Table III.
Participant Characteristics by Consistency of Study Website Use
| Infrequent Internet Use (n = 26) | Intermittent Internet Use (n = 31) | Consistent Internet Use (n = 25) | F or χ2 | Sig. | |
|---|---|---|---|---|---|
| Internet Use Patterns | |||||
| Number of overall visits | 3.6 (7.3) | 8.2 (9.8) | 62.0 (50.8) | NA | NA |
| Percentage of study periods web use | 21.8 (20.4) | 49.5 (18.0) | 90.0 (11.8) | NA | NA |
| Overall minutes of use | 18.6 (26.2) | 59.7 (44.4) | 274.4 (145.5) | NA | NA |
| Number of days between first and last sign-on | 216.2 (297.7) | 472.4 (191.5) | 630.6 (54.5) | NA | NA |
| Self-reported weekly use | 4.0A (2.7) | 4.60 A (4.6) | 7.9 B (5.2) | 4.42 | .02 |
| Demographics | |||||
| Age (years at randomization) | 15.5 (0.5) | 15.7 (0.6) | 15.7 (0.7) | 1.42 | .25 |
| Percentage white | 84.6% | 80.6% | 76.0% | .60 | .74 |
| Mother's education (percentage post-secondary education) | 73.9% | 82.8% | 79.2% | .60 | .74 |
| Distance between home and study meeting site | 12.6A (5.4) | 18.0B (10.1) | 13.6A (6.8) | 3.86 | .03 |
| Study adherence | |||||
| Team meeting attendance | 1.8A (1.9) | 2.1A (1.9) | 3.6B (2.2) | 6.59 | 0.00 |
| Number of self-monitoring postcards returneda | 19.6A (25.8) | 25.7A (29.8) | 46.7B (31.9) | 6.06 | 0.00 |
| Baseline behavioral characteristics | |||||
| Calcium intake (mg/day) | 915.1 (444.3) | 1080.8 (482.4) | 977.4 (495.2) | .89 | .41 |
| Fruit/vegetable servings/day | 3.3 (1.6) | 3.7 (2.2) | 4.2 (3.5) | .99 | .37 |
| Total physical activity (min/week) | 610.7 (718.5) | 445.2 (401.8) | 377.4 (308.4) | 1.47 | .24 |
| High impact activity (min/week) | 48.7 (122.4) | 115.8 (157.2) | 116.0 (128.8) | 2.09 | .13 |
| Strength/weight training (min/week) | 54.4 (186.8) | 27.3 (63.4) | 25.7 (86.4) | .46 | .63 |
| Screen time hours/day | 2.3 (1.4) | 2.3 (1.5) | 2.8 (2.1) | .73 | .49 |
Note. A, B superscripts denote groups that are significantly different. NA, not applicable.
aIt was possible for participants to complete and return 100 weekly self-monitoring postcards over the 2 years of the project; thus the numbers can be roughly interpreted as 20%, 26%, and 47% of the postcards returned among the infrequent, intermittent, and consistent internet users, respectively.