Table 1.

Characteristics of 100 study participants, overall and by gender^*

Characteristic	Overall	Females	Males
N (%)	100 (100.0)	55 (55.6)	44 (44.4)
Age, years	15.7 (1.2)	15.8 (1.3)	15.5 (1.0)
BMI, kg/m2	21.6 (3.5)	22.0 (4.0)	21.1 (2.8)
Melatonin level, ng/mL	72.3	71.4	71.2
Creatinine level, mg/dL	158.6	152.5	165.0
Age at first menstrual period, median (range)†	N/A	12 (9–14)	N/A
Caucasian (%)	67 (67.8)	33 (61.1)	33 (75.0)
Reported tobacco use	2 (2.0)	0 (0.0)	2 (4.8)
Reported alcohol use in past 30 days	18 (18.6)	11 (20.0)	7 (17.9)
Current OC Use†	N/A	5 (9.3)	N/A
Exercise 4 or more hours/week	67 (67.1)	35 (64.8)	32 (76.2)
Use of sleep aid in past 3 months	8 (8.0)	6 (10.9)	2 (4.6)

^*One individual did not provide data on gender but was retained in all analyses not stratified by sex

^†Females only