Table 3

Percentage increase in odds of overweight and obesity per calendar year from 1994 to 2013, by decade, sex and age group

Subgroup	Number of observations	Percentage increase per calendar year*
Subgroup	Number of observations	Per cent	95% CI	z, p value
All	507 483	4.2	3.9 to 4.5	28.4, <0.001
Decade
Decade 1 (1994–2003)	197 757	8.1	7.2 to 8.9	20.1, <0.001
Decade 2 (2004–2013)	309 726	0.4	−0.2 to 1.1	1.3, 0.2
Year×Decade interaction				−13.6, <0.001
Sex
Boys	259 612	4.5	4.0 to 4.9	21.5, <0.001
Girls	247 871	3.7	3.3 to 4.2	16.8, <0.001
Year×Sex interaction	507 483			−1.2, 0.2
Boys
Decade 1†	102 335	8.6	7.4 to 9.7	15.3, <0.001
Decade 2†	157 277	0.5	−0.5 to 1.4	1.0, 0.3
Year×Decade interaction	259 612			−10.5, <0.001
Girls
Decade 1†	95 422	7.5	6.3 to 8.8	12.5, <0.001
Decade 2†	152 449	0.5	−0.5 to 1.6	1.1, 0.3
Year×Decade interaction	247 871			−8.4, <0.001
Age group (years)
2–5	136 857	2.4	1.9 to 2.9	9.6, <0.001
6–10	162 976	5.1	4.5 to 5.7	17.4, <0.001
11–15	207 650	5.7	5.2 to 6.3	20.5, <0.001
Year×Age group interaction	507 483			1.7, 0.08
2–5 years
Decade 1†	66 172	3.5	2.2 to 4.7	5.6, <0.001
Decade 2†	70 685	0.1	−1.2 to 1.5	0.2, 0.8
Year×Decade interaction	136 857			−4.5, <0.001
6–10 years
Decade 1†	65 923	9.9	8.2 to 11.6	12.2, <0.001
Decade 2†	97 053	−1.2	−2.5 to 0.1	−1.8, 0.08
Year×Decade interaction	162 976			−10.6, <0.001
11–15 years
Decade 1†	65 662	12.0	10.3 to 13.7	14.6, <0.001
Decade 2†	141 988	2.6	1.4 to 3.8	4.3, <0.001
Year×Decade interaction	207 650			−10.2, <0.001‡

*Analyses are based on multilevel models including level for child and practice, adjusting for age and sex. Values represent the percentage increase in odds of overweight (including obesity) per calendar year, in the full sample and in subgroups by decade, sex and age group.
†Decade 1, 1994–2003; decade 2, 2004–2013. ‡Presented results are from a model adjusted for sex only (model including age as a covariate failed to converge).