Table 1.

Baseline characteristics of the study subjects

	Male (N=240)	Female (N=293)	All Subjects (N=533)
Developmental Characteristics
Chronological Age (yr)	13.7 (1.8)	12.8 (1.7)	13.2 (1.8)
Skeletal age (yr)	13.8 (2.3)	13.3 (2.0)	13.5 (2.2)
Sexual maturation
Tanner 1	24 (10%)	26 (9%)	50 (9%)
Tanner 2	47 (20%)	45 (15%)	92 (17%)
Tanner 3	31 (13%)	58 (20%)	89 (17%)
Tanner 4	48 (20%)	74 (25%)	122 (23%)
Tanner 5	90 (38%)	90 (31%)	180 (34%)
Anthropometric Characteristics
Height Z-score	0.2 (0.8)	0.2 (0.8)	0.2 (0.8)
Weight Z-score	0.3 (0.8)	0.5 (0.8)	0.4 (0.8)
BMI Z-score	0.3 (0.9)	0.5 (0.8)	0.4 (0.8)
DXA Z-score
Whole body less head BMC	0.0 (1.0)	0.2 (0.9)	0.1 (1.0)
Whole body less head BMD	0.1 (0.9)	0.2 (0.9)	0.1 (0.9)
AP spine BMC	−0.1 (1.0)	0.1 (1.0)	0.0 (1.0)
AP spine BMD	−0.1 (1.0)	0.0 (1.0)	0.0 (1.0)
Hip total BMC	0.0 (1.0)	0.1 (1.0)	0.1 (1.0)
Hip total BMD	0.0 (1.0)	0.1 (1.0)	0.1 (1.0)
Hip neck BMC	0.0 (0.9)	0.1 (0.9)	0.1 (0.9)
Hip neck BMD	0.0 (1.0)	0.1 (1.0)	0.0 (1.0)
1/3 forearm BMC	−0.1 (0.9)	0.1 (0.9)	0.0 (0.9)
1/3 forearm BMD	−0.1 (1.0)	0.1 (1.1)	0.0 (1.1)

Continuous variables are shown as mean (standard deviation).

Categorical variables are N (%).