title: Incident Type 2 Diabetes Risk is Influenced by Obesity and Diabetes in Social Contacts: a Social Network Analysis.
abstract: Obesity and diabetes family history are the two strongest risk factors for type 2 diabetes (T2D). Prior work shows that an individual's obesity risk is associated with obesity in social contacts, but whether T2D risk follows similar patterns is unknown.
  
  
  
  We aimed to estimate the relationship between obesity or diabetes in an individual's social contacts and his/her T2D risk. We hypothesized that obesity and diabetes in social contacts would increase an individual's T2D risk.
  
  
  
  This was a retrospective analysis of the community-based Framingham Offspring Study (FOS).
  
  
  
  FOS participants with T2D status, height and weight, and at least one social contact were eligible for this study (n = 4797 at Exam 1). Participants' interpersonal ties, cardiometabolic and demographic variables were available at eight exams from 1971 to 2008, and a T2D additive polygenic risk score was measured at the fifth exam.
  
  
  
  Primary exposures were T2D (fasting glucose ≥ 7 mmol/L or taking diabetes medications) and obesity status (BMI ≥ 30 kg/m(2)) of social contacts at a prior exam. Primary outcome was incident T2D in participants.
  
  
  
  Incident T2D was associated with having a social contact with diabetes (OR 1.32, p = 0.004) or with obesity (OR 1.21, p = 0.004). In stratified analyses, incident T2D was associated with diabetes in siblings (OR 1.64, p = 0.001) and obesity in spouses (OR 1.54, p = 0.0004). The associations between diabetes and obesity in social contacts and an individual's incident diabetes risk were stronger in individuals with a high diabetes genetic risk score.
  
  
  
  T2D and obesity in social contacts, particularly siblings and spouses, were associated with an individual's risk of incident diabetes even after accounting for parental T2D history. Assessing risk factors in an individual's siblings and spouses can inform T2D risk; furthermore, social network based lifestyle interventions involving spouses and siblings might be a novel T2D prevention approach.
authors.affiliation: Division of General Internal Medicine, Department of Medicine, Harvard Medical School and Massachusetts General Hospital, Boston, MA, USA.|Department of Veterans Affairs Medical Center, Eastern Colorado Health Care System, Denver, CO, USA.|Division of General Internal Medicine, Department of Medicine, University of Colorado School of Medicine, Denver, CO, USA.
authors.forename: Sridharan
authors.initials: S
authors.lastname: Raghavan
authors.affiliation: Department of Sociology, Computational Social Science Institute, University of Massachusetts, Amherst, MA, USA.
authors.forename: Mark C
authors.initials: MC
authors.lastname: Pachucki
authors.affiliation: Division of General Internal Medicine, Department of Medicine, Harvard Medical School and Massachusetts General Hospital, Boston, MA, USA.
authors.forename: Yuchiao
authors.initials: Y
authors.lastname: Chang
authors.affiliation: Division of General Internal Medicine, Department of Medicine, Harvard Medical School and Massachusetts General Hospital, Boston, MA, USA.
authors.forename: Bianca
authors.initials: B
authors.lastname: Porneala
authors.affiliation: Laboratory for Metabolic and Population Health, National Heart, Lung, and Blood Institute, Framingham, MA, USA.
authors.forename: Caroline S
authors.initials: CS
authors.lastname: Fox
authors.affiliation: Department of Biostatistics, Boston University School of Public Health, Boston, MA, USA.|The National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA.
authors.forename: Josée
authors.initials: J
authors.lastname: Dupuis
authors.affiliation: Division of General Internal Medicine, Department of Medicine, Harvard Medical School and Massachusetts General Hospital, Boston, MA, USA. jmeigs@partners.org.
authors.forename: James B
authors.initials: JB
authors.lastname: Meigs
mesh_terms: D000328:Adult; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology / Q000209:etiology* / Q000235:genetics; D005192:Family Health / Q000706:statistics & numerical data; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000453:epidemiology; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D012944:Social Support; D018454:Spouses; D014481:United States / Q000453:epidemiology
keywords: epidemiology; family history; obesity; social network; type 2 diabetes