Table 1.
Characteristics of the Study Population
| Males | Females | ME | |||||
|---|---|---|---|---|---|---|---|
| Prepubertal (n = 27) | Postpubertal (n = 30) | Prepubertal (n = 28) | Postpubertal (n = 27) | Sex | Pubertal phase | Sex × pubertal phase | |
| Category | Mean ± SEM | Mean ± SEM | Mean ± SEM | Mean ± SEM | p | p | p |
| Age (years) | 8.6 ± 0.14a | 15.8 ± 0.13 | 8.5 ± 0.13a | 15.8 ± 0.14 | 0.89 | <0.0001 | 0.99 |
| BMI (kg/m2) | 19.2 ± 0.98a | 24.4 ± 0.93 | 19.1 ± 0.96a | 23.0 ± 0.98 | 0.71 | <0.0001 | 0.81 |
| Average daily caffeine consumption (mg/day) | 47.1 ± 15.6a | 98.9 ± 14.8 | 47.4 ± 15.3a | 63.3 ± 15.6 | 0.25 | 0.029 | 0.24 |
| Child race | 0.27 | 0.79 | 0.98 | ||||
| Asian, n (%) | 1 (4) | 1 (3) | 1 (4) | 1 (4) | |||
| Black or African American, n (%) | 2 (7) | 6 (21) | 5 (17) | 6 (22) | |||
| White, n (%) | 23 (85) | 22 (73) | 18 (64) | 19 (70) | |||
| Other or mixed race, n (%) | 1 (4) | 1 (3) | 1 (4) | 1 (4) | |||
| Parental education: | 0.86 | 0.63 | 0.48 | ||||
| High school, n (%) | 3 (11) | 3 (10) | 4 (15) | 4 (15) | |||
| Some college, n (%) | 6 (22) | 9 (30) | 6 (23) | 4 (15) | |||
| Completed college, n (%) | 13 (48) | 14 (47) | 11 (43) | 14 (52) | |||
| Graduate school, n (%) | 5 (19) | 4 (13) | 5 (19) | 5 (18) | |||
| Household income: | 0.78 | 0.43 | 0.99 | ||||
| <$30,000, n (%) | 0 (0) | 4 (16) | 3 (13) | 7 (25) | |||
| $30,000–$50000, n (%) | 4 (18) | 4 (16) | 5 (22) | 3 (11) | |||
| $50,000–$70,000, n (%) | 7 (30) | 5 (20) | 3 (13) | 5 (19) | |||
| $70–$110,000 | 6 (26) | 8 (32) | 8 (35) | 5 (19) | |||
| >$110,000, n (%) | 6 (26) | 4 (16) | 4 (17) | 7 (26) | |||
Participant characteristics are shown as mean (SEM) or n (%). For mean (SEM), ANOVA analyses were conducted, and for n (%), chi-squared analyses were conducted to determine ME and interactions of sex and pubertal phase. The p-values for ME and interactions are shown in the columns to the right.
a
Significantly different from postpubertal participants of the same sex (p < 0.05).
ANOVA, analysis of variance; BMI, body–mass index; ME, main effect.