Table 2.

Comparison of Summer and Fall–Winter Study Cohorts

Characteristic	Summer Cohort	Fall–Winter Cohort	P Value*
	N =362	N =539
	%
Women	45.6	46.6	.75
Age, y
17–25	8.6	7.7	.69
26–35	16.6	16.5
36–45	25.1	22.6
46–55	30.4	30.1
56–65	19.3	23.1
Race
White	21.3	24.1	.03
Black	76.0	69.8
Other	2.7	6.1
Service
General medicine, academic center's hospital	63.5	71.6	.002
General medicine, affiliated tertiary care hospital	19.9	19.5
Trauma, academic center's hospital	16.6	8.9
Region
West Philadelphia	39.0	35.0	.61
Other Philadelphia regions	42.5	43.6
Suburbs	11.9	13.6
Outside Pennsylvania	6.6	7.8

^*P values were calculated from χ² tests