A 4-year prospective follow-up study of childhood OSA and its association with BP.

BACKGROUND: Childhood OSA is a prevalent condition associated with raised BP as documented in cross-sectional studies. This study aimed to determine whether baseline or change in OSA severity was associated with ambulatory BP at 4-year follow-up. METHODS: Children who participated in our previous OSA prevalence research were invited to undergo a repeat overnight sleep study and 24-h ambulatory BP monitoring in this 4-year follow-up study. BP parameters of subjects with differing baseline OSA severity, that is, obstructive apnea-hypopnea index (OAHI) < 1/h, 1 to 5/h, and > 5/h, were compared. Overweight and normal-weight children were analyzed separately. RESULTS: One hundred eighty-five of 306 subjects (60%) were included in the analysis, of whom 58 were overweight at baseline. Linear increasing trends of wake systolic BP (SBP), wake diastolic BP (DBP), and sleep SBP z scores at follow-up were found across groups of increasing baseline OSA severity in the normal weight but not in the overweight subgroup. After adjusting for BMI z score, baseline OAHI was independently associated with all BP z scores at follow-up but not associated with changes in BP z scores across 4 years. On the other hand, change in OAHI was independently associated with sleep SBP and DBP z scores at follow-up and with changes in sleep SBP and DBP z scores across 4 years. CONCLUSIONS: This study provides longitudinal data as additional proof that childhood OSA is associated with elevated BP independent of obesity.

Familial aggregation of narcolepsy.

OBJECTIVES: To determine the familial aggregation of narcolepsy from perspectives of clinical symptomatology, polysomnographic data, and human leukocyte antigen (HLA) typing. METHODS: This was a Family study at the University-affiliated hospital. The participants were narcolepsy probands and their first degree relatives, and, also, age and sex matched unrelated healthy controls. Interventions were not applicable. MEASUREMENTS AND RESULTS: All study subjects underwent structured interviews, overnight polysomnography followed by a multiple sleep latency test (MSLT), and HLA typing. Altogether, 33 probands and 81 first degree relatives (response rate 65%) were recruited. Among the relatives, 12.3% were diagnosed with narcolepsy and 39.5% had narcolepsy spectrum as defined by unexplained abnormal MSLT (shortened MSL and SOREMP) results. The relative risk of narcolepsy in first degree relatives was 361.8. Familial aggregation of narcolepsy symptoms, excessive daytime sleepiness, HLA status, abnormal MSLT, and nocturnal polysomnographic findings were observed. CONCLUSIONS: The familial risk of narcolepsy among first degree relatives is much higher than previously reported. There exists a spectrum of narcolepsy features among relatives, ranging from full clinical tetrads to asymptomatic abnormal MSLT findings.

Parasomnia among psychiatric outpatients: a clinical, epidemiologic, cross-sectional study.

OBJECTIVE: Epidemiologic studies from general population and clinical case series suggest association of parasomnias with mental illnesses and psychotropic medications. This cross-sectional study aimed at determining the prevalence rate of sleepwalking, sleep-related eating disorder (SRED), rapid eye movement sleep behavior-like disorder (RSBD-like disorder), and sleep-related injury (SRI) and their associated factors in an adult psychiatric outpatient clinic. METHOD: Subjects aged 18 to 65 years who were attending an outpatient clinic in Hong Kong from May 2006 through June 2006 were included in this cross-sectional study. A 3-phase design was employed, including a structured questionnaire on parasomnias, followed by clinical interviews of both questionnaire-positive and -negative groups, and polysomnography for subjects having active parasomnias in recent 1 year. In addition, the principal psychiatric diagnoses, medical illnesses, and detailed drug history over recent 1 year were retrieved from the computerized records. RESULTS: Twelve hundred thirty-five subjects completed the phase 1 interview. The estimated prevalence of the lifetime diagnoses of sleepwalking, SRED, SRI, sleep violence, and RSBD-like disorder were 8.5%, 4.0%, 21.0%, 3.6%, and 5.8%, respectively, while the 1-year prevalence of these conditions were 2.9%, 2.4%, 8.8%, 2.5%, and 3.8%, respectively. These conditions were associated with depression and a constellation of sleep disturbances. Specific combinations of psychotropics were found to pose risk in particular parasomnias: sedative antidepressants and nonbenzodiazapine hypnotics in sleepwalking, regular zolpidem and antidepressants in SRED, and selective serotonin reuptake inhibitors in RSBD-like disorder. CONCLUSIONS: Sleepwalking, SRED, RSBD-like disorder, and SRI were common and underrecognized among the psychiatric population in this study. Their occurrences were likely contributed by interacting effect of mental illnesses, sleep disturbances, and specific psychotropic medications. Further prospective study is warranted for clarification of the etiology and clinical management of these potentially dangerous and "hidden" parasomnias.