TABLE 1.

Descriptive characteristics of Shift Worker Study participants according to work shift status and gender

Covariate	Day Shift				Night Shift
	Female		Male		Female		Male
	N	%*	N	%**	N	%*	N	%**
Age group (years) †
20 – 25	20	13	20	13	25	15	25	14
26 – 30	25	16	32	20	31	18	55	30
31 – 35	26	17	24	15	34	20	25	14
36 – 40	39	26	31	20	37	21	36	20
41 – 45	41	27	19	12	42	24	13	7
46 – 50	1	1	14	9	3	2	15	8
51 – 55	0	0	18	11	0	0	13	7
Body mass index (wt (kg)/ht (m)2)
< 18	0	0	1	1	0	0	0	0
18 – 25	97	64	65	41	95	55	67	37
25 – 30	54	35	91	58	75	44	109	60
> 30	1	1	1	1	2	1	6	3
Number of Alcoholic Beverages Consumed§
0	109	72	113	71	125	73	112	61
1	24	16	17	11	17	10	17	9
2	12	8	15	9	10	6	17	9
3 or more	7	5	13	8	20	12	36	20
Tobacco use (any) §
Any	10	7	13	8	16	9	20	11
By type
Cigarettes	10	7	9	6	16	9	18	10
Patch	0	0	2	1	0	0	1	1
Medication use (any§)
Psychotheraputics	20	13	14	9	16	9	8	4
Sedatives	2	1	1	1	1	1	4	2
Beta blockers	2	1	0	0	3	2	3	2
Thyroid medications	11	7	0	0	11	6	1	1
Steroids	7	5	1	1	7	4	1	1

^*Percent calculated from 152 female day shift participants and 172 female night shift participants with nighttime sleep urine samples

^**Percent calculated from 158 male day shift participants and 182 male night shift participants with nighttime sleep urine samples

^†Calculated according to date of first urine collection

^§In the 24 hours ending the nighttime sleep period