The association of Apolipoprotein E allele 4 polymorphism with the recovery of sleep disturbance after mild traumatic brain injury

Purpose: Mild traumatic brain injury (mTBI) is a major public health concern. The apolipoprotein E (APOE) gene contains three polymorphisms, and the APOE4 polymorphism may affect several physiological states, such as the recovery from mTBI as well as sleep. This study aims to investigate the association between APOE4 with the recovery of sleep disturbance after mTBI. Methods: From May 2012 to Aug 2015, 189 mTBI patients completed baseline (1st week post-mTBI) and follow-up (6th week post-mTBI) sleep assessments that involved using the Pittsburgh Sleep Quality Index (PSQI). APOE genotypes were determined by sequencing the products of polymerase chain reaction from genomic DNA. Statistical analyses were performed using the Wilcox signed-rank or chi-square test. Results: Thirty-five (18.5%) participants were APOE4 carriers. At baseline, the demographic data and the severity of sleep disturbance were similar in both groups. APOE4 carriers demonstrated significant improvement in the overall PSQI score (8.34±3.9 at baseline and 7.43±3.99 at follow-up, p = 0.05) and scores of several PSQI subscales, including sleep disturbance, sleep latency, daytime dysfunction caused by sleepiness, and overall sleep quality, which was similar to APOE4 noncarriers. Conclusion: APOE4 is not associated with the recovery of sleep disturbance after mTBI.