Nutritional Aspects of Osteoporosis

Peter Burckhardt, Bess Dawson-Hughes, Robert P. Heaney

• Publisher: Academic Press
• Year: 2004
• Print ISBN: 9780121417048
• eBook ISBN: 9780080551104
• Edition: 2
• Topic: Medicine
• Subtopic: Nutrition, Dietics & Bariatrics

Nutritional Aspects of Osteoporosis is based on presentations given at the Fifth International Symposium on Nutritional Aspects of Osteoporosis held in Lausanne, Switzerland in 2003. Although an often neglected chapter of medical research, the nutritional influences on bone health was a discussed topic at this congress. Also discussed were new insights into the role of proteins, vitamins, potassium, vegetables, food acid load, mineral waters and calcium.- Based on presentations given at the Fifth International Symposium on Nutrional Aspects of Osteoporosis held in Lausanne, Switzerland in 2003- Medical research, the nutritional influences on bone health was covered- New insights into the role of proteins, vitamins, potassium, vegetables, food acid load, mineral waters and calcium

Part I

Calcium in Childhood

Chapter 1

Bone Mineral Density of the Skull and Lower Extremities During Growth and Calcium Supplementation

Velimir Matkovic¹; John D. Landoll¹; Prem Goel¹; Nancy Badenhop-Stevens¹; Eun-Jeong Ha¹; Bin Li¹; Zeljka Crncevic-Orlic^{2 1} Osteoporosis Prevention and Treatment Center, Bone and Mineral Metabolism Laboratory, and Department of Statistics, The Ohio State University, Columbus, Ohio, USA;
² Department of Endocrinology, University of Rijeka, Croatia

ABSTRACT

The skull occupies a higher proportion of the total skeletal mass during growth than later in life. The bone mineral areal density of the skull is the highest among the other skeletal regions of interest due to its high ratio of volume to projected area. Whole-body studies provide an assessment of skeletal health; however, they may be less sensitive to changes in bone density due to the dominance of the head region. Reporting the subcranial skeleton, therefore, is more meaningful with regard to evaluating the bone status of children and adolescents and assessing the effects of dietary intervention. Calcium supplementation has been shown to exert a significant influence on bone mineral areal density of the skull and lower extremities during the bone modeling phase. Complete catch-up in bone mineral density of the skull has been observed during the bone consolidation phase of late adolescence, as compared to the long bones of the lower extremities; this suggests a site-specific difference in bone behavior as related to nutritional challenge.

INTRODUCTION

Dual-energy x-ray absorptiometry (DEXA) analyses of various skeletal regions of interest depend on the size, shape, and volumetric density of the measured bones. Because of its high ratio of volume to projected area, the skull is the densest part of the skeleton (Table I). It contributes significantly to the whole-body bone mineral areal density of growing individuals; therefore, whole-body DEXA scans of children may be less sensitive to small changes in bone mineral areal density. Moreover, the skull enlarges much less during adolescence than the long bones of the lower extremities [1]. This results in a decrease in its contribution to the whole-body bone mineral areal density as an individual grows during adolescence (Table I). In addition, biomechanical factors influence bone mass acquisition of the skull much less than they influence the lower extremities. Thus, a long-term calcium intervention during growth could have a different impact on these two skeletal regions of interest.

Table I

Results of Regions of Interest Taken from Whole-Body DEXA Scans for Two Females

Age	YSM	Head	Arms	Legs	Trunk	Ribs	Pelvis	Spine	TBBMD	SCBMD	%Difference
6.0	—	1.307	0.495	0.680	0.562	0.481	0.632	0.600	0.733	0.602	21.7
10.5	− 2.6	1.381	0.613	0.814	0.687	0.566	0.830	0.727	0.825	0.731	12.9
13.0	− 0.1	1.459	0.712	1.002	0.804	0.612	0.991	0.874	0.946	0.874	8.2
15.5	+ 2.4	1.818	0.853	1.200	0.939	0.748	1.172	0.963	1.108	1.027	7.9
17.7	+ 4.6	2.029	0.889	1.343	1.005	0.789	1.226	1.078	1.196	1.106	8.1

Note: Data for age 6 are from one subject, while those for ages 10.5 through 17.7 are for longitudinal scans from a second subject. TBBMD = total-body bone mineral areal density; SCBMD = subcranial bone mineral areal density (total body without skull). The percent difference between the TBBMD and SCBMD analyses demonstrates the changing contribution of the skull to the whole-body bone mineral areal density.

To evaluate the effectiveness of calcium supplementation on the bone mineral areal density of the skull and lower extremities, whole-body scans of young females who participated in a 7-year randomized controlled clinical trial were analyzed for regions of interest [2]. The study included the period of pubertal growth spurt, characterized by a high rate of bone modeling, as well as the post-puberty period when epiphyses are closed and bone consolidation dominates. Of particular interest was evaluating the bone behavior and trajectories of the skull and lower extremities as they relate to dietary intervention during growth.

METHODS

The study was conducted in a cohort (n = 354) of young females who participated in a 7-year, randomized, double-blind, placebo-controlled clinical trial with calcium supplementation (calcium citrate–malate, 1000 mg/day; Procter & Gamble Company, Cincinnati, OH). A total of 177 subjects were randomly assigned to each arm of the trial. For this study, only subjects completing at least 7 of 15 semiannual visits were included (n = 236). Inclusion criteria included: Caucasian, normal health (absence of previous history of chronic disease/treatment that might interfere with growth), pubertal stage 2 (either breast or pubic hair development), and calcium intake below the threshold level (1480 mg/day) [3]. The average cumulative dietary calcium intake among the study participants was between 800 and 900 mg/day and was considered a habitual dietary calcium intake of the study population [2]. All minors and their parents gave informed consent according to guidelines of the Human Subjects Committee at The Ohio State University.

Physical examination, anthropometry, nutritional status, and whole-body bone mineral density were obtained at baseline and every 6 months. The subject’s weight and standing height were measured according to standard procedures described previously [4]. Pubertal stage based on breast development and pubic hair distribution was self-assessed by marking corresponding figures of sexual development (scale of 1–5). The timing of menarche was recorded. Nutritional status was assessed from 3-day dietary food records using Nutritionist III, v8.5 (Hearst Corp., San Bruno, CA) [4]. Total calcium intake in the supplemented group included dietary calcium plus pill calcium, adjusted for compliance. Bone mineral areal densities of the skull and lower extremities were obtained from the whole-body scan measured by DEXA (1.3q software, GE-Lunar DPX-L, Madison, WI).

The statistical analysis was conducted on an intent-to-treat basis to measure the effectiveness of calcium supplementation irrespective of compliance in average teenage females accustomed to dietary calcium intake between 800 and 900 mg/day for 7 years. Because this was a long-term study dealing with human growth and skeletal development from childhood to young adulthood, it was possible to evaluate the effectiveness of calcium sup...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright page
• Sponsors
• Contributors
• Preface
• Part I: Calcium in Childhood
• Part II: Dairy Products, Calcium Metabolism
• Part III: Vitamins, Flavonoids
• Part IV: Nutrition and Bone Health Miscellaneous
• Part V: Vitamin D—First Part
• Part VI: Vitamin D—Second Part
• Part VII: Acid Load From Food—First Part
• Part VIII: Acid Load From Food—Second Part
• Part IX: Protein
• Part X: Protein—Mineral Water
• Index