• Journal of Biosystems Engineering
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• v.40 no.1
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• pp.78-88
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• 2015

Purpose: The objective of this study is to review researches regarding factors that potentially affect adolescent calcium (Ca) metabolism, and to suggest a potential modeling approach for optimizing gastrointestinal Ca absorption and peak bone mass. Background: Optimal gastrointestinal Ca absorption is a key to maximizing peak bone mass in adolescents. Urine Ca excretion in adolescents rises only after bone accretion is saturated, indicating that higher intestinal Ca absorption and bone retention is necessary to ensure maximum bone accretion. Hence, maximizing peak bone mass is possible by controlling the factors influencing gastrointestinal Ca absorption and bone accretion. However, a mechanism that explains the unique adolescent Ca metabolism has not yet been elucidated. Review: Dietary factors that enhance gastrointestinal Ca absorption may increase the available Ca pool usable for bone accretion, and a specific hormone may direct optimal Ca utilization to maximize peak bone mass. IGF-1 is an endocrine hormone whose levels peak during adolescence and increase fractional Ca absorption and bone Ca accretion. Prebiotics, generally obtained from dietary sources, have been reported to exert a beneficial effect on Ca absorption via microbiota activity. We selected and reviewed three candidates that could be used to propose a comprehensive Ca metabolic model for optimal Ca absorption and peak bone mass in adolescents. Modeling: Modeling has been used to investigate Ca metabolism and its regulators. Herein, we reviewed previous Ca modeling studies. Based on this review, we proposed a method for developing a comprehensive model that includes regulatory effectors of IGF-1 and prebiotics.

• Journal of the East Asian Society of Dietary Life
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• v.5 no.1
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• pp.41-51
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• 1995

Bone mass accretion during puberty appears to be critical in the development of peak bone mass. Although bone density of females in Korea has been studied, only a few studies have related bone mass with anthropometric patterns or puberty in the pubescent girls. This study was conducted as part of a study of major determinants of bone development during puberty. Subjects were aged 14∼16 yr(mean 14.97), and had no history of disorders or dedication use likely to influence bone or calcium metabolism. Bone mineral density and content were measured by dual energy X-ray absorptiometry using a Lunar DPX+Scanner (Lunar Madison, WI). Also, total body fat, and total lean body mass were assessed using a Lunar DPX dual-energy X-ray absorptiometer, Pubertal status was assessed according to the Marshall and Tanner guidelines. Serum levels of osteocalcin was measured by RIA using a commercial kit assay. Skinfold measurements were taken with a skinfold caliper(Lange Caliper, USA). Data were analyzed using the regression and GLM procedure of the statistical package SAS. The results indicated that the observed means for lumbar spine BMD and femoral BMD correspond to approximately 91% and 96% of the means for young adult females, respec tively. All subjects were menarchal, with the majority being in the middle to end stages of pubertal development. Total body BMD was positively related to fat mass(P<0.001), lean body mass and time since menarche, and negatively related to urine pyridinoline, serum alkaline phosphatase and osteocalcin. The data indicate that girls who reported lower age for menarche had significantly higher bone densities than girls who reported higher age for menarche. Attaining peak skeletal bone mass during puberty may reduce the incidence of osteoporosis in later life. this finding suggests that early menarche may augment peak bone mass, influencing the extent of bone loss later in adulthood. The results suggest that good nutrition in childhood appears to be needed not for growth and development, but possibly also to assure an optimal peak of bone mass and thus greater latitude for the maintenance or skeletal integrity in the face of bone losses. Troeps skinfold thickness was a better predictor of total BMD and total BMC than was any other skinfold thickness. The study did not find a relationship between total BMD and body fat %, but total fat was significantly positively related to total BMD(r=0.49) and total BMC(r=0.60). It supports earlier report that there was a significant correlation between TBMD and body weight. Conclusively, total fat, lean body mass and pubertal development could influence BMD in pubescent girls. Clearly, longitudinal studies are required to assess the effect of puberty on peak bone mass, and to define further the potential determinants of peak bone mass.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.3
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• pp.480-487
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• 1997

The present study was designed to examine how Ca intake contributes to the increase of peak bone mass with growing female rats. Weaned rats were fed experimental diets consisting in five levels of Ca; very low(0.1%), low(0.2%), moderate(0.5%), high(1.0%) and very high(1.5%) for 4, 8 and 12 weeks. Bone growth, metabolism and Ca metabolism were determined. As for the rats fed for 4 weeks, the bone weight, length and breaking force and bone metabolism were not significantly affected by dietary Ca levels, whereas the current intakes of Ca were observed to have significantly affected the rats fed for 8 or 12 weeks with regard to the bone weight, length and breaking force and bone metabolism. The bone ash and Ca contents of the rats were affected by dietary Ca levels for the total period of feeding. It is suggested that dietary Ca itself affected the mineralization process either during the growth or later, although the resulting bone mass is not a linear function of dietary Ca content.

