Stanley J. Birge

Weight-Bearing Exercise Training and Lumbar Bone Mineral Content in Postmenopausal Women

STUDY OBJECTIVE To assess the effect of weight-bearing exercise training and subsequent detraining on lumbar bone mineral content in postmenopausal women. DESIGN Non-randomized, controlled, short-term (9 months) trial and long-term (22 months) exercise training and detraining (13 months). SETTING Section of applied physiology at a university school of medicine. PATIENTS Thirty-five healthy, sedentary postmenopausal women, 55 to 70 years old. All women completed the study. There was 90% compliance with exercise training. INTERVENTIONS All women were given calcium, 1500 mg daily. The exercise group did weight-bearing exercise (walking, jogging, stair climbing) at 70% to 90% of maximal oxygen uptake capacity for 50 to 60 min, 3 times weekly. MEASUREMENTS AND MAIN RESULTS Bone mineral content increased 5.2% (95% confidence interval [CI], 2.0% to 8.4%; P = 0.0037) above baseline after short-term training whereas there was no change (-1.4%) in the control group. After 22 months of exercise, bone mineral content was 6.1% (95% CI, 3.9% to 8.3% above baseline; P = 0.0001) in the long-term training group. After 13 months of decreased activity, bone mass was 1.1% above baseline in the detraining group. CONCLUSIONS Weight-bearing exercise led to significant increases above baseline in bone mineral content which were maintained with continued training in older, postmenopausal women. With reduced weight-bearing exercise, bone mass reverted to baseline levels. Further studies are needed to determine the threshold exercise prescription that will produce significant increases in bone mass.

The prevalence and correlates of fear of falling in elderly persons living in the community

OBJECTIVES Fear of falling has been recognized as a potentially debilitating consequence of falling in elderly persons. However, the prevalence and the correlates of this fear are unknown. METHODS Prevalence of fear of falling was calculated from the 1-year follow-up of an age- and gender-stratified random sample of community-dwelling elderly persons. Cross-sectional associations of fear of falling with quality of life, frailty, and falling were assessed. RESULTS The prevalence of fear increased with age and was greater in women. After adjustment for age and gender, being moderately fearful of falling was associated with decreased satisfaction with life, increased frailty and depressed mood, and recent experience with falls. Being very fearful of falling was associated with all of the above plus decreased mobility and social activities. CONCLUSIONS Fear of falling is common in elderly persons and is associated with decreased quality of life, increased frailty, and recent experience with falls.

Characteristics and Circumstances of Falls in a Hospital Setting: A Prospective Analysis

OBJECTIVE: To describe the epidemiology of hospital inpatient falls, including characteristics of patients who fall, circumstances of falls, and fall-related injuries.DESIGN: Prospective descriptive study of inpatient falls. Data on patient characteristics, fall circumstances, and injury were collected through interviews with patients and/or nurses and review of adverse event reports and medical records. Fall rates and nurse staffing levels were compared by service.SETTING: A 1,300-bed urban academic hospital over 13 weeks.PATIENTS: All inpatient falls reported for medicine, cardiology, neurology, orthopedics, surgery, oncology, and women and infants services during the study period were included. Falls in the psychiatry service and falls during physical therapy sessions were excluded.MEASUREMENTS AND MAIN RESULTS: A total of 183 patients fell during the study period. The average age of patients who fell was 63.4 years (range 17 to 96). Many falls were unassisted (79%) and occurred in the patient’s room (85%), during the evening/overnight (59%), and during ambulation (19%). Half of the falls (50%) were elimination related, which was more common in patients over 65 years old (83% vs 48%; P<.001). Elimination-related falls increased the risk of fall-related injury (adjusted odds ratio, 2.4; 95% confidence interval 1.1 to 5.3). The medicine and neurology services had the highest fall rates (both were 6.12 falls per 1,000 patient-days), and the highest patient to nurse ratios (6.5 and 5.3, respectively).CONCLUSIONS: Falls in the hospital affect young as well as older patients, are often unassisted, and involve elimination-related activities. Further studies are necessary to prevent hospital falls and reduce fall injury rates.

Clock completion : an objective screening test for dementia

Objective To develop a simple, readily administered and scored screening test for dementia utilizing the clock‐drawing task.

Bone Cells: Biochemical and Biological Studies after Enzymatic Isolation

Short-term incubation of rat calvaria in buffered crude collagenase permitted the isolation of morphologically intact cells that absorb vital dyes, contain alkaline phosphatase, and multiply in tissue culture. Freshly harvested cells were similar to whole bone segments in aerobic glucose metabolism.

A Case‐control Study of Patient, Medication, and Care‐related Risk Factors for Inpatient Falls

AbstractOBJECTIVE: To comprehensively analyze potential risk factors for falling in the hospital and describe the circumstances surrounding falls. DESIGN: Case-control study. Data on potential risk factors and circumstances of the falls were collected via interviews with patients and/or nurses and review of adverse event reports, medical records, and nurse staffing records. SETTING: Large urban academic hospital. PATIENTS: Ninety-eight inpatients who fell and 318 controls matched on approximate length of stay until the index fall. MEASUREMENTS AND MAIN RESULTS: In a multivariate model of patient-related, medication, and care-related variables, factors that were significantly associated with an increased risk of falling included: gait/balance deficit or lower extremity problem (adjusted odds ratio [aOR], 9.0; 95% confidence interval [CI], 2.0 to 41.0), confusion (aOR, 3.6; 95% CI, 1.6 to 8.4), use of sedatives/hypnotics (aOR, 4.3; 95% CI, 1.6 to 11.5), use of diabetes medications (aOR, 3.2; 95% CI, 1.3 to 7.9), increasing patient-to-nurse ratio (aOR, 1.6; 95% CI, 1.2 to 2.0), and activity level of “up with assistance” compared with “bathroom privileges” (aOR, 8.7; 95% CI, 2.3 to 32.7). Urinary or stool frequency or incontinence was of borderline significance (aOR, 2.3; 95% CI, 0.99 to 5.6). Having one or more side rails raised was associated with a decreased risk of falling (aOR, 0.006; 95% CI, 0.001 to 0.024). CONCLUSIONS: Patient health status, especially abnormal gait or lower extremity problems, medications, as well as care-related factors, increase the risk of falling. Fall prevention programs should target patients with these risk factors and consider using frequently scheduled mobilization and toileting, and minimizing use of medications related to falling.

Is There a Role for Estrogen Replacement Therapy in the Prevention and Treatment of Dementia

Studies in experimental animal models provide a convincing rationale for a role for ERT in the treatment and prevention of dementia. These studies establish the role of estrogen in the regeneration and preservation of neuronal elements within the CNS that are analogous to those regions of the brain most sensitive to the neurodegenerative changes associated with AD. Furthermore, behavioral studies in these animals establish a correlation between the hormone dependent changes in the neuronal architecture and learning and memory. However, extrapolation of these studies to post-menopausal women must be done with caution. Surgical and natural loss of ovarian function does not result in a clinically relevant decline in cognitive function over the short term (1 to 2 decades) or ever in some women. The modest changes that are observed may relate to the hormones effect on neurotransmitter levels or their receptors. Although Singh et al. noted changes in neurotransmitter concentrations 5 weeks after ovariectomy, changes in cognitive performance in their rat model did not become significant until 28 weeks after ovariectomy--the equivalent of approximately 2 decades of human life. Except for the familial forms of the disease, AD is rarely seen in the first 2 decades after the menopause. However, by the third decade after the menopause, 50% of women can be expected to manifest the histopathological changes of AD. Approximately half of these women are without clinical evidence of disease. Thus, the neurodegenerative process of AD probably precedes by many years the age of onset of the disease. We do not know what factors contribute to the selective neuronal injury which, over time, eventually leads to the neuronal loss and reduced synaptic density that result in the cognitive impairment of AD. At this time we can only speculate as to estrogens role in modifying this process. Data from experimental animal models suggest that estrogen deficiency would selectively increase the vulnerability of estrogen-responsive neural elements, for example, the cholinergic neurons of the basal forebrain and hippocampus--offulnerability mediated perhaps by the reduced expression of neurotrophic factors, decreased clearance of the amyloid protein, and/or reduced cerebral blood flow that are associated with estrogen deficiency. The brains ability to adapt to the neuronal loss by stimulating axonal and synaptic regeneration would also be impaired by estrogen deficiency as suggested by estrogens ability to restore the synaptic density of lesioned brains of ovariectomized animals. Thus, estrogen deficiency, like the apolipoprotein E4 allele, can be considered not a cause of AD but one of perhaps several factors modifying the neuronal injury and loss leading to AD. The limited epidemiologic data and intervention trials currently available are consistent with this interpretation. Because of the urgency and enormity of the problem of dementia in our aging society, there would now appear to be sufficient reason to allocate the resources needed to conduct the appropriate clinical trials to determine estrogens efficacy in both the treatment and prevention of this devastating condition. These trials are needed so that women and their physicians can adequately weigh the risks and benefits of hormone replacement for the treatment and, more importantly, the prevention of dementia.

