title: Is the national nutrition survey in Japan representative of the entire Japanese population?
abstract: OBJECTIVE
  We examined the representativeness of the sample used in the National Nutrition Survey in Japan (J-NNS).
  
  
  METHODS
  The distribution of the J-NNS sample from 1995 to 2000 was compared with that of the national census with respect to gender, age group, place of residence, and number of household members.
  
  
  RESULTS
  In the survey sample, as compared with the national census distributions, the proportion of females was 1% to 2% larger, the proportion of individuals who were 20 to 39 y of age was a few percentages smaller, and a slight bias toward rural areas was seen. Among individuals who were 20 to 59 y of age, the proportion of individuals who lived in single-person households was 50% to 66% of that found in the national census. Observed disparities between the sample and the population were minimal except in the case of the proportion of individuals who lived alone.
  
  
  CONCLUSIONS
  The sample used in the J-NNS is generally representative of the entire Japanese population with the exception of individuals in single-person households.
authors.affiliation: Division of Health Informatics and Education, National Institute of Health and Nutrition, Tokyo, Japan. katanoda-tky@umin.ac.jp
authors.forename: Kota
authors.initials: K
authors.lastname: Katanoda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nitta
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Hayashi
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Matsumura
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D003710:Demography; D005191:Family Characteristics; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D012494:Sampling Studies; D017678:Sex Distribution