Study Report
Study Information
Basic Info
| Reference |
Kimbrel, N. A.,2015 PMID: 25709077
|
| Citation |
Kimbrel, N. A., et al. (2015). "EFFECT OF THE APOE epsilon4 ALLELE AND COMBAT EXPOSURE ON PTSD AMONG IRAQ/AFGHANISTAN-ERA VETERANS." Depress Anxiety 32(5): 307-315. |
| Phenotype |
Lifetime PTSD, PTSD symptom severity |
| Trauma |
Iraq/Afghanistan-era war |
| Study Design |
Case-control |
| Study Type |
Candidate gene association study, Gene-environment interaction study |
| Sample Size |
765 NHW and 859 NHB Iraq/Afghanistan-era veterans (total N=1,624) |
| SNP/Marker Size |
1 Variant |
| Predominant Ethnicity |
Black, Caucasian |
| Population |
765 non-Hispanic White (NHW) and 859 non-Hispanic Black (NHB) |
| Gender |
79.5% male |
| Age |
No detial information. |
Detail Info
| Sample Diagnosis |
DSM-IV-TR |
| Related Diagnostic Tools |
Trained clinical interviewers administered the Structured Clinical Interview for DSM-IV-TR Axis I Disorders (SCID-I) to determine psychiatric diagnoses. The Combat Exposure Scale (CES) is a brief self-report measure used to assess combat exposure. The Davidson Trauma Scale (DTS) was used to assess PTSD symptom severity. |
| Sample Status |
Participants were drawn from an ongoing multisite research study known as the Veterans Affairs (VA) Mid-Atlantic Mental Illness Research, Education and Clinical Center (MIRECC) Repository. To be eligible, participants had to have served in the U.S. military after September 11, 2001. |
| Controls Exposed |
Yes |
| Replication Size |
None |
| Result Summary |
The most common lifetime diagnoses were depression (39.2%), PTSD (38.4%), and alcohol dependence (24.38%). After correcting for multiple comparisons, no significant effects were observed on any of the outcomes among the NHW sample; however, within the NHB sample, significant gene x environment (G x E) interactions were observed for lifetime PTSD (P-value=.0029) and PTSD symptom severity (P-value= .0009). In each case, the APOE euro4 allele had no effect on the outcomes when combat exposure was low; however, when combat exposure was high, an additive effect was observed such that euro4 homozygotes exposed to high levels of combat reported the highest rates of PTSD (92%) and the worst symptom severity scores on the Davidson Trauma Scale (M=79.5). Although preliminary, these findings suggest that the APOE euro4 allele, in conjunction with exposure to high levels of combat exposure, may increase veterans' risk for developing PTSD. |
| Potential Biomarker |
None |
Genetic result reported by this study
Gene * Environment result reported by this study (count: 2)
| Marker |
Phenotype |
Related Gene |
Environment |
Statistical Values |
Author Comments |
Marker's Category |
|
APOE_euro4
|
PTSD symptom severity |
APOE |
Combat exposure (The Combat Exposure Scale, CES) |
APOE and combat exposure interaction to predict current PTSD symptom severity: P-value= .0009, with high combat exposure: P-value= .0011. |
No significant G x E effects were observed within the NHW sa......
No significant G x E effects were observed within the NHW sample. APOE and combat exposure also interacted to predict current PTSD symptom severity. Again, as the number of euro4 alleles increased, the mean severity score on the DTS increased by 10.25 points, but only among those with high combat exposure.
More...
|
Significant |
|
APOE_euro4
|
Lifetime PTSD |
APOE |
Combat exposure (The Combat Exposure Scale, CES) |
Interaction between APOE and combat exposure for lifetime PTSD diagnosis: P-value= .0029, with high combat exposure: P-value=.0077. |
No significant G x E effects were observed within the NHW sa......
No significant G x E effects were observed within the NHW sample. In contrast, significant G x E effects were observed for all three of the main outcomes examined in the NHB sample (all P's < .0083). A significant interaction between APOE and combat exposure was observed for lifetime PTSD diagnosis. For each additional euro4 allele, the odds of having a lifetime PTSD diagnosis increased by 1.61, but only among those with high combat exposure. The rates of lifetime PTSD among the high combat exposure group were 49.3% for participants with no euro4 alleles, 56.4% for those with one euro4 allele, and 92.3% for those with two euro4 alleles (Fig. 1).
More...
|
Significant |
