Cerebrospinal Fluid Nitric Oxide Synthase is a Potential Mediator Between Cigarette Smoke Exposure and Sleep Disorders.

Objective: Cigarette smoking and low peripheral nitric oxide synthase (NOS) levels are strongly associated with sleep disorders. However, whether cerebrospinal fluid (CSF) NOS relates to sleep disorders and whether CSF NOS mediates the relationship between cigarette smoking and sleep disorders is unclear. Methods: We measured CSF levels of total NOS (tNOS) and its isoforms (inducible NOS [iNOS] and constitutive NOS [cNOS]) in 191 Chinese male subjects. We applied the Pittsburgh Sleep Quality Index (PSQI). Results: The PSQI scores of active smokers were significantly higher than those of non-smokers, while CSF tNOS, iNOS, and cNOS were significantly lower (all p < 0.001). CSF tNOS, iNOS, and cNOS were negatively associated with PSQI scores in the general population (all p < 0.001). Mediation analysis suggested that CSF tNOS, iNOS, and cNOS mediate the relationship between smoking and PSQI scores, and the indirect effect accounted for 78.93%, 66.29%, and 81.65% of the total effect, respectively. Conclusion: Cigarette smoking is associated with sleep disorders. Active smokers had significantly lower CSF levels of tNOS, iNOS, and cNOS. Furthermore, tNOS, iNOS, and cNOS mediate the relationship between cigarette smoking and sleep quality. This study provides insights into how cigarette smoke affects sleep disorders.

Associations between Milk Intake and Sleep Disorders in Chinese Adults: A Cross-Sectional Study.

We aimed to examine the association of milk intake with sleep disorders and their specific indicators. The current study included 768 adults aged 28-95 from Wenling, China. Milk intake was assessed using a food frequency questionnaire with ten food items, while sleep disorders were measured using the Pittsburgh Sleep Quality Index (PSQI), with higher scores indicating poorer sleep. The participants were divided into two groups according to the average intake of milk per week: rare intake (≤62.5 mL/week) and regular intake (>62.5 mL/week). Primary measurements were multivariate-adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for the prevalence of sleep disorders concerning regular milk intake compared with rare intake. In secondary analyses, linear regression analyses were performed to assess the effects of milk intake on sleep disorders and their specific dimensions. Regular intake of milk did not have a significant association with sleep disorders compared with rare intake (adjusted OR: 0.72, 95%; CI: 0.51, 1.03), but this association was found to be pronounced with sleep disturbances (OR: 0.49, 95%; CI: 0.28, 0.87). Increased intake of milk was significantly associated with the lower scores of PSQI for sleep quality (ß: -0.045, 95%; CI: -0.083, -0.007) and sleep disturbances (ß: -0.059, 95%; CI: -0.090, -0.029), respectively. When stratified by age and gender, the benefits of milk intake for sleep disorders and sleep disturbances were more significant in older adults (≥65) and men than in younger persons and women. In summary, regular milk intake benefits sleep quality, which may contribute to nutritional psychiatric support for prevention against sleep disorders.