Yun Kwok Wing

Gender differences in insomnia—a study in the Hong Kong Chinese population

OBJECTIVE To study the epidemiology of insomnia in the adult Chinese population in Hong Kong and to examine the potential gender-related demographic and lifestyle factors in insomnia. METHODS A population study via random telephone survey with a structured questionnaire was carried out for noninstitutionalized Chinese adults aged 18-65 by trained lay interviewers. The questionnaire included demographic data, sleep habits and problems, insomnia symptoms and lifestyle questions. RESULTS A total of 9851 subjects (46.4% male; 53.6% female) were included in the final analysis. The overall prevalence of Hong Kong Chinese as suffering from insomnia during the preceding month (with a frequency of sleep disturbance of at least three times per week) was 11.9% (95% CI 11.2-12.6), including difficulty in initiating sleep (DIS) (4.5%; 95% CI 4.1-5.0), difficulty in maintaining sleep (DMS) (6.9%; 95% CI 6.4-7.5) and early morning awakening (EMA) (4.0%; 95% CI 3.6-4.4). Females were about 1.6 times at higher risk for insomnia than males. The prevalence of insomnia was also shown to increase with age. Multivariate analysis showed that unemployment, lower economic status, alcohol consumption, regular medication and psychiatric disturbance were all associated with higher risks of insomnia in both sexes. Furthermore, lower education level and being retired was associated with a higher risk of insomnia in males, but being a housewife, divorced/widowed, and complaining of a nocturnal noisy environment were associated with a higher risk of insomnia in females. Among all these factors, psychiatric disturbance was the most influential risk factor for insomnia in both sexes. The reasons for gender differences of insomnia may include their differences in the prevalence of psychiatric morbidities, symptom endorsement, gonadal steroids, sociocultural factors and coping strategies. CONCLUSIONS Overall, 11.9% of the Hong Kong Chinese adult population complained of frequent insomnia in the preceding month. There was a higher prevalence of insomnia in females. Although there were common risk factors for insomnia in both sexes, there existed gender-specific risk factors.

Associations of sleep duration with obesity and serum lipid profile in children and adolescents.

INTRODUCTION The association between sleep duration, obesity, and serum lipid profile in the youth population is under-explored. OBJECTIVE To evaluate the association between sleep duration, obesity and serum lipid profile in the youth population. METHODS We conducted a cross-sectional population-based study with students recruited from primary and secondary schools in Hong Kong. Anthropometric measurements, fasting lipid profiles and validated questionnaires on sleep duration were performed. A subgroup (n=138) was randomly selected for both questionnaires and actigraphy to assess the agreement between subjective and objective measurements of sleep duration. RESULTS We studied 2053 healthy children and adolescents aged 6-20 years. Their mean ages were 13.0±3.3 (boys) and 13.6±3.3 (girls) years. The average sleep duration during schooldays, weekends, and long holidays was 8.0±1.1, 9.6±1.2, and 9.8±1.2h in boys and 7.7±1.1, 9.9±1.2, and 10.1±1.2h in girls, respectively. Using logistic regression, age, and pubertal stage were associated with obesity in secondary school students, whereas male gender and short sleep duration were associated with obesity in primary school children. In secondary school children, those with long sleep duration, as compared to those with short sleep duration, were significantly associated with reduced risk to have high TC and LDL-C levels after adjustment for age, gender, BMI, and pubertal stage. There was no significant association between sleep duration and lipid levels in primary school children. CONCLUSION Reduced sleep duration was associated with obesity and atherogenic dyslipidemia in young school children in Hong Kong.

The Effect of Weekend and Holiday Sleep Compensation on Childhood Overweight and Obesity

OBJECTIVES: A growing trend in childhood sleep habits is to compensate for the weekday sleep deficit by longer weekend and holiday sleep duration. We aimed to investigate the effect of weekend/holiday sleep compensation in relation to childhood overweight and obesity. METHODS: This is a community-based cross-sectional study with 5159 children (49.6% boys), mean age of 9.25 years (SD: 1.78), from 13 primary schools in Hong Kong. Data on sleep patterns, lifestyle, body weight, and height of children were obtained from questionnaires. Sleep durations during weekdays, weekends, and holidays were predictor variables. BMI z scores and obesity/overweight status were the outcome measures. RESULTS: Children slept significantly longer during holidays (mean [SD]: 10.20 (0.92) hours) and weekends (school terms) (10.07 [0.93] hours) than during school weekdays (9.18 [0.95] hours). Children with shorter sleep duration had higher BMI z scores regardless of the sleep parameters used in the analysis. Among children who slept <8 hours during weekdays, those children who did not compensate for their sleep deficit during weekends or holidays had significantly increased risk of overweight/obesity compared with those children with sleep compensation (odds ratios: 2.59 [95% confidence interval: 1.22–5.48] and 2.32 [95% confidence interval: 1.00–5.53], respectively). CONCLUSIONS: There was a prominent difference in sleep duration between weekdays and weekends/holidays among school children. Short sleep duration was associated with higher BMI, but compensation of sleep during weekends/holidays may partly ameliorate the risk of childhood overweight/obesity. Further prospective and interventional study is needed to delineate the risk-benefit effect of these increasingly common sleep habits among children and adolescents.

