title: Omega-3 index levels and associated factors in a middle-aged French population: the MONA LISA-NUT Study.
abstract: OBJECTIVE
  The omega-3 index (the summed percentage content of eicosapentaenoic and docosahexaenoic acids in red blood cells) is associated with a lower risk of fatal coronary heart disease and sudden cardiac death. We aimed to determine which socio-demographic, behavioural or clinical factors are independently associated with the omega-3 index and the extent to which seafood consumption mediates the index's association with socio-economic status (SES).
  
  
  METHODS
  As part of the cross-sectional MONA LISA-NUT survey (2005-2007), gas chromatography was used to analyse the red blood cell fatty acid composition in 503 French subjects aged 35-64 years. Dietary data were collected by trained dieticians via a validated food frequency questionnaire and a prospective 3-day food record. Risk factors were estimated with standardised measurements and questionnaires. SES was assessed through the self-reported educational and income tax levels.
  
  
  RESULTS
  The mean ± s.d. omega-3 index was 6.02 ± 1.75%. In the best parsimonious predictive model (which explained 32% of the variability in the omega-3 index), age, educational level and seafood servings were significantly and positively associated with the index. In contrast, waist circumference and smoking were inversely associated with the index. In a mediation analysis that took account of all these factors, seafood servings explained about 40% of the association between educational level and the omega-3 index. Similar results were obtained for the income tax level.
  
  
  CONCLUSIONS
  The inverse association between SES and omega-3 index is largely explained (40%) by an insufficient seafood intake. It remains to be seen which other factors mediate this association.
authors.affiliation: Department of Epidemiology and Public Health, EA 3430, FMTS, University of Strasbourg, Strasbourg, France.
authors.forename: A
authors.initials: A
authors.lastname: Wagner
authors.affiliation: CarMen, INSERM 1060/University Lyon 1, INRA U1235, CRNH Rhônes-Alpes, Lyon, France.
authors.forename: C
authors.initials: C
authors.lastname: Simon
authors.affiliation: 1] Clermont University, University of Auvergne, Department of Human Nutrition, Clermont-Ferrand, France [2] INRA, UMR 1019, UNH, CRNH Auvergne, Clermont-Ferrand, France.
authors.forename: B
authors.initials: B
authors.lastname: Morio
authors.affiliation: Department of Epidemiology and Public Health, INSERM U744, Lille Pasteur Institute, University Lille Nord-de France, Lille, France.
authors.forename: J
authors.initials: J
authors.lastname: Dallongeville
authors.affiliation: Department of Epidemiology, INSERM UMR 1027, University Paul Sabatier of Toulouse, Toulouse, France.
authors.forename: J B
authors.initials: JB
authors.lastname: Ruidavets
authors.affiliation: Department of Epidemiology and Public Health, EA 3430, FMTS, University of Strasbourg, Strasbourg, France.
authors.forename: B
authors.initials: B
authors.lastname: Haas
authors.affiliation: 1] Clermont University, University of Auvergne, Department of Human Nutrition, Clermont-Ferrand, France [2] INRA, UMR 1019, UNH, CRNH Auvergne, Clermont-Ferrand, France.
authors.forename: B
authors.initials: B
authors.lastname: Laillet
authors.affiliation: Department of Epidemiology and Public Health, INSERM U744, Lille Pasteur Institute, University Lille Nord-de France, Lille, France.
authors.forename: D
authors.initials: D
authors.lastname: Cottel
authors.affiliation: Department of Epidemiology, INSERM UMR 1027, University Paul Sabatier of Toulouse, Toulouse, France.
authors.forename: J
authors.initials: J
authors.lastname: Ferrières
authors.affiliation: Department of Epidemiology and Public Health, EA 3430, FMTS, University of Strasbourg, Strasbourg, France.
authors.forename: D
authors.initials: D
authors.lastname: Arveiler
mesh_terms: D000328:Adult; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D004032:Diet; D015930:Diet Records; D004912:Erythrocytes / Q000737:chemistry; D015525:Fatty Acids, Omega-3 / Q000097:blood*; D005260:Female; D005602:France; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015596:Nutrition Assessment; D011446:Prospective Studies; D012307:Risk Factors; D017747:Seafood; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D055105:Waist Circumference; D044465:White People
chemical_list: D015525:Fatty Acids, Omega-3