Prevalence and characteristics of misreporting of energy intake in Japanese adults: the 2012 National Health and Nutrition Survey.

BACKGROUND AND OBJECTIVES: Information on a whole array of characteristics associated with dietary misreporting in a representative sample in each country is still limited. Using data from the 2012 National Health and Nutrition Survey, Japan, we investigated the prevalence and characteristics of under- and over-reporting of energy intake among 19,986 Japanese adults aged >=20 years.

METHODS AND STUDY DESIGN: Each individual's energy intake was calculated based on a 1-day semi-weighed dietary record. Under-, plausible, and over-reporters were identified based on the 95% confidence limits 1) for agreement between the ratio of energy intake to basal metabolic rate and a physical activity level for sedentary lifestyle (1.55), and 2) of the expected ratio of energy intake to estimated energy requirement of 1.0, assuming 'low active' level of physical activity.

RESULTS: Almost all subjects (>=92.8%) were classified as plausible reporters by any of the methods applied, with very low percentages of under- and over-reporters (<=6.3% and <=2.0%, respectively). Under-reporting was associated with younger age, overweight and obesity (compared with normal weight), current smoking (compared with never smoking), no alcohol drinking (compared with drinking everyday), and household consisting of a single person (compared with that consisting of two persons). Over-reporting was associated with gender (female), normal weight (compared with overweight), and household consisting of a single person.

CONCLUSIONS: Overall mean energy intake obtained in this sample of Japanese adults appears to be plausible, but caution should be exercised when assessing the plausibility of energy intake in some subgroups.