title: Prevalence, associated factors and heritabilities of metabolic syndrome and its individual components in African Americans: the Jackson Heart Study.
abstract: OBJECTIVE
  Both environmental and genetic factors play important roles in the development of metabolic syndrome (MetS). Studies about its associated factors and genetic contribution in African Americans (AA) are sparse. Our aim was to report the prevalence, associated factors and heritability estimates of MetS and its components in AA men and women.
  
  
  METHODS
  Data of this cross-sectional study come from a large community-based Jackson Heart Study (JHS). We analysed a total of 5227 participants, of whom 1636 from 281 families were part of a family study subset of JHS.
  
  
  METHODS
  Participants were classified as having MetS according to the Adult Treatment Panel III criteria. Multiple logistic regression analysis was performed to isolate independently associated factors of MetS (n=5227). Heritability was estimated from the family study subset using variance component methods (n=1636).
  
  
  RESULTS
  About 27% of men and 40% of women had MetS. For men, associated factors with having MetS were older age, lower physical activity, higher body mass index, and higher homocysteine and adiponectin levels (p<0.05 for all). For women, in addition to all these, lower education, current smoking and higher stress were also significant (p<0.05 for all). After adjusting for covariates, the heritability of MetS was 32% (p<0.001). Heritability ranged from 14 to 45% among its individual components. Relatively higher heritability was estimated for waist circumference (45%), high density lipoprotein-cholesterol (43%) and triglycerides (42%). Heritability of systolic blood pressure (BP), diastolic BP and fasting blood glucose was 16%, 15% and 14%, respectively.
  
  
  CONCLUSIONS
  Stress and low education were associated with having MetS in AA women, but not in men. Higher heritability estimates for lipids and waist circumference support the hypothesis of lipid metabolism playing a central role in the development of MetS and encourage additional efforts to identify the underlying susceptibility genes for this syndrome in AA.
authors.affiliation: Cardiovascular Section, Metabolic, Cardiovascular and Inflammatory Disease Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Rumana J
authors.initials: RJ
authors.lastname: Khan
authors.affiliation: Cardiovascular Section, Metabolic, Cardiovascular and Inflammatory Disease Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Samson Y
authors.initials: SY
authors.lastname: Gebreab
authors.affiliation: Division of Hypertension, Department of Internal Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA.
authors.forename: Mario
authors.initials: M
authors.lastname: Sims
authors.affiliation: Cardiovascular Section, Metabolic, Cardiovascular and Inflammatory Disease Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Pia
authors.initials: P
authors.lastname: Riestra
authors.affiliation: Cardiovascular Section, Metabolic, Cardiovascular and Inflammatory Disease Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Ruihua
authors.initials: R
authors.lastname: Xu
authors.affiliation: Cardiovascular Section, Metabolic, Cardiovascular and Inflammatory Disease Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Sharon K
authors.initials: SK
authors.lastname: Davis
mesh_terms: D052242:Adiponectin / Q000097:blood; D000328:Adult; D001741:Black or African American; D000368:Aged; D001786:Blood Glucose / Q000235:genetics / Q000378:metabolism; D001794:Blood Pressure / Q000235:genetics; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D015444:Exercise; D005260:Female; D006710:Homocysteine / Q000097:blood; D006801:Humans; D050356:Lipid Metabolism / Q000235:genetics*; D008055:Lipids / Q000097:blood; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood / Q000208:ethnology* / Q000209:etiology / Q000235:genetics; D008875:Middle Aged; D015995:Prevalence; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects; D012959:Socioeconomic Factors; D013315:Stress, Psychological / Q000150:complications; D055105:Waist Circumference / Q000235:genetics*
chemical_list: D052242:Adiponectin; D001786:Blood Glucose; D008055:Lipids; D006710:Homocysteine
keywords: African Americans; Heritability; Metabolic Syndrome