Cross-cultural comparison of the sleep-disordered breathing prevalence among Americans and Japanese

The aim of the present study was to compare the prevalence of sleep-disordered breathing among Hispanic and white Americans and Japanese. A 1-night sleep study using a single-channel airflow monitor was performed on 211 Hispanics and 246 Whites from the Minnesota field centre (St Paul, MN, USA) of the Multi-Ethnic Study of Atherosclerosis (MESA), and 978 Japanese from three community-based cohorts of the Circulatory Risk in Communities Study (CIRCS) in Japan. The respiratory disturbance index and sleep-disordered breathing, defined as a respiratory disturbance index of > or =15 events x h(-1), were estimated. The prevalence of sleep-disordered breathing was higher in males (34.2%) than females (14.7%), and among Hispanics (36.5%) and Whites (33.3%) than among Japanese (18.4%), corresponding to differences in body mass index. Within body mass index strata, the race difference in sleep-disordered breathing was attenuated. This was also true when body mass index was adjusted for instead of stratification. The strong association between body mass index and sleep-disordered breathing was similar in Japanese and Americans. The prevalence of sleep-disordered breathing was lower among Japanese than among Americans. However, the association of body mass index with sleep-disordered breathing was strong, and similar among the race/ethnic groups studied. The majority of the race/ethnic difference in sleep-disordered breathing prevalence was explained by a difference in body mass index distribution.