title: Reciprocal interactions of obstructive sleep apnea and hypertension associated with ACE I/D polymorphism in males.
abstract: BACKGROUND
  The angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism gene contributes to the genesis of hypertension (HTN) and may help explain the relationship between obstructive sleep apnea (OSA) and HTN. However, ACE is a pleiotropic gene that has several influences, including skeletal muscle and control of ventilation. We therefore tested the hypothesis that ACE polymorphism influences OSA severity.
  
  
  METHODS
  Male OSA patients (apnea-hypopnea index [AHI]>5 events/h) from 2 university sleep centers were evaluated by polysomnography and ACE I/D polymorphism genotyping.
  
  
  RESULTS
  We studied 266 males with OSA (age=48+/-13 y, body mass index=29+/-5 kg/m(2), AHI=34+/-25 events/h). HTN was present in 114 patients (43%) who were older (p<0.01), heavier (p<0.05) and had more severe OSA (p<0.01). The I allele was associated with HTN in patients with mild to moderate OSA (p<0.01), but not in those with severe OSA. ACE I/D polymorphism was not associated with apnea severity among normotensive patients. In contrast, the only variables independently associated with OSA severity among patients with hypertension in multivariate analysis were BMI (OR=1.12) and II genotype (OR=0.27).
  
  
  CONCLUSIONS
  Our results indicate reciprocal interactions between OSA and HTN with ACE I/D polymorphism, suggesting that among hypertensive OSA males, the homozygous ACE I allele protects from severe OSA.
authors.affiliation: Department of Psychobiology, Universidade Federal de São Paulo, São Paulo, Brazil.
authors.forename: Renata G
authors.initials: RG
authors.lastname: Koyama
authors.forename: Luciano F
authors.initials: LF
authors.lastname: Drager
authors.forename: Geraldo
authors.initials: G
authors.lastname: Lorenzi-Filho
authors.forename: Fátima D
authors.initials: FD
authors.lastname: Cintra
authors.forename: Alexandre C
authors.initials: AC
authors.lastname: Pereira
authors.forename: Dalva
authors.initials: D
authors.lastname: Poyares
authors.forename: José Eduardo
authors.initials: JE
authors.lastname: Krieger
authors.forename: Rosa M R P S
authors.initials: RM
authors.lastname: Castro
authors.forename: Sérgio
authors.initials: S
authors.lastname: Tufik
authors.forename: Marco Túlio
authors.initials: MT
authors.lastname: de Mello
authors.forename: Mario
authors.initials: M
authors.lastname: Pedrazzoli
mesh_terms: D000328:Adult; D000368:Aged; D000483:Alleles; D015992:Body Mass Index; D005787:Gene Frequency / Q000235:genetics; D005838:Genotype; D006720:Homozygote; D006801:Humans; D006973:Hypertension / Q000175:diagnosis / Q000235:genetics*; D054643:INDEL Mutation; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D007703:Peptidyl-Dipeptidase A / Q000235:genetics*; D010641:Phenotype; D011110:Polymorphism, Genetic / Q000235:genetics*; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000235:genetics*
chemical_list: D007703:Peptidyl-Dipeptidase A