Backgrounds and aims. Insomnia is a common sleep problem with significant health burden to individuals, families and society. Several risk factors contributed to the development of insomnia with significant familial aggregation phenomenon. According to this prospective study, we aimed to (1) explore the longitudinal course and outcomes of insomnia in both children and their parents; (2) confirm the familial aggregation and heritability of insomnia by detailed clinical interviews; (3) explore the potential biological markers of insomnia in terms of heart rate variability, 24-hour urinary cortisol and serial salivary cortisol. / Conclusions. Insomnia is commonly found in both adolescents and adults with moderate persistence rate after 5 years in Hong Kong Chinese. Our findings of increased risk of chronic medical burdens and various upper airway inflammatory diseases in both adolescent and adult subjects with insomnia suggested that insomnia requires comprehensive medical attention. Insomnia is a highly heritable disorder with robust familial aggregations, with a heritability of 0.67 for lifetime insomnia. We found gene-environment interaction on the pathogenesis of insomnia. Our findings strongly suggested the necessity of further molecular genetic analysis on insomnia. Daytime HRV, 24-hour urinary cortisol and serial salivary cortisol might not be the reliable biological markers for insomnia. (Abstract shortened by UMI.) / Results. Phase 1. The prevalences of insomnia were 4.5%, 10.8% and 13.9% at baseline and 6.6%, 8.1% and 11.6% at follow-up for children, fathers and mothers respectively. Similar incidence rate of insomnia was found across adolescents, fathers and mothers (6.2%, 5.4% and 6.8% respectively, p>0.05), while highest persistence rate of insomnia was found in mothers (43.8%), followed by fathers (26.9%) and adolescents (14.9%) (mothers vs adolescents OR(95%CI)=4.43(2.22--8.86); mothers vs fathers OR(95%CI) = 2.11(1.31--3.42); fathers vs adolescents OR(95%CI) = 2.17(0.98--4.52)). Insomnia at baseline was significantly associated with frequent episodes of allergic rhinitis, asthma, and laryngopharyngitis and chronic use of medicine at follow-up in adolescents (p<0.05). Insomnia at baseline was also significantly associated with poor medical outcomes in adults, including frequent allergic rhinitis, otitis media, hypertension, arthritis, psychiatric disorders, chronic pain and gastroesophageal reflux disease at follow-up in middle-aged adults (p<0.05). Phase 2 study . The first degree relatives' recurrent rate was higher in those adolescents with insomnia than those adolescents without insomnia (43.9% vs 22.9% for current insomnia and 51.1% vs 28.0% for lifetime insomnia, respectively p<0.001). Genetic analysis showed that the heritabilities were 0.57 +/- 0.19 for current insomnia and 0.67 +/- 0.13 for lifetime insomnia after adjusted for age and gender. There was significant synergistic interaction between parental history of insomnia and life stress on the development of insomnia of offsprings (p=0.002). Insomnia disorder and its severity were also found to correlate with neuroticism personality, psychological distress and poor quality of life. The phenotypic correlations of insomnia with these factors could be mainly explained by genetic component in bivariate genetic analysis. Phase 3 study. (1) Subjective sleep quantity and quality was consistently and negatively correlated with 24-hour urinary cortisol and salivary cortisol levels in adolescents. However, there was no such association in adults. (2) Adolescents with insomnia diagnosis had lower salivary cortisol at 0 minute after waking up (T1) but less decrease in AUCi3 than non-insomniac adolescents. Although there was no difference in serial salivary cortisol between insomniacs and non-insomniacs in adult, insomnia diagnosis interacted with gender on the effects of AC1Ji and salivary cortisol level at 10:00 pm. (3) There was no difference in 24-hour urinary cortisol between insomniacs and non-insomniacs. (4) There were some inconsistent associations of salivary cortisol with objective and subjective sleep parameters between continuous and dichotomized approaches. Fox example, there was no correlation between salivary cortisol and objective sleep measures in adults when using continuous variables, but, short sleepers as defined by objective TIB≤400 minutes had higher cortisol levels at T1 (13.5+/-7.9 nmol/L vs 11.2+/-5.0 nmol/L) and T2 (14.0+/-6.0 vs 11.5+/-6.2 nmol/L) than their counterparts (TIB>400 minutes). In brief, cortisol (both salivary and urinary samples) level was more likely to be correlated with subjective measures of sleep than objective measures or insomnia diagnosis. In particular, the association predominantly occurred in adolescent group. / Zhang, Jihui. / Adviser: Yun-bwote Wing. / Source: Dissertation Abstracts International, Volume: 73-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 245-249). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_344681 |
| Date | January 2010 |
| Contributors | Zhang, Jihui, Chinese University of Hong Kong Graduate School. Division of Medical Sciences. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, theses |
| Format | electronic resource, microform, microfiche, 1 online resource (xxiv, 249 leaves : ill.) |
| Coverage | China, Hong Kong, Hong Kong |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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