Sleep-disordered breathing (SDB) is the major determinants of hypertension. Recent studies indicated sleep duration, in addition to shift work, were also associated with hypertension. But very little attention has been paid to these two factors when looking at the effects of SDB on blood pressure. We conducted the present study to evaluate the relationship between SDB and hypertension adjusting for sleep duration and shift work in a sample of Japanese steel workers. In this cross-sectional study, we measured blood pressure and oxygen desaturations index (ODI) by nocturnal pulse oximetry of 249 male workers aged 20 to 65 yr. SDB was defined by 3%ODI level of 15 or more events per hour. Logistic regression analyses were performed to estimate the associations of SDB with hypertension after adjustment for age, body mass index, alcohol intake, smoking, usual sleep duration, shift work, and occupation. The prevalence of SDB was 18.1%. The adjusted odds ratio of hypertension for high (> or =15) vs. low (<15) category of 3%ODI level was 2.86 (95% confidence interval, 1.23-6.66). The significant association between SDB and hypertension suggests that screening for SDB among steel workers is useful for prevention of hypertension.