Gender differences in the relationship between percent body fat (%BF) and body mass index (BMI) in Japanese children

Correlations and consistency of body composition measurement indicators and BMI: a systematic review

OBJECTIVE

It is critical to accurately determine the level of obesity and health status since overweight/obesity has become a main global public health problem. This systematic review attempted to evaluate the consistency and correlation between body composition measurement indicators and body mass index (BMI) in childhood and adolescence.

METHODS

Seven electronic databases (Web of Science, PubMed, Cochrane Library, Embase, CNKI, WANFANG DATA, SinoMed) were searched to collect the literature published since 1999 with the focus on the relationship between body composition measurement indicators and BMI to measure obesity in childhood and adolescence.

RESULTS

Among the 28 articles included, 13 articles reported a moderate to very strong correlation between %BF and BMI in obesity measurement (range: 0.49-0.907), while two articles reported a strong to very strong correlation between FM and BMI (range: 0.60-0.86). Six articles reported good to excellent obesity measurement consistency between %BF and BMI (range: 0.441-0.876), one article reported WC (0.58) and WHtR (0.46) in the moderate consistency with BMI, and one article reported a relatively poor to fair consistency between FM and BMI (range: 0.167-0.409). WC, WHtR, and BMI showed the moderate consistency in pre-adolescent children. In pre-adolescence and adolescence, the measurement consistency between %BF and BMI was higher than that between FM and BMI. Gender difference existed in the consistency between %BF and BMI during adolescence.

CONCLUSION

A range of body composition indicators such as %BF, WC, WHtR, and FM could provide valuable body composition measurements, complement BMI for obesity assessment in children and adolescents, and facilitate efficient and comprehensive surveillance of childhood obesity.

REGISTRATION

PROSPERO CRD42024506932.

The Impact of Physical Activity at School on Body Fat Content in School-Aged Children

(1) Background: Excessive amounts of adipose tissue is a health risk. The aim of this study was to assess the impact of increased physical activity (PA) at school on body fat content in children aged 10 to 12 years over a 2-year follow-up. (2) Methods: Children born in 2007 (n = 245) in two groups, (1) standard PA and (2) increased PA at school, 4 and 10 h of physical education lessons per week, respectively. BIA measurements of body fat content were taken twice a year. Results were interpreted based on children's fat content reference curves. (3) Results: During 2 years of observation, the percentage of children with excessive fat mass (overweight and obese) increased by one-third (from 28.11% to 39.67%) in the group of standard PA, while decreased by one-third in the increased PA one (from 28.92% to 21.00%); with normal fat content increased by one-quarter in the increased PA group (from 59.86% to 76.26%) and decreased by one-tenth in the standard PA one (from 61.61% to 56.29%). (4) Conclusions: An increase in PA at school has a positive impact on children's body fat content. It is recommended to increase the number of physical education lessons at school, which has a positive effect on children's health, reducing the risk of obesity.

Trends in BMI Percentile and Body Fat Percentage in Children 12 to 17 Years of Age

This study evaluates the cross-sectional trends in body fat percentage (BF%) and body mass index (BMI) percentile rank, and the relationship between the two in 332 (177 boys, 155 girls) 12- to 17-year-old children. Body mass index (BMI) was calculated using measured height and body mass, and sex-specific BMI for age percentile rank was determined using CDC growth charts. Body fat percentage (BF%) was measured with DEXA. Fat mass index (FMI) and fat-free mass index (FFMI) were calculated by normalizing the fat mass and fat-free mass for height. Compared to boys of the same age, girls had significantly higher BF% and FMI values and lower FFMI values. Compared to boys, at a given BMI percentile rank, females had a higher BF% and FMI, and a lower FFMI. In both boys and girls, there was an exponential increase in adiposity above the 70th percentile rank. BMI percentile rank is not an equivalent indicator of body fatness in boys and girls. Other measures of body composition can further inform the practitioner of a child’s adiposity.

