Period 3 gene polymorphism and sleep adaptation to stressful urban environments

Abstract

Summary This study's objective was to investigate the relationship between a variable‐number tandem‐repeat (VNTR) Period 3 gene (PER3) polymorphism and sleep adaptation to stressful urban environments. Seventy‐five (49 female) African American participants (ages 18–35 years) living in neighbourhoods with high rates of violent crime were selected for the study based on converging criteria for good or poor sleep. Categorization of sleep quality was based on the Insomnia Severity Index (ISI), estimates of typical sleep duration and sleep efficiency. Other assessments included the Fear of Sleep Index (FOSI) and City Stress Inventory (CSI). Whole blood DNA was analysed for the 4 and 5 VNTR alleles using polymerase chain reaction (PCR) and restrictive enzyme digestion. Fifty‐seven per cent of those who were homo‐ or heterozygous for the 4‐repeat allele were poor sleepers versus 25% of those homozygous for the 5‐repeat allele; χ2 = 4.17, P = 0.041. In a logistic regression model with all the variables with significant bivariate relationships to sleep quality group, FOSI was the only significant predictor (χ2 = 5.68, P = 0.017). FOSI scores were higher among those with the 4‐repeat allele (t = 2.66, P = 0.013). The PER3 4 and 5 VNTR polymorphisms appear to influence sensitivity to the effects of stressful urban environments on sleep. While FOSI was the only variable associated independently with sleep quality category, the candidate vulnerability allele was also associated with greater ‘fear of sleep’.

Daytime Sleep Disturbance in Night Shift Work and the Role of PERIOD3

“…23 Another study found that individuals living in high-crime neighborhoods were more likely to report sleep related anxiety and more severe insomnia symptoms if they possessed the 4-repeat allele. 24 A different study demonstrated that insomnia associated with alcohol dependence was more severe in PER3 4/4 relative to carriers of the 5-repeat allele (PER3 5/− ). 25 Together, the evidence suggests that PER3 genotype in shift workers may also show differences in vulnerability to insomnia.…”

Potential genetic and epigenetic mechanisms in insomnia: A systematic review

“…Interestingly in another study the authors found a significant association between PER2 genotype and insomnia, as well as a Genes × Environmental (G × E) interaction with PER2 , work stress, and insomnia (Li et al, 2015). This G × E interaction was evaluated in another study assessing stress related to urban environments (Anderson et al, 2017). Authors reported that the PER3 , 4 and 5 variable number tandem repeat (VNTR) polymorphisms appear to influence sensitivity to the effects of stressful urban environments on sleep.…”

A message from the new editor in chief

“…Therefore, introducing blood pressure as a new important outcome variable in insomnia treatment research makes sense, and is supported by these data. Not being related directly to the insomnia field, Anderson et al (2017) looked at Period 3 gene polymorphism and the process of sleep adaptation to stressful urban environments. This brief report investigated 75 African American participants who were divided into groups of good and poor sleepers, living in neighbourhoods with high rates of violent crime.…”