Gender differences in the relative frequency of sleep-disordered breathing (SDB) have been observed in surveys of patient groups referred for clinical evaluation compared with population surveys. In this study, we assessed the associations of gender, SDB, and symptoms of SDB in 389 participants (16 to 84 yr of age) in an ongoing genetic-epidemiologic study of sleep apnea. Subjects included index probands with laboratory-confirmed obstructive sleep apnea syndrome (laboratory sample, n = 36) and their family members and neighbors (the community sample). SDB was assessed with overnight in-home monitoring of airflow, oximetry, heart rate, and chest wall impedance, and symptoms were assessed with standardized questionnaires. In the entire sample, SDB, defined as a respiratory disturbance index [RDI] > or = 15, was more prevalent among males (38%) than among females (15%) (p < 0.05). Males predominated by a ratio of 8:1 in the laboratory sample (31 males, five females). In contrast, the proportion of males to females with SDB was only 2:1 in the community sample, in which an RDI > or = 15 was observed among 26% of males and 13% of females. In the laboratory sample, females tended to be younger and were significantly heavier than males. However, in the community sample, females with SDB were older than male apneic subjects (63.4 +/- 13.9 versus 47.2 +/- 15.6 years, mean +/- SD; p < 0.01), and included a majority of postmenopausal women (75%). No differences in body mass index were noted between males and females with SDB recruited from the community.(ABSTRACT TRUNCATED AT 250 WORDS)