Trends in thin body stature among Japanese male adolescents, 2003–2012

Misreporting of height and weight by primary school children in Japan: a cross-sectional study on individual and environmental determinants

BACKGROUND

Appropriate body constitution during childhood is important for future health. However, it has been suggested that thinness is increasing among adolescent girls and boys in Japan. Since misreporting of height/weight may be a possible reflection of the child's ideal body image, we investigated the magnitude and direction of height/weight misreporting and its determinants among Japanese young adolescents.

METHODS

A total of 1019 children in public primary schools were included in the analysis. Both measured and self-reported values of height/weight were obtained. Misreporting of height/weight was calculated by subtracting the measured value from the self-reported value. The association between misreporting and several variables such as the BMI z-score of individuals and body constitution of surrounding children was explored by multivariate linear mixed models.

RESULTS

As BMI z-score increased, 'overreporting' of height by boys and 'underreporting' of height by girls became larger (p = 0.06 in boys, p = 0.02 in girls). Both boys and girls with a larger body size tended to underreport their weight (p < 0.01 in boys, p < 0.01 in girls). Boys who belonged to a school with a larger average BMI z-score were more likely to overreport their weight. This tendency was not observed for girls.

CONCLUSIONS

Self-reported height/weight was generally accurate in Japanese primary school children. However, even primary school children misreported their height/weight intentionally like adults, possibly due to social pressure to lose weight or that not to stand out. Thus, health education about appropriate body constitution should be provided from the beginning of adolescence, particularly for girls.

Health-Related Lifestyles in Relation to Body Mass Index Among Young and Middle-Aged Women in Japan

BACKGROUND

Being underweight, overweight, or obese can lead to adverse health effects. Hence, it is important to understand the specific factors that change the burden of underweight and overweight to target appropriate disease control strategies. This study was designed to examine the prevalence and factors associated with underweight and overweight among young and middle-aged women in Japan.

MATERIALS AND METHODS

A cross-sectional study was conducted among women aged 20-59 years who participated in health checkups at a regional health care center in 2018 and 2019 (N = 1722). The assessments included anthropometric, blood pressure measurements, and a standardized self-administered questionnaire. Multivariable logistic regression analysis assessed lifestyle factors associated with body mass index for underweight <18.5 kg/m²) and overweight/obesity (25.0 kg/m² and above).

RESULTS

The prevalence of underweight and overweight/obesity were 12.3%, and 22.5%, respectively. No lifestyle factors were found to be significantly associated with being underweight. Having dinner within 2 hours before bed was positively associated with being overweight/obese [adjusted odds ratio (AOR): 1.448, 95% confidence interval (CI): 1.014-2.068]. Women who gained 10 kg since their 20s were more likely to fall into overweight/obesity category (AOR: 9.674, 95% CI: 1.014-2.068). Women who were using a lipid-lowering medication (AOR: 3.150, CI: 1.892-5.246) were associated with three times higher risk of being overweight/obese. Hypertension and dyslipidemia were significantly associated with overweight/obesity (AOR: 3.094, 95% CI: 2.201-4.351 and AOR: 2.498, 95% CI: 1.831-3.409, respectively).

CONCLUSION

One in five middle-aged women was overweight or obese, whereas one in eight was underweight. In relation to the prevention of overweight/obesity, specific health promotion messages regarding eating timing should be developed.

Maternal pre-pregnancy underweight is associated with underweight and low bone mass in school-aged children

INTRODUCTION

A number of studies have reported that pre-pregnancy overweight status is associated with offspring obesity, yet only a few studies have examined pre-pregnancy underweight status as it associates with offspring health. The aim of the present study was to assess the effect of pre-pregnancy underweight status in a mother on health outcomes in her offspring. To this end, the primary outcome examined in the present study was underweight status in the offspring, with a secondary outcome of offspring low bone mass.

MATERIALS AND METHODS

The present retrospective cohort study, conducted from 2008 to 2011, targeted a source population of all students registered as fifth-graders at three public elementary schools in Hamamatsu and Fukuroi cities. Maternal height and weight before and after pregnancy and offspring weight and height at birth were obtained from the Maternal and Child Health Handbook. Offspring weight and height at age 10 years were measured using standard procedures. Offspring total body less head (TBLH) bone mineral content (BMC) was determined with a dual-energy X-ray absorptiometry scanner.

RESULTS

Pre-pregnancy underweight status was found to be associated with an increased risk of an underweight status in female offspring (OR = 2.88, 95% CI 1.06-7.81). Offspring TBLH BMC in the underweight mother group was significantly lower than that in the non-underweight mother group.

CONCLUSIONS

We determined that pre-pregnancy underweight status was more likely to lead to an underweight status and low TBLH BMC in school-aged offspring.

Impact of the school lunch program on overweight and obesity among junior high school students: a nationwide study in Japan

BACKGROUND

Japan has experienced a low prevalence of childhood obesity. The Japanese nationwide school lunch program is suggested to have helped this phenomenon, but it has not been proven.

