Table 1.
Characteristics of participants by age and gender, Project HeartBeat!, 1991–1995 (N=556), % unless otherwise indicated
| Boys (n=277) | Girls (n=279) | |||||
|---|---|---|---|---|---|---|
| Variables | Aged 8 years (n=122) % | Aged 11 years (n=89) % | Aged 14 years (n=66) % | Aged 8 years (n=124) % | Aged 11 years (n=82) % | Aged 14 years (n=73) % |
| Descriptive characteristics | ||||||
| Sexual maturation | ||||||
| Pubic stage | ||||||
| 1 | 97.2 | 69.9 | 3.5 | 88.0 | 25.6 | 0.0 |
| 2 | 2.8 | 24.7 | 17.5 | 10.3 | 46.2 | 1.7 |
| 3 | 0.0 | 5.5 | 17.5 | 1.7 | 16.7 | 6.9 |
| 4 | 0.0 | 0.0 | 45.6 | 0.0 | 10.3 | 39.7 |
| 5 | 0.0 | 0.0 | 15.8 | 0.0 | 1.3 | 51.7 |
| Genital stage | Breast stage | |||||
| 1 | 93.4 | 47.9 | 1.8 | 90.8 | 13.9 | 0.0 |
| 2 | 6.6 | 45.2 | 7.0 | 7.6 | 48.1 | 0.0 |
| 3 | 0.0 | 6.8 | 28.1 | 1.7 | 25.3 | 14.8 |
| 4 | 0.0 | 0.0 | 40.4 | 0.0 | 10.1 | 24.6 |
| 5 | 0.0 | 0.0 | 22.8 | 0.0 | 2.5 | 60.7 |
| M (SD) | M (SD) | M (SD) | M (SD) | M (SD) | M (SD) | |
| Age (years) | 8.5 (0.3) | 11.5 (0.3) | 14.4 (0.1) | 8.5 (0.3) | 11.5 (0.4) | 14.4 (0.2) |
| Height (cm) | 131.6 (5.8) | 147.8 (7.1) | 166.6 (6.7) | 130.7 (6.8) | 147.9 (8.1) | 162.8 (5.4) |
| Weight (kg) | 29.7 (5.9) | 43.6 (11.5) | 57.8 (12.4) | 29.7 (8.0) | 42.0 (12.9) | 60.4 (14.5) |
| Nutrient intake per day | ||||||
| Energy (kcal) | 2277 (680) | 2323 (754) | 2796 (881) | 2026 (576) | 2193 (717) | 2190 (680) |
| Protein (g) | 82 (27) | 82 (29) | 102 (40) | 69 (25) | 77 (28) | 74 (27) |
| Protein (% kcal) | 14 (2) | 14 (2) | 14 (2) | 14 (2) | 14 (2) | 14 (2) |
| Carbohydrate (g) | 298 (91) | 303 (102) | 362 (107) | 274 (91) | 286 (94) | 293 (97) |
| Carbohydrate (% kcal) | 53 (6) | 52 (5) | 53 (7) | 54 (6) | 53 (6) | 54 (8) |
| Total fat (g) | 88 (32) | 91 (34) | 109 (42) | 77 (23) | 86 (32) | 85 (34) |
| Total fat (% kcal) | 34 (5) | 35 (5) | 35 (5) | 34 (5) | 35 (4) | 34 (7) |
| Saturated fat (g) | 33 (12) | 34 (12) | 41 (17) | 28 (9) | 32 (12) | 31 (12) |
| Saturated fat (% kcal) | 13 (2) | 13 (2) | 13 (2) | 13 (2) | 13 (2) | 12 (3) |
| Cholesterol (mg) | 255 (109) | 258 (123) | 310 (144) | 216 (102) | 251 (115) | 230 (104) |
| Fiber (g) | 14 (6) | 15 (6) | 17 (7) | 14 (5) | 14 (6) | 14 (5) |
| Calcium (mg) | 1196 (503) | 1146 (509) | 1438 (755) | 1020 (424) | 1109 (617) | 1077 (614) |
| Physical activity per day | ||||||
| TV viewing (min) | 102 (96) | 106 (93) | 95 (86) | 79 (92) | 119 (125) | 99 (104) |
| Moderate physical activity (min) | 14 (28) | 33 (58) | 27 (44) | 11 (18) | 11 (22) | 11 (23) |
| Vigorous physical activity (min) | 74 (81) | 61 (66) | 63 (70) | 59 (52) | 38 (48) | 44 (70) |
| Moderate-to-vigorous physical activity (min) | 87 (88) | 94 (80) | 90 (72) | 70 (56) | 50 (55) | 55 (73) |