. Author manuscript; available in PMC: 2018 Dec 6.

Published in final edited form as: Chronobiol Int. 2018 Sep 5;35(12):1702–1712. doi: 10.1080/07420528.2018.1508152

Table 1.

Cohort characteristics. The sleep cohort was matched by length of record, age, gender and race. Numbers for gender, race, and ethnicity correspond to percentages. Numbers for age, phecodes and visits correspond to mean (SD). P values are based on a student’s t-test.

	Sleep Cohort (n = 3652)	Matched Cohort (n = 3646)	P-value
Gender (male/female)	50.7/49.3	-	-
Race (black/white/other)	14.2/80.6/5.2	-	-
Age at visit	48.0 (13.7)	-	-
Total number of unique phecodes	54.0 (52.1)	27.7 (30.6)	2.9 · 10⁻¹⁴⁶
Number of visits	91.3 (111.1)	38.8 (60.4)	5.3 · 10⁻¹³³