• Journal of Nutrition and Health
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• v.34 no.5
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• pp.532-540
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• 2001

This study explored the effect of calcium levels and/or ovariectomy on bone composition and its related factors using the female Sprague-Dawley rats which achieved peak bone mass in normal(0.5%) calcium intake during growth period. The rats were randomly divided into six groups and fed 0.1%, 0.5% and 1.5% calcium diets for 8 weeks after ovariectomized and sham operation. The results indicated that body weight gain was higher in ovariectomized groups than sham groups, regardless of dietary calcium levels and food intakes. Serum Ca and P concentrations were normal level regardless of dietary calcium levels and operation. Estrogen concentration was decreased in ovariectomized rat groups. Serum alkaline phosphatase activity and urinary hydroxyproline were increased in ovariectomized groups. When rats were fed normal Ca diet during growing period, weight, length and breaking force of femur were not significantly different in all groups but increased the same level. Generally, lipid contents in lumbar and femur were lower in low calcium groups and this effect was more pronounced in femur. In case of femur, the significant decrease in Ca contents of bone was observed in a relatively short period of feeding low Ca diet, even though it appeared th desirable peak bone mass had achieved through the growing period by supplementing the adequate amount of calcium. The marked decrease of estrogen levels after ovariectomy did not seem to influence greatly bone parameters measured except bone wet weight. Therefore, this study indicated that lower intake of Ca might be more important determinating factor against osteoporosis than postmenopausal state stimulated by ovariectomy in female rats. With normal or high intake of Ca it appears possible to prevent bone loss in postmenopausal period, and this might apply only in case of achieving peak bone mass in the growing with the adequate intake of calcium. (Korean J Nutrition 34(5) : 532∼540, 2001)

• The Journal of Pediatrics of Korean Medicine
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• v.19 no.1
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• pp.53-66
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• 2005

Objectives : Osteoporosis is generally occurred in old age, especially postmenopausal women therefore, it is relatively overlook osteoporosis in children, but the authors have paid attention to bone density in children because maximizing peak bone mass of childhood is advocated as a way to prevent osteoporosis and environmental factor of childhood play role in the regulation of bone density. the present study was performed to measure bone density of children and to assess the influence of age, sex, body size, exercise, weak symptoms on bone density during the period of bone growth. Methods : We have measured bone density of calcaneus bone in 283 children (male 144 female 139, ranged from3 to 18) who visited in growth clinic of Pediatrics, Dongguk University Bundang Oriental Hospital, using quantitative ultra sound densitometry and they were divided into 3 groups by age(3-10, 11-15, 15-18 years). Pearson's correlation was used to assessed the influence of age, body size and Student's t-test was used to detect differences in sex, exercise, weak symptoms between the groups on bone density Results : The bone density correlated with age, height, weight, body mass index in this study. Bone density were significantly higher in males than in female. Digestive weak children's bone density were lower than normal children. Conclusion : Weight-bearing exercise and food rich in nutrition are necessary to increase maximizing peak bone mass in children.

• Journal of Korean Academy of Nursing
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• v.35 no.3
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• pp.621-630
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• 2005

Purpose: The purpose of this study was to -retrospectively describe the childhood sports activity level of Korean adult men and women and to determine whether a higher level of childhood sports activity was positively associated with adult bone mineral density. Methods: A cross-sectional study of 100 Korean men (n=40) and women (n=60) was completed. Participants completed a detailed lifetime sports activity questionnaire and had their bone mineral density of the femur and lumbar spine measured using dual energy x-ray densitometry (DEXA). All sports activities were classified into four categories of peak strain score on the basis of ground reaction forces (GRF). Results: During the age of high school, women and men who participated in a high intensity sports activity demonstrated higher bone density in the femur site after adjustment for the effects of body weight, fat body mass, lean body mass, the level of calcium intake, and breast feeding period than those who did not participate in sports activity at all. Conclusion: These results highlight the need to participate in high intensity sports activity during high school age as a means of increasing peak bone mass in the femur site.