METHODS

From official statistics, we combined annual data for 2006-15 about the prefecture-level school lunch coverage rate for public junior high school students and the prefecture-level nutritional indicators calculated by randomly selected age-sex groups of 13-15-year olds: the percentage of overweight, obese or underweight children, who are 20% heavier, 30% heavier or 20% lighter than the standard weight by sex, age and height; and mean body weight (kg) or height (cm). We estimated the impact of the school lunch coverage rate on the nutritional indicators in subsequent years, adjusting for the lagged dependent variable and dummies for prefecture, age and year.

RESULTS

A 10 percentage point increase in the prefecture-level school lunch coverage rate significantly decreased the percentage of overweight (0.37%, 95% CI: 0.18-0.56) and obesity (0.23%, 0.10-0.37) in subsequent years among boys, but not among girls. No significant effect on the percentage of underweight or mean body weight/height was observed for either sex.

CONCLUSIONS

Appropriate nutritional intake through school lunch may be effective to reduce childhood obesity.

An exploration of the psychometric properties of the SATAQ-4 among adolescent boys in Japan

Research among Western adult and adolescent males suggests that sociocultural influences are implicated in the drive for muscularity and weight-change behaviors. However, few studies have examined these relationships among adolescent boys from non-Western backgrounds. The current study sought to assess the psychometric properties of the Sociocultural Attitudes Towards Appearance Questionnaire-4 (SATAQ-4), a 22-item, 5-factor measure of sociocultural influence on appearance ideals, among Japanese (n = 984) adolescent boys. Relationships between appearance-related pressures, appearance ideal internalization, appearance-related teasing, drive for muscularity, and weight-change behaviors were also assessed. Exploratory and confirmatory factor analyses identified a four factor solution (Internalization: Thin/Low Body Fat, Internalization: Muscular/Athletic, Pressures: Media, and Pressures: Family/Peers) with 16 items in this sample. Correlational analyses supported the construct validity of the SATAQ-4. Thin internalization was associated with strategies to lose weight, while muscular internalization was associated with drive for muscularity and strategies to gain weight. Further, peer and parental appearance teasing was associated with perceived appearance pressures from family and peers, as well as weight change strategies. Overall, results suggested modification of the SATAQ-4 when used with Japanese samples, but supported its use to assess sociocultural influences. Additionally, the results highlight that sociocultural influences and muscularity concerns among Japanese adolescent boys are associated in similar ways with weight change strategies as has been established for adolescent males in Western countries.

The Relationship of Eating Rate and Degree of Chewing to Body Weight Status among Preschool Children in Japan: A Nationwide Cross-Sectional Study

There is growing recognition that eating slowly is associated with a lower risk of obesity, and chewing well might be an effective way to reduce the eating rate. However, little is known about these relationships among children. We therefore investigated the associations of eating rate and chewing degree with weight status among 4451 Japanese children aged 5⁻6 years. Information on eating rate (slow, medium, or fast), degree of chewing (not well, medium, or well), and nutrient intake of children were collected from guardians using a diet history questionnaire. Weight status was defined using the International Obesity Task Force cut-offs based on BMI calculated from guardian-reported height and weight. The prevalence of overweight and thinness was 10.4% and 14.3%, respectively. A higher eating rate and a lower degree of chewing were associated with being overweight (both p < 0.001). Eating slowly was associated with being thin (p < 0.001), but no association was observed between chewing degree and thinness. These associations were still evident after controlling for potential confounders including parental educational attainment, weight status, and the child's nutrient intake. In conclusion, this cross-sectional study suggested that chewing well, rather than eating slowly, might be a more effective way for healthy weight management among Japanese preschool children.

Lifestyle factors associated with underweight among Japanese adolescents: a cross-sectional study

Background

Because underweight in adolescents poses several health problems, it is important to prevent it in adolescence. For the prevention of underweight, it is necessary to investigate risk factors, especially lifestyles, because these can be modified. However, a limited number of studies exist regarding lifestyle factors associated with underweight among adolescents. The present study aimed to investigate the relationship between lifestyle factors and underweight among Japanese adolescents.

Methods

Study subjects comprised 2641 seventh-grade school children (age 12 or 13 years) from the town of Ina, Saitama Prefecture, Japan. Measurements of height and weight were made for each subject, while information regarding lifestyles of each subject was obtained using a self-administered questionnaire. Underweight was determined by the age- and sex-specific body mass index cut-off points. A logistic regression model was used to estimate the odds ratio (OR) and 95% confidence interval (95% CI) for underweight.

Results

Adolescents who ate slowly were more likely to be underweight than those who did not eat slowly; the OR (95% CI) was 2.78 (1.77–4.39) in boys and 2.69 (1.81–3.98) in girls. Girls who did not exercise were more likely than those who exercised to be underweight (OR: 1.64, 95% CI: 1.07–2.51).

Conclusions

The present study showed that eating slowly and exercise were associated with underweight among Japanese adolescents. These results suggest that eating speed and exercise need to be considered in school health programs for healthy body weight.