Falls in the Elderly: Reliability of a Classification System

To determine risk factors for falls, previous studies have classified falls according to the contribution of factors both intrinsic and extrinsic to the host. Due partly to the lack of operational definitions and the absence of information on reliability, no consensus on classification has been reached. Consequently, in a 3‐year prospective study of falls occurring in a probability sample of community‐dwelling elderly (n = 1,358), a fall classification system was developed and tested for interrater reliability. The 366 falls in the first year of the study were independently classified by two reviewers on the basis of a narrative description and structured interview. The falls in the four major categories of the classification system included: falls related to extrinsic factors (55%), falls related to intrinsic factors (39%), falls from a non‐bipedal stance (8%) and unclassified falls (7%). The interrater reliability for the four major categories was 89.9% with a kappa of 0.828. The system provides operational definitions for types of falls and a reliable and flexible method for classifying falls in the elderly.

The metabolic fate of vitamin D3-3H in chronic renal failure

The absorption and metabolism of vitamin D(3)-(3)H was studied in eight patients with chronic renal failure. Although the intestinal absorption of vitamin D(3)-(3)H was normal, the metabolic fate of the vitamin was abnormal as characterized by a twofold increase in fractional turnover rate, an abnormal accumulation of biologically inactive lipid-soluble metabolites, and the urinary excretion of both vitamin D(3)-(3)H and biologically inactive metabolites. Neither alterations in water-soluble vitamin D(3) metabolites nor qualitative abnormalities in protein-binding of vitamin D(3) were observed in the uremic subjects. Although hemodialysis proved ineffectual in reversing the observed abnormalities in vitamin D(3) metabolism and excretion, renal homotransplantation was completely successful in this regard. These experiments support the conclusion that the resistance to therapeutic doses of vitamin D often seen in patients with chronic renal failure and renal osteodystrophy results from an acquired defect in the metabolism and excretion of vitamin D.

Study of calcium absorption in man: a kinetic analysis and physiologic model

A physical model of calcium absorption was developed from analysis of data obtained on 23 subjects, including 13 patients having a variety of abnormalities of calcium metabolism. The model was tested and found consistent in all subjects studied. This technique provides a quantitative description of the rate of entry of oral dose of (47)Ca into the circulation as a function of time by analysis of serum or forearm radioactivity in response to intravenous and oral administration of (47)Ca. The kinetics of the absorption process as proposed by the model are characterized by an initial delay phase of 15-20 min, by a maximal rate of absorption at 40-60 min after ingestion, and by 95% completion of the absorption within 2(1/2) hr. Partial identification of the physiological counterparts of the model was possible by introduction of the isotope at various levels of the gut. Although the region of the duodenum was found to have the greatest rate of absorption per unit length in normal subjects, it was least responsive to stimulation by parathyroid hormone and suppression by calcium loading. Furthermore, the response of the gut to parathyroid hormone was delayed, whereas the suppression of absorption by intravenous or oral calcium loading was rapid and dramatic. The implications of these observations are discussed.