Table 1. Descriptive characteristics of Male Shift Worker Study participants according to work shift status.

Covariate	Day Shift		Night Shift
	N	%*	N	%*
Age group (years) †
20 – 25	20	13	25	13
26 – 30	32	20	55	30
31 – 35	24	15	25	13
36 – 40	31	20	37	20
41 – 45	19	12	13	7
46 – 50	14	9	15	8
51 – 55	18	11	15	8
Body mass index (wt (kg)/ht (m)2)
< 18	1	1	0	0
18 – 25	65	41	67	36
25 – 30	91	57	112	61
> 30	1	1	6	3
Alcohol consumption§
Any	45	28	73	39
Number of drinks
0	113	71	114	62
1	17	11	18	10
2	15	9	17	9
3 or more	13	8	36	19
Tobacco use (any) §
Any	13	8	20	11
By type
Cigarettes	9	6	18	20
Patch	2	1	1	0
Other tobacco	3	2	2	1
Medication use (any§)
Psychotheraputics	14	9	9	5
Sedatives	1	1	4	2
Beta blockers	0	0	4	2
Thyroid medications	0	0	1	1
Steroids	1	1	1	1

^*Percent calculated from 158 day shift participants and 185 night shift participants

^†Calculated according to date of first urine collection

^§In the 24 hours ending the nighttime sleep period