No abstract

MATSUSHITA, YUMI, NOBUO YOSHIIKE, FUMI KANEDA, KATSUSHI YOSHITA, AND HIDEMI TAKIMOTO. Trends in childhood obesity in Japan over the last 25 years from the National Nutrition Survey. Obes Res. 2004;12:205-214. Objective: To describe the 25-year changes in BMI (measured in kilograms per meters squared) and the prevalence of obesity in Japanese children with special reference to urban-rural differences. Research Methods and Procedures:We used the data sets from the cross-sectional annual nationwide surveys (National Nutrition Survey, Japan) conducted from 1976 to 2000 and comprising 29,052 boys and 27,552 girls between 6 and 14 years of age. We carried out the trend analyses with the data on sex and age groups and on residential areas according to the size of the municipality (metropolitan areas, cities, and small towns). Results: The mean (age-adjusted) BMI increased by ϩ0.32 kg/m 2 per 10 years in boys and by ϩ0.24 kg/m 2 per 10 years in girls, increases that were remarkable in small towns. The prevalence of obese boys and girls increased from 6.1% and 7.1%, respectively, in the time-period 1976 to 1980, to 11.1% and 10.2% in 1996 to 2000. The increasing trend was most evident in 9-to 11-year-old children of both sexes living in small towns, whereas no changes were observed in girls in metropolitan areas. Discussion: Our data clearly show increasing trends in obesity prevalence in Japanese school children. Degrees of the increasing trends, however, differed across sex and age groups and residential areas, demonstrating a particular phenomenon that girls in metropolitan areas were unlikely to become obese. These epidemiological aspects indicate the priorities for intervention in population strategies to control obesity in children.

Further studies regarding topics such as increased smoking prevalence are needed to identify the underlying causes of increasing thinness.

The present study describes findings in relation to perceived body size and 'desire for thinness' by age and residential areas ('metropolitan areas', 'large cities', 'small cities' and 'towns') among young Japanese women. Data on 1731 non-pregnant, non-lactating women aged 15-39 years from the 1998 National Nutrition Survey of Japan were used. Current body size was evaluated by BMI percentiles (lean, <5th; underweight, 5th or = BMI <25th; normal, 25th< or = BMI< 75th; overweight, 75th < or =BMI <95th; obese, > or =95th), calculated for 5-year age groups. Perceived body size was obtained by self-report. We defined 'overestimation' as non-overweight, non-obese women who perceived themselves as being 'overweight' or 'obese'. Desired body size was evaluated by applying the desired BMI to these cut-off points. Of all the women, 48.4% perceived themselves as being 'overweight' or 'obese', and 43.7% desired a 'lean' or 'underweight' body size. Adjusted for the current BMI, the OR for 'overestimation' calculated by a logistic regression model was significantly elevated in the 15-19-year age group (OR 2.79; 95% CI 1.76, 4.43), compared with the 25-29-year age group. The OR for 'desire for thinness' was significantly high in the 35-39-year age group (OR 2.74; 95% CI 1.93, 3.89) and the 15-19-year age group (OR 2.26; 95% CI 1.57, 3.24). Women living in metropolitan areas had higher OR for 'desire for thinness' (but not for 'overestimation') than did women in towns (OR 1.47; 95% CI 1.05, 2.07). The findings suggest the nature of excessive weight concerns of young women in Japan; thus efforts to control such health-risk behaviours at a national level are urgent.

Our data suggest that higher plasma tHcy in the third trimester is a predictor of lower birth weight. In general, the dietary intake of B-vitamins and energy may be inadequate in our population, suggesting intervention is necessary.