Structural And Biomechanical Basis Of Differences In Bone Fragility In Asian And Caucasian Men And Women
Funder
National Health and Medical Research Council
Funding Amount
$188,500.00
Summary
Lay Summary Fractures occur less commonly in males than females because males have greater periosteal apposition than females during ageing. This increases bone size (reducing load per unit area - stress), and reduces net bone loss, more in males than females so that the increase in bone fragility with advancing age seen in both sexes is less in males than females. Few males than females have a fracture risk index for vertebral fractures (FRI or ratio of load-bone strength) above unity. The purp ....Lay Summary Fractures occur less commonly in males than females because males have greater periosteal apposition than females during ageing. This increases bone size (reducing load per unit area - stress), and reduces net bone loss, more in males than females so that the increase in bone fragility with advancing age seen in both sexes is less in males than females. Few males than females have a fracture risk index for vertebral fractures (FRI or ratio of load-bone strength) above unity. The purpose of this study is to define the structural and biomechanical basis responsible for the racial differences in fracture rates between Asians and Caucasians. Following the same biomechanical principles as published in Caucasian males and females, we hypothesise that racial differences in periosteal expansion during aging may contribute, in part, to the racial differences in bone fragility at the spine and hip. A cross-sectional study will be conducted in 500 healthy Chinese men and 500 Chinese women age ranged 18 to 90 years living in Melbourne, Australia. We have recruited larger numbers of Caucasian men and women in our Centre. BMD and bone size will be measured at the spine, hip and total body by using dual x-ray bone densitometer (DXA). Vertebral body width, depth, height, cross-sectional area (CSA), stress (load per unit CSA) and fracture risk index (load-strength) at the third lumbar vertebrae will be measured by PA and lateral scanning. Femoral neck periosteal-endocortical diameter, cortical thickness, cross-section moment of inertia (CSMI), section modulus buckling index will be measured by using hip structural analysis program. Just as insight into bone fragility in women has been obtained by studies in men, we believe that the results of this study will provide important insights into the pathogenesis of bone fragility in both racial groups.Read moreRead less
The Fremantle Diabetes Study Phase II: A Community-based Study Of Diabetes Care, Control, Complications And Cost
Funder
National Health and Medical Research Council
Funding Amount
$1,307,780.00
Summary
In Phase I of the Fremantle Diabetes Study (FDS), valuable and detailed data on a wide range of subjects were obtained from a community-based patient cohort between 1993 and 2001. There is a large body of evidence that the nature and treatment of diabetes in Australia is changing rapidly. In order to provide up to date information to health care providers and government agencies, to confirm observations made in FDS I and to venture into new research areas, Phase II will be conducted.
Sex Differences In The Mechanisms By Which Stress Inhibits The Secretion And Actions Of GnRH
Funder
National Health and Medical Research Council
Funding Amount
$408,055.00
Summary
It is well known that stress can impair reproduction in humans and animals but it is not understood how this occurs. Consequently there are no therapies available to overcome the detrimental effects of stress on reproduction. Stress can take many forms, such as psychological stress, surgical trauma, strenuous exercise, undernutrition, all of which may inhibit reproduction. We now know that males and females respond differently to stress and we have shown that stress is also likely to have differ ....It is well known that stress can impair reproduction in humans and animals but it is not understood how this occurs. Consequently there are no therapies available to overcome the detrimental effects of stress on reproduction. Stress can take many forms, such as psychological stress, surgical trauma, strenuous exercise, undernutrition, all of which may inhibit reproduction. We now know that males and females respond differently to stress and we have shown that stress is also likely to have different effects on reproduction in males and females. In this project we aim to determine how stress impairs reproduction in males and females. A major effect of stress appears to be to inhibit the secretion of a substance produced by the brain that is necessary for the regulation of reproduction. This substance is called gonadotrophin releasing hormone (GnRH) and it acts on a small gland at the base of the brain to cause the release of hormones that are essential for reproduction in both males and females. It is also possible that stress may inhibit the actions of GnRH. Our research suggests that there may be differences between males and females in the extent to which stress inhibits the secretion of GnRH from the brain and its actions to cause the release of other reproductive hormones. In this project we will determine how stress acts in the brain to affect the secretion and actions of GnRH in males and females. Our research will make a major contribution to our knowledge of the way that stress inhibits reproduction in males and females. This information is essential in order to develop specific remedies to overcome reproductive disorders caused by stress and to improve reproductive health in both sexes.Read moreRead less
Is Periosteal Bone Formation Responsible For Sexual Dimorphism In Bone Fragility
Funder
National Health and Medical Research Council
Funding Amount
$316,320.00
Summary
Men and women sustain fractures as they age because their bones become fragile. Women sustain fractures more often than men. Bone thinning occurs in both sexes but it is usually believed that this thinning or loss of bone is greater in women than men. We have evidence to suggest that this may not be correct. In fact, it is likely that men and women lose a similar amount of bone, about half what they started with, but during ageing, men lay down more bone on the outside surface of the bone than w ....Men and women sustain fractures as they age because their bones become fragile. Women sustain fractures more often than men. Bone thinning occurs in both sexes but it is usually believed that this thinning or loss of bone is greater in women than men. We have evidence to suggest that this may not be correct. In fact, it is likely that men and women lose a similar amount of bone, about half what they started with, but during ageing, men lay down more bone on the outside surface of the bone than women compensating for the similar amount lost on the inside of the bone. We also have evidence to suggest than men and women who get spine fractures do so because the process of laying down bone may fail to occur normally. We will study these processes of bone loss inside the bone and bone gain outside the bone to try to better understand why bones become weak. We will measure the bone size and its density in healthy men and women and patients with fractures to determine how the increasing size of the bone produced by laying down bone on its outside helps to keep it strong and to preserve the bone that would otherwise be lost if it didn't occur or if a disease developed that might reduce the compensatoryRead moreRead less