Subgroup | Number of observations | Percentage increase per calendar year* | ||
---|---|---|---|---|
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).