The prevalence of narcolepsy among Chinese in Hong Kong

Narcolepsy is a lifelong, crippling sleep disorder. Although the discovery of the hypocretin system has been a breakthough in genetics, the epidemiological aspects of narcolepsy remain elusive. Ethnic predisposition was suggested to partially account for the 2,500‐fold difference in the reported prevalence rates of narcolepsy between Japanese (0.59%) and Israeli Jews (0.00023%). We carried out a general population study, conducting a random telephone survey with a structured questionnaire, which included a validated screening instrument (a Chinese version of the Ullanlinna Narcolepsy Scale). It was followed by clinical‐polysomnographic‐HLA confirmation of the subjects determined to be positive for narcolepsy based on the questionnaire. Of 9,851 subjects interviewed, 28 subjects (0.28%, 58% female) were screened positive. Ninety percent had a second detailed interview, 64% had HLA typing, and over half of them had a sleep assessment. Only three subjects were found to have genuine narcolepsy. The most common nonnarcolepsy diagnoses were sleep apnea syndrome and sleep‐wake schedule disorder. The prevalence rate of narcolepsy in Southern (Hong Kong) Chinese was found to be 0.034% (95% confidence interval = 0.010–0.117%). All available narcoleptic subjects were HLA DRB1‐1501 positive and 50% were DQB1‐0602 positive. The prevalence rate of narcolepsy among Chinese is comparable to the rates for other populations in studies with stringent epidemiological designs, suggesting that major cross‐ethnic differences in the prevalence rates of narcolepsy previously reported likely resulted from methodological limitations.

Roles of Parental Sleep/Wake Patterns, Socioeconomic Status, and Daytime Activities in the Sleep/Wake Patterns of Children

OBJECTIVES To determine sleep/wake patterns of primary school children and their correlates. STUDY DESIGN A total of 4470 sets of mother-father-child community-based trios were recruited in this study. We constructed 3 integrated models with structural equation modeling to predict sleep/wake patterns of children (bedtime, wakeup time, and time in bed [TIB]). RESULTS Our best-fitting models explained 40% to 71% variances of various sleep/wake patterns of the children, which were influenced by a web of interactive factors including school start time, parental sleep/wake patterns, sociodemographics, and daytime activities. The strongest predictor of various sleep/wake patterns was school start time. Higher socioeconomic status would shorten TIB of both children and parents, but through different pathways (by advancing wakeup time and delaying bedtime in children but by delaying bedtime in parents). Media use and homework shortened TIB of children, while leisure extracurricular activities and later school start time lengthened it. The age and sex effects on sleep/wake patterns, at least in part, were mediated by daytime activities. Daytime activities of children also influenced their parental sleep/wake patterns, especially their maternal one. A consistent pattern of stronger mother-child than father-child associations were found in various sleep/wake patterns. CONCLUSIONS There was a complex and interactive relationship among school schedule, parental sleep/wake patterns, socioeconomic status, and daytime activities in determining the sleep/wake patterns of children. These findings have important clinical implications for the management of childhood sleep/wake habits and problems.

SARS-related perceptions in Hong Kong.

To understand different aspects of community responses related to severe acute respiratory syndrome (SARS), 2 population-based, random telephone surveys were conducted in June 2003 and January 2004 in Hong Kong. More than 70% of respondents would avoid visiting hospitals or mainland China to avoid contracting SARS. Most respondents believed that SARS could be transmitted through droplets, fomites, sewage, and animals. More than 90% believed that public health measures were efficacious means of prevention; 40.4% believed that SARS would resurge in Hong Kong; and ≈70% would then wear masks in public places. High percentages of respondents felt helpless, horrified, and apprehensive because of SARS. Approximately 16% showed signs of posttraumatic symptoms, and ≈40% perceived increased stress in family or work settings. The general public in Hong Kong has been very vigilant about SARS but needs to be more psychologically prepared to face a resurgence of the epidemic.

