Compounding Effects of Traumatic Brain Injury, Military Status, and Other Factors on Pittsburgh Sleep Quality Index: A Meta-analysis

Perpetuating and protective factors in insomnia across racial/ethnic groups of veterans

Few studies have examined racial/ethnic differences in rates and correlates of insomnia among veterans. This study compared rates of insomnia and interest in sleep treatment among veterans of diverse racial/ethnic backgrounds. Consistent with the 3P model, we tested racial discrimination as a predictor of insomnia, with post-traumatic stress disorder symptoms and romantic partners as perpetuating and protective moderators of this association, respectively. A total of 325 veterans (N = 236 veterans of colour; 12% Asian, 36% Black, 14% Hispanic/Latine) completed questionnaires online from remote locations. Descriptive statistics were used to compare patterns across racial/ethnic groups. Linear regression was used to test moderators of the association between racial discrimination and insomnia severity. Overall, 68% of participants screened positive for insomnia: 90% of Asian; 79% of Hispanic/Latine; 65% of Black; and 58% of White participants. Of those, 74% reported interest in sleep treatment, and 76% of those with partners reported interest in including their partner in treatment. Racial discrimination and post-traumatic stress disorder were correlated with more severe insomnia, while romantic partners were correlated with less severe insomnia. Only post-traumatic stress disorder moderated the association between racial discrimination and insomnia severity. Rates of insomnia were highest among Asian and Hispanic/Latine participants, yet these groups were among the least likely to express interest in sleep treatment. Racial discrimination may exacerbate insomnia symptoms among veterans, but only among those who do not already have disturbed sleep in the context of post-traumatic stress disorder. Romantic partners may serve as a protective factor in insomnia, but do not seem to mitigate the impact of racial discrimination.

The association between long-term exposure to outdoor artificial light at night and poor sleep quality among Chinese veterans: A multi-city study

BACKGROUND

A handful of previous studies have reported the association between exposure to outdoor artificial light at night (ALAN) and sleep problems. However, evidence for such association is limited in low- and middle-income countries. This study aimed to examine the association between outdoor ALAN exposure and sleep quality in veterans across different regions of China.

METHODS

Within the network of the Chinese Veteran Clinical Research Platform, we selected 7258 participants from 277 veteran communities in 18 cities across China during December 2009 and December 2011, using a multi-stage stratified cluster sampling strategy. Face-to-face interviews with the participants were conducted by trained investigators. We used the Pittsburgh Sleep Quality Index (PSQI) to assess participants' sleep quality. We defined poor sleep quality as a PSQI global score >7. The 3-year average exposure to outdoor ALAN prior to the baseline interview was calculated using satellite imagery data, according to participants' geolocation information. The association of ALAN exposure with sleep quality was examined using the mixed-effects logistic regression models with natural cubic splines.

RESULTS

The exposure-response curve for sleep quality associated with ALAN exposure was nonlinear, with a threshold value of 49.20 nW/cm2/sr for the 3-year average exposure to outdoor ALAN prior to the baseline interview. Higher ALAN exposure above the threshold was associated with increased risk of poor sleep quality. After adjusting for potential confounders, the odds ratios (and 95%CI, 95% confidence intervals) were 1.15 (0.97, 1.36) and 1.45 (1.17, 1.78) at the 75th and 95th percentiles of ALAN against the threshold. The association of ALAN exposure with poor sleep quality was more pronounced in veterans with depression than those without. Higher OR of poor sleep quality at the 75th percentile of ALAN against the threshold was observed in veterans with depression than those without [2.09 (1.16, 3.76) vs. 1.09 (0.92, 1.30)].

CONCLUSIONS

Long-term exposure to outdoor ALAN was associated with higher risk of poor sleep quality in Chinese veterans. Effective outdoor ALAN management may help to reduce the burden of sleep disorders in Chinese veterans.

Lower cortical volume is associated with poor sleep quality after traumatic brain injury

Traumatic brain injury (TBI) is known to be associated with poor sleep. In this report, we aimed to identify associations between differences in cortical volume and sleep quality post-TBI. MRI anatomical scans from 88 cases with TBI were analyzed in this report. Subjective sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). Voxel Based Morphometry (VBM), was used to obtain statistical maps of the association between PSQI and cortical volume in gray matter and white matter voxels. Higher PSQI total scores (poor sleep quality) were strongly associated with smaller gray matter volume in the cerebellum. White matter volume was not associated with total PSQI. The sleep disturbance subcomponent showed a significant association with gray and white matter volumes in the cerebellum. Although not significant, cortical areas such as the cingulate and medial frontal regions were associated with sleep quality. The cerebellum with higher contribution to motor and autonomic systems was associated strongly with poor sleep quality. Additionally, regions that play critical roles in inhibitory brain function and suppress mind wandering (i.e., default mode network including medial frontal and cingulate regions) were associated (although to a lesser extent) with sleep. Our findings suggest that poor sleep quality following TBI is significantly associated with lower cerebellar volume, with trending relationships in regions associated with inhibitory function.