Search PubMed⌕ Search

Biomedical subjects

S Boonen

Publications and source records attributed to S Boonen.

89 records · Page 5Linked to original sources
PubMed1996

Deficiency of the growth hormone-insulin-like growth factor-I axis potentially involved in age-related alterations in body composition.

Because the body composition effects of growth hormone and insulin-like growth factor-I (IGF-I) are opposite to those of advancing age, it has been hypothesized that the decreased activity of the growth hormone-IGF-I axis is partly responsible for the loss of bone and muscle mass that characterizes normal human aging. The aim of the present cross-sectional analysis was to test this hypothesis in a well-defined community-based sample of 245 healthy elderly women. Dual-energy X-ray absorptiometry was used to measure body composition. To establish the major determinants of total bone mineral content (TBBMC), we assessed the relationships between TBBMC and age, height, weight, body mass index, muscle strength and serum concentrations of IGF-I, calcidiol, calcitriol, parathyroid hormone and sex hormone-binding globulin. Total body lean mass (TBLM), an indication of muscle mass, was related to the following potential determinants: age, habitual physical activity and serum IGF-I. Multiple regression was used to adjust for potential confounders. A significant relationship between circulating IGF-I and TBLM was not apparent in this study. On the other hand, serum IGF-I was found to be an independent predictor of TBBMC, despite the inclusion of established determinants of bone mass. These findings suggest that the demineralization of the skeleton in aging women is in part due to a deficiency of the somatotrophic axis.

Absorptiometry, Photon↗
PubMed1996

Age-related endocrine deficiencies and fractures of the proximal femur. I implications of growth hormone deficiency in the elderly.

Growth hormone activates osteoblasts to increase local synthesis of IGF-I, which acts in an autocrine or paracrine way to enhance bone matrix apposition, suggesting a role in the preservation of bone mass. Growth hormone deficiency in the elderly may therefore be of pathogenetic significance in senile osteoporosis. However, critical evidence does not yet support the concept that the decreased activity of the growth hormone-IGF-I axis alters bone remodelling, and the extent to which geriatric hyposomatotropism contributes to the age-related femoral bone loss remains to be elucidated. Despite the fact that biochemical estimates of bone turnover indicate that (short-term) administration of rhGH and IGF-I stimulates bone metabolism in non-osteoporotic older people, no significant changes have been observed in bone mineral density at the proximal femur. Additional studies are needed to assess the therapeutic potential for rhGH in attenuating or reversing bone loss in elderly people. Moreover, data on long-term adverse side effects of rhGH therapy are not yet available. Because of the known mitogenic action of IGF-I, the neoplastic potential of long-term rhGH therapy needs to be considered.

Age Factors↗
PubMed1996

Age-related endocrine deficiencies and fractures of the proximal femur. II implications of vitamin D deficiency in the elderly.

In the United Kingdom, as many as 60% of institutionalized people who are not taking vitamin D supplements may be deficient. Both impaired mineralization and a hyperparathyroidism-related increase in bone turnover have been identified in the presence of vitamin D deficiency. Recent interventional data have confirmed the role of vitamin D deficiency in the pathogenesis of senile osteoporosis and indicated the need to maintain serum cholecalciferol levels within the normal range in elderly people.

Aged↗
PubMed1996

Age-related factors in the pathogenesis of senile (Type II) femoral neck fractures.

A variety of age-related factors may affect the two ultimate determinants of hip fracture: propensity to trauma and femoral bone quality. The decline in muscle function that occurs with aging increases the incidence and impact of falls. Vitamin D deficiency, common in the elderly, causes impaired mineralization and a hyper-parathyroidism-related increase in bone turnover, reducing bone quality. Skeletal growth factors, essential regulators of bone-cell replication and differentiation, may mediate the maintenance of normal bone mass; the age-related deficiency of these factors may contribute to senile osteoporosis as well. In elderly women, these age-related factors add to estrogen-deficiency-related bone loss, leading to a lifetime risk of hip fracture of approximately 16%. The relative clinical importance of these potential pathogenetic factors remains to be elucidated.

Accidental Falls↗
PubMed1995

Measurement of femoral geometry in type I and type II osteoporosis: differences in hip axis length consistent with heterogeneity in the pathogenesis of osteoporotic fractures.

