Modelling of age-related bone loss using cross-sectional data
I Malkin1, D Karasik, G Livshits
1Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv 69978, Tel Aviv, Israel.
Annals of Human Biology
|May 29, 2002
Summary
A two-interval function accurately models bone mineral density (BMD) changes across the lifespan, regardless of ethnicity or sex. This model reveals distinct periods of bone acquisition, stabilization, and age-related bone loss, with specific parameters varying by gender and ethnic group.
Area of Science:
- Osteology
- Anthropometry
- Biostatistics
Background:
- Current bone mineral density (BMD) analysis in aging studies faces limitations.
- Inaccurate mathematical modeling of BMD changes across youth, maturity, and senescence can yield flawed conclusions.
Purpose of the Study:
- To identify the optimal mathematical function for describing age-related BMD variations.
- To assess the universal applicability versus population-specific nature of the best-fitting BMD model.
Main Methods:
- Analysis of compact BMD in hand phalanges from 5,000 individuals across 13 ethnic samples (Europe and Asia).
- Measurement via photodensitometry from plain radiographs.
- Development of specialized statistical software for maximum likelihood parameter estimation.
Main Results:
- A two-interval function proved to be the most parsimonious and best-fitting model for BMD changes with age in all representative samples.
- This model identified age-specific thresholds for bone loss onset (T(0)), occurring between 37-47 years in females and 27-49 years in males.
- Annual cortical bone loss was linear post-threshold, averaging 0.51-1.15% in men and 0.74-1.77% in women.
Conclusions:
- Phalangeal BMD changes with age are best modeled by a two-interval function, irrespective of sex or ethnicity.
- Specific model parameters are influenced by gender and ethnic background.
- A robust, well-fitted model for BMD dependence on age is established for population studies.
Related Concept Videos
01:40Bone Remodeling
Bone remodeling is a continuous and balanced process of bone resorption by osteoclasts and bone formation by osteoblasts. In adults, it helps maintain bone mass and calcium homeostasis. While mechanical stress can stimulate turnover as part of the normal maintenance and reparative process, several hormones also regulate bone remodeling.
01:31Osteoclasts in Bone Remodeling
Osteoclasts are cells responsible for bone resorption and remodeling. They originate from hematopoietic progenitor cells present in the bone marrow. Numerous progenitor cells fuse to form multinucleated cells, each with 10-20 nuclei. A single osteoclast has a diameter of 150 to 200 µM. These cells have ruffled borders that break down the underlying bone tissue and release minerals such as calcium into the blood in bone resorption. Osteoclasts cling to bones with their ruffled edges during bone...
01:19The Effect of Aging on Tissues
Several body functions deteriorate with age. The external signs of aging are easily identifiable. For example, the skin becomes dry, less elastic, and thins out, forming wrinkles. The skin of the face begins to appear looser due to a decrease in the levels of elastic and collagen fibers in the connective tissue. Additionally, melanin production in the hair follicle decreases with age, resulting in gray hair. Moreover, the senses of sight and hearing decline, so glasses and hearing aids may...
01:29Bone Disorders
Aging and its effect on bone remodeling is the most common cause of bone disorders. In young and healthy people, bone deposition and resorption happen at an equal rate to maintain optimal bone health.
Bone deposition is also affected by the levels of sex hormones like estrogen and testosterone that promote osteoblast activity and bone matrix synthesis. When the level of these hormones decreases due to aging, it causes a reduction in bone deposition. As a result, bone resorption by osteoclasts...
Bone deposition is also affected by the levels of sex hormones like estrogen and testosterone that promote osteoblast activity and bone matrix synthesis. When the level of these hormones decreases due to aging, it causes a reduction in bone deposition. As a result, bone resorption by osteoclasts...
01:09Changes in the Appendicular Skeleton with Age
The upper and lower limb initially develops as a small bulge called a limb bud, which appears on the lateral side of the early embryo. The upper limb bud appears near the end of the fourth week of development, with the lower limb bud appearing shortly after.
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...