Discordance of international adiposity classifications in Australian boys and girls - the LOOK study.
BACKGROUND
Various charts based on body mass index (BMI) and per cent body fat (%BF) are used to classify childhood body composition but outcomes may vary.


OBJECTIVE
The study investigated variation in incidences of childhood obesity as depicted by four classification charts.


METHODS
BMI and DXA-derived %BF were assessed in 741 children. Incidences of overweight and obesity were compared between two BMI charts and two bioelectrical impedance (BIA)-based %BF charts.


RESULTS
The International Obesity Task Force (IOTF)-adopted BMI chart designated 21%, 6% (boys), and 26%, 9% (girls) as overweight and obese, respectively. Corresponding figures using the USA CDC BMI chart were 27%, 11% (boys) and 27%, 12% (girls). Using a USA-derived %BF chart incidences were 17%, 2% (boys) and 21%, 8% (girls) and using a UK-derived %BF chart 51%, 24% (boys) and 53%, 36% (girls). Sensitivity of BMI varied according to the %BF reference chart.


CONCLUSIONS
In contrast to the BMI-based charts, there were considerable variations in depicted incidences of obesity between the %BF-based charts. These discordances were considered to result from previously reported variation within and between BIA and DXA %BF assessments underlying the charts. The present study highlights the need for valid, reliable, unchanging BIA and DXA procedures.
Faculty of Medicine, Australian National University, Canberra, ACT, Australia. rtelford@cominst.org.au
Richard D
RD
Telford
Ross B
RB
Cunningham
Robin M
RM
Daly
Graham J
GJ
Reynolds
Antony R A
AR
Lafferty
Karen J
KJ
Gravenmaker
Marc M
MM
Budge
Ahmad
A
Javaid
Shona L
SL
Bass
Rohan M
RM
Telford
D015502:Absorptiometry, Photon; D050154:Adiposity; D000367:Age Factors; D001315:Australia / Q000453:epidemiology; D001827:Body Height; D015992:Body Mass Index; D002648:Child; D017097:Electric Impedance; D005260:Female; D006801:Humans; D008297:Male; D009765:Obesity / Q000175:diagnosis* / Q000453:epidemiology; D012015:Reference Standards; D012016:Reference Values; D012107:Research Design / Q000592:standards; D012680:Sensitivity and Specificity; D012737:Sex Factors; D014481:United States