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Biomedical subjects

M C Nevitt

Publications and source records attributed to M C Nevitt.

At least 91 records · Page 5Linked to original sources
PubMed1995

The association of radiographic changes of osteoarthritis of the hand and hip in elderly women.

OBJECTIVE: To examine the association of radiographic features of hand and hip osteoarthritis (OA) in elderly women. METHODS: Hand and hip radiographs were read for changes of OA from a sample of 1422 women aged 65 and above who were participants in the Study of Osteoporotic Fractures. Definite hip OA required the presence of 2 or more of the following: moderate or large osteophytes, moderate or severe joint space narrowing, subchondral sclerosis, cysts, and femoral head deformity. Definite hand OA required moderate or large osteophytes at 2 or more of the following 6 sites: 2nd and 3rd distal and proximal interphalangeal joints and 1st interphalangeal and carpometacarpal joints. Data were analyzed using multiple logistic regression adjusting for age, weight at age 50, and current height. RESULTS: Overall, 147 (10.4%) women had radiographic changes of definite hip OA and 68 (4.8%) had severe hip OA; 56 had bilateral and 87 had unilateral disease. Definite hand OA was present in 732 (51.4%) women. Hand OA was significantly associated with definite hip OA [odds ratio (OR) = 3.25, 95% confidence intervals (CI) 2.19, 4.84], and severe hip OA (OR = 3.23, 95% CI 1.82, 5.73). Hand OA was significantly associated with bilateral hip OA (OR = 3.54, 95% CI 1.87, 6.73) as well as unilateral hip OA (OR = 3.06, 95% CI 1.84, 5.08). CONCLUSION: These data are consistent with the inclusion of radiographically defined hip OA in the construct of generalized OA, particularly in elderly women.

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PubMed1994

Smoking, alcohol, and neuromuscular and physical function of older women. Study of Osteoporotic Fractures Research Group.

OBJECTIVE: To determine the associations of current and lifetime smoking and alcohol use with physical function in an older population. DESIGN: Survey. SETTING: Four clinic centers in the United States. PARTICIPANTS: A total of 9704 community-dwelling, ambulatory white women 65 years or older recruited from four areas of the United States. MAIN OUTCOME MEASURES: Twelve performance tests of muscle strength, agility and coordination, gait and balance, and self-reported functional status. RESULTS: Compared with women who never smoked, current smokers had significantly poorer function on all of the performance measures except grip strength after adjusting for age, history of stroke, body mass index, clinic site, physical activity, and alcohol use (P < .05). This decrease in function was 50% to 100% as great as that associated with a 5-year increase in age, and most measures worsened with increasing numbers of pack-years. Compared with current moderate drinkers, nondrinkers had significantly poorer function on all of the performance measures except tandem walk (P < .05). Evaluation of a dose effect with alcohol was limited by the small number of heavy drinkers in the study. CONCLUSIONS: In this population, women who currently smoke are weaker and have poorer balance and poorer performance on measures of integrated physical function than nonsmokers. Smoking is associated with a decline in physical function. Current moderate drinkers have better physical function compared with nondrinkers, but associations of function with heavy drinkers could not be assessed.

Activities of Daily Living↗
PubMed1994

Falls.

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Accidental Falls↗
PubMed1994

Black-white differences in serum sex hormones and bone mineral density.

To determine if differences in serum sex hormones contribute to racial differences in bone mass, independent of obesity, the authors compared bone mass and sex steroid hormone levels in 273 white women and 86 black women aged 65 years or older. This study was ancillary to the Study of Osteoporotic Fractures. Black women were recruited at two clinical centers in Baltimore, Maryland, and the Monongahela Valley, near Pittsburgh, Pennsylvania. An age-stratified random sample of white women was chosen from the Pittsburgh clinic. Demographic and historical information and anthropometric measurements were obtained from a clinic questionnaire, interview, and examination. Single photon absorptiometry was obtained at three sites: the distal radius, the proximal radius, and the calcaneus. Serum estrone, androstenedione, and testosterone were measured using extraction, column chromatography, and radioimmunoassay. Serum estrone concentrations were significantly higher and androstenedione levels were significantly lower in black women compared with white women. Racial differences in estrone could be explained largely by differences in the degree of obesity. Bone mass was greater in black women compared with white women within age, body mass index, (kg/m2), and estrone strata. Androgens were not related to bone mass. Within each race, bone mass increased linearly with increasing concentration of serum estrone. There was no interaction between race and serum estrone on bone mass. Each factor contributed independently and significantly to the regression model predicting bone mass. There was no attenuation of the effect of race if estrone was included in the model. In conclusion, race and serum estrone were independent determinants of bone mass.

