Physical activity, calcium intake, and bone mineral content in children in The Netherlands.

Study Objective: To examine the relation between physical activity, calcium intake, and bone mineral content in children.

Design: Population based, cross sectional study.

Setting: Primary schools in Zoetermeer, The Netherlands.

Calcium and magnesium in human toenails do not reflect bone mineral density.

Nail mineral composition is influenced by several physiological and pathological processes. Potentially, nails could be used to monitor alterations in the level of incorporation of specific elements produced by nutritional abnormalities, disease states or chronic exposure to toxic agents. The purpose of this study was to investigate whether the calcium and magnesium content in nail clippings, as measured by instrumental neutron activation analysis (INAA), correlates with bone mineral density (BMD), as measured by quantitative microdensitometry (QMD), and therefore could be interesting as a screening instrument for osteoporosis.

Cross-sectional and longitudinal study of age-related phalangeal bone loss in adult females.

To establish a comprehensive model for peripheral phalangeal bone loss, bone mass was studied in 1984 and 1989 using quantitative microdensitometry (QMD) in a total of 330 healthy women (age range 43-78.7 years). Bone mass and changes in bone mass were analyzed in relation to age and menopausal status.

Determinants of bone mineral content in childhood.

In a sample of 1190 children (574 boys and 616 girls), aged 6.8-10.7 years, bone mineral content was studied using quantitative röntgen microdensitometry (QMD) at the diaphyseal and the metaphyseal site of the left second digit.

Evaluation of postprocessing dual-energy methods in quantitative computed tomography. Part 2. Practical aspects.

Three facets of dual-energy quantitative computed tomography are studied: (1) the algorithm for postprocessing data (the methods of Cann, Laval-Jeantet et al, Goodsitt et al [two methods], and Nickoloff et al); (2) the influence of choice of tissue-equivalent materials for calibration; and (3) the difference between central and peripheral calibration. The different tissue-equivalent materials include bone mineral-equivalent (K2HPO4 solutions and calcium hydroxyapatite), fat-equivalent (liquid paraffin, polyethylene, and 70% ethanol solution), and red marrow-equivalent (plastic). Deviation from the manufacturer's quoted content is least with central positioning of the calibration materials.