Table 1.

Demographic and clinical characteristics of the study population (n = 838).

Variable	All	Male	Female
Sex, n (%)		405 (48.3)	433 (51.7)
Race, n (%)
Caucasian	698 (83.3)	343 (84.7)	355 (82.0)
African-American	125 (14.9)	58 (14.3)	67 (15.5)
Other	1 (0.1)	0 (0)	1 (0.2)
Unknown	14 (1.7)	4 (1.0)	10 (2.3)
Height z-score, mean (s.d.)	0.32 (0.97)	0.35 (0.99)	0.28 (0.95)
Weight z-score, mean (s.d.)	0.51 (0.97)	0.52 (0.99)	0.49 (0.94)
BMI z-score, mean (s.d.)	0.46 (0.95)	0.45 (0.97)	0.47 (0.94)