Determination of Body Fat Ratio Standards in Children at Early School Age Using Bioelectric Impedance

Background and objectives: Body mass index (BMI) is commonly used to assess the proportionality of body mass; however, there are currently no standards for assessing the weight status of the child population for the needs of epidemiological studies. This study aims to establish bioelectric impedance analysis (BIA) standards for assessing the body weight of children (body fat, visceral fat) using BMI percentile growth charts. Materials and Methods: The study was implemented in a group of 1674 children (816 boys and 858 girls), ages 6 to 11. To classify the subjects at a percentile level, the percentile growth charts from the 6th national anthropological study in the Czech Republic were used. Body composition parameters were ascertained by BIA. Results: Body fat (%) and visceral fat standard values were determined for all age categories. The standards were in three-stages, enabling the determination of underweight, normal weight and overweight children aged 6-11 years. For boys with proportionate body mass, standard body fat values ranging from 14.3-16.0% to 15.5-18.0% were determined, while for girls' values ranging from 16.7-19.4% to 18.3-20.5% were determined, depending on age. As far as visceral fat is concerned, standard values in boys ranging from 30.3-36.9 cm2 to 36.1-44.9 cm2 and in girls 30.3-36.9 cm2 to 36.1-44.9 cm2 were determined, depending on age. Conclusions: Standards for assessing weight status are applicable to children aged 6-11 years, while it can be confirmed that BMI can be considered as an objective tool in assessing body mass and body composition in children.

Comparison of Body Mass Index and fat percentage criteria classification of 7-13 year-old rural boys in South Africa

Background

The aim of this paper was to investigate whether BMI and fat percentage classification criteria, would classify a sample of 7–13 year old boys from a rural background in similar nutritional categories.

Methods

A cross-sectional study with a stratified random sampling included 601 rural boys (7–13 years old). Fat percentage criteria classification and BMI were calculated and compared. Maturity status, and age at peak height velocity (PHV) were indirectly determined. Statistical techniques included descriptive statistics, Pearson product correlation coefficients, the Kappa agreement test and the McNemar’s test. The level of statistical significance was set at p ≤ 0.05.

Results

All age groups presented with statistically significant high correlations between BMI and fat percentage, and low to medium correlations between fat percentage and maturity age (MA). Measurement of agreement between BMI and fat percentage classifications showed poor to fair agreements for all age groups, with the exception of the eight-year old group which presented a moderate agreement.

Conclusions

Classifications based on BMI and fat percentage, results in different classifications for the same population. Until further research has been done to determine the best classification for nutritional status, it is recommended that both classification methods be used for more accurate classification of nutritional status.

Childhood Adiposity and Nonalcoholic Fatty Liver Disease in Adulthood

OBJECTIVE

To investigate the association of childhood adiposity and change in adiposity status from childhood to adulthood with nonalcoholic fatty liver disease (NAFLD) and abnormal liver enzyme levels in adulthood.

METHODS

Data were obtained from a population-based cohort of children aged 6 to 18 years started in 1987. From 2010 to 2014, 1350 subjects (aged 28-45 years) from the original cohort were followed. Childhood overweight and obesity were defined using BMI and subscapular skinfold thickness, respectively. In adulthood, ultrasound-based NAFLD, abnormal liver enzymes, and related risk factors were assessed.

RESULTS

Overweight or obese children were more likely to have adult NAFLD (males: odds ratio [OR] = 2.49 for BMI and 2.78 for subscapular skinfold thickness; females: OR = 3.34 and 3.61; all Ps < .001) and alanine aminotransferase (ALT) elevation (males: OR = 1.64 and 1.66; females: OR = 2.12 and 3.01; all Ps < .05) than children with normal weight for both sexes. Compared with subjects who had normal weight in childhood and were nonobese in adulthood, subjects who were obese in adulthood, irrespective of their childhood adiposity status, were more likely to have NAFLD and ALT elevation in adulthood for both sexes. However, subjects who were overweight or obese in childhood but became nonobese in adulthood had similar likelihood of having NAFLD and ALT elevation in adulthood for both sexes.

CONCLUSIONS

Overweight or obese children are more likely to have NAFLD and ALT elevation in adulthood. However, the risk associated with increased weight during childhood can be mitigated by becoming nonobese in adulthood.

