Apolipoprotein E polymorphism and outcome after closed traumatic brain injury: influence of ethnic and regional differences.
OBJECTIVE
The presence of the apolipoprotein E-epsilon4 (APOE-epsilon4) allele is reported to be associated with poor outcome after traumatic brain injury (TBI). This study was performed to determine if the presence of the APOE-epsilon4 allele influenced outcome in a cohort of black patients with TBI who had homogeneous neuropathological findings.


METHODS
Venous blood was collected at the time of admission to determine the APOE genotype in black Zulu-speaking patients who presented with traumatic cerebral contusions. The frequency of the APOE-epsilon4 allele's appearance was correlated with outcome at a minimum of 6 months of follow up. Univariate and multivariate analyses were performed to determine independent risk factors and to control for confounding factors. In 110 black Zulu-speaking patients with traumatic cerebral contusions, genotypes for APOE were analyzed. Eleven of 45 (24.4%) with the APOE-epsilon4 allele experienced a poor outcome, compared with 10 (15.4%) of 65 without this allele (p = 0.34). Both patients with homozygous APOE-epsilon4 alleles experienced a good outcome (Glasgow Outcome Score 5). Univariate and multivariate analysis revealed no significant relationship in patients with the APOE-epsilon4 allele with regard to age, admission Glasgow Comas Scale score, contusion volume, type of neurosurgical management, and outcome. The risk of a poor outcome was, however, greater in patients with the APOE-epsilon4 allele (relative risk 1.59; 95% confidence interval 0.74-3.42).


CONCLUSIONS
The authors recorded no relationship between APOE-epsilon4 allele status and outcome after TBI in black patients. Given the high regional susceptibility to the APOE gene, further studies, possibly even community-based investigations and studies conducted in other geographic areas, are probably warranted.
Nathoo
Narendra
N
Department of Neurosurgery, Wentworth Hospital, Nelson R. Mandela School of Medicine, University of Natal, South Africa. nathoon@ccf.org
Chetry
Runjan
R
van Dellen
James R
JR
Connolly
Catherine
C
Naidoo
Richard
R
D000293:Adolescent; D000328:Adult; D001741:Black or African American; D053327:Apolipoprotein E4; D001057:Apolipoproteins E / Q000235:genetics*; D044383:Black People / Q000235:genetics*; D001930:Brain Injuries / Q000208:ethnology* / Q000235:genetics* / Q000628:therapy; D002648:Child; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D005838:Genotype; D016489:Head Injuries, Closed / Q000208:ethnology* / Q000235:genetics* / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011110:Polymorphism, Genetic / Q000235:genetics*; D013019:South Africa / Q000208:ethnology
D053327:Apolipoprotein E4; D001057:Apolipoproteins E