Table 1

Prevalence of severe obesity by international and UK90 proposed definitions

Sex	Boys				Girls
	4–5		10–11		4–5		10–11
Age group	Per cent	n	Per cent	n	Per cent	n	Per cent	n
2006/2007
IOTF morbid obesity (boys 2.93 SDs, girls 2.822 SDs)	1.7	3685	0.8	1737	2.0	4203	0.9	1838
≥99.6th centile UK90 (2.67 SDs)	2.7	5903	3.6	8107	2.0	4267	2.5	5330
≥99.87th centile UK90 (3 SDs)	1.7	3810	1.3	3020	1.2	2487	1.0	2124
≥99.98th centile UK90 (3.5 SDs)	0.8	1837	0.1	312	0.4	941	0.2	339
2012/2013
IOTF morbid obesity (boys 2.93 SDs, girls 2.822 SDs)	1.5	4400	0.8	2102	1.8	5287	1.0	2503
≥99.6th centile UK90 (2.67 SDs)	2.3	6956	3.9	9886	1.9	5360	2.9	6889
≥99.87th centile UK90 (3 SDs)	1.5	4435	1.5	3729	1.1	3113	1.2	2742
≥99.98th centile UK90 (3.5 SDs)	0.7	2152	0.2	392	0.4	1194	0.2	428