Research

Determinants of bone mass and bone size in a large cohort of physically active young adult men

JA Ruffing¹ , F Cosman^1,2 , M Zion¹ , Susan Tendy³ , P Garrett¹ , R Lindsay^1,2 and JW Nieves^1,2

¹Clinical Research and Regional Bone Centers, Helen Hayes Hospital, West Haverstraw, New York, USA

²Departments of Medicine and Epidemiology, College of Physicians and Surgeons of Columbia University, New York, USA

³United States Military Academy, West Point, New York, USA

author email corresponding author email

Nutrition & Metabolism 2006, 3:14doi:10.1186/1743-7075-3-14

Published:	15 February 2006

Abstract

The determinants of bone mineral density (BMD) at multiple sites were examined in a fit college population. Subjects were 755 males (mean age = 18.7 years) entering the United States Military Academy. A questionnaire assessed exercise frequency and milk, caffeine, and alcohol consumption and tobacco use. Academy staff measured height, weight, and fitness. Calcaneal BMD was measured by peripheral dual-energy x-ray absorptiometry (pDXA). Peripheral-quantitative computed tomography (pQCT) was used to measure tibial mineral content, circumference and cortical thickness. Spine and hip BMD were measured by DXA in a subset (n = 159). Mean BMD at all sites was approximately one standard deviation above young normal (p < 0.05). African Americans had significantly higher hip, spine and heel BMD and greater tibial mineral content and cortical thickness than Caucasians and Asians. In Caucasians (n = 653), weight was a significant determinant of BMD at every skeletal site. Prior exercise levels and milk intake positively related to bone density and size, while caffeine had a negative impact. There was an apparent interaction between milk and exercise in BMD at the heel, spine, hip and tibial mineral content and cortical thickness. Our data confirm the importance of race, body size, milk intake and duration of weekly exercise as determinants of BMD and bone size.