Search for Promotion Factors of Ultrasound Bone Measurement in Japanese Males and Pre/Post-Menarcheal Females Aged 8-14 Years

Abstract

SummaryThere is little evidence regarding the associations between bone growth and environmental factors among growing children, especially in Asians. The aim of this crosssectional study was to search for the promotion factors of bone growth in Japanese children during growth. The study subjects were male (nϭ333) and pre/post-menarcheal female (nϭ179/nϭ68) school children aged 8-14 y. Bone status at the calcaneus was evaluated by quantitative ultrasound (Benus III), and the bone area ratio (BAR) was used as an evaluation index. Dietary intakes were assessed via brief self-administered diet history questionnaires. The participants were asked to record all of their activities for 3 d (2 weekdays and 1 holiday). They were also required to provide the most recent anthropometric measurement records at their schools and answer questions about the frequency of fractures and, for females, the length of time since menarche. Multiple regression analysis with dummy variables demonstrated that age, magnesium (more than the RDA), vitamin B1 (more than the RDA), mean physical activity intensity per day (more than 1.7 METs), vitamin C (more than the RDA) and calcium (more than the RDA) were signifi cantly positive infl uential factors of BAR for males. For premenarcheal females, age, vitamin A (more than the RDA), BMI, and mean physical activity intensity per day (more than 1.7 METs) were signifi cantly positive infl uential factors of BAR, and for postmenarcheal females, only BMI and age were signifi cantly positive infl uential factors of BAR. The results suggest that several manageable factors correlate with the bone mass, and the associations differ depending on gender and menarcheal status.

Effects of the National School Lunch Program on Bone Growth in Japanese Elementary School Children

“…The primary objective of this study was to evaluate the effects of meals, particularly the school-provided lunch with milk, on bone growth in children. For this purpose, the measurement of BARs and comparisons of BARs between the school-lunch and box-lunch groups were performed considering the factors that could affect bone growth in children, such as BMI, mean physical activity intensity per day (9), and time spent sleeping (17). It is also known that sex hormones remarkably affect bone growth in children (9,18).…”

“…For this purpose, the measurement of BARs and comparisons of BARs between the school-lunch and box-lunch groups were performed considering the factors that could affect bone growth in children, such as BMI, mean physical activity intensity per day (9), and time spent sleeping (17). It is also known that sex hormones remarkably affect bone growth in children (9,18). Therefore, in this study, we selected fourth-grade students in whom secondary sex characteristics were not yet prominent (19) and for whom the duration of exposure to school lunch was probably the longest.…”

“…The assessment of the mean physical activity intensity per day was performed following the method reported by Kohri et al (9). In brief, the participants were asked to record all of their activities at home for 3 d (2 weekdays and 1 holiday) with the help of their parent/guardian so that we could estimate their mean physical activity intensity per day.…”

“…The survey on the status of nutrient and food groups intake and the questionnaire survey were conducted following the method reported by Kohri et al (9). In brief, nutrient and food groups intake were assessed using a brief self-administered diet history questionnaire modified for elementary school children (BDHQ-10y) (12) to assess the habitual diets of elementary school children aged 9-10 y.…”

“…Bone measurement was performed following the method reported by Kohri et al (9). In brief, the bone status of the right calcaneus was evaluated using quantitative ultrasound densitometry (Benus III; Ishikawa Seisakusho, Ltd., Japan).…”