Association between subjective sleep quality and depression on immunocompetence in low-income women at risk for cervical cancer

Objective: The purpose of this study was to investigate whether subjective sleep quality is more strongly associated with immunocompetence than depression among women at risk for cervical cancer. Methods: Participants were 91 women referred for colposcopy because of abnormal results on a Pap smear. On the day of the procedure, participants completed the Center for Epidemiological Studies Depression Scale, two indices of subjective sleep quality (ie, satisfaction with sleep obtained and degree of sleep restfulness), and a health behaviors assessment questionnaire. Levels of peripheral blood lymphocyte subpopulations (helper T, cytotoxic/suppressor T, NK, and B cells) were also assessed at this time. Approximately 10 days later, the presence of depressive disorder was assessed using the Structured Clinical Interview for DSM-III-R. Results: Hierarchical regression analyses revealed that satisfaction with the amount of sleep obtained was significantly associated with the circulating number and percentage of helper T cells (T(H)/CD4⁺) and the percentage of cytotoxic/suppressor T cells (T(C)/CD8⁺), after controlling for confounder variables (ie, age, smoking status, and drug use). Depression was significantly associated only with the percentage of T(C) cells. Sleep satisfaction remained significantly associated with the number and percentage of T(H) cells and percentage of T(C) cells after controlling for the variance explained by depression. Conclusions: Results of this study suggest that subjective sleep quality shares a significant and independent portion of the variance with immunity that is not accounted for by depression. Although the long-term impact of these immune alterations on disease progression needs to be directly explored, it may be important to systematically screen for and manage sleep disturbance in women at high risk for cervical cancer.