CHANGES IN BONE MINERAL CONTENT AND BIOMARKERS OF BONE TURNOVER IN CHILDREN FED WITH MILK AIDA C. MALLILLIN Food and Nutrition Research Institute, Department of Science and Technology Bicutan, Taguig City Philippines

INTRODUCTION Osteoporosis is a public health problem in Asia and its prevalence is increasing as individuals age. Recent advances in measuring bone mass density (BMD) and bone mineral content (BMC) have provided strategies to assess the presence and extent of early and asymptomatic osteoporosis. Osteoporosis has long been considered a disease of the post menopausal women and the elderly; however, there is now a general agreement that predisposition begins in childhood and adolescence; thus rational approaches to prevention of the disease should be started during childhood and adolescence. Osteoporosis is a public health problem in Asia and its prevalence is increasing as individuals age. Recent advances in measuring bone mass density (BMD) and bone mineral content (BMC) have provided strategies to assess the presence and extent of early and asymptomatic osteoporosis. Osteoporosis has long been considered a disease of the post menopausal women and the elderly; however, there is now a general agreement that predisposition begins in childhood and adolescence; thus rational approaches to prevention of the disease should be started during childhood and adolescence.

Bone is the substance that forms the skeleton of the body. It is composed chiefly of calcium phosphate and calcium carbonate. It also serves as a storage area for calcium, playing a large role in calcium balance in the blood. Bone mineral density (BMD), a measure of bone density, reflects the strength of bones as represented by calcium content. Calcium intake is an important modifiable factor related to attainment of peak bone mass. Absorptiometric techniques are used widely for the in vivo assessment of bone mineral in humans. These methods are quick, patient-friendly, highly precise, and involve only minimal radiation exposure. Bone mineral density (BMD), a measure of bone density, reflects the strength of bones as represented by calcium content. Calcium intake is an important modifiable factor related to attainment of peak bone mass. Absorptiometric techniques are used widely for the in vivo assessment of bone mineral in humans. These methods are quick, patient-friendly, highly precise, and involve only minimal radiation exposure.

OBJECTIVES (1) To determine the bone mineral density (BMD) and bone mineral content (BMC), as well as calcium intake, height, and weight of children, and (1) To determine the bone mineral density (BMD) and bone mineral content (BMC), as well as calcium intake, height, and weight of children, and (2) To compare the bone-related variables by gender. (2) To compare the bone-related variables by gender.

MATERIALS AND METHODS MATERIALS AND METHODS Subjects Subjects were Grade II pupils from the Upper Bicutan Elementary School. Of the eligible 126 pupils, 99 pupils (52 boys and 47 girls) participated in the study. Subjects Subjects were Grade II pupils from the Upper Bicutan Elementary School. Of the eligible 126 pupils, 99 pupils (52 boys and 47 girls) participated in the study. Dietary Assessment Dietary Assessment Dietary assessment was performed using three (3) 24- hour recalls (2 weekdays and 1 weekend). Dietary assessment was performed using three (3) 24- hour recalls (2 weekdays and 1 weekend).

Bone Mineral Assessment Bone Mineral Assessment Bone scans were performed at Roche, Philippines in Makati City. Subjects wore t-shirts and loose-fitting shorts during measurement. Shoes and metal objects such as jewelry were removed. Dual energy X-ray absorptiometry (DXA) using the GE Lunar Prodigy was used to measure BMD and BMC of the total body. Bone scans were performed at Roche, Philippines in Makati City. Subjects wore t-shirts and loose-fitting shorts during measurement. Shoes and metal objects such as jewelry were removed. Dual energy X-ray absorptiometry (DXA) using the GE Lunar Prodigy was used to measure BMD and BMC of the total body.  Anthropometric Measurements Measurements of height and weight were made by trained study personnel. Subjects wore t-shirts and loose-fitting shorts during measurement. Shoes and jewelry were removed. Height and weight measurements were obtained on the same day as the DXA scan.

Table 1. Characteristics of the Subjects Variable Boys (n=52) Mean±SEM Girls (n=47) Mean±SEM Age, years 7.6±0.17.6±0.1 Weight, kg 22.3± ±0.6 Height, cm 120.3± ±0.7

RESULTS Characteristics of the 99 subjects who had DXA measurements are presented in Table 1. The mean age was approximately 8 years. There were no significant differences between genders and the variables: BMD, BMC, weight, and height. Comparisons by gender of the actual BMD and BMC values against the normal range-for-age based on Z-scores showed that 94% of the children were in the normal range, except for 2 girls and 4 boys. For boys, the mean BMD was 0.61±0.01 g/cm2 and for girls, 0.63±0.01 g/cm2. BMC for boys was 731.5±12.6 g and for girls, 736.8±18.6 g. Characteristics of the 99 subjects who had DXA measurements are presented in Table 1. The mean age was approximately 8 years. There were no significant differences between genders and the variables: BMD, BMC, weight, and height. Comparisons by gender of the actual BMD and BMC values against the normal range-for-age based on Z-scores showed that 94% of the children were in the normal range, except for 2 girls and 4 boys. For boys, the mean BMD was 0.61±0.01 g/cm2 and for girls, 0.63±0.01 g/cm2. BMC for boys was 731.5±12.6 g and for girls, 736.8±18.6 g.

Normal weights and heights were observed in 91% and 95% of the children, respectively. The mean weights for boys and girls were 22.3±0.4 kg and 22.5±0.6 kg, respectively, while the mean heights were 120.3±0.5 cm and 121.6±0.7 cm, respectively. Calcium intakes for boys and girls were 426.6±73.0 and 330.1±35.0 mg/day, respectively, but were not significantly different, and did not meet the recommended calcium intake of 700 mg/day. Overall, there were no significant differences between genders and the variables: BMD, BMC, weight, height, and calcium intake.

Conclusion and Recommendation Almost all of the children have normal BMD and BMC as well as weights and heights. Calcium intakes of children were below the recommended calcium requirement for their age. Therefore, children should be started on increased calcium intake from the diet to reduce the risk of osteoporosis in later life. Almost all of the children have normal BMD and BMC as well as weights and heights. Calcium intakes of children were below the recommended calcium requirement for their age. Therefore, children should be started on increased calcium intake from the diet to reduce the risk of osteoporosis in later life.

We have started feeding the experimental group (49) with pasteurized milk (200 mL) containing 278 mg of calcium last August 12, 2007 during school days (5 days a week except holidays and suspension of classes due to typhoon) and will end November 12, The control group (50) was given pineapple juice (240 mL) containing 40 mg calcium. Our schedule for the final DXA measurement will be on November 13 – 22, We are still waiting for the delivery of our calcium biomarkers.