Kumiko Ohara

Vitamin D status and body fat measured by dual-energy X-ray absorptiometry in a general population of Japanese children

OBJECTIVE For a general population of children, data on the relationship between vitamin D status and adiposity are limited. The aim of this study was to assess the relationships between the serum concentration of 25-hydroxyvitamin D (25-OH-D) and body fat variables measured by dual-energy X-ray absorptiometry (DXA) in a general population of Japanese children, including underweight, normal, and overweight children. METHODS The source population comprised 521 fifth-grade children who attended either of the two public schools in Hamamatsu, Japan. Total and regional body fat mass (FM) measured by DXA were evaluated along with the serum concentration of 25-OH-D. RESULTS We were able to analyze the FM and 25-OH-D data of 400 of the 521 children. Among boys, significant inverse relationships were observed between serum vitamin D levels and body fat variables (total FM, r = -0.201; trunk FM, r = -0.216; appendicular FM, r = -0.187; P < 0.05 for all values). Mean values of total FM and trunk FM in the vitamin D-deficient group (25-OH-D <50 nmol/L) were larger than those in the vitamin D-sufficient group (25-OH-D ≥75 nmol/L) after adjusting for confounding factors, such as sedentary behavior (P < 0.05). No relationship was observed between vitamin D status and FM among girls. CONCLUSIONS Vitamin D deficiency was associated with higher total and trunk adiposities in a general population of Japanese children, particularly boys.

Combined influence of media use on subjective health in elementary school children in Japan: a population-based study

BackgroundIn recent years in Japan, electronic games, home computers, and the internet have assumed an important place in people’s lives, even for elementary school children. Subjective health complaints have also become a problem among children. In the present study, we investigated the relationship between media use and health status in elementary school children in Japan.MethodsA cross-sectional school-based population survey was conducted in 2009 with a sample of fourth-, fifth-, and sixth-grade children (age range: 10–12 years old) in elementary schools in Japan (n = 3,464). Self-reported health, lifestyle habits, and time spent using media were assessed.ResultsThe use of games, television, and personal computers was significantly associated with lifestyle (p < 0.05) and subjective health (p < 0.05). In addition, the use of games, the use of television, and the use of personal computers were mutually associated. The greater the number of media used for more than 1 hour was, the higher the odds ratio of the association of media use with unhealthy lifestyle and subjective health complaints was. The plural use of these media had stronger associations with unhealthy lifestyle and subjective health complaints.ConclusionsGame, television, and personal-computer use were mutually associated, and the plural use of these media had stronger associations with unhealthy lifestyle and subjective health complaints. Excessive use of media might be a risk for unhealthy lifestyle and subjective health complaints.

Fat mass is positively associated with bone mass in relatively thin adolescents: Data from the Kitakata Kids Health Study

Epidemiologic studies have found that higher body weight is associated with better bone health. Body weight consists of both fat mass (FM) and lean soft tissue mass (LSTM). Previous studies have examined the effects of FM levels during childhood on bone health, with conflicting results. In the present study, we investigated the independent contributions of FM to bone mass in Japanese adolescents. Subjects were 235 adolescents aged 15-18 years old in August 2010 and in August 2013 from the Kitakata Kids Health Study in Japan. We obtained cross-sectional data on body composition as well as bone mineral density (BMD). Body composition and BMD were measured using a dual-energy X-ray absorptiometry scanner. We found moderate and positive relationships between FM index and LSTM index (males, r=0.69; females, r=0.44). To verify a potentially additive effect of FM on the variance of bone variables beyond LSTM, we assessed the association between FM index and bone variables after stratification by tertiles of the LSTM index. In the lowest tertile of the LSTM index, FM index was significantly (P<0.05) associated with both femoral neck BMD (males, β=0.48; females, β=0.33) and whole body BMC (males, β=0.41; females, β=0.25). On the other hand, we found no significant associations between FM index and bone variables in other tertiles of the LSTM index. These findings indicate that FM can influence how high bone mass is obtained among relatively thin adolescents, but not among those who are of normal weight or overweight.

Increased Ratio of Trunk-to-Appendicular Fat and Decreased Adiponectin: A Population-Based Study of School Children in Hamamatsu, Japan.

