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RESEARCH AND PRACTICE |
At the time of the study, Hidemi Takimoto, Nobuo Yoshiike, Fumi Kaneda, and Katsushi Yoshita were with the Division of Health and Nutrition Monitoring, National Institute of Health and Nutrition.
Correspondence: Requests for reprints should be sent to Hidemi Takimoto, MD, Office of International Collaboration, National Institute of Health and Nutrition, 1-23-1, Toyama, Shinjuku-ku, Tokyo 162–8636, Japan (e-mail: thidemi{at}nih.go.jp).
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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Objectives. 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.
Methods. 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).
Results. 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.
Conclusions. Further studies regarding topics such as increased smoking prevalence are needed to identify the underlying causes of increasing thinness.
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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Yoshiike et al.15 reported a declining trend in the average body mass index (BMI) (in kilograms per square meter) of adult women (aged 20–39 years) over 1976 to 1995 on the basis of their analysis of nationwide data from the National Nutrition Survey, Japan (NNS-J). However, in this study, there was insufficient discussion of (1) whether this trend could be related to the population size of the participants’ residence area; (2) whether this trend was starting at younger ages; and (3) whether these changes were caused by an increase in the proportion of extremely thin (BMI < 17 kg/m2) subjects. Therefore, we performed in-depth analyses focusing on women aged 15 to 29 years to describe the changes in anthropometry of Japanese women.
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METHODS |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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The subjects were divided into 3 age groups (15–19, 20–24, and 25–29 years of age) and were also divided according to the location of their residence (metropolitan, cities, and small towns), which were defined according to population size. Twelve major cities so designated by government ordinance and 23 Tokyo Metropolitan Wards were defined as metropolitan, municipalities with 50 000 to 1 000 000 residents were defined as cities, and those with fewer than 50 000 residents were defined as small towns. The census units were not always the same every year; therefore, the chance of selecting the same subjects twice was small over the 25-year period.
To evaluate the prevalence of thinness, we defined a BMI of 18.5 kg/m2 as the cutoff for thinness according to the criteria set by the Japan Society for the Study of Obesity.17 Furthermore, we analyzed the prevalence of extreme thinness using a BMI cutoff of 17 kg/m2.
To evaluate the trend in mean height, weight, and BMI, a general linear model was used to obtain the increment of each parameter per 10 years, as previously described by Yoshiike et al.15 Logistic regression analysis was used to investigate trends in the prevalence of thinness across survey year periods within the same age and residential area group. All statistical analyses were performed with the SPSS statistical package program (SPSS Inc, Chicago, Ill).
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RESULTS |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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. Increases in mean height were significant in all age and residential area groups. Significant increases in weight were observed in only 3 groups: those aged 15 to 19 years in small towns and those aged 25 to 29 years in both cities and small towns. A trend of decreasing mean BMI was significant for all groups of young women, except for subjects in the 15- to 19-year-old group who lived in small towns. The greatest decrease was observed in subjects aged 25 to 29 years in metropolitan areas, whose change in BMI was –0.42 kg/m2 per 10 years. The decrease in BMI of subjects aged 15 to 19 years and 25 to 29 years was greater in metropolitan areas and cities compared with small towns. No such difference by residential area was observed in the subjects aged 20 to 24 years.
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. A significant increase in the percentage of thin women was observed in all groups. The percentage of thin women in the metropolitan areas was greater in all age groups in the initial survey period (1976–1980), and this difference persisted until 2000. The difference between the metropolitan areas and the other 2 areas was obvious in the youngest age group (15–19 years of age); however, the prevalence of thinness among subjects aged 20 to 24 years and 25 to29 years was similar in metropolitan areas and cities in the most recent survey period (1996–2000). Approximately one fourth of young women surveyed in 1996–2000 were thin in the age groups 20 to 24 and 25 to 29 years.
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shows the changes in the prevalence of extreme thinness (BMI < 17 kg/m2). There were significant increases in all age groups. Among the subjects aged 15 to 19 years, there were no significant increases when women were grouped according to their residential area. The prevalence of extreme thinness significantly increased among subjects aged 20 to 24 years living in all 3 residential area groups. In the group aged 25 to 29 years, the increases in extreme thinness were significant in women living in cities and small towns but not in those living in metropolitan areas.
