title: Study design, exposure variables, and socioeconomic determinants of participation in Diet, Cancer and Health: a population-based prospective cohort study of 57,053 men and women in Denmark.
abstract: OBJECTIVE
  Diet is considered an important aspect of lifestyle related to cancer development. To contribute further knowledge within this field a Danish prospective cohort study "Diet, Cancer and Health" has been initiated. The aims of this paper are to give a description of the study design, measurement procedures, and differences between participants and non-participants with special reference to socioeconomic characteristics.
  
  
  METHODS
  A total of 160,725 individuals 50-64 years of age living in Copenhagen or Aarhus were invited to participate. Information concerning diet and other lifestyle factors was obtained from 57,053 participants using questionnaires and interviews. Anthropometric measurements were taken and biological material collected. In addition, detailed (selected) socioeconomic information on all invited persons including 103,671 non-participants was obtained from statistical registers in Statistics Denmark.
  
  
  RESULTS
  Differences were seen between participants and non-participants on a number of socioeconomic factors. The highest participation in relation to education was found among participants with higher education, with a significant tendency to be highest in the second highest level of higher education (3-4 years). Married people were more likely to participate than persons living alone or cohabiting.
  
  
  CONCLUSIONS
  Results from the prospective cohort study "Diet, Cancer and Health" support the general assumption that lower socioeconomic groups are underrepresented in epidemiological studies.
authors.affiliation: Danish Cancer Society, Institute of Cancer Epidemiology, Copenhagen, Denmark.
authors.forename: Anne
authors.initials: A
authors.lastname: Tjønneland
authors.forename: Anja
authors.initials: A
authors.lastname: Olsen
authors.forename: Katja
authors.initials: K
authors.lastname: Boll
authors.forename: Connie
authors.initials: C
authors.lastname: Stripp
authors.forename: Jane
authors.initials: J
authors.lastname: Christensen
authors.forename: Gerda
authors.initials: G
authors.lastname: Engholm
authors.forename: Kim
authors.initials: K
authors.lastname: Overvad
mesh_terms: D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D004032:Diet; D004812:Epidemiologic Methods; D005247:Feeding Behavior; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007407:Interviews as Topic; D008019:Life Style; D008297:Male; D009369:Neoplasms / Q000453:epidemiology* / Q000209:etiology; D011446:Prospective Studies; D012107:Research Design; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires