Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Descriptive characteristics of the study population.
| Socio-demographic characteristics | Total sample (n = 955) | Analytical sample (n = 892) |
|---|---|---|
| Age in years, mean (SD)a | 9.3 (1.8) | 9.3 (1.8) |
| Sex, n (%) | ||
| Boy | 461 (48.3) | 426 (47.8) |
| Girl | 494 (51.7) | 466 (52.2) |
| School grade, n (%) | ||
| Grade 1 | 261 (27.3) | 234 (26.2) |
| Grade 3 | 367 (38.4) | 341 (38.2) |
| Grade 5 | 327 (34.2) | 317 (35.5) |
| School type, n (%) | ||
| Public | 741 (77.6) | 690 (77.4) |
| Private | 214 (22.4) | 202 (22.6) |
Missing data for three children.
