Table 1.
Characteristics of included studies.
| Characteristics | No. of studies | No. of children |
|---|---|---|
| Total | 53 | 122,395 |
| Age group (years) | ||
| 0−9 | 3 | 9,134 |
| 0−5 | 12 | 17,600 |
| 4−5 | 4 | 6,897 |
| 2−9 | 3 | 56,654 |
| 6−9 | 23 | 28,786 |
| 8−9 | 8 | 3,324 |
| Study | ||
| Cross-sectional | 49 | 112,688 |
| Cohort | 4 | 9,707 |
| Sample source | ||
| School-based | ||
| Public and private | 26 | 27,530 |
| Public | 7 | 6,421 |
| Population-based | ||
| Household | 15 | 78,505 |
| Maternity | 5 | 9,939 |
| Region | ||
| Brazil | 5 | 69,713 |
| North | 2 | 577 |
| Northeast | 11 | 13,147 |
| Southeast | 14 | 10,711 |
| South | 19 | 26,985 |
| Midwest | 2 | 1,262 |
| Decade | ||
| 1990sa | 4 | 10,313 |
| 2000s | 29 | 97,413 |
| 2010s | 20 | 14,669 |
| Limitations in methodological quality | ||
| Sample frame | 1 | 1,640 |
| Sampling | 11 | 10,390 |
| Sample size | 6 | 4,687 |
| Setting and participants description | 30 | 40,278 |
| Coverage of data analysis | 12 | 8,992 |
| Method for outcome measurement | 16 | 23,355 |
| Standardization of outcome measurement | 1 | 713 |
| Statistical analysis | 17 | 20,191 |
| Response rate | 42 | 112,279 |
a
Includes one study held in 1986.