Objectives: We evaluated the associations between blood mercury (Hg), lead (Pb), and cadmium (Cd) concentrations and sleep duration among Korean adults and explored whether these associations differed across subgroups.Methods: This cross-sectional study included 17,831 adults aged ≥20 years from the Korea National Health and Nutrition Examination Survey (KNHANES 2005–2017). Sleep duration was assessed using self-reported data. Associations between blood heavy metal concentrations and sleep duration were examined using complex-sample multiple linear regression, accounting for the survey design with adjustments for sociodemographic and health-related covariates.Results: In the covariate-adjusted models, higher blood concentrations of Hg, Pb, and Cd were significantly associated with shorter sleep duration. Sleep duration decreased by 0.113 hours per 10 μg/L increase in Hg (95% confidence interval [CI]: -0.183 to -0.043; p=0.002), 0.076 hours per 1 μg/dL increase in Pb (95% CI: -0.098 to -0.054; p<0.0001), and 0.106 hours per 1 μg/L increase in Cd (95% CI: -0.146 to -0.066; p<0.0001). Subgroup analyses suggested that the magnitude of the associations varied according to sex and work type, with stronger inverse associations observed among female participants and shift workers.Conclusions: Higher blood heavy metal concentrations are inversely associated with sleep duration among Korean adults. These findings suggest that environmental exposure may be related to sleep quantity. Further longitudinal studies incorporating objective sleep measures are needed to clarify the temporal relationships and underlying mechanisms.
Objectives: The growing use of digital devices, along with factors such as economic stress, social issues, caffeine intake, and high-fat diets, disrupts circadian rhythms and contributes to sleep deprivation. Sleep disorders can worsen conditions, such as depression and anxiety, leading to decreased performance and health issues. This study investigated the associations among demographics, socioeconomic factors, sleep duration, chronotype, chronic conditions, and sleep quality in Korea.Methods: We analysed data from the 2018 Community Health Survey (CHS) involving 96,489 males and 119,951 females. Sleep quality was assessed using the Korean version of the Pittsburgh Sleep Quality Index, with scores above 5 indicating poor quality. Participants were categorised by chronotype based on wake-up time, and self-reported sleep duration was grouped into 6 hours or less, 7–8 hours, and 9 hours or more. Chronic conditions such as hypertension and diabetes were self-reported by participants. We included sociodemographic factors and health behaviours in our analysis, employing frequency analysis, the Rao-Scott chi-square test, and multiple logistic regression.Results: Poor sleep quality (PSQ) was associated with factors such as rural residency, non-drinking, non-smoking, being underweight, having hypertension or diabetes, experiencing stress, being identified as a non-morning-type and sleeping less than 6 hours. The non-morning-type had worse sleep quality than the morning-type, regardless of sleep duration. Chronic conditions were associated with sleep quality differently based on sleep duration, affecting those with shorter sleep duration, but not those sleeping over 9 hours.Conclusions: This study emphasises the need to consider chronotypes and chronic conditions to better understand PSQ in the Korean population.
Insomnia causes substantial distress in patients with obsessive-compulsive disorder (OCD), worsens symptom severity, and reduces overall quality of life. Recent studies have highlighted a complex association between insomnia and OCD, suggesting a possible bidirectional relationship mediated by depression, anxiety, and stress. Insomnia symptoms are not merely features of psychopathology but may also share neurophysiological links with OCD. Recent evidence has clarified possible epigenetic and neuropsychological mechanisms underlying insomnia symptoms in OCD. Although insomnia symptoms have limited diagnostic value in OCD, their effects on phenomenology, symptom severity, and treatment outcomes are clinically relevant. Insomnia symptoms are recognized as negative contributors to OCD treatment outcomes, yet they are rarely assessed or treated. Concurrent treatment of insomnia symptoms is recommended to improve OCD symptoms and treatment outcomes. Effective management typically combines non-pharmacological and pharmacological interventions tailored to each patient’s needs. This review examines current evidence and approaches to treating insomnia in patients with OCD.
Objectives: Cognitive behavioral therapy for insomnia (CBT-I) is the first-line treatment for chronic insomnia; however, individual responses vary. Although caffeine disrupts sleep, its effect on CBT-I outcomes remains unclear. This study investigated the relationship between caffeine consumption and efficacy of CBT-I.Methods: This retrospective study included 37 adults with chronic insomnia who completed a standardized 4-week CBT-I program. The participants were classified into the caffeine (n=19) and non-caffeine (n=18) groups. Insomnia severity and sleep quality were assessed before treatment and 2 weeks after completion using the Insomnia Severity Index (ISI) and Pittsburgh Sleep Quality Index (PSQI).Results: CBT-I significantly improved ISI and PSQI scores over time in both groups (p<0.001). No significant group differences or Group×Time interactions were observed for overall insomnia severity or sleep quality, indicating comparable treatment efficacy, regardless of caffeine intake. Treatment response rates, defined by clinically meaningful reductions in ISI (>7 points) or PSQI (≥3 points), did not differ between groups. However, the caffeine group consistently reported poorer subjective sleep quality and greater daytime dysfunction than the non-caffeine group at both time points.Conclusions: CBT-I effectively improved insomnia severity and sleep quality irrespective of daily caffeine consumption. While caffeine intake does not appear to reduce the overall CBT-I efficacy, persistent subjective sleep impairment and daytime dysfunction among caffeine consumers suggest that individualized caffeine education may help optimize perceived treatment outcomes.
Objectives: The apnea–hypopnea index (AHI) does not capture desaturation depth or duration. We examined whether total hypoxic burden (THB) describes hypoxemic variation beyond event frequency and whether a THB threshold identifies a higher-risk subgroup in mild obstructive sleep apnea (OSA; 5≤AHI <15).Methods: We retrospectively analyzed 924 patients undergoing overnight polysomnography at a single tertiary center. THB was the cumulative desaturation area. Within mild OSA, the ≥25%·min/h threshold was the subgroup mean plus one standard deviation. Hierarchical logistic models were adjusted for age, sex, body mass index (BMI), and AHI. Incremental value was assessed by likelihood ratio tests and DeLong comparisons of areas under the curve (AUCs).Results: Mean age was 47.96±13.31 years; 73.6% were male. AHI and THB correlated strongly (r=0.848). Within mild OSA (n=230), THB varied 20.9-fold across a 3.0-fold AHI range (R2=0.389). THB ≥25 (n=483) was crudely associated with hypertension, diabetes mellitus, arrhythmia, and stroke/cerebrovascular accident (CVA), but none persisted after adjustment for age, sex, and BMI (hypertension odds ratio, 1.23; 95% confidence interval, 0.85 to 1.77). For the first three, adding THB ≥25 to adjusted AHI models negligibly changed AUCs (ΔAUC≤0.004); stroke/CVA modeling was unstable. Within mild OSA, no excess comorbidity was detected among 35 patients with THB ≥25.Conclusions: THB quantifies hypoxemic heterogeneity within AHI-defined categories, but its association with comorbidities was not independent of age, sex, and BMI; the ≥25%·min/h threshold remains exploratory.
