title: Prevalence and risk factors for obstructive sleep apnea in a multiethnic population of patients presenting for bariatric surgery in Singapore.
abstract: BACKGROUND
  Obesity is becoming more prevalent world wide. Bariatric surgery is one treatment option for patients with severe or morbid obesity. There have been few comprehensive studies examining prevalence and risk factors for obstructive sleep apnea (OSA) in the multiracial Singaporean bariatric surgery population.
  
  
  METHODS
  We performed full polysomnography on 176 consecutive patients undergoing assessment for bariatric surgery. Questionnaires regarding snoring, the presence of witnessed apneas and the Epworth Sleepiness Scale (ESS) were administered. Anthropometric and demographic measurements include age, sex, race, body mass index (BMI) and neck circumference.
  
  
  RESULTS
  The prevalence of OSA was 72%, and 49% of the 176 patients had an AHI >= 15. There was a male predominance of OSA (X(2) = 29.7; p<0.001). OSA subjects had larger neck circumference (43.9 +/- 4.5 vs. 39.4 cm +/- 3.3; p<0.001) and higher BMI (43.1 +/- 7.6 vs. 39.1 +/- 5.4 kg/m(2); p<0.001). The neck circumference (OR = 1.37; p<0.001), presence of snoring (OR = 8.25; p<0.001) and an ESS >10 (OR = 3.24; p = 0.03) were significant independent predictors of an AHI >= 15. A neck circumference of 43 cm had an 80% sensitivity and 83% specificity for predicting an AHI >= 15.
  
  
  CONCLUSIONS
  OSA is common amongst Singaporeans undergoing evaluation for bariatric surgery, with a high prevalence of moderate and severe disease. An increased neck circumference is a strong independent predictor for an AHI >= 15, with a neck circumference of greater than 43 cm being a sensitive and specific predictor. Race was not found to be a risk factor.
authors.affiliation: Division of Respiratory Medicine, Department of Medicine, Alexandra Hospital, 378 Alexandra Road, Singapore 159964, Singapore. yeow_hian_lee@alexhosp.com.sg
authors.forename: Yeow Hian
authors.initials: YH
authors.lastname: Lee
authors.forename: Azman
authors.initials: A
authors.lastname: Johan
authors.forename: Keith Keat Huat
authors.initials: KK
authors.lastname: Wong
authors.forename: Natalie
authors.initials: N
authors.lastname: Edwards
authors.forename: Colin
authors.initials: C
authors.lastname: Sullivan
mesh_terms: D000293:Adolescent; D000328:Adult; D050110:Bariatric Surgery; D002681:China / Q000208:ethnology; D015331:Cohort Studies; D005006:Ethnicity / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007194:India / Q000208:ethnology; D008296:Malaysia / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000150:complications* / Q000208:ethnology / Q000601:surgery; D015995:Prevalence; D012307:Risk Factors; D012846:Singapore; D020181:Sleep Apnea, Obstructive / Q000208:ethnology*; D055815:Young Adult