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PubMed1994

Bone mineral density predicts non-spine fractures in very elderly women. Study of Osteoporotic Fractures Research Group.

To determine the ability of bone density to predict fractures in very elderly women, we examined the association of bone density with non-spine, hip, wrist and humerus fractures in 8699 Caucasian women aged 65-79 years and 1005 women aged 80 years and older who were participants in the prospective Study of Osteoporotic Fractures. Follow-up averaged 4.9 (+/- 1.0) years after baseline measurement of appendicular bone density (single-photon absorptiometry; Osteon-Osteo Analyzer) and 2.9 (+/- 0.6) years after measurement of hip and anteroposterior lumbar spine bone density (dual-energy X-ray absorptiometry; Hologic QDR 1000) at a later examination. In general, measurements of bone density in the oldest women retained their predictive value for fractures. Among women aged 80 and over a 1 standard deviation decrease in bone density of the distal radius was associated with an increased risk of non-spine (relative risk: 1.6; 95% confidence interval: 1.3, 1.8), wrist (1.7; 1.2, 2.4) and humerus fracture (2.9; 1.8, 4.7), while a 1 standard deviation decrease in femoral neck bone density was associated with an increased risk of non-spine (1.9; 1.6, 2.4), humerus (2.4; 1.2, 4.7) and hip fracture (2.1; 1.4; 3.2). However, only trochanteric but not femoral neck fractures were associated with low bone density in these oldest women. The excess risk of fracture in women with below-median bone density was greater in those aged 80 years and over compared with the younger women: 38.4 v 20.4 per 1000 woman-years for non-spine fracture and 12.2 v 3.2 per 1000 woman-years for hip fracture.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1994

Non-skeletal determinants of fractures: the potential importance of the mechanics of falls. Study of Osteoporotic Fractures Research Group.

Bones break because the forces applied to them exceed their strength. For most non-spine fractures, this force results from a fall. Falls generate at least 10 times the energy necessary to fracture the proximal femur, but only 5%-10% of falls in older white women cause fractures and only 1% cause hip fractures. The mechanics of the fall plays a very important role in whether a fracture will occur and which bone will fracture. This review postulates that orientation of the fall and location of the impact determine the type of fracture, and whether a fracture occurs depends on the energy of the fall (distance to impact and weight of the moving parts) and how much of that energy is absorbed by protective responses, the impact surface and soft tissues over the bone. Recent case-control studies support the view that the mechanics of a fall are the most important determinant of whether it will result in a hip fracture.

Accidental Falls↗
PubMed1994

Kyphosis in older women and its relation to back pain, disability and osteopenia: the study of osteoporotic fractures.

To test the hypothesis that thoracic kyphosis is associated with substantial pain, disability, and height loss, we measured thoracic curvature, using an architect's flexicurve, of 610 women aged 65-91 years who were recruited from population-based listings. We assessed study subjects for back pain, back-related disability, height loss since age 25 years, perceived state of health, and bone mineral density (BMD) at the spine, calcaneus, proximal radius, and distal radius. Compared with the rest of the cohort, the 10% of women with the most severe kyphosis had 7%-17% lower BMD (p < 0.001) and had lost an additional 2.4 cm height (p < 0.001). However, kyphotic women had no greater back pain, disability caused by back problems, or poorer health. This cross-sectional study suggests that kyphosis is associated with decreased BMD and loss of height but does not cause substantial chronic back pain, disability, or poor health in older women.

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PubMed1994

Validation and use of performance measures of functioning in a non-disabled older population: MacArthur studies of successful aging.