• Nuclear Engineering and Technology
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• v.52 no.10
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• pp.2410-2414
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• 2020

Heavy ions have a high potential for destroying deep tumors that carry the highest dose at the peak of Bragg. The peak caused by a single-energy carbon beam is too narrow, which requires special measures for improvement. Here, carbon-12 (¹²C) ion with different energies has been used as a source for calculating the dose distribution in the water phantom, soft tissue and bone by the code of Monte Carlobased FLUKA code. By increasing the energy of the initial beam, the amount of absorbed dose at Bragg peak in all three targets decreased, but the trend for this reduction was less severe in bone. While the maximum absorbed dose per bone-mass unit in energy of 200 MeV/u was about 30% less than the maximum absorbed dose per unit mass of water or soft tissue, it was merely 2.4% less than soft tissue in 400 MeV/u. The simulation result showed a good agreement with experimental data at GSI Darmstadt facility of biophysics group by 0.15 cm average accuracy in Bragg peak positioning. From 200 to 400 MeV/u incident energy, the Bragg peak location increased about 18 cm in soft tissue. Correspondingly, the bone and soft tissue revealed a reduction dose ratio by 2.9 and 1.9. Induced neutrons did not contribute more than 1.8% to the total energy deposited in the water phantom. Also during ¹²C ion bombardment, secondary fragments showed 76% and 24% of primary 200 and 400 MeV/u, respectively, were present at the Bragg-peak position. The combined treatment of carbon ions with neutron or electron beams may be more effective in local dose delivery and also treating malignant tumors.

• Korean Journal of Adult Nursing
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• v.18 no.5
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• pp.790-797
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• 2006

Purpose: The purpose of this study was to investigate bone density and risk factors related to osteopenia to unmarried young adult women. Methods: The subjects consisted of 125 female college students. SPSS 12.0 program was used for the data analysis with t-test, ${\chi}^2-test$. The BMD of the calcaneus and body mass index (BMI) were measured with peripheral dual energy X-ray absorptionmetry. Other physical characteristics were measured with a scale and questionnaires. Results: The general characteristics of these people showed that the average age was 22.1 years old and that the average BMI was 20.8. The mean of BMD was normal, but 24.8% were osteopenia, 75.2% were normal. In the normal and osteopenia groups, there were significant differences in the status of the BMD according to age, height, weight, BMI, regular exercise, house chores, and the experiences of being on a diet. Conclusion: Women in their twenties had some osteoporosis risk, but they can change their BMD by doing regular exercise and by eating food to peak bone mass. For building peak bone mass, they need take exercise programs and education programs to prevent osteoporosis and follow-up care.

• Journal of Nutrition and Health
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• v.29 no.7
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• pp.778-787
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• 1996

The purpose of present study was to assess the change of bone mineral density(BMD) and the influences of anthroopometric indices and body composition on BMD in Korean women in Taegu. Subjects were 242 healthy female in the range of 7-67 years old, were divided into 4 age groups in order to assess the influence o factors on BMD according to age. Body composition and BMD measurements of lumbar spine, femur(neck, ward's triangle, trochanter) and total body were performed by dual energy X-ray absorptiometry. The analysis indicated that BMD of most region was positively related to body weight, BMI in all groups 4(50-67years), and closely related to femurs than lumbar spine. This study found correlations between BMD and both total fat body mass and total lean body mass in group 1, 2, 3, and correlations between BMD and only total fat body mass and in group 4. But on regression models the most significant prediction of BMD throughout the skeleton was total lean body mass in group 1(7-16years)and 2(17-34years, and total fat body mass in group 3 and 4. It is concluded that the our data can be used to screen early women of low bone mass. This study confirms that one of the most effective way to prevent osteoporosis and the fractures is to maximize peak bone mass in early life and to minimize bone loss through maintaining adequate weight.

• Journal of the Korean Applied Science and Technology
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• v.36 no.3
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• pp.797-803
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• 2019

Recently, osteosarcopenic obesity (OSO) has been identified and notified world wide. Therefore, this study reviewed OSO related to lifestyle factors such as nutritional intake and exercise. Due to aging, OSO may be initiated by dietary factors and obesity related factors. Reduced muscle mass and increased fat mass may negatively impact bone health causing OSO. The complication of OSO development should be related to dietary imbalance combined with declined exercise and this may contribute to induce OSO by decreasing bone mass, muscle mass, and increasing obesity with aging. To prevent OSO, reaching peak bone mass and building optimal muscle and fat mass through exercise would be recommended. For treating OSO, balanced dietary intake and regular exercise through a whole life would be needed. In addition, sufficient carbohydrate and fat intake for minimizing protein catabolism would be recommended to prevent OSO. The combination of aerobic exercise and resistance training also would be an effective intervention for OSO population.