandemic.

KW - World Health Organization

KW - WHO

KW - obsesity

KW - public health

KW - Ghana

KW - Kenya

KW - Mauritius

KW - Moroco

KW - Namibia

KW - Senegal

KW - Tunsia

KW - Tanzania

KW - body mass index

KW - BMI

KW - Africa

KW - children

KW - childhood obesity

U2 - 10.2471/BLT.17.205948

DO - 10.2471/BLT.17.205948

M3 - Article

VL - 96

SP - 772

EP - 781

JO - Bulletin of the World Health Organization

T2 - Bulletin of the World Health Organization

JF - Bulletin of the World Health Organization

SN - 0042-9686

ER -