Effects of nocturnal intermittent hypoxia on metabolic syndrome in Japanese adults without abdominal obesity.

Abstract

The association between nocturnal intermittent hypoxia and metabolic syndrome (MetS) in individuals without abdominal obesity has not yet been fully explored. We conducted a longitudinal study to investigate the association between nocturnal intermittent hypoxia and the incidence of MetS and its components in Japanese individuals without abdominal obesity. This prospective cohort study included 647 participants without baseline MetS and abdominal obesity, defined as a waist circumference of <90 cm in men and <80 cm in women. Nocturnal intermittent hypoxia was assessed using 3% oxygen desaturation index (ODI). MetS was diagnosed according to the modified National Cholesterol Education Program Adult Treatment Panel III criteria. Incident MetS and its components were assessed at the five-year follow-up survey. The median follow-up period was 5.0 years (IQR, 4.8-5.1). The association between nocturnal intermittent hypoxia and the incidence of MetS and its components was evaluated using a modified Poisson regression analysis. The analysis was stratified by age group (<65 years vs. ≥65 years). In the younger age group, 3% ODI ≥ 5 was associated with a significantly higher risk ratio (RR) for MetS incidence (RR 2.10, 95% confidence interval [CI]: 1.18-3.76). Participants with 3% ODI ≥ 5 in the younger age group also had significantly higher RRs for abdominal obesity (RR 2.17, 95% CI: 1.42-3.33), low high-density lipoprotein cholesterol (RR 2.01, 95% CI: 1.02-3.96), and hypertriglyceridemia (RR 2.41, 95% CI: 1.35-4.30). In the older age group, 3% ODI ≥ 5 was not significantly associated with increased RRs for MetS or its components. Nocturnal intermittent hypoxia was associated with an increased risk of developing MetS and some of its components in younger individuals without abdominal obesity.