Several prediction equations for estimating body composition of Japanese men and women have recently been developed using a linear regression model with a combination of impedance and anthropometric measurements as independent variables. The purpose of this study was to determine the cross-validity of body density (Db) estimated from bioelectrical impedance (BI) and skinfold thickness (ST) methods in comparison with underwater weighing (UW) as a criterion reference method. Percentage body fat (%BF) was derived from Db according to the equation Brozek et al. Fifty-seven healthy Japanese women, aged 19 to 57 years, volunteered to participate in the study. Impedance was measured by use of a portable four-terminal impedance plethysmograph (Selco, SIF-891) . %BF derived from the BI method (r=0.860-0.875) was correlated with hydrodensitometrically determined %BF to a greater extent than %BF obtained using the ST method (r=0.7330.758) or ultrasound method (r=0.536-0.721) . Correlations of various anthropometric indices (r=0.655-0.691) with hydrodensitometrically determined %BF were even lower. It was noteworthy, however, that mean %BF derived from existing BI equations differed significantly from hydrodensitometrically determined mean %BF. Therefore, we attempted to develop a new equation that was applicable to Japanese adult women as follows: Db=1.1613-0.1038 (Wt⋅Z ) /Ht², where Wt=weight in kg, Z=impedance in ohms, and Ht=height in cm. The prediction accuracy of this equation was r=0.866 or SEE=0.0077 g/ml. Cross-validation of this equation on a different sample (122 Japanese women, aged 18 to 59 years) revealed a correlation of r=0.869 in terms of %BF, SEE=3.2%, and no significant difference between estimated %BF and the criterion. We suggest that the BI method is one of the most convenient, valid means of assessing human body composition, and that the newly developed BI equation could be useful particularly when the subjects are Japanese adult women in their late teens to fifties.

A study was conducted to investigate the validity of skinfold-based prediction equations for body density (Db, g/ml) developed by Nagamine et al. (1974), and to formulate convenient, useful equations for predicting Db by the skinfold thickness (ST) method in junior high school boys and girls. The subjects of the study were 269 healthy boys and girls, aged 12-15 years. The dependent variable, Db, was determined by underwater weighing (UW) . Independent variables included single skinfold thickness at three sites (triceps, subscapular and abdomen) and the sum of two skinfolds. Db by the ST method was estimated from the equations developed by Nagamine et al. (1974) for boys and girls, using the sum of skinfold thickness at the triceps and subscapular area. Skinfold thickness was measured on the right side of the body with an Eiken-type skinfold caliper. Db estimated by the ST method was correlated significantly with Db determined by UW (r=0.873 for boys and r=0.723 for girls) . However, average Db values estimated by the ST method were significantly lower than those deter-mined by UW (differences in Db values when predicted by the Nagamine equations: 0.0099 for boys and 0, 0114 for girls) . Therefore, we developed linear regression equations for predicting Db. The best-fitting prediction equation for Db was Db=1.0881-0.0010·X for boys, and Db=1.0715-0.0007·X for girls, where X is the sum of the triceps and subscapular skinfold thickness (mm) for boys and girls. Db estimated from the respective equation was correlated significantly with hydrodensitometrically determined Db (r=0.872, SEE=0.0089 for boys; r=0.722, SEE=0.0104 for girls) .
Furthermore, in a cross-validation analysis of prediction equations for Db developed in the present study, Db estimated from the respective equation was correlated highly with hydrodensitometrically determined Db (r=0.887 for boys and r=0.740 for girls) . There were no significant differences between the Db values predicted by the ST method against hydrodensitometrically determined Db values (difference values: 0.0012 for boys and 0.0013 for girls) . The final phase of this study was to develop more stable equations, combining validation and cross-validation samples. On the basis of the final analyses, we recommend the equations Y=1.0875-0.0010X and Y=1.0716-0.0007X, with SEE of 0.0088g/ml for boys and 0.0105g/ml for girls, respectively. It is suggested that the prediction equations finally developed in the present study will be applicable to junior high school boys and girls.

The tetrapolar bioelectrical impedance (BI) method has been proposed as a convenient, valid approach for estimating the body composition of normal healthy adults. However, the validity of the BI method has not yet been confirmed for Japanese junior high school boys and girls. The purpose of this study was to develop convenient and useful equations for predicting the body composition in junior high school boys and girls by the BI method. The subjects were 297 healthy boys and girls, aged 12.15 years, all of whom were Japanese. Impedance was measured using a tetrapolar bioelectrical impedance plethysmograph (800 pA, 50 kHz SIF-891) manufactured by Selco. Multiple regression analysis was used to derive prediction equations for Db that were specifically applicable to boys and girls. The effective prediction equations for Db were as follows : 1) Db=1.1860-0.1282 (Wt·Z) /Ht², and 2) Db=1.1402-0.0706 (Wt·Z) /Ht²-0.0007· (abdomen) for boys. 1) Db=1.1337-0.0778 (Wt·Z) /Ht², and 2) Db=1.1124-0.0498 (Wt·Z) /Ht²-0.0006· (subscapular) for girls, where Db=body density (g/ml), Wt=weight (kg), Z =impedance (ohms), Ht=height (cm) . Db estimated by each respective equation was highly correlated with body density measured by underwater weighing (UW-Db) : 1) r=0.881, SEE=0.00868/ml, 2) r=0.902, SEE=0.00788/nil for boys and 1) r= 0.741, SEE=0.0101 g/ml, 2) r=0.775, SEE =0.0095g/ml for girls. Furthermore, in a cross-validation analysis of prediction equations for Db, another sample consisting of 40 boys and 66 girls was used. Db estimated from each respective equation was correlated highly with UW-Db : 1) r=0.856, 2) r=0.887 for boys and 1) r=0.837, 2) r=0.860 for girls. There were no significant differences between the mean Db obtained by the BI method and that by the criterion method. We suggest that the prediction equations proposed in this study are useful for valid assessment of body composition of Japanese junior high school boys and girls aged 12 through 15 years.