Relationship between family meal frequency and individual dietary intake among diabetic patients

Background

Notoriously, the island of Mauritius has one of the highest prevalence of diabetes in the world. Management of the disease is very important and family meals are undoubtedly beneficial to patients as they promote the development of healthy eating behaviours and food choices. This study has aimed to probe into potential relationship(s) between family meal frequency and individual dietary intake among diabetic patients and to establish whether family cohesion may be a plausible mediator of this relationship.

Methods

A cross-sectional survey was carried out with a random sample of 384 diabetic patients. The Family Adaptability and Cohesion Evaluation Scale III was used to obtain information on two general aspects of family functioning, that is, cohesiveness and adaptability. Chi-squared (χ²) tests, independent sample t-tests and one-way ANOVA were used to determine statistical significance. Pearson correlation was used to examine associations between family meal frequency, individual dietary intake and family cohesion. Hierarchical linear regression models were performed for the mediation analysis.

Results

Family meal frequency (breakfast, lunch and dinner) was observed to be positively associated with intake of fish, raw vegetables, dried and fresh fruits, low-fat milk, cheese, yogurt, nuts and light butter and negatively associated with intake of red meat, white rice, white bread, whole egg fried, chocolates, fried cakes, burgers, chips, and fried noodles/rice. Average mediation (52.6 %) was indicated by family cohesion for the association between family meal frequency and individual dietary intake among diabetic patients. Sobel’s test further confirmed the trend towards complete mediation (z = 15.4; P < 0.05).

Conclusions

A strong relationship between family meal frequency and individual dietary intake among diabetic patients was recorded. The present study is one of the few studies that have examined family cohesion as a mediator of the relationship and to our best knowledge is the first work to demonstrate a trend towards complete mediation. Results obtained can be used by health professionals to devise strategies for increasing knowledge and awareness of both diabetic patients and their respective families to curd down this public health burden.

Relationship between body mass index and body fat in children-Age and gender differences

SUMMARY

When defining obesity body mass index (BMI) has been used as the main criterion. However it indicates only the nutritional status, whereas body fat demonstrates the real body composition picture. This study aimed at analyzing the relationship between nutritional status and adiposity in the population of 2284 Serbian children (1217 boys and 1067 girls). According to BMI subjects were divided into underweight, normal-weight, overweight and obese, and %BF values (based on skinfold thickness measurements) were analyzed with regard to BMI-category, age and gender. Girls showed stronger correlation between BMI and %BF comparing to boys (r = 0.834 vs. 0.577). Differences in %BF between underweight, normal weight and overweight children from different age groups were more obvious in girls, whereas in boys younger than 8 years overlapping in %BF values between different BMI-categories was registered. In normal weight children we found age-related oscillations in %BF values: 8- and 9-year-old boys had lower %BF comparing to 7-year-old boys, which was followed by %BF increasement in 10- and 11-year-old ones; in girls %BF values gradually increased with aging, with significant jumps in 9-, 10- and 11-year-old ones. Thus, adiposity rebound may appear somehow later in boys. In overweight and obese children of both genders %BF continually increased with aging, whereas in underweight children %BF values remained unchanged. Our results pointed to age- and gender-dependent variations of %BF in normal weight and overweight children. We also indicated inconsistency between %BF and BMI especially in boys, and the need for definition of references for %BF.:

Association between body mass index, body fat per cent and muscle power output in soccer players

The objectives of this study were to examine (a) the prevalence of overweight/obesity, (b) the relationship between body mass index (BMI) and body fat percent (BF), and (c) the association between BMI, BF and power output in adult male soccer players. Members of competitive soccer clubs (n=169, aged 22.7±4.2yr) were examined for anthropometric characteristics and body composition, and performed the physical working capacity in heart rate 170 min−1 test (PWC170), a force-velocity test (F-v) and the Wingate anaerobic test (WAnT). Based on international BMI cut-off points, 17.8% (n=30) of participants were classified as overweight. BMI was correlated with BF (r=0.67, p<0.001) and could be predicted based on the equation BF=1.193·BMI-12.24 (standard error of estimate 2.49). BMI and BF were in inverse relationship with mean power during WAnT (r=−0.30, p<0.001; r=−0.47, p<0.001, respectively). BF was also in inverse relationship with PWC170 (r=−0.26, p<0.001) and maximal power of the F-v test (r=−0.18, p=0.020).The prevalence of overweight among participants was lower than what is observed in general population. The findings confirmed previous observations on general population about the negative effect of overweight and fatness on selected parameters of physical fitness.