The epidemiologic patterns of vertebral and femoral fractures are sufficiently different to suggest that they represent distinct disorders (type I versus type II osteoporosis) although osteopenia is common in both. To determine whether differences in femoral geometry, one of the main determinants of bone quality, might contribute to the heterogeneity in osteoporotic fractures, we obtained dual energy X-ray absorptiometry scans on 210 women age 60 or older, including 105 type I fracture cases, 30 type II patients, and 75 controls. Hip axis length, measured on the scan printout, was significantly increased (p < 0.01) in hip fracture patients compared with women with postmenopausal osteoporosis, whereas femoral neck density (BMD) was equal in both groups. The best discrimination between both fracture types was obtained by a logistic regression model based on age and axis length. Adding BMD to the model did not improve the discriminative power (p = 0.67). These data provide further evidence that geometric characteristics may be implicated in hip fracture risk. Furthermore, these findings suggest that an increase in hip axis length may predispose osteopenic subjects to a femoral localization of fragility fractures, consistent with the postulated heterogeneity in the pathogenesis of osteoporotic fractures.

Absorptiometry, Photon↗
PubMed1995

Age-related bone loss and senile osteoporosis: evidence for both secondary hyperparathyroidism and skeletal growth factor deficiency in the elderly.

Aging is characterized by a decrease in bone volume, implying that net bone resorption exceeds net bone formation. This age-related bone loss can be regarded as the main determinant of hip fracture risk in the elderly. In the concept of senile osteoporosis, a key role has been attributed to vitamin D deficiency. Lack of vitamin D activity may affect femoral strength through impaired mineralization as well as through a hyperparathyroidism-mediated increase in bone resorption. In addition to vitamin D-related mechanisms, recent evidence has indicated a decline in the skeletal content of anabolic growth factors--such as insulin-like growth factor-I (IGF-I)--in femoral (cortical) bone, suggesting that skeletal growth factor deficiency may contribute to the age-related bone loss in the proximal femur as well. It is tempting to speculate that skeletal IGF-I loss might, at least partially, be accounted for by growth hormone deficiency. However, critical evidence does not yet support the concept that the decreased activity of the growth hormone-IGF-I-axis alters bone remodeling, and the extent to which serum concentrations of growth factors are reflective of skeletal activity remains to be clarified.

Aged↗
PubMed1995

Senile (type II) osteoporosis: pathogenesis and prevention of estrogen deficiency-related bone loss at the proximal femur.

Fractures of the proximal femur are associated with considerable morbidity and mortality. The residual effects of estrogen deficiency-related bone loss (partially) account for the higher incidence of hip fracture in elderly women compared to elderly men. This accelerated phase of postmenopausal bone loss can be prevented by estrogen substitution therapy. However, when estrogen substitution is discontinued, bone density declines at a rate similar to the perimenopausal one. In line with these densitometric data, several studies have provided evidence that the protective effect of estrogen therapy on hip fracture incidence does not persist after discontinuation of substitution. To prevent hip fractures in old age, estrogen treatment may have to be initiated perimenopausally and never discontinued. At present, however, such a strategy cannot be recommended as it has not been settled yet whether the benefits of estrogen substitution outweigh the risks.

Aged↗
PubMed1995

Steroid myopathy induced by epidural triamcinolone injection.

Epidural steroid injections are widely used for the treatment of lumbago and sciatica although their efficacy has not yet been demonstrated in a convincing way. Moreover, systemic complications, although rare, have been documented. The present case report illustrates that even a single low-dose epidural injection may induce Cushing's syndrome and even steroid myopathy.

Aged↗
PubMed1995

[Gait disorders and repeated falls in Steele-Richardson-Olszewski syndrome].

Progressive supranuclear palsy (syndrome of Steele-Richardson-Olszewski) represents one of the neuro-degenerative diseases, difficult to distinguish from other forms of parkinsonism. Although uncommon, the syndrome should be included in the differential diagnosis of recurrent falls in the elderly, especially in cases of parkinsonism presenting with axial rigidity and associated with gaze paralysis and/or poor response to L-dopa-therapy. The diagnosis is mainly based on the clinical findings. At present, no effective therapy is known.

Accidental Falls↗
PubMed1994

Nonvalvular atrial fibrillation and primary stroke prevention from a geriatric point of view.

Cerebrovascular disease constitutes one of the major causes of death. Patients with atrial fibrillation are known to be at high risk for stroke. The efficacy of oral anticoagulant therapy in the primary prevention of stroke in individuals with nonvalvular atrial fibrillation has been demonstrated in several large randomized trials. However, many geriatricians remain reluctant to prescribe anticoagulants. This article focuses on the risks and benefits of stroke prophylaxis with anticoagulant therapy in elderly patients with nonvalvular atrial fibrillation.

