A single survey team including three nurse observers carried out all measurements during school terms between October 2004 and February 2007; each measured approximately one-third of all children in each ethnic group and visited schools in different parts of London, Leicester and Birmingham in rotation. The observers received initial training in all measurement techniques in accordance with standard recommendations.24 (link) The observers’ measurement performance was reviewed before the study and at regular intervals during the study. For each anthropometric measure, a single measurement was obtained for each child. Height was measured to the last complete millimetre using a portable stadiometer (Chasmors Ltd, London, UK). Weight was measured to the nearest 0.1 kg using an electronic digital scale (Tanita Inc., Tokyo, Japan). Waist circumference was measured at the mid-point between the lower margin of the ribs and the pelvic crest in the mid-axillary line. Skinfold thickness was measured in subscapular, suprailiac, biceps and triceps locations (right sided) using a Holtain skinfold caliper. Sum of all skinfolds was based on the sum of all four measurements of skinfold thickness, sum of trunk skinfolds on the sum of subscapular and suprailiac skinfolds and sum of limb skinfolds on the sum of biceps and triceps skinfolds. Leg to arm bioimpedance (right sided) was measured using the Bodystat 1500 bioimpedance monitor (Bodystat Ltd, Isle of Man, UK). Fat free mass was derived using an equation derived specifically for children of a similar age using DXA validation:25

Fat mass was obtained by subtracting fat free mass from total body weight.
Pubertal status was assessed in girls using the Tanner breast development scoring system.26