Elevated body mass index and body fat percentage are associated with decreased physical fitness in soccer players aged 12-14 years

Purpose

Adolescents are in increased risk for the development of obesity, while sport has been suggested as an effective means against adolescent obesity. The objectives of this study were to examine (a) the prevalence of overweightness/obesity, (b) the relationship between body mass index (BMI) and body fat percent (BF), and (c) the association between BMI, BF and physical fitness in adolescent soccer players.

Methods

Members (n=136, aged 13.1±0.6 yr) of competitive soccer clubs were examined for physical and physiological characteristics.

Results

Based on international BMI cut-off points, 19.9% (n=27) of participants were classified as overweight. BMI was highly correlated with BF (r=0.77, P<0.001). BMI and BF were in inverse relationship with aerobic power (r= − 0.29, P<0.001; r= − 0.44, P<0.001, respectively), maximal anaerobic power (r= − 0.23, P=0.009; r= − 0.47, P<0.001) and local muscular endurance (r= − 0.36, P<0.001; r= − 0.67, P<0.001).

Conclusions

The strong relationship between BMI and BF suggest the further use of BMI in adolescent soccer players. The findings confirmed previous observations in the general population about the negative effect of overweight and fatness on physical fitness. The prevalence of overweightness among participants was similar with what is observed in general population. Therefore, sport participation cannot guarantee physiological body mass and body composition, and it is necessary to prescribe exercise targeting body mass and fat control.

Number of siblings, birth order, and childhood overweight: a population-based cross-sectional study in Japan

Background

Although several studies have investigated the relationship between the number of siblings or birth order and childhood overweight, the results are inconsistent. In addition, little is known about the impact of having older or younger siblings on overweight among elementary schoolchildren. The present population-based study investigated the relationship of the number of siblings and birth order with childhood overweight and evaluated the impact of having younger or older siblings on childhood overweight among elementary schoolchildren in Japan.

Methods

Subjects comprised fourth-grade schoolchildren (age, 9–10 years) in Ina Town during 1999–2009. Information about subjects’ sex, age, birth weight, birth order, number of siblings, lifestyle, and parents’ age, height, and weight was collected by a self-administered questionnaire, while measurements of subjects’ height and weight were done at school. Childhood overweight was defined according to age- and sex-specific cut-off points proposed by the International Obesity Task Force. A logistic regression model was used to calculate the odds ratio (OR) and 95% confidence intervals (95% CI) of "number of siblings" or "birth order" for overweight.

Results

Data from 4026 children were analyzed. Only children (OR: 2.13, 95% CI: 1.45-3.14) and youngest children (1.56, 1.13-2.16) significantly increased ORs for overweight compared with middle children. A larger number of siblings decreased the OR for overweight (P for trend < 0.001). Although there was no statistically significant relationship between a larger number of older siblings and overweight, a larger number of younger siblings resulted in a lower OR for overweight (P for trend < 0.001).

Conclusions

Being an only or youngest child was associated with childhood overweight, and having a larger number of younger siblings was negatively associated with overweight. The present study suggests that public health interventions to prevent childhood overweight need to focus on children from these family backgrounds.

Eating behavior and childhood overweight among population-based elementary schoolchildren in Japan

This study investigated the relationship between eating behavior and childhood overweight among population-based elementary schoolchildren in Japan. Data was collected from fourth graders (9 or 10 years of age) from Ina Town, Saitama Prefecture, Japan from 1999 to 2009. Information about subjects' sex, age, and lifestyle, including eating behaviors (eating until full and chewing thoroughly), was obtained using a self-administered questionnaire, and height and weight were measured directly. Overweight was determined according to the definition established by the International Obesity Task Force. Data from 4027 subjects (2079 boys and 1948 girls) were analyzed. Chewing thoroughly was associated with a significantly decreased odds ratio (OR) for being overweight, whereas eating until full significantly increased the OR for being overweight (OR: 1.50, 95% confidence interval: 1.16-1.94) among boys. However, eating until full was not associated with a significantly increased OR for being overweight among the group that reported chewing thoroughly, whereas it was associated with a significantly increased OR for being overweight (2.02, 1.38-2.94) among boys who did not chew thoroughly. In conclusion, eating until full or not chewing thoroughly was associated with being overweight among elementary schoolchildren. Results of this study suggest that chewing thoroughly may be an avenue to explore childhood overweight prevention efforts.

Body mass index, waist circumference, body fat, fasting blood glucose in a sample of moroccan adolescents aged 11-17 years

Objectives. The study aimed to assess the relationship between body fat and each of body mass index (BMI) and waist circumference (WC), and to test the effectiveness of fat mass (FM), percent of body fat (PBF), BMI, and WC in predicting high levels of fasting blood glucose (FBG). Methods. A total of 167 adolescents aged 11–17 years were recruited from Rabat region. BMI and WC were determined using standard equipments. FM and PBF were derived from isotope dilution technique. FBG was determined by the hexokinase method. Results. Regardless of the weight status, BMI showed a strong positive correlation with FM and PBF in both genders. WC was significantly correlated with FM in boys and girls, and with PBF in different groups of girls and boys of the study sample. However, there was no significant relationship between WC and PBF in normal weight and overweight-obese groups of boys. FBG was highly correlated with FM and PBF in girls of the study sample and in overweight-obese girls. Similar significant relationship between FBG and both BMI and WC was observed in overweight-obese girls, while there was no significant association between FBG and other variables in boys and normal-weight girls. Conclusion. BMI and WC were closely associated with FM and PBF, respectively. However, the degree of these associations depends on gender and weight status. BMI may provide a better proxy estimate of overall adiposity than WC; nevertheless, both of them would appear to be a reasonable surrogate for FM and PBF as screening tools to identify adolescents at risk of developing excess body fat and high level of FBG.

Relationship of body mass index to percent body fat and waist circumference among schoolchildren in Japan--the influence of gender and obesity: a population-based cross-sectional study

Background

Although the correlation coefficient between body mass index (BMI) and percent body fat (%BF) or waist circumference (WC) has been reported, studies conducted among population-based schoolchildren to date have been limited in Japan, where %BF and WC are not usually measured in annual health examinations at elementary schools or junior high schools. The aim of the present study was to investigate the relationship of BMI to %BF and WC and to examine the influence of gender and obesity on these relationships among Japanese schoolchildren.

Methods

Subjects included 3,750 schoolchildren from the fourth and seventh grade in Ina-town, Saitama Prefecture, Japan between 2004 and 2008. Information about subject's age, sex, height, weight, %BF, and WC was collected from annual physical examinations. %BF was measured with a bipedal biometrical impedance analysis device. Obesity was defined by the following two criteria: the obese definition of the Centers for Disease Control and Prevention, and the definition of obesity for Japanese children. Pearson's correlation coefficients between BMI and %BF or WC were calculated separately for sex.

Results

Among fourth graders, the correlation coefficients between BMI and %BF were 0.74 for boys and 0.97 for girls, whereas those between BMI and WC were 0.94 for boys and 0.90 for girls. Similar results were observed in the analysis of seventh graders. The correlation coefficient between BMI and %BF varied by physique (obese or non-obese), with weaker correlations among the obese regardless of the definition of obesity; most correlation coefficients among obese boys were less than 0.5, whereas most correlations among obese girls were more than 0.7. On the other hand, the correlation coefficients between BMI and WC were more than 0.8 among boys and almost all coefficients were more than 0.7 among girls, regardless of physique.

Conclusions

BMI was positively correlated with %BF and WC among Japanese schoolchildren. The correlations could be influenced by obesity as well as by gender. Accordingly, it is essential to consider gender and obesity when using BMI as a surrogate for %BF and WC for epidemiological use.