The Somatotropic Axis in the Sleep Apnea-Obesity Comorbid Duo.

Background: Growth hormone (GH) stimulates the production of insulin-like growth factor 1 (IGF-1) in most tissues and together GH and IGF-1 profoundly impact adipose tissue deposition, glucose metabolism and cardiovascular function. A low serum IGF-I level has been reported as being associated with obstructive sleep apnea (OSA) and might be one of the mechanisms underlying cardio-metabolic risk in OSA patients. Methods: In a multicenter national study, 817 patients consulting for suspicion of OSA (OSA confirmed for 567 patients) underwent serum IGF-1 measurements. We analyzed the association between an IGF-1 level below the median value of the population and variables related to cardio-metabolic risk: body mass index (BMI) and waist circumference, apnea hypopnea index (AHI), cholesterol and triglycerides (expressed as median and divided into quartiles for continuous variables). Results: After adjustment for age and gender, low IGF-1 levels were associated with increased BMI and AHI (Odds ratios (OR) = 2.83; p < 0.0001 and OR = 3.03, p < 0.0001 for Quartile 4 vs. Quartile1, respectively), with elevated cholesterol levels (OR = 1.36, p = 0.0444), and elevated triglyceride levels (OR = 1.36; p = 0.0008). Conclusions: Both adiposity and sleep apnea synergistically predict low levels of IGF-1 and thus could together contribute toward cardio-metabolic risk. Further work are needed to confirm whether IGF-1 levels allow grading severity and predicting response to treatments to aim at a personalized medicine for patients suffering from OSA.

Nocturia is an independent predictive factor of prevalent hypertension in obstructive sleep apnea patients.

OBJECTIVE: The aim of this study was to determine whether nocturia is an independent predictor for prevalent hypertension in obstructive sleep apnea (OSA). METHODS: We analyzed data from a national prospective clinical cohort of OSA patients participating in the French national prospective registry. Anthropometric data, comorbidities, OSA severity, and number of voids/night were included in multivariate analyses to determine the independent variables associated with prevalent hypertension. RESULTS: A total of 22,674 OSA patients were included, of which 11,332 were hypertensive. The prevalence of hypertension among OSA patients was about 1.3 times higher in patients suffering from nocturia at 61.45% versus 46.52% in hypertensive and non-hypertensive OSA patients (p <0.001). There was a significant positive relationship between hypertension and the severity of nocturia beyond two voids/night: two voids/night versus none: odds ratio (OR) = 1.270 (95% confidence interval (CI) = 1.175; 1.372), three voids/night versus none: OR = 1.422 (95% CI = 1.293; 1.565), and four voids/night versus none: OR = 1.575 (95% CI = 1.394; 1.781). The strength of the association was enhanced in patients over 64 years of age. CONCLUSIONS: Nocturia is a strong independent predictor of prevalent hypertension in OSA. This association exhibited a "dose-response" relationship beyond two voids/night. The resolution of nocturia after continuous positive airway pressure (CPAP) treatment might be an important outcome to consider for the response of hypertension to CPAP.