Assessment of physical functioning in older persons has generally focused on identifying and characterizing subjects at the disabled end of the functional spectrum. This paper examines the validity of objective, standardized performance measures of physical functioning in characterizing the hierarchy of functioning in non-disabled, higher functioning older persons. Data are from 1192 participants aged 70-79 years in The MacArthur Research Network on Successful Aging Field Study. Participants were drawn from three community-based populations and represented the upper tertile of functioning, based on cognitive and physical screening assessments. The cohort showed a great deal of heterogeneity on most of the performance measures of functioning that were used. Several analyses provided evidence that this variability was not random and that the performance measures were valid measures of functioning in this cohort: 1) individual performance measures showed a moderate degree of correlation with each other; 2) a summary measure of performance showed an association with chronic diseases and other factors known to be associated with health status; and 3) a larger group than expected by chance alone was found to be functioning at the very highest level.

Age Distribution↗
PubMed1994

Correlates of impaired function in older women.

OBJECTIVE: To determine the factors associated with impaired function in older women. DESIGN: Cross-sectional analysis of baseline data collected for a multicenter, prospective study of risk factors for osteoporotic fractures. SETTING: Four clinical centers in Portland, Oregon, Minneapolis, Minnesota, Baltimore, Maryland, and the Monongahela Valley, Pennsylvania. PARTICIPANTS: A total of 9,704 ambulatory, non-black women, aged 65 years and older, recruited from population-based listings. MEASUREMENTS: Independent variables, including demographic and historical information (medical conditions, health habits, and medications) and physiologic measures (anthropometry, blood pressure, mental status, vision, and neuromuscular performance) were obtained from a baseline questionnaire, interview, and examination. Measurement of function was assessed by self-reported ability to perform six physical and instrumental activities of daily living (ADL) and impaired function (dependent variable) was defined as difficulty performing three or more physical and instrumental ADLs. RESULTS: In order of decreasing strength of association, hip fracture, osteoarthritis, parkinsonism, slower walking speed, lower hip abduction force, back pain, greater Quetelet index, osteoporosis, former alcohol use, stroke, never drinking alcohol, lower mental status, use of anxiolytics and/or sleeping medications, inability to hold the tandem position, postural dizziness, cataracts, greater waist to hip ratio, lower physical activity in the past year, greater lifetime cigarette consumption, and lower grip strength were independently associated with impaired function in multivariate analyses. Age, low educational level, diabetes, current heavy alcohol use, postural hypotension, depth perception, and contrast sensitivity were not independent predictors. A combination of neuromuscular performance measures, including decreased muscle strength and impaired balance and gait, appeared to account for the effect of age on disability. CONCLUSION: A combination of many factors, including medical conditions, health habits such as obesity, smoking, alcohol abstinence, and physical inactivity, and direct measures of neuromuscular performance are associated with impaired function in older women.

Activities of Daily Living↗
PubMed1994

Development of a physical performance and mobility examination.

