Table 2.
Characteristics of the Longitudinal Cohort
| Characteristic | Group 1 (I→IV/V adolescents) (n=27) | Group 2 (II/III→IV/V adolescents) (n=27) | Group 3 (V→adults) (n=24) | ANOVA P value for group comparison |
|---|---|---|---|---|
| Baseline age, yr | 8.6±1.4a | 10.3±1.8b | 16.5±1.8c | <0.001 |
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| Age at follow-up, yr | 17.1±3.2a | 16.2±2.2a | 21.8±2.0b | <0.001 |
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| Baseline BMI SD score | 1.07±1.01a | 1.72±1.04b | 1.74±0.98b | 0.028 |
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| Race | ||||
| Non-Hispanic White, % | 77.8 | 51.9 | 66.7 | 0.133 |
| Non-Hispanic Black, % | 22.2 | 48.1 | 33.3 | |
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| Male sex, % | 63.0 | 37.0 | 54.2 | 0.154 |
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| Baseline body fat, % | 26.4±10.7a | 39.4±12.0b | 34.3±11.6b | <0.001 |
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| Follow-up body fat, % | 32.1±14.4 | 37.7±12.1 | 35.4±12.9 | 0.301 |
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| Change in body fat, % | 5.7±9.2a | −1.7±8.1b,c | 1.2±7.2a,c | 0.006 |
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| Baseline testosterone (in male), ng/dL | 12.1±4.0a | 40.2±47.1a | 352±151.5b | <0.001 |
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| Follow-up testosterone (in male), ng/dL | 425.4±242.1 | 375.7±118.5 | 471.4±161.4 | 0.499 |
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| Baseline estradiol (in female), pg/mL | 9.2±6.2a | 23.3±38.9a | 60.9±24.8b | 0.001 |
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| Follow-up estradiol (in female), pg/mL | 104.6±48.5 | 94.8±96.9 | 111.5±110.4 | 0.888 |
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| Baseline first-phase insulin secretion, μU/mL/15 min | 42.7±36.5a | 129.5±129.7b | 94.8±68.2b | 0.002 |
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| Follow-up first-phase insulin secretion, μU/mL/15 min | 55.7±36.3a | 128.2±106.1b | 92.0±64.3a,b | 0.001 |
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| Baseline steady-state insulin secretion, μU/mL/60 min | 72.4±41.9a | 162.5±131.9b | 140.1±72.9b | 0.001 |
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| Follow-up steady-state insulin secretion, μU/mL/60 min | 96.7±44.0a | 183.0±131.8b | 127.8±65.3a | 0.003 |
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| Baseline insulin sensitivity, mg/kg/min/μU/mL | 12.5±13.1a | 8.3±7.0b | 5.7±3.3b | <0.001 |
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| Follow-up insulin sensitivity, mg/kg/min/μU/mL | 8.9±7.5 | 6.6±9.0 | 7.6±6.1 | 0.542 |
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| Change in first-phase insulin secretion, μU/mL/15 min | 13±33.5 | −0.8±115.3 | −2.7±70.9 | 0.740 |
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| Change in steady-state insulin secretion, μU/mL/60 min | 24.3±41.2 | 24.5±134 | −12.3±76 | 0.274 |
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| Change in insulin sensitivity, mg/kg/min/μU/mL | −13.6±13.3a | −1.8±8.7b | 1.8±6.1b | <0.0001 |
Values are expressed as mean±standard deviation. P values for comparisons between groups are not adjusted for any covariates. Roman numerals in group description refer to pubertal development groups at baseline and follow-up. Girls with Tanner breast stage 1 and boys with testes ≤3 mL were considered pre-pubertal and classified as pubertal group I. Girls with Tanner breast stage 2 and boys with testes >3 to <10 mL were considered to be in early puberty and classified as pubertal group II. Girls with Tanner breast stage 3 and boys with testes ≥10 to <15 mL were considered to be in mid-puberty and classified as pubertal group III. Girls with Tanner breast stage 4 and boys with testes ≥15 to <25 mL were considered to be in late puberty and classified as pubertal group IV. Girls with Tanner breast stage 5 and boys with testes ≥25 mL were considered end-pubertal and classified as pubertal group V. Adult participants (age >18 years) had all achieved pubertal groups IV or V when last examined. Group 1 was pre-pubertal (pubertal group I) at baseline and late-pubertal (pubertal groups IV or V) at follow-up, group 2 was early-pubertal (pubertal groups II or III) at baseline and late-pubertal (pubertal groups IV or V) at follow-up, and group 3 was late-pubertal (pubertal groups IV or V) at baseline and studied again at follow-up as adults 4 to 10 years later.
ANOVA, analysis of variance; BMI, body mass index; SD, standard deviation.
Values followed by different superscripted letters on the same line were significantly different (P≤0.05).