Eveningness and Insomnia: Independent Risk Factors of Nonremission in Major Depressive Disorder

BACKGROUND It is unclear whether there is an association between chronotype and nonremission of depression, and whether the association is related to the confounding effect of insomnia. METHOD A cohort of patients with major depressive disorder were assessed for chronotype (by Morningness-Eveningness Questinnaire [MEQ]), depressive symptoms, insomnia severity and clinical outcomes in a naturalistic follow-up study. RESULTS Of the 253 recruited subjects (age 50.8 ± 10.2 y; female: 82.6%; response rate 90.0%), 19.4%, 56.1% and 24.5% patients were classified as eveningness, intermediate, and morningness, respectively. Evening-type subjects had higher insomnia severity, more severe depressive symptoms, and higher suicidality. Eveningness was associated with nonremission of depression with an odds ratio (OR) of 3.36 (95% confidence interval [CI] 1.35-8.34, P < 0.01), independent of insomnia severity. In addition, insomnia was an independent significant factor in contributing to nonremission of depression (OR = 1.12; 95% CI 1.05-1.19, P < 0.001). CONCLUSION The independent association of eveningness with nonremission of depression suggested a significant underpinning of circadian involvement in major depressive disorder. Our findings support the need for a comprehensive assessment of sleep and circadian disturbances as well as integration of sleep and chronotherapeutic intervention in the management of depression.

Prospective outcome of rapid eye movement sleep behaviour disorder: psychiatric disorders as a potential early marker of Parkinson's disease

Increasing evidence suggests that rapid eye movement sleep behaviour disorder (RBD) is a heralding feature associated with evolving α-synucleinopathy-related neurodegenerative disorders.1–4 Several neurobiological markers such as olfactory abnormality were associated with the development of neurodegenerative disorders in ‘idiopathic’ RBD (iRBD) patients.5 On the other hand, pre-morbid psychiatric disorders were suggested as an important but often neglected preclinical marker of Parkinsons disease (PD),6 and its role is unclear in iRBD patients. The current study aimed to provide a quantitative risk estimate of neurodegenerative outcome, and to investigate the role of psychiatric disorders in predicting future neurodegenerative disorders in a prospective cohort of Hong Kong Chinese iRBD patients. Ninety-one iRBD patients (82.4% men) (recruited during 1994–2009) were prospectively followed-up with routine clinical assessments in our sleep centre for a mean duration of 5.6 years (SD 3.3).1 An additional research-based follow-up protocol has been implemented since 2008, which included neuropsychiatric examinations as conducted by the research …

A control study of the cutaneous side effects of chronic lithium therapy.

BACKGROUND To assess the nature and prevalence of skin disorders among psychiatric patients on chronic lithium therapy and to compare them with patients on other psychotropic medications. METHOD 51 patients on lithium and 57 patients on other psychotropics were recruited. Dermatological assessment included a semi-structured questionnaire and clinical examination of the subjects by two dermatologists who were blind to the psychiatric diagnosis and treatment. Secondary cutaneous reaction was defined as skin eruption that developed or deteriorated after commencement of psychiatric medication. RESULTS Lithium treated patients developed significantly more secondary cutaneous reactions than the control group. This applied particularly to acne and psoriasis. Male patients on lithium were more likely to be affected than female patients. CONCLUSION Lithium aggravates or triggers cutaneous conditions that are characterized by the pathological findings of neutrophilic infiltration. Since these cutaneous problem can be distressing to patients and may affect medication compliance, there should be heightened attention to skin problems in patients receiving lithium treatment.

REM sleep behaviour disorder in Hong Kong Chinese: clinical outcome and gender comparison

REM sleep behaviour disorder (RBD) is a parasomnia characterised by a history of dream-enactment behaviours during REM sleep, resulting in shouting, punching, jerking, kicking, falling out of bed and sleep-related injuries (SRI).1–3 The estimated prevalence rate of RBD was similarly about 0.4–0.5% in both Caucasian and Hong Kong Chinese elderly populations. There were only few large clinical series of RBD of Caucasian descents.1–3 Hence, we aimed to report our RBD series for cross-cultural comparison of clinical and gender-related findings. View this table: Table 1 Comparison of demographic data, clinical features, comorbidities and treatment efficacy among reported case series From 1994 to 2006, 82 patients (male: 81.7%) were diagnosed to have RBD according to the International Classification of Sleep Disorder (1st and 2nd editions) in our sleep clinic, which was a main centre in receiving clinical referrals from different disciplines locally. The mean age of onset and diagnosis was 62.1 (SD 12.9) and 67.4 (SD 10.0) years, respectively. Sleep talking, shouting, vigorous movements of arms and legs were commonly reported nocturnal behaviours. Dream recall was available in 75.6% patients (62/82). The violent themes emerged from their dreams consisted of active defence against others (50%, 31/62), defence against animals (17.7%, 11/62) and aggression towards others (24.2%, 15/62). Two patients (3.2%) reported dreams of being chased by a ghost, …