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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). The decrease was prominent among women aged 20 to 30 years old. The prevalence of thin women (BMI < 18.5 kg/m2) and extremely thin women (BMI < 17 kg/m2) significantly increased over the 25-year period. There were no differences in BMI changes and prevalence of thinness between the 3 residential areas, with the exception of the youngest age group (Table 1). The decline in BMI or increase in prevalence of thinness was observed in all age groups. The increased prevalence in extremely thin women was not the sole reason for the decline in overall BMI values (Tables 2 and 3). There may be several reasons for the dramatic increase in thinness or the decline in BMI values among Japanese women of childbearing age. First, the women who were surveyed had a misconception regarding self–body image as evidenced by the data shown by the 1998 NNS-J,16 in which over 40% of young women answered that they were overweight despite the fact that the mean BMI was between 20 and 21 kg/m2.16 The mean daily energy intake in this population was approximately 1800 kcal/d, with a standard deviation of approximately 600, indicating that over 15% of this population consumed fewer than 1200 kcal/d.16 Second, the continuous increase in the smoking rate of young women may be the reason for the changes in BMI. Although smoking status is assessed only in subjects aged 20 years or older in the NNS-J, the smoking rate in women aged 20–29 years increased from 11.9% in 1990 to 20.9% in 2000, nearly doubling in those 10 years.18 Third, it has been suggested that the overall increase in eating disorders among young Japanese women in recent years may be the cause of the decline in BMI values. However, this is unlikely to be the cause. Estimates of the incidence of eating disorders in young Japanese women are 17.1 to 30.7 per 100 000 for anorexia and 5.8 per 100 000 for bulimia,19,20 which is strikingly low compared with other industrialized countries, such as the United States (269.9 per 100 000), the United Kingdom (115.4 per 100 000), and Switzerland (70 per 100 000).21–23 However, we cannot exclude the possibility that extremely thin women in our study were not affected by eating disorders, because our survey participants were noninstitutionalized individuals.
At 21.6% in the most recent survey period (1996–2000), the high incidence of thinness in young Japanese women presents a striking contrast to that in other industrialized countries. In the United States, for example, the percentage of thin women (BMI < 18.5 kg/m2) of those aged 18 to 24 years was 7.2% in the National Health Interview Survey, 1997–1998.24 Using the same cutoff of BMI value for thinness, the prevalence in young Australian women (aged 18–23 years) was 12%.25
Health problems associated with thinness or underweight have rarely been investigated in industrialized countries. However, recent reports from Australia suggest that underweight women (BMI < 18.5 kg/m2) are more likely to report irregular menstruation or "low iron"23 and are less likely to use preventive health services such as breast examinations.26 Further studies are needed to identify the presence of health risk behaviors in these thin young Japanese women.
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Acknowledgments |
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Human Participant Protection
No protocol approval was needed for this study.
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Footnotes |
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Accepted for publication September 3, 2003.
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References |
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TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
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2. Rozin P, Fallon A. Body image, attitudes to weight, and misperceptions of figure preferences of the opposite sex: a comparison of men and women in two generations. J Abnorm Psychol. 1988;97(3):342–345.[ISI][Medline]
3. Patton GC, Selzer R, Coffey C, Carlin JB, Wolfe R. Onset of adolescent eating disorders: population based cohort study over 3 years. BMJ. 1999;318:765–768.
4. Russell JD, Mira M, Allen BJ, et al. Protein repletion and treatment in anorexia nervosa. Am J Clin Nutr. 1994;59:98–102.