OBJECTIVE: To develop and validate the Physical Performance and Mobility Examination (PPME), an observer-administered, performance-based instrument assessing 6 domains of physical functioning and mobility for hospitalized elderly. DESIGN: Development of a pass-fail and 3-level scoring system and training manuals for the PPME instrument for use in both clinical and research settings. Two patient samples were used to assess construct validity and interrater reliability of the PPME. A third sample was selected to assess the test-retest reliability of the instrument. SETTING/PATIENTS: (1) 146 subjects > or = 65 years of age with impaired mobility admitted to Medical Units of Stanford University Hospital. (2) 352 subjects > or = 65 admitted to acute Medical and Surgical Services of the Palo Alto VA Medical Center. Patient samples were obtained during hospitalization and followed until 3 months post-discharge. To study test-retest reliability, 50 additional patients, whose clinical condition was stable, were selected from both settings. METHODS: An expert panel selected 6 mobility tasks integral to daily life: bed mobility, transfer skills, multiple stands from chair, standing balance, step-up, and ambulation. Tasks were piloted with frail hospitalized subjects for appropriateness and safety. Test-retest and interrater reliability and construct validity were evaluated. Construct validity was tested using the Folstein Mini-Mental State Examination, Activities of Daily Living (ADL), Instrumental Activities of Daily Living (IADL), Geriatric Depression Scale, and modified Medical Outcomes Study Measure of Physical Functioning (MOS-PFR). Two scoring schema were developed for each task: (1) dichotomous pass-fail and (2) 3-level high pass, low pass, and fail. A summary scale was developed for each method of scoring. MAIN RESULTS: High interrater reliability and intrarater reliability were demonstrated for individual tasks. The mean percent agreement (interrater) for each pass/fail task ranged from 96 to 100% and from 90 to 100% for the 3 pairs of raters for each task using the 3-level scoring. Kappas for individual pairs of raters ranged from .80 to 1.0 for pass-fail scoring and from .75 to 1.0 for 3-level scoring (all P < 0.01). Intraclass correlation coefficients for 3-level scoring by pairs of raters ranged from .66 to 1.0. For summary scales, the mean intraclass correlation was .99 for both scoring schema. Test-retest reliability for summary scales using kappa coefficients was .99 for both pass-fail and 3-level scoring, and .99 and .98, respectively, using Pearson Product Moment Correlation. Correlations of PPME with other instruments (construct validity) suggest that the PPME adds a unique dimension of mobility beyond that measured by self-reported ADLS and physical functioning, and it is not greatly influenced by mood or mental status (r = 0.70 (ADL), r = 0.43 (IADL), r = 0.36 (MMSE), r = 0.71 (MOS-PFR), r = 0.23 (GDS)). The 3-level summary scale was sensitive to the variability in the patient population and exhibited neither ceiling nor floor effects. CONCLUSIONS: The PPME is a reliable and valid performance-based instrument measuring physical functioning and mobility in hospitalized and frail elderly.

Activities of Daily Living↗
PubMed1994

Functional status and mobility among elderly women with lower extremity arterial disease: the Study of Osteoporotic Fractures.

OBJECTIVE: To investigate the relationship between lower extremity arterial disease, functional status, and mobility among elderly women. DESIGN: Cross-sectional study. SETTING: Community. PARTICIPANTS: 1492 healthy white women, 65 years of age or older, residing in a rural community, able to walk without the assistance of another person, and enrolled in the Pittsburgh clinic of the multicenter Study of Osteoporotic Fractures. Those with bilateral hip replacement were excluded. MEASUREMENTS: Ankle/arm index (AAI); instrumental activities of daily living (IADLs); measures of recent physical activity, muscle strength, gait and balance; general demographic, lifestyle, and physical variables. RESULTS: Women with lower extremity arterial disease (defined as an AAI of 0.9 or less) were more likely to report difficulty with one or more IADLs than were women free of this disease. After adjusting for age and other potential confounders, only difficulty with walking 2-3 blocks remained highly correlated with disease (relative risk (RR) 2.8, 95% confidence interval (CI) 1.6, 4.8). Several measures of physical activity were inversely and independently related to a low AAI. Muscle strength in the hip, arm, knee, and hand and measures of static and dynamic balance were correlated with low AAI in the univariate analysis, but most of these trends were not statistically significant after adjustment for age and other confounders. Exclusion of women with symptomatic arterial disease did not substantially affect the results obtained. CONCLUSION: Women with mild, predominantly subclinical, lower extremity arterial disease living in the community have decreased functional status and mobility.

Activities of Daily Living↗
PubMed1994

Epidemiology of osteoporosis.

Prevention is particularly important in osteoporosis since the loss of bone strength that accompanies bone loss is not known to be reversible. Identification of those at risk by measurement of risk factors may help target prevention efforts. Low bone mass and a propensity for falling are established risk factors for osteoporotic fracture in the elderly; some other risk factors for fracture may operate through these two pathways. There has been little epidemiologic study of other potential causes of fracture such as poor bone quality and trauma biomechanics, and little is known about risk factors that may operate through these pathways.

Accidental Falls↗
PubMed1993

Effects of thiazide diuretic therapy on bone mass, fractures, and falls. The Study of Osteoporotic Fractures Research Group.

