Body Mass Index cut offs to define thinness in children and adolescents.( Cameron N BMJ2007, vol 335, 166-7).
Central to any science is measurement. Body Mass Index ( weight/height2 )is a measure of overweight and it is suggested that there is continuous monitoring from childhood through to the elderly. The strength and weakness of these measurements and identification of the limits or cut off points is that the tables are based on developed countries.
The validity of these is less good in impoverished countries.
Cole and his colleagues (Body Mass Index cut offs to define thinness in children and adolescents. BMJ 2007, vol 335 , 194-7 ) have looked at this in nearly 200,000 males and females between birth to 25 years living in Great Britain, The Netherlands, Singapore and the United States.
WHO defines grade 2 thinness as having a BMI of under 17.
Cole and his colleagues define body mass index at age 18 as 18.5 kg/m2 for WHO grade 1, 17 kg/m2 and 16kg/m2 for WHO grade 3. thinness.
As childhood mortality is related to malnutrition these are very important sets of information.
- Martin Eastwood