5. Turner JM, Bulsara MK, McDermott BM, Byrne GC, Prince RL, Forbes DA. Predictors of low bone density in young adolescent females with anorexia nervosa and other dieting disorders. Int J Eat Disord. 2001;30:245–251.[ISI][Medline]
6. Selzer R, Caust J, Hibbert M, Bowes G, Patton G. The association between secondary amenorrhea and common eating disordered weight control practices in an adolescent population. J Adolesc Health. 1996;19:56–61.[ISI][Medline]
7. Seidell JC, Verschuren WM, van Leer EM, Kromhout D. Overweight, underweight, and mortality: a prospective study of 48 287 men and women. Arch Intern Med. 1996;156:958–963.[Abstract]
8. Troiano RP, Frongillo EA Jr, Sobal J, Levitsky DA. The relationship between body weight and mortality: a quantitative analysis of combined information from existing studies. Int J Obes Relat Metab Disord. 1996;20:63–75.[ISI][Medline]
9. Tsugane S, Sasaki S, Tsubono Y. Under- and overweight impact on mortality among middle-aged Japanese men and women: a 10-y follow-up of JPHC study cohort I. Int J Obes Relat Metab Disord. 2002;26:529–537.[ISI][Medline]
10. Singh PN, Lindsted KD, Fraser GE. Body weight and mortality among adults who never smoked. Am J Epidemiol. 1999;150:1152–1164.
11. Miyazaki M, Babazono A, Ishii T, et al. Effects of low body mass index and smoking on all-cause mortality among middle-aged and elderly Japanese. J Epidemiol. 2002;12:40–44.[Medline]
12. Nandi C, Nelson MR. Maternal pregravid weight, age, and smoking status as risk factors for low birth weight births. Public Health Rep. 1992;107:658–662.[ISI][Medline]
13. Mendelson R, Dollard D, Hall P, Zarrabi SY, Desjardin E. The impact of the Healthiest Babies Possible Program on maternal diet and pregnancy outcome in underweight and overweight clients. J Can Diet Assoc. 1991;52:229–234.[ISI][Medline]
14. Abrams B, Newman V. Small-for-gestational-age birth: maternal predictors and comparison with risk factors of spontaneous preterm delivery in the same cohort. Am J Obstet Gynecol. 1991;164:785–790.[ISI][Medline]
15. Yoshiike N, Seino F, Tajima S, et al. Twenty-year changes in the prevalence of overweight in Japanese adults: the National Nutrition Survey 1976–95. Obes Rev. 2002;3:183–190.[Medline]
16. Research Group for Health and Nutrition Information. Nutritional Status of Japanese: Results of 1998 Survey [in Japanese]. Tokyo: Daiichi Shuppan Publishing; 2000.
17. Editorial Board of the Japan Society for the Study of Obesity. Manual for Controlling Obesity. 2nd ed [in Japanese]. Tokyo: Ishiyaku Shuppan Publishing; 2001.
18. Research Group for Health and Nutrition Information. Nutritional Status of Japanese: Results of 2000 Survey [in Japanese]. Tokyo: Daiichi Shuppan Publishing; 2002.
19. Kuboki T, Nomura S, Ide M, Suematsu H, Araki S. Epidemiological data on anorexia nervosa in Japan. Psychiatry Res. 1996;62:11–16.[ISI][Medline]
20. Nakamura K, Yamamoto M, Yamazaki O, et al. Prevalence of anorexia nervosa and bulimia nervosa in a geographically defined area in Japan. Int J Eat Disord. 2000;28:173–180.[ISI][Medline]
21. Lucas AR, Beard CM, O’Fallon WM, Kurland LT. 50-year trends in the incidence of anorexia nervosa in Rochester, Minn.: a population-based survey. Am J Psychiatry. 1991;148:917–922.
22. Rooney B, McClelland L, Crisp AH, Sedgwick PM. The incidence and prevalence of anorexia nervosa in three suburban districts in southwest London, U.K. Int J Eat Disord. 1995;18:299–307.[ISI][Medline]
23. Steinhausen HC, Winkler C, Meier M. Eating disorder in adolescence in a Swiss epidemiological study. Int J Eat Disord. 1997;22:147–151.[ISI][Medline]
24. Schoenborn CA, Adams PF, Barnes PM. Body weight status of adults: United States, 1997–98. Adv Data Vital Health Stat. September 6, 2002;1–15. Publication 330.
25. Brown WJ, Mishra G, Kenardy J, Dobson A. Relationship between body mass index and well-being in young Australian women. Int J Obes Relat Metab Disord. 2000;24:1360–1368.[ISI][Medline]
26. Reidpath DD, Crawford D, Tilgner L, Gibbons C. Relationship between body mass index and the use of healthcare services in Australia. Obes Res. 2002;10:526–531.[ISI][Medline]
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| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
