title: Association between sleep-disordered breathing, aminoterminal pro-brain natriuretic peptide (NT-proBNP) levels and insulin resistance in morbidly obese young women.
abstract: OBJECTIVE
  Sleep-disordered breathing (SDB) is often encountered in morbid obesity (MO) in conjunction with insulin resistance (IR) and several cardio-vascular risk factors. Aminoterminal pro-brain natriuretic peptide (NT-proBNP) is a promising marker for left ventricular dysfunction (LVD) in MO. The aim of this study was to look for possible correlations between SDB, IR, heart structure and function indexes and NT-proBNP levels in MO female subjects.
  
  
  METHODS
  Cross-sectional study involving 110 MO (44.5+/-0.7 kg m(-2)) apparently healthy, young (37.8+/-1.0 y.o.) female patients. NT-proBNP was measured using an ELISA kit (Roche). Echo-cardiograms were performed to quantify left ventricular ejection fraction values (LVEF), cardiac output (CO), left ventricular mass (LVM), left atria size (LA) and left ventricular filling pressures (the E/Em ratio). The Berlin Questionnaire (BQ) was used to assess the risk of SDB. IR and sensitivity were assessed using the HOMA index and adiponectin measurements, respectively.
  
  
  RESULTS
  All patients had a normal LVEF (>50%). Hypertension and Type 2 diabetes mellitus prevalences were 34.5 and 4.5% (respectively). Log-transformed NT-proBNP levels correlated with BQ categories (P<0.0005), creatinine (P<0.001), age (P<0.05), LVM (P<0.001), CO (P<0.001), LA (P<0.0005) and E/Em (P<0.01). NT-proBNP levels, LVD and LVM increased significantly along with BQ scores (P<0.0001). Stepwise multiple regression analysis identified BQ and log-transformed HOMA as independent variables predicting as much as 48.0% of log-transformed NT-proBNP's variability (dependent variable).
  
  
  CONCLUSIONS
  NT-proBNP levels are independently predicted by SDB and IR in asymptomatic MO women. Additionally, SDB worsens along with LVH and diastolic dysfunction. Larger prospective studies are warranted.
authors.affiliation: Instituto de Cardiología y Medicina Avanzada, Spain. juanybarra@hotmail.com
authors.forename: Juan
authors.initials: J
authors.lastname: Ybarra
authors.forename: Francesc
authors.initials: F
authors.lastname: Planas
authors.forename: Francesc
authors.initials: F
authors.lastname: Navarro-López
authors.forename: Sandra
authors.initials: S
authors.lastname: Pujadas
authors.forename: Jaume
authors.initials: J
authors.lastname: Pujadas
authors.forename: Jeroni
authors.initials: J
authors.lastname: Jurado
authors.forename: Jose M
authors.initials: JM
authors.lastname: Pou