Characteristics of food group intake by household income in the National Health and Nutrition Survey, Japan.

This study examines the relationship between of food group intake and household income in a representative Japanese population. A total of 11,015 subjects (5,127 men and 5,888 women) aged 20 to 79 years, in 5,475 households who were part of the National Health and Nutrition Survey, Japan, in 2010 and 2011 were analyzed. Dietary intake was recorded for one day in November for those aged one year and older, from 300 randomly selected survey districts. Household income per year was recorded in the questionnaire in three categories: low (<2 million yen), middle (2-6 million yen) and high (>=6 million yen). Multilevel regression modelling was applied to take into account the hierarchical data structure of subjects nested within households, and households nested within survey districts. Dichotomous variables divided at the median intake of each food group were used. In a model where sex, age, household size and population size of municipalities to which survey districts belonged were adjusted, the total energy intake was found to be highest in individuals from middle income households, and lowest for those from low income households. In models where a total energy intake was additionally adjusted, household members with low and middle incomes had a significantly higher intake of cereals, and a lower intake of potatoes and starches, pulses, vegetables, fruits, mushrooms, fish and shellfish, milk and seasonings and spices compared with those with high incomes. In conclusion, household members with lower incomes in Japan consumed more staple foods, but less vegetable, fruit and fish.