Association between distorted body image and changes in weight status among normal weight preadolescents in Japan: a population-based cohort study

BACKGROUND

Distorted body image may be important risk factors for being underweight and overweight. The objective of this study was to investigate the association between having a distorted body image and being overweight or underweight among normal weight preadolescents in a population-based cohort study in Japan for each sex.

METHODS

The study participants were 1431 normal weight fourth-grade students (age range: 9-10 years) in Ina town, Japan from 2002 to 2007. The height and weight of each student were measured while they were in the fourth grade (at baseline) and seventh grade (3 years later). Childhood underweight and overweight were defined using the body mass index cut-off points proposed by the International Obesity Task Force. Information regarding the self-perceived weight status of each student at baseline was collected using a self-administered questionnaire. Children who were normal weight but perceived themselves as heavy or thin were regarded as having a distorted body images. A logistic regression model was used to calculate the odds ratios (ORs) and 95 % confidence interval (95 % CI) for being overweight or underweight 3 years later among those having a distorted body image at baseline.

RESULTS

Both boys and girls who perceived themselves to be heavy at baseline were at a statistically significantly greater risk of being overweight 3 years later as compared to boys and girls, respectively, who identified as being at a normal weight at baseline (boys: adjusted OR: 4.66, 95 % CI: 1.01-21.48; girls: 3.88, 1.56-9.65). Both boys and girls who perceived oneself to be thin at baseline were at a statistically significantly greater risk of bring underweight 3 years later as compared to boys and girls, respectively, who identified as being at a normal weight at baseline (boys: 5.51, 2.20-13.80; girls: 2.93, 1.40-6.11).

CONCLUSION

The results of the present study suggest that having a distorted body image in preadolescence is associated with being overweight or underweight in adolescence, among boys and girls, separately. Therefore, education regarding self-perceived weight could be important to help prevent underweight and overweight/obesity among preadolescent boys and girls in Japan.

The relationship between distorted body image and lifestyle among Japanese adolescents: a population-based study

Background

Distorted body image plays a significant role in the development of obesity, eating problems, and eating disorders. The aim of this study was to investigate the relationship between distorted body image and lifestyle among Japanese adolescent boys and girls.

Methods

Subjects were 1731 seventh graders (age 12–13 years) from the Ina-town’s junior high schools, Japan, from 2005–2009. The height and weight of each subject were measured. Childhood underweight, overweight, and obesity were defined using the body mass index cutoff points proposed by the International Obesity Task Force. Information regarding the self-perceived weight status and lifestyles (exercise, snacking after dinner, breakfast, wakeup time, bedtime) of each subject was collected using a self-administered questionnaire. Self-perceived weight status was categorized into three groups (thin, normal, or heavy), and compared with the subjects’ actual weight status. Body image perception was categorized into the following three groups: an underestimated own weight status group (underestimated group), a correct own weight status group (correct group) and an overestimated own weight status group (overestimated group).

Results

The proportion of boys in the underestimated group was higher than that of girls, while the opposite was true for the overestimated group (P < 0.001). There were no statistically significant differences in lifestyle between the underestimated group and the correct group regardless of sex. In contrast, there were statistically significant differences between the overestimated group and the correct group in the lifestyle factors of exercise among boys and snacking after dinner among girls. The adjusted odds ratio (OR) in boys who exercised daily significantly decreased (OR: 0.35, 95 % CI: 0.16–0.77), while a significantly increased OR was observed in girls who snacked after dinner (OR: 1.53, 95 % CI: 1.07–2.19).

Conclusion

Adolescent boys tended to underestimate their body weight, whereas adolescent girls were likely to overestimate their body weight. Furthermore, lifestyle factors associated with distorted body image differed by sex, with exercise affecting body image perception among boys and snacking after dinner affecting body image perception among girls. Thus, lifestyle may lead to distorted body image among adolescents.

Body weight status misperception and its association with weight control behaviours, depressive mood and psychological distress in nulliparous normal-weight young women

BACKGROUND

Understanding body weight status dissatisfaction may be important for understanding weight control behaviours and mental health.

AIMS

To investigate the relationships between body weight status misperceptions in nulliparous normal-weight young women and weight control-related behaviours and mental health.

SUBJECTS AND METHODS

Body weight perceptions, weight control methods, depressive mood and psychological distress were measured in 717 nulliparous normal-weight women, aged 18-40 years, who participated in the 2007-2009 Korean National Health and Nutrition Examination Surveys (KNHANES-IV).

RESULTS

Among 717 participants, 24 subjects (4.1 ± 1.0%) misperceived themselves to be underweight and 295 subjects (39.2 ± 2.2%) misperceived themselves to be overweight. Those with overweight misperceptions were more likely to fail to maintain their targeted body weights, despite weight control efforts (p < 0.001). Weight control behaviours such as taking diet pills were more common among women with overweight misperception (p < 0.001). Compared to the accurate body weight perception group, age-adjusted ORs for depressive mood and psychological distress were 1.82 (1.06-3.13) and 1.65 (1.10-2.47) in the overweight misperception group.

CONCLUSIONS

Body weight status misperception may be important for understanding weight control-related behaviours and psychiatric illness among nulliparous normal-weight young women.