OBJECTIVE: To determine the relation between the use of thiazide diuretics and bone mass, fractures, and falls in older women. DESIGN: Cross-sectional study of thiazide diuretics, bone mass, and prevalent vertebral deformities; cohort analysis of thiazide diuretics and nonspinal fractures and falls. SETTING: Four clinical centers located in Baltimore, Maryland; Minneapolis, Minnesota; Portland, Oregon; and the Monongahela Valley, Pennsylvania. PARTICIPANTS: A total of 9704 ambulatory, nonblack women who were 65 years or older. MEASUREMENTS: Information on thiazide use, demographic data, medical history, and anthropometric measurements were obtained by questionnaire, interview, and examination. Appendicular bone mass was measured by single-photon absorptiometry. Incident falls and fractures were ascertained every 4 months. RESULTS: Women using thiazide diuretics for more than 10 years had significantly higher bone mass than women who had never used thiazide diuretics (for example, 0.381 g/cm2 compared with 0.355 g/cm2 for the distal radius [P < 0.001]). Current users of thiazide diuretics had an incidence of falls (relative risk, 1.06; 95% CI, 0.90 to 1.25) that was similar to that of those who had never used these drugs. After adjusting for age, body weight, functional status, total calcium intake, duration of estrogen replacement therapy, and self-reported health status, we found that current users of thiazide diuretics who had taken these drugs for more than 10 years had a risk for nonspinal (relative risk, 0.99; CI, 0.81 to 1.20) and osteoporotic (relative risk, 0.98; CI, 0.79 to 1.22) fractures that was similar to that of women who had never used thiazides; however, thiazide users did have a lower risk for fractures of the hip (relative risk, 0.63; CI, 0.34 to 1.16) and wrist (relative risk, 0.66; CI, 0.40 to 1.08), neither of which was significant. CONCLUSIONS: Thiazide diuretics have no effect on a women's risk for falling or for experiencing nonspinal fractures. The trend toward a lower risk for hip and wrist fractures is consistent with findings in previous cohort studies but may reflect selection factors for the use of thiazide diuretics. A randomized trial is needed to determine the effect ot thiazide diuretics on the incidence of fractures.

Accidental Falls↗
PubMed1993

Bone density at various sites for prediction of hip fractures. The Study of Osteoporotic Fractures Research Group.

Women with low bone density in the radius or calcaneus are at increased risk of hip fracture. To see whether bone density of the hip measured by dual X-ray absorptiometry is a better predictor of hip fracture than measurements of other bones, we assessed bone density at several sites in 8134 women aged 65 years or more. 65 women had hip fractures during a mean follow-up of 1.8 years. Each SD decrease in femoral neck bone density increased the age-adjusted risk of hip fracture 2.6 times (95% CL 1.9, 3.6). Women with bone density in the lowest quartile had an 8.5-fold greater risk of hip fracture than those in the highest quartile. Bone density of the femoral neck was a better predictor than measurements of the spine (p < 0.0001), radius (p < 0.002), and moderately better than the calcaneus (p = 0.10). Low hip bone density is a stronger predictor of hip fracture than bone density at other sites. Efforts to prevent hip fractures should focus on women with low hip bone density.

Absorptiometry, Photon↗
PubMed1993

Vertebral fracture assessment using a semiquantitative technique.

The assessment of vertebral fracture by conventional radiography has been refined and improved using either semiquantitative or quantitative criteria. The inter- and intraobserver variability was determined for a semiquantitative visual approach that we routinely use in clinical studies for assessing prevalent and incident vertebral fractures. In addition, the semiquantitative approach was compared with a quantitative morphometric approach. The incidence and prevalence of vertebral fractures were determined in 57 postmenopausal women (age 65-75 years) by three independent observers. The radiographic basis for fracture definitions and the source of interobserver agreement for the semiquantitative technique. We conclude that the semiquantitative approach can be applied reliably in vertebral fracture assessment when performed using well-defined criteria.

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PubMed1993

Design of the Fracture Intervention Trial.

The Fracture Intervention Trial (FIT) is a randomized, double-masked, placebo-controlled trial designed to test the hypothesis that alendronate, an amino-bisphosphonate, will reