Table 2: Characteristics of participants, by result of screening for traumatic brain injury
CharacteristicResult of screening, no. (%) of participants
Negative
n = 61
Positive
n = 50
Total
n = 111
p value
Age,* yr, mean ± SD55.4 ± 11.252.8 ± 11.854.2 ± 11.50.2
< 40 6/61 (10) 6/50 (12)12/111 (11)
40–5930/61 (49)26/50 (52)56/111 (50)
≥ 5925/61 (41)18/50 (36)43/111 (39)
Ethnic origin† (n = 110)0.5
White, Caucasian45/61 (74)39/49 (80)84/110 (76)
Black, African, African American 6/61 (10) 0/49 (0) 6/110 (5)
Other10/61 (16)10/49 (20)20/110 (18)
Highest level of education (n = 110)0.4
Some high school or less23/61 (38)25/49 (51)48/110 (44)
High school or equivalent12/61 (20) 7/49 (14)19/110 (17)
Vocational training, college or above26/61 (43)17/49 (35)43/110 (39)
Homelessness duration, mo, median (IQR) (n = 83)18 (9.0–60.0)30 (7.3–88.5)20.5 (8.0–72.0)0.5
History of arrest (n = 87)33/52 (63)30/35 (86) 63/87 (72)0.02
Lifetime history of substance abuse (n = 110)36/60 (60)34/50 (68)70/110 (64)0.4
Lifetime history of mental illness (n = 103)23/57 (40)28/46 (61)51/103 (50)0.04
Lifetime history of seizures (n = 86)14/45 (31)19/41 (46) 33/86 (38)0.2
Parental history of substance abuse (n = 95)19/55 (35)22/40 (55) 41/95 (43)0.05

Note: IQR = interquartile range, SD = standard deviation.
*The youngest participant was 27 years of age, and the oldest was 81. 
†Categories as listed in the original Brain Injury Screening Questionnaire,25 which was developed in the United States. χ2 test was used to compare white versus nonwhite (black, African, African American and other combined).