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.
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.