Abstract P315: Three-year Progression of Sleep-disordered Breathing is Associated with Cardiovascular Disease Risk Factors in Young Adults

Abstract

Introduction: Sleep-disordered breathing (SDB) is a common sleep disorder that is significantly associated with cardiovascular disease (CVD) risk. Less is known about the short-term cardiovascular implications of mild-severity SDB progression, as mild SDB is less commonly associated with CVD but often develops into more severe SDB over time if left untreated. Hypothesis: We hypothesized that worsening of SDB severity over 3 years would be associated with greater changes in common CVD risk factors (body weight, heart rate [HR], blood pressure [BP], insulin resistance, and C-reactive protein [CRP]). Methods: A sample of 32 adults (38.6±6.4 y; 31.9±4.0 kg/m2; 72% female) who previously had participated in a 1-year lifestyle intervention were followed from 1-year post-intervention (2Y) for an additional 3 years (5Y). At 2Y and 5Y, SDB was assessed with an ambulatory monitor (ResMed ApneaLink); the oxygen desaturation index (ODI; the number of times per hour of recording that the blood oxygen saturation [SaO2] level was reduced by ≥4%) and mean SaO2 served as the primary indices of SDB severity. At 2Y and 5Y, body weight and resting BP and HR were assessed using standard procedures and fasting blood samples were obtained and measured for glucose, insulin, and CRP. Insulin resistance was measured via the Homeostatic Model Assessment method. Multiple linear regression and analysis of covariance were used to examine the associations between changes in SDB severity and changes in CVD risk factors, adjusting for 2Y values of CVD risk factors. Results: ODI at 2Y was 5.3±6.6. At 5Y, ODI had changed (i.e., improved) by -0.2±4.9, with ODI worsening by ≥2 in 7 adults and improving by ≥2 in 11 adults. Mean SaO2 at 2Y was 95.5±1.6% and changed (i.e., improved) by +0.1±1.1% at 5Y; mean SaO2 worsened in 10 adults and improved in 12 adults. Three-year change in ODI, but not SaO2, was significantly associated with weight change (β=.42, P=.02). Compared to those whose ODI worsened or did not change, improved ODI was associated with more favorable changes in CRP (-1.8 vs. +0.8 mg/L; P=.04) and heart rate (-5.0 vs. +0.2 beats/min; P=.05); however, these associations were weakened after further adjustment for weight change (P=.16 and P=.07, respectively). Compared to those whose SaO2 remained unchanged or improved, worsened SaO2 was associated with increased insulin resistance (+1.1 vs. -0.4; P<.01); results were unchanged following adjustment for weight change (P=.01). Changes in ODI and SaO2 were not related to changes in BP. Conclusions: Even marginal worsening of SDB severity over 3 years is associated with elevation in some CVD risk markers. Treatment of mild SDB in young- to middle-aged adults may reduce risk for CVD.