Validity of self-reported 1-year body weight change in Japanese adults

Abstract

Objective: To examine the validity of self-reported 1-year body weight change among Japanese adults and compare characteristics between those who did and did not accurately recognize a > 3-kg body weight change.
Methods: We performed a longitudinal study of 2,982 workers (1,492 men, 1,490 women) who underwent specific health checkups by a health insurance society in 2009 and 2010 in Japan. We divided the participants into two groups based on their responses to the statement, “I had a > 3-kg body weight change in this year” (in 2010). They were then divided into four groups according to the amount of body weight change within 1 year, and the validity was examined. Finally, the four groups were divided into two subgroups (actual body weight gain or loss), and only the groups who experienced actual body weight changes of > 3 kg were analyzed.
Results: There were 679 participants in the inaccurate/no-change group and 191 in the inaccurate/change group; thus, 29.2% (870/2,982) of all participants were inaccurate. There were more men than women in the inaccurate/gain than accurate/gain group (64.8%, p = 0.012). Amounts and percentages of body weight gain were smaller in the inaccurate/gain than in the accurate/gain group among both men and women (all, p < 0.05).
Conclusion: About 30% of participants did not estimate their body weight change accurately. A greater number of men did not estimate their body weight gain accurately, and the gain was small in the inaccurate participants among both men and women.