Interaction between serotonin transporter gene-linked polymorphic region (5-HTTLPR) and job-related stress in insomnia: a cross-sectional study in Sichuan, China

• There was a significant interaction between 5-HTTLPR genotype and job-related stress in the risk of insomnia.
• Job-related stress played a predominant role in the risk of insomnia.
• The effect of 5-HTTLPR for insomnia was relatively weaker than high job-related stress.

ObjectiveInsomnia, a widely occurring sleep disorder in modern society, has a large impact on life quality and work safety. A cross-sectional study was conducted to explore the possible link between serotonin transporter-linked polymorphic region (5-HTTLPR), job-related stress, and insomnia in West China.MethodsOf the total 462 workers recruited, 177 had insomnia according to the Athens Insomnia Scale (AIS-5). The 5-HTTLPR genotypes were determined by polymerase chain reaction. Job-related stress was assessed for each participant by the General Job Stress Questionnaire.ResultsUnconditional logistic regression models showed that the 5-HTTLPR genotype was significantly associated with insomnia, and >80% increased risk per S allele was observed. High job-related stress had a higher risk for insomnia than low job-related stress (odds ratio [OR], 6.14; 95% confidence interval [CI], 3.94–9.59). Crossover analysis found significant job-related stress × 5-HTTLPR interaction. Compared to individuals with both low job-related stress and SL/LL genotype, those with both higher job-related stress and SS genotype had a higher risk of insomnia (OR, 5.16; 95% CI, 3.13–8.54), whereas those with both low job-related stress and SS genotype showed a lower risk of insomnia (OR, 0.26; 95% CI, 0.08–0.74). The interaction remained statistically significant after adjusting for potential confounding factors.ConclusionsThe findings indicated that 5-HTTLPR could modify the effect of job-related stress on employees' insomnia, suggesting that a work environment-based personalized intervention may be applied to prevent employees' insomnia by alleviating job-related stress in the workplace.