title: Implementation of permutation testing to determine clustering of social and behavioral risk factors for coronary heart disease, National Health and Nutrition Examination Survey 2001-2004.
abstract: OBJECTIVE
  To determine whether social and behavioral risk factors for coronary heart disease, including education, physical activity, fruit/vegetable intake, and smoking, cluster (i.e., co-occur more than expected as the result of chance) in U.S. adults.
  
  
  METHODS
  The study included 4305 male and 4673 female subjects aged ≥20 years from the National Health and Nutrition Examination Survey. Risk factors included: ≤high school diploma/general educational development certificate; <150 minutes of moderate/vigorous physical activity per week; <3 or <2 servings of vegetables and fruit, respectively, per day; and smoking cigarettes. Indicator variables were summed into a sociobehavioral risk index (SRI, range 0 [no risk factors] to 4 [all risk factors]). Ratios of observed-to-expected prevalence (under the assumption of independence) of the SRI were assessed. Statistical significance was evaluated by the use of randomly permuted average observed-to-expected SRI ratios and 95% confidence intervals (95% CIs).
  
  
  RESULTS
  In male subjects, the ratio of observed-to-expected prevalence of SRI = 0 was 1.70 (permuted ratio = 1.00; 95% CI: 0.92-1.08), and SRI = 4 was 2.10 (permuted ratio = 1.00, 95% CI: 0.86-1.14), demonstrating significant clustering. In females, the ratio of observed-to-expected prevalence of SRI = 0 was 1.67 (permuted ratio = 1.00, 95% CI: 0.92-1.08), and SRI = 4 was 1.86 (permuted ratio = 1.00, 95% CI: 0.85-1.15).
  
  
  CONCLUSIONS
  Social and behavioral risk factors for coronary heart disease cluster in this sample of U.S. adults.
authors.affiliation: Department of Epidemiology, Warren Alpert Medical School, Brown University, Providence, RI 02912, USA.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Everage
authors.forename: Crystal D
authors.initials: CD
authors.lastname: Linkletter
authors.forename: Annie
authors.initials: A
authors.lastname: Gjelsvik
authors.forename: Stephen T
authors.initials: ST
authors.lastname: McGarvey
authors.forename: Eric B
authors.initials: EB
authors.lastname: Loucks
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D016000:Cluster Analysis; D003327:Coronary Disease / Q000453:epidemiology*; D004522:Educational Status; D015444:Exercise; D005260:Female; D005638:Fruit; D015438:Health Behavior; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009749:Nutrition Surveys; D015995:Prevalence; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology; D014675:Vegetables; D055815:Young Adult