Association between Insomnia Symptoms and Hemoglobin A1c Level in Japanese Men

Background: The evidence for an association between insomnia symptoms and blood hemoglobin A1c (HbA1c) level has been limited and inconclusive. The aim of this study was to assess whether each symptom of initial, middle, and terminal insomnia influences HbA 1c level in Japanese men. Methods: This cross-sectional study examined 1,022 male workers aged 22–69 years with no history of diabetes at a Japanese company’s annual health check-up in April 2010. High HbA1c was defined as a blood level of HbA1c $6.0%. Three types of insomnia symptoms (i.e., difficulty in initiating sleep, difficulty in maintaining sleep, and early morning awakening) from the previous month were assessed by 3 responses (i.e., lasting more than 2 weeks, sometimes, and seldom or never [reference group]). Results: The overall prevalence of high HbA1c was 5.2%. High HbA1c was positively and linearly associated with both difficulty in maintaining sleep (P for trend =.002) and early morning awakening (P for trend =.007). More specifically, after adjusting for potential confounding factors, high HbA1c was significantly associated with difficulty in maintaining sleep lasting more than 2 weeks (adjusted odds ratio, 6.79 [95 % confidence interval, 1.86–24.85]) or sometimes (2.33 [1.19–4.55]). High HbA1c was also significantly associated with early morning awakening lasting more than 2 weeks (3.96 [1.24–12.59]). Conclusion: Insomnia symptoms, particularly difficulty in maintaining sleep and early morning awakening, were found t

Author’s Reply to Bender and Samuels “Does Elite Sport Degrade Sleep Quality? A Systematic Review”

This is a post-peer-review, pre-copyedit version of an article published in Sports Medicine. The final authenticated version is available online at: http://dx.doi.org/10.1007/s40279-017-0710-6

DQB1 locus alone explains most of the risk and protection in narcolepsy with cataplexy in Europe.

STUDY OBJECTIVE: Prior research has identified five common genetic variants associated with narcolepsy with cataplexy in Caucasian patients. To replicate and/or extend these findings, we have tested HLA-DQB1, the previously identified 5 variants, and 10 other potential variants in a large European sample of narcolepsy with cataplexy subjects. DESIGN: Retrospective case-control study. SETTING: A recent study showed that over 76% of significant genome-wide association variants lie within DNase I hypersensitive sites (DHSs). From our previous GWAS, we identified 30 single nucleotide polymorphisms (SNPs) with P < 10(-4) mapping to DHSs. Ten SNPs tagging these sites, HLADQB1, and all previously reported SNPs significantly associated with narcolepsy were tested for replication. PATIENTS AND PARTICIPANTS: For GWAS, 1,261 narcolepsy patients and 1,422 HLA-DQB1*06:02-matched controls were included. For HLA study, 1,218 patients and 3,541 controls were included. MEASUREMENTS AND RESULTS: None of the top variants within DHSs were replicated. Out of the five previously reported SNPs, only rs2858884 within the HLA region (P < 2x10(-9)) and rs1154155 within the TRA locus (P < 2x10(-8)) replicated. DQB1 typing confirmed that DQB1*06:02 confers an extraordinary risk (odds ratio 251). Four protective alleles (DQB1*06:03, odds ratio 0.17, DQB1*05:01, odds ratio 0.56, DQB1*06:09 odds ratio 0.21, DQB1*02 odds ratio 0.76) were also identified. CONCLUSION: An overwhelming portion of genetic risk for narcolepsy with cataplexy is found at DQB1 locus. Since DQB1*06:02 positive subjects are at 251-fold increase in risk for narcolepsy, and all recent cases of narcolepsy after H1N1 vaccination are positive for this allele, DQB1 genotyping may be relevant to public health policy