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Wada K.,Gifu University | Nakamura K.,Gifu University | Masue T.,Gifu University | Sahashi Y.,Gifu University | And 2 more authors.
American Journal of Epidemiology | Year: 2011

The authors investigated whether soy intake is associated with sex steroid levels in Japanese children. This cross-sectional study was conducted in autumn 2006. Subjects were substantially healthy preschoolers, 230 boys and 198 girls, aged 3-6 years. Dietary data, including soy intake, were assessed using 3-day dietary records. Each child's dietary intake was controlled for total energy intake using the Willett method (Nutritional Epidemiology. Oxford, United Kingdom: Oxford University Press; 1990:245-271). Urinary estrone, estradiol, testosterone, and 5-androstene-3β,17α diol levels measured using liquid chromatography-electrospray ionization tandem mass spectrometry, and urinary dehydroepiandrosterone level measured with a radioimmunoassay, were adjusted for urinary creatinine levels. In the analysis of covariance for sex steroids after adjustments for age and body mass index, soy intake was significantly negatively related to estrone and estradiol in boys and positively related to testosterone and 5-androstene-3β,17α diol in girls. Isoflavone had a significant tendency to be negatively associated with estradiol in boys and to be positively associated with testosterone in girls. Total energy intake was not associated with any sex steroids in boys or girls. These results suggest that soy intake might affect the secretion or metabolism of sex steroids in childhood and that the effects might differ by sex. © 2011 The Author. Source


Nishii T.,Mie University | Sukigara E.,Aichi Bunkyo Womens College | Abe R.,SHIMANO Inc. | Takaishi T.,Nagoya City University
Japanese Journal of Physical Fitness and Sports Medicine | Year: 2012

The purpose of this study was to reveal physiological conditions of commuter cyclist from the standpoint of multiple approaches. Ten male employees (37 ± 9 yr) who usually commute by bicycle participated in this study. Global Positioning System (GPS) was used to analyze their commuting route three-dimensionally. And heart rate was recorded simultaneously to determine their exercise intensity. Blood test, oral glucose tolerance test (OGTT), and maximal aerobic test was conducted in our laboratory. Semantic differential method (SD) questionnaire was conducted to clarify their feelings during and after their commute. The results of blood test and OGTT showed that all of determined values were good and no one exceeded the standard value. GPS log showed that subjects covered 13.3 ± 7.2 km and 40 ± 20 minute with integrating 201 ± 114 meter altitude gain per commute. Heart rate data showed 129 ± 12 bpm per commute. However, subjects demonstrated higher peak heart rate during their commute ranged between 157 and 181 bpm, we determined details by frequency distribution method. The data revealed that commuter cycling was consisted by aerobic exercise with intermittent vigorous intensity exercise. Despite of such a hard exercise cycling to work, the result of SD questionnaire indicated that subjects felt briskness with less tiredness when they commute. Commuter cycling with a higher than moderate exercise intensity, could have good physical and mental effects for employees. Source


Wada K.,Gifu University | Nakamura K.,Gifu University | Tamai Y.,Gifu University | Tsuji M.,Gifu University | And 3 more authors.
Cancer Causes and Control | Year: 2012

Purpose: We aimed to assess the association of body size at birth or physical activity with sex steroid levels, independent of body mass among young children. Methods: The cross-sectional study was conducted in 2006. Subjects were 230 boys and 198 girls, aged 3-6 years. Birth weight was based on parents' reports. Questions about physical activity focused on outdoor playtime. Urinary estrone, estradiol, testosterone, and 5-androstene-3β,17α diol (3β,17α-AED) levels were measured by liquid chromatography - electrospray ionization tandem mass spectrometry. Urinary dehydroepiandrosterone level was measured with a radioimmunoassay. Results: After adjustments for age and BMI, girls with lower birth weight had higher testosterone (trend p = 0.038) and 3β,17α-AED (trend p = 0.028). Girls with low birth weight and high birth weight had higher estrone (p = 0.014) and estradiol (p = 0.074) than those who had middle birth weight. Boys who were physically active had lower testosterone (p = 0.028) and 3β,17α-AED (p = 0.003) than those who were not active. Girls who were physically active had lower estrone (p = 0.015). Conclusions: Sex steroid levels in childhood might be affected by body size at birth or by physical activity during childhood. These effects might differ by sex. © 2011 Springer Science+Business Media B.V. Source


Wada K.,Gifu University | Nakamura K.,Gifu University | Tamai Y.,Gifu University | Tsuji M.,Gifu University | And 4 more authors.
Annals of Epidemiology | Year: 2013

Purpose: We aimed to assess the associations of sex, age, body mass, sex steroid hormones, and lifestyle factors with the levels of melatonin in young children. Methods: This study followed a cross-sectional design and was conducted two preschools in Japan. Subjects were 235 boys and 203 girls, aged 3-6 years. Information related to demographics, body mass, and lifestyle factors was obtained from parent-administered questionnaires. The levels of 6-sulfatoxymelatonin and dehydroepiandrosterone in first-void morning urine were measured by radioimmunoassay. Urinary estrone, estradiol, testosterone, and 5-androstene-3β, 17α diol levels were measured by liquid chromatography-electrospray ionization tandem mass spectrometry. Results: The creatinine-corrected 6-sulfatoxymelatonin levels and the estimated value of 6-sulfatoxymelatonin excretion were higher in girls than in boys. After adjustments for age, the creatinine-corrected 6-sulfatoxymelatonin was negatively associated with weight and body mass index among boys and with weight and height among girls. However, the estimated value of 6-sulfatoxymelatonin excretion was not associated with any indices of body mass. No significant relationships of urinary sex steroids, light exposure at night, sleep time, sedentary lifestyles, or passive smoking with urinary 6-sulfatoxymelatonin were observed. Conclusions: Our findings suggest that melatonin levels depend on sex and body size among young healthy children. Our results should be confirmed in future researches. © 2013 Elsevier Inc. Source


Wada K.,Gifu University | Nakamura K.,Gifu University | Tamai Y.,Gifu University | Tsuji M.,Gifu University | And 3 more authors.
Cancer Causes and Control | Year: 2012

Purpose: We investigated whether seaweed intake is associated with sex steroid levels in young Japanese children. Methods: The design of the study was cross-sectional and it was conducted in October-November 2006. Subjects were substantially healthy preschoolers, 230 boys and 198 girls, aged 3-6 years. Dietary data, including seaweed intake, were assessed using 3-day dietary records covering 2 consecutive weekdays and 1 weekend day. Urinary estrone, estradiol, testosterone, and 5-androstene-3β,17α diol levels were measured by liquid chromatography-electrospray ionization tandem mass spectrometry. Urinary dehydroepiandrosterone level was measured with a radioimmunoassay. Steroid hormones were adjusted for urinary creatinine levels. Results: Spearman's correlation coefficient between seaweed intake and estrone level was -0.144 (p = 0.030) in boys and -0.147 (p = 0.041) in girls after adjustments for age, BMI, and total energy intake. Seaweed intake was neither associated with estradiol, testosterone, 3β,17α-AED nor with DHEA among boys and girls. Conclusions: The negative association between seaweed intake and estrone level suggests that dietary seaweed intake might affect estrogen metabolism in childhood. © 2011 Springer Science+Business Media B.V. Source

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