Sleep disorders among Yusho patients highly intoxicated with dioxin-related compounds: A 140-case series

• Published in: Environmental research 2018-10, Vol.166, p.261-268
• Main Authors: Kondo, Hideaki, Tanio, Keiko, Nagaura, Yuki, Nagayoshi, Mako, Mitoma, Chikage, Furue, Masutaka, Maeda, Takahiro
• Format: Article
• Language: English
• Subjects: DESIGN; DIOXIN; ENVIRONMENTAL EXPOSURE; ENVIRONMENTAL SCIENCES; Insomnia; PATIENTS; POLYCHLORINATED BIPHENYLS; Restless legs syndrome/Willis–Ekbom disease; SLEEP; Sleep quality; SYMPTOMS; Yusho
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2018.05.033

Patients with Yusho, a condition caused by exposure to dioxins and dioxin-like compounds, have diverse mental and physical complaints. However, the relationship between dioxins and sleep disorders has not yet been examined. This cross-sectional study was designed to investigate problems associated with sleep among patients with Yusho. A total of 140 participants (52.9% men, average age: 67.1 ± 12.2 years) were examined using questionnaires and medical interviews by an expert on sleep medicine. Demographic and clinical characteristics, including blood concentrations of 2,3,4,7,8-pentachlorodibenzofuran (PeCDF), which is the major cause of Yusho, were obtained from the results of recent surveys conducted by the Yusho Study Group. Moderate to severe symptoms of insomnia were present in 51.8% of the patients. The median Pittsburgh Sleep Quality Index global score (PSQI GS) was 8 (interquartile range: 5–11). The prevalence of restless legs syndrome/Willis–Ekbom disease (RLS/WED) was 30.7%; 24.3% of patients had severe RLS/WED (distressing symptoms with a frequency ≥ 1day per week). A higher blood concentration of 2,3,4,7,8-PeCDF (≥72.27 pg/g lipid) and severe RLS/WED were associated with higher odds of a PSQI GS ≥8, after adjusting for covariates (odds ratio [95% confidence interval]: 4.84 [1.10–21.25] and 4.15 [1.53–11.28], respectively). Symptoms of insomnia were frequent, and the prevalence of RLS/WED was high in patients with Yusho. In addition to the presence of RLS/WED, a higher blood concentration of 2,3,4,7,8-PeCDF was associated with lower subjective sleep quality. •Symptoms of insomnia were frequent among patients with Yusho.•A notably high prevalence of RLS/WED was found among patients with Yusho.•Dioxin was associated with a lower sleep quality and the presence of RLS/WED.