Incidence of sleep-disordered breathing in an urban adult population - The relative importance of risk factors in the development of sleep-disordered breathing

Context Sleep-disordered breathing (SDB) is both prevalent and associated with serious chronic illness. The incidence of SDB and the effect of risk factors on this incidence are unknown. Objective To determine the 5-year incidence of SDB overall and as influenced by risk factors. Design, Setting, and Participants Of the 1149 participants in the Cleveland Family Study, those aged 18 years or older, from either case or control families, who had 2 in-home sleep studies 5 years apart. The first had to have been performed before June 30, 1997, and had to have normal results (apnea hypopnea index [AHI] <5). Data included questionnaire information on medical and family history, SDB symptoms; measurement of height, weight, blood pressure, waist and hip circumference, and serum cholesterol concentration; and overnight sleep monitoring. Main Outcome Measure Apnea hypopnea index, defined as number of apneas and hypopneas per hour of sleep. Sleep-disordered breathing was defined by an AHI of at least 10 (mild to moderate) or of at least 15 (moderate). Results Forty-seven (16%) of 286 eligible participants, (95% confidence interval [CI], 13%-21%) had a second-study AHI of at least 10 and 29 (10%) participants (95% CI, 7%-14%) had a second-study AHI result of at least 15. For the AHI results of at least 15, we estimate that about 2.5% may represent test variability. By ordinal logistic regression analysis, AHI was significantly associated with age (odds ratio [OR] per 10-year increase, 1.79; 95% CI, 1.41-2.27), body mass index (BMI; OR per 1-unit increase, 1.14; 95% CI, 1.10-1.19), sex (OR for men Vs women, 4.12; 95% CI, 2.29-7.43), waist-hip ratio (OR per 0.1 unit increase, 1.61; 95% CI, 1.04-2.28), and serum cholesterol concentration (OR per 10-mg/dL [0.25-mmol/L] increase, 1.11; 95% Cl, 1.03-1.19). Interactions were noted between age and both sex (P=.003) and BMI (P=.05). The OR for increased AHI per 10-year age increase was 2.41 in women (95% CI, 1.78-3.26) and 1.15 in men (95% CI, 0.78-1.68), with the male vs female OR decreasing from 5.04 (95% CI, 2.19-11.6) at age 30 years to 0.54 (95% CI, 0.15-1.99) at age 60 years. The OR for increased AHI per 1-unit increase in BMI decreased from 1.21 (95% CI, 1.11-1.31) at age 20 years to 1.05 (95% CI, 0.96-1.15) at age 60 years. Conclusions The 5-year incidence is about 7.5% for moderately severe SDB and 16% (or less) for mild to moderately severe SDB. Incidence of SDB is influenced independently by age, sex, BMI, waist-hip ratio, and serum cholesterol concentration. Predominance in men diminishes with increasing age, and by age 50 years, incidence rates among men and women are similar. The effect of BMI also decreases with age and may be negligible at age 60 years.