Thinness among young Japanese women.

Abstract

We described changes in body mass index (BMI) and the prevalence of thinness among young Japanese women (aged 15-29 years) from 1976 to 2000 by reanalyzing the nationwide data in the National Nutrition Survey, Japan. We used height and weight data sets for 30 903 nonpregnant, nonlactating women during the 25-year period. We calculated the mean values of BMI and the prevalence of thinness for 3 age groups (15-19, 20-24, and 25-29 years of age). Changes in BMI per 10 years were -0.17 kg/m2, -0.22 kg/m2, and -0.34 kg/m2 for each age group, respectively. Extreme thinness (BMI < 17 kg/m2) increased from 2.4% in 1976-1980 to 4.2% in 1996-2000. Further studies regarding topics such as increased smoking prevalence are needed to identify the underlying causes of increasing thinness.