Aged↗
PubMed1993

Risk factors for falls as a cause of hip fracture in the elderly.

Almost all epidemiologic studies have shown that the age-adjusted incidence of osteoporotic hip fracture has been increasing during the last decades. Although the age-related bone loss is considered to be a crucial determinant of the incidence of hip fracture, spontaneous fractures appear to be uncommon: about 90% of hip fractures in the elderly result from a fall. This article focuses on the different risk factors for falls. Poor health status (especially chronic illness), impaired mobility and postural instability, and a history of prior falls have been associated with the risk of falling. Balance can also be impaired by disease (such as a broad spectrum of ophthalmologic and neurologic disorders) or age-related changes in number of anatomical structures, by medications which reduce their efficient functioning (such as some psychotropic or antihypertensive drugs) and by environmental hazards. The identification of elderly patients at risk for falling and intervention to minimize risk without compromising functional independence should receive a high priority in the health care of elderly persons.

Accidental Falls↗
PubMedDate not supplied

Costs and consequences of hip fracture occurrence in old age: an economic perspective.

PURPOSE: To summarize the reported short- and long-term costs associated with hip fracture occurrence in old age, based on a systematic literature review of published studies. A further aim is to provide a clinician-oriented discussion of the different types of economic evaluations, with an emphasis on studies that examined potential determinants of the costs of care after hip fracture. METHOD: Literature review. MAIN RESULTS: Even after the initial hospitalization, hip fractures continue to generate significant costs throughout the one-year period after discharge, but particularly during the first three months. Cost estimates based on data obtained prospectively from hip-fracture patients and matched controls showed that the costs associated with the treatment of hip-fracture patients are about three times greater than those resulting from the treatment of age and residence-matched controls without a fracture. Two-fifths of these excess costs are incurred during the first three months following hospital discharge. Increasing age at the time of injury and living in an institution before the fracture are among the most important determinants of an increased cost of care after hospital discharge. Programs that focus on continuity of care, adopt a multidisciplinary approach, and accelerate rehabilitation have shown to be able to reduce the cost of care after hip fracture. CONCLUSIONS: This review emphasizes the importance of current and future interventions to decrease the incidence of hip fracture. While the current review cannot provide definite answers to the questions of cost containment, our review provides critically important evidence about the need to base health policy decisions on empirical observations. Comprehensive economic analyses of financial costs and health outcomes are needed to develop cost-effective strategies.

Age Factors↗
PubMedDate not supplied

Process evaluation of a nurse-led multifactorial intervention protocol for risk screening and assessment of fall problems among community-dwelling older persons: a pilot-study.

This pilot study investigated the feasibility of a nurse-led fall prevention strategy in community-dwelling older persons. The sample included 126 subjects (mean age = 76 years) who could rise from a chair and transfer independently. During a home visit, a research nurse identified individuals at risk: a history of >or= 2 falls in the previous year or difficulties in gait and/or balance. Patients not at risk received an educational leaflet. Older persons at risk received an evaluation of risk factors for falling. Whenever problems were identified, the nurses gave specific advice and subjects were referred to their general practitioner (GP). After one month, adherence to these recommendations was evaluated. Twenty-seven individuals showed an increased risk of falling (21.4%). The mean number of risk factors per person was 3.4 (SD=1.2). Noncompliance with one or more of the fall prevention recommendations was 58.3%. Differentiated by type of recommendations, a high degree of compliance was observed for recommendations related to gait and balance, use of medication, orthostatic hypotension, urge-incontinence, environment and behavior (81.8%-100%). While most individuals followed the recommendation to consult their GP (66.7%-80%), most of the GP's failed to propose any further measures to prevent falls. Screening, evaluation of risk factors, giving advice and follow-up required on average 3.1 (SD=0.8), 29.4 (SD=15.1), 15.8 (SD=11.0) and 13.1 (SD=3.9) minutes, respectively. Of those subjects who were not at risk, 76.1% had read the leaflet and 74.6% of those considered it useful. This study provides preliminary evidence for the feasibility in terms of time investment to integrate a nurse-led multifactorial fall intervention in current care for older persons living at home. However, further investigation to increase compliance with recommendations and more insight in the GP's role relating to the management of patients at risk for falls is needed.

Accidental Falls↗