Leptospirosis is a worldwide zoonosis and common in tropical and subtropical areas with high rainfall. It should be noted as an imported infectious disease although it is sporadic in Japan. Some imported cases already have been reported in Japan and these cases occurred mainly in Southeast Asia. The case discussed in this article is the first reported Japanese case infected in Vietnam. Four days after returning back to Japan after a two-week stay in the mountain area near Hue, in the middle part of Vietnam, the patient suddenly experienced chills, a high fever, sore throat, gastrocnemius pain, and headache. Conjunctival jaundice, renal function disorder, and proteinuria were observed on the third day of onset. Significant increase in antibody titers against serovar Australis and Autumnalis strains was observed in paired serum samples by microscopic agglutination test (MAT). Consequently we recognized this case as a diagnosis of severe leptospirosis (Weil’s disease). Finally, renal function disorder did not deteriorate further, and then the patient recovered after the tenth day of onset with the administration of antibiotics and supportive care without sequelae. We experienced the first imported Japanese case of severe human leptospirosis infection from Vietnam that was successfully treated with ceftriaxone and minocycline.

BACKGROUND: Limited evidence exists regarding the relationship between central-to-peripheral fat ratio measured by dual-energy X-ray absorptiometry (DXA) and subsequent cardiometabolic risk in both pediatric and adult populations. METHODS: The present cohort study investigated the relationship between DXA-measured body fat distribution and cardiometabolic parameters. The source population was 275 4th-6th graders (aged 9.6-12.6 years) in the northeast region of Japan (Shiokawa area in Kitakata). A 3-year follow-up was conducted to obtain complete information from 155 normal-weight children (87 boys and 68 girls). Normal-weight children were identified using sex- and age-specific international cut-offs for body mass index (BMI) based on adult BMI values of 25 kg/m and 18.5 kg/m, respectively. Body fat distribution was assessed using the trunk-to-appendicular fat ratio (TAR) and trunk-to-leg fat ratio (TLR) measured by DXA. RESULTS: In boys, systolic blood pressure (SBP) at follow-up showed a significant relationship with TAR at baseline after adjusting for age, height, pubic hair appearance, SBP, and whole body fat at baseline (β = 0.24, P < 0.05), and SBP also showed a significant relationship with TLR after adjusting for confounding factors including whole body fat (β = 0.25, P < 0.05). In girls, there were no significant relationships between blood pressure and TAR/TLR. CONCLUSION Body fat distribution in normal-weight boys predicted subsequent blood pressure levels in adolescence. The relationship between fat distribution and blood pressure was independent of fat volume.
Absorptiometry, Photon ; Adolescent ; Blood Pressure ; Body Fat Distribution ; Child ; Cohort Studies ; Humans ; Japan ; Male

BACKGROUND: Children in Ulaanbaatar are exposed to air pollution, but few epidemiological studies have been conducted on the effects of environmental risk factors on children's health. Also, no studies have yet examined the prevalence of respiratory symptoms in children in suburban areas, where air quality-monitoring stations have not yet been installed. This cross-sectional study evaluated the associations between outdoor air pollution and respiratory symptoms among schoolchildren in urban and suburban districts of Ulaanbaatar. METHODS: The ATS-DLD-78 C questionnaire was used to investigate the respiratory symptoms of schoolchildren aged 6-12 years (n = 1190) who lived in one of three urban districts or a suburban district of Ulaanbaatar. In each district, the outdoor concentrations of nitrogen dioxide (NO) and sulfur dioxide (SO) were measured at two sites (at ≤100 m and > 100 m from the nearest major road) in the 2-year period from 2015 to 2016. The associations between health outcomes and exposure to air pollutants were estimated using the multinomial logistic regression method. RESULTS: The outdoor concentration of SO was significantly associated with persistent cough symptom (OR = 1.12, 95% CI 1.04-1.22). Furthermore, the outdoor concentration of NO was significantly associated with the current wheezing symptom (OR = 1.33, 95% CI 1.01-1.75) among children in urban and suburban. CONCLUSIONS The prevalence of persistent cough symptom was markedly high among the schoolchildren in urban/suburban districts of Ulaanbaatar. Overall, the increases in the prevalence of respiratory symptoms among children might be associated with ambient air pollution in Ulaanbaatar.