Unique sleep disorders profile of a population-based sample of 747 Hmong immigrants in Wisconsin

Concerns regarding sleep disorders in Hmong immigrants in the US emerged when an astonishingly high mortality rate of Sudden Unexplained Nocturnal Death Syndrome (SUNDS) was documented in Hmong men. Stress, genetics, and cardiac abnormalities interacting with disordered sleep were hypothesized as contributing factors to SUNDS. Most recently, sleep apnea has been implicated in nighttime deaths of Brugada Syndrome. This syndrome is thought to comprise a spectrum of sudden cardiac death disorders, including SUNDS. However, little research since has placed SUNDS in its context of Hmong cultural beliefs, health, or the prevalence of other sleep disorders. Because the epidemiology of sleep disorders and terrifying nighttime experiences in Hmong is poorly documented, we investigated the prevalence and correlates of sleep apnea, rapid eye movement (REM) sleep stage related disorders, and insomnia in 3 population-based samples (collected from 1996 to 2001) comprising 747 Hmong immigrants in Wisconsin. Participants were questioned on sleep problems, cultural beliefs, health, and other factors. A random subsample (n = 37) underwent in-home polysomnography to investigate sleep apnea prevalence. Self-report and laboratory findings were compared with similarly collected data from the Wisconsin Sleep Cohort (WSC) study (n = 1170), a population-based longitudinal study of sleep. The results inform a unique Hmong sleep disorder profile of a high prevalence of sleep apnea, sleep paralysis, and other REM-related sleep abnormalities as well the interaction of culturally related nighttime stressors with these sleep problems. For example, experiences of dab tsog (frightening night spirit pressing on chest) was prevalent and related to sleep apnea indicators, sleep paralysis, nightmares, hypnogogic hallucinations, and insomnia. Understanding the role of sleep disorders and the cultural mechanisms that may trigger or condition response to them could ultimately provide a basis for screening and intervention to reduce the adverse health and emotional consequences of these conditions in Hmong.