Statistical methods for using calcium-41 to assess treatment effects on bone turnover
Abstract
Effective treatments for decreasing bone resorption rates are necessary to reduce the risk of osteoporosis. Conventional methods for analysis of treatment effects rely on indirect assessments based on changes in the levels of biochemical markers. Direct measurement of bone resorption using small dosages of 41Ca, a rare, long-lived isotope of calcium with a half-life 100,000 years, has been proposed as a gold-standard for assessing rates of bone resorption. We consider several potential models for the relationship between urinary 41Ca/Ca ratio and time. For a given subject, the relationship is essentially linear beginning somewhere between 12-24 months post-dose. An effective treatment will result in a perturbation of this linear relationship. Studies with multiple subjects are required to establish the effectiveness of treatments. We establish statistical methods for analyzing data collected from such studies and illustrate the methods using data collected from 18 subjects in a cross-over design.
Degree
Ph.D.
Advisors
McCabe, Purdue University.
Subject Area
Statistics|Nutrition
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