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Table 1 Characteristics of the study population and dropout population

From: Associations between serum levels of insulin-like growth factor-I and bone mineral acquisition in pubertal children: a 3-year follow-up study in Hamamatsu, Japan

 Study populationDropout population
BaselineFollow-upaBaseline vs follow-upBaselinebStudy vs dropout populations
Boys, N = 121Girls, N=133bBoys vs girlsBoys, N = 121Girls, N = 133BoysGirlsBoys, N = 81Girls, N = 73BoysGirls
Age (years)11.2 ± 0.311.2 ± 0.3ns14.2 ± 0.314.2 ± 0.3< 0.001< 0.00111.2 ± 0.311.2 ± 0.3nsns
Height (cm)141 ± 6143 ± 70.007162 ± 6155 ± 5< 0.001< 0.001142 ± 6143 ± 7nsns
Weight (kg)34.7 ± 7.435.1 ± 5.9ns49.9 ± 8.447.0 ± 5.8< 0.001< 0.00135.4 ± 7.135.5 ± 8.7nsns
TBLH BMC (g)644 ± 140700 ± 1620.0031143 ± 2511044 ± 180< 0.001< 0.001656 ± 121690 ± 178nsns
TB bone area (cm2)1288 ± 1741336 ± 1860.0361789 ± 2111680 ± 153< 0.001< 0.0011305 ± 1551329 ± 195nsns
TBLH aBMD (g/cm2)0.609 ± 0.0400.624 ± 0.0500.0050.739 ± 0.0740.720 ± 0.062< 0.001< 0.0010.613 ± 0.0370.618 ± 0.057nsns
TB BMAD (g/cm3)0.081 ± 0.0080.080 ± 0.006ns0.075 ± 0.0040.078 ± 0.005< 0.0010.0030.081 ± 0.0070.080 ± 0.007nsns
25-hydroxyvitamin D (ng/mL)34.3 ± 7.829.6 ± 7.7< 0.001        
IGF-I (ng/mL)198 ± 80281 ± 81< 0.001        
Sedentary behavior (media use), N (%)           
< 1 h/day29 (24)33 (25)ns        
≥1, < 2 h/day54 (45)63 (47)        
≥ 2, < 3 h/day20 (17)29 (22)        
≥ 3, < 4 h/day11 (9)6 (5)        
≥ 4 h/day7 (6)2 (2)        
Pubic hair appearance, N (%)
<Grade 50 (0)10 (8)< 0.001        
Grade 58 (7)36 (27)        
No appearance113 (93)87 (65)        
  1. N number, ns not significant, TBLH total body less head, BMC bone mineral content, TB total body, aBMD areal bone mineral density,
  2. BMAD bone mineral apparent density as an estimate of volumetric bone mineral density, IGF-I insulin-like growth factor-I
  3. Values represent mean ± SD or N (%)
  4. aPaired t test was used to assess the difference between baseline and follow-up surveys
  5. bP value calculated with unpaired t test or Mann-Whitney U test. P < 0.05 was considered statistically significant