Table 1.
Descriptive analyses of the factors associated with screen-time change (min/d) from age 11 to 15 years—1993 Pelotas (Brazil) Birth Cohort Study (N = 4,118)
| Variable | n | Screen time at baseline (min/d) | Mean change (min/d) | p value |
|---|---|---|---|---|
| Sex | <.001 | |||
| Male | 2,054 | 265 | 74 | |
| Female | 2,164 | 248 | 46 | |
| Skin color | .03 | |||
| White | 2,692 | 263 | 67 | |
| Mixed | 602 | 241 | 50 | |
| Black | 765 | 242 | 46 | |
| Assets index | <.001 | |||
| Poorest | 1,352 | 238 | 29 | |
| Intermediate | 1,363 | 252 | 60 | |
| Wealthiest | 1,360 | 282 | 95 | |
| Maternal schooling (years) | <.001 | |||
| 0–4 | 1,067 | 239 | 20 | |
| 5–8 | 1,819 | 253 | 55 | |
| 9–11 | 903 | 272 | 91 | |
| ≥12 | 405 | 287 | 115 | |
| Adolescent failure in school | <.001 | |||
| No | 2,643 | 270 | 77 | |
| Yes | 1,552 | 235 | 30 | |
| Time spent outside compared with peers | .25 | |||
| Mostly outdoor | 1,096 | 251 | 67 | |
| Mostly indoor | 3,111 | 259 | 58 | |
| Fear of living in the neighborhood | .22 | |||
| No | 3,538 | 254 | 62 | |
| Yes | 671 | 270 | 51 | |
| Relationship with parents | .02 | |||
| Fair | 1,453 | 250 | 50 | |
| Excellent | 2,666 | 262 | 67 | |
| BMI at age 11 years | .18 | |||
| Normal | 2,905 | 249 | 56 | |
| Overweight | 852 | 269 | 69 | |
| Obese | 456 | 277 | 69 | |
| Active at age 11 years | .89 | |||
| No | 2,949 | 254 | 60 | |
| Yes | 1,151 | 261 | 59 | |
| Diet rich in fat | .11 | |||
| No | 2,667 | 249 | 56 | |
| Yes | 1,547 | 269 | 67 | |
| Sexual maturation | .004 | |||
| Least | 1,849 | 252 | 49 | |
| Most | 1,525 | 270 | 71 | |
| Total | 4,218 | 256 | 60 | — |
BMI = body mass index.