Very few epidemiological studies have examined the relative impact of visceral fat and subcutaneous fat on serum adiponectin levels. Trunk-to-extremity fat ratio is reportedly a better surrogate for visceral fat than for subcutaneous fat. In the present study, we investigated the association between adiponectin and trunk-to-appendicular fat ratio (TAR) in a school population. The source population was all fifth graders (799 pupils) enrolled in the 2 elementary schools in Hamamatsu, Japan. Of the source population, we analyzed cross-sectional data from 609 children (mean age: 11.2 yr). TAR was evaluated by dual-energy X-ray absorptiometry and calculated as trunk fat mass divided by appendicular (arms and legs) fat mass. After stratification by tertiles of total body fat, multiple regression analysis was used to examine the relationships between adiponectin and TAR adjusted for potential confounding factors. In the highest tertile of total body fat, increasing TARs were significantly (p < 0.05) associated with decreasing serum adiponectin levels after stratification by total body fat (β = -0.32 in boys; β = -0.31 in girls). In the second tertile of total body fat, TAR in girls also showed significant inverse relationships with serum adiponectin levels (β = -0.27). Data from this population-based study demonstrated that an increased proportion of trunk fat is associated with decreased adiponectin in relatively overweight children, and also demonstrated that girls with a normal volume of body fat that follows a more centralized distribution show decreased adiponectin.

Trunk-to-Peripheral Fat Ratio Predicts Subsequent Blood Pressure Levels in Pubertal Children With Relatively Low Body Fat – Three-Year Follow-up Study –

BACKGROUND Only a few studies have examined the relationship between fat distribution measured by dual-energy X-ray absorptiometry (DXA) and blood pressure (BP), and no cohort study has targeted a pediatric population. METHODSANDRESULTS The source population comprised all students registered as fifth graders in the 2 elementary schools in Hamamatsu, Japan. Of these, 258 children participated in both baseline (at age 11) and follow-up (at age 14) surveys. Body fat distribution was assessed using trunk-to-appendicular fat ratio (TAR) and trunk-to-leg fat ratio (TLR) measured by DXA. Relationships between BP levels and fat distribution (TAR or TLR) were examined after stratification by tertiles of whole-body fat.Systolic BP at follow-up was significantly (P<0.05) associated with both TAR (boys, β=0.33; girls β=0.36) and TLR (girls β=0.35) at baseline, after adjusting for confounding factors such as baseline BP in the lowest tertile of whole-body fat. Moreover, adjusted means of systolic and diastolic BPs in girls showed a significant increase from the lowest to highest tertile of TAR within the lowest tertile of whole-body fat. CONCLUSIONS Body fat distribution in childhood could predict subsequent BP levels in adolescence. Children with a relatively low body fat that is more centrally distributed tended to show relatively high BP later on. (Circ J 2016; 80: 1838-1845).

Fat mass is positively associated with bone mass acquisition in children with small or normal lean mass: A three-year follow-up study

The independent impact of fat mass (FM) on bone health is difficult to assess, as FM is correlated with lean soft tissue mass (LSTM). In a previous cross-sectional study, FM was suggested to help promote high bone mass acquisition in adolescents with small LSTM. The present prospective cohort study investigated the effects of FM on bone in pubertal children after stratification by height-normalized index of LSTM (LSTMI). The source population was all 5th grade children enrolled in either one of the two public elementary schools in Hamamatsu, Japan. Of these, 545 children who participated in both baseline (at age 11) and follow-up (at age 14) surveys were included in the present analysis. Body composition and whole body areal bone mineral density (aBMD) were measured using dual-energy X-ray absorptiometry. From baseline to follow-up, significant (P<0.05) differences were observed in changes in aBMD among tertiles of change in FM in both sexes after adjusting for confounding factors including LSTMI. After stratification by tertiles of sex-specific LSTMI, adjusted means of changes in aBMD according to tertiles of change in FM within the lowest and second lowest tertiles of LSTMI in both sexes showed a significant increase from the lower tertiles to the highest tertile of change in FM. In the highest tertile of LSTMI, changes in FM showed no significant association with changes in aBMD. These findings suggest that adipose tissue might help promote high bone mass acquisition in pubertal children with small or normal LSTMI.

Influences of peers’ and family members’ body shapes on perception of body image and desire for thinness in Japanese female students

Purpose The present study investigated the influence of peers’ and family members’ body shapes on the perception of body image and desire for thinness in Japanese female students. Methods The study included 342 female, Japanese university students between the ages of 18 years and 22 years. They completed an anonymous questionnaire, which included questions related to anthropometry and body perception. Eating behavior was assessed by the Japanese version of the Eating Attitude Test-26. Results Many students overestimated their body shape (81.2% of underweight students and 74.6% of normal students) and had a desire for thinness (41.0% of underweight students, 88.2% of normal students, and 100% of overweight students). One of the main reasons for the overestimation of their body shape was comparison with others. Participants who were interested in a friend’s body shape were almost three times more likely to have a desire for thinness than those who were not interested in a female friend’s body shape (odds ratio: 3.06, P=0.014). Conclusion The results indicate a possibility that a female Japanese student’s young female friends’ body shapes, influences her desire for thinness or her perception of her own body shape.