Table 1. Population characteristics by long-term shift status.

Characteristic	Day Shifts (n = 34)	Afternoon Shifts (n = 23)	Night Shifts (n = 8)	Afternoon + Night Shifts (n = 31)
Age group (yrs)
<40 (n = 25)	6 (18%)	16 (70%)	3 (38%)	19 (61%)
40–49 (n = 25)	16 (47%)	5 (22%)	4 (50%)	9 (29%)
>50 (n = 15)	12 (35%)	2 (9%)	1 (13%)	3 (10%)
Sex
Male (n = 42)	18 (53%)	17 (74%)	7 (88%)	24 (77%)
Female (n = 23)	16 (47%)	6 (26%)	1 (13%)	7 (23%)
Race
European American (n = 46)	19 (56%)	21 (91%)	6 (75%)	27 (87%)
African American (n = 19)	15 (44%)	2 (9%)	2 (25%)	4 (13%)
Education
≤High School (n = 10)	5 (15%)	3 (13%)	2 (25%)	5 (16%)
College (n = 19)	9 (26%)	6 (26%)	4 (50%)	10 (32%)
>College (n = 36)	20 (59%)	14 (61%)	2 (25%)	16 (52%)
Marital status
Single (n = 12)	6 (18%)	3 (13%)	3 (38%)	6 (19%)
Married (n = 43)	21 (62%)	17 (74%)	5 (63%)	22 (71%)
Divorced (n = 10)	7 (21%)	3 (13%)	0 (0%)	3 (10%)
Rank
Police officer (n = 40)	16 (47%)	16 (70%)	8 (100%)	24 (77%)
Sergeant/Lieutenant (n = 10)	8 (24%)	2 (9%)	0 (0%)	2 (6%)
Captain/Detective (n = 15)	10 (29%)	5 (22%)	0 (0%)	5 (16%)
Years worked
1–5 (n = 12)	2 (6%)	6 (26%)	4 (50%)	10 (32%)
6–10 (n = 7)	2 (6%)	4 (17%)	1 (13%)	5 (16%)
11–15 (n = 18)	9 (26%)	7 (30%)	2 (25%)	9 (29%)
>15 (n = 28)	21 (62%)	6 (26%)	1 (13%)	7 (23%)
Shift changes/year (mean ± SD)	5.0 ± 8.4	7.4 ± 6.7	2.9 ± 3.0	6.3 ± 6.2
Mean % time on shift (mean ± SD)	90.1 ± 13.5	80.0 ± 17.5	77.7 ± 17.6	85.1 ± 13.1
Impact of Events Scale (mean ± SD)	29 ± 15	18 ± 15	13 ± 12	17 ± 15
Life Events Scale (mean ± SD)	3 ± 3	2 ± 2	3 ± 2	2 ± 2

Shift assigned represents >50% of work hours during study period. SD = standard deviation. Column percentages not totaling 100% are due to rounding.