title: Synergy of BMI and family history on diabetes: the Humboldt Study.
abstract: OBJECTIVE
  To examine the joint effect of family history and BMI on diabetes.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  A rural community in Saskatchewan, Canada.
  
  
  METHODS
  The analysis was based on data from 2081 adults, 18-79 years of age, who participated in the Humboldt Study conducted in 2003. Doctor-diagnosed diabetes and family history of diabetes of biological parents and siblings were self-reported. Body weight and height were objectively measured. The interaction of family history and BMI on diabetes was assessed on an additive scale.
  
  
  RESULTS
  The prevalence of diabetes was 7.9 %, and BMI and history of diabetes were two important predictors. The adjusted prevalence ratios were 1.76 (95 % CI 1.37, 2.27) and 2.59 (95 % CI 2.05, 3.31) for those with a BMI of 25.0-29.9 kg/m2 and of at least 30 kg/m2, respectively, compared with a BMI of less than 25 kg/m2, and was 2.41 (95 % CI 2.08, 2.80) for those with a family history of diabetes v. those without. The data indicated an additive interaction of family history and BMI on diabetes.
  
  
  CONCLUSIONS
  When exposed to both family history and overweight/obesity, individuals would have an increased risk that was greater than the sum of their single effects. Reduction of BMI would also reduce the risk of diabetes associated family history.
authors.affiliation: Department of Epidemiology and Community Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada. ychen@uottawa.ca
authors.forename: Yue
authors.initials: Y
authors.lastname: Chen
authors.forename: Donna C
authors.initials: DC
authors.lastname: Rennie
authors.forename: James A
authors.initials: JA
authors.lastname: Dosman
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology / Q000235:genetics* / Q000517:prevention & control; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009765:Obesity; D015995:Prevalence; D012307:Risk Factors; D012424:Rural Population / Q000706:statistics & numerical data; D012525:Saskatchewan / Q000453:epidemiology; D012737:Sex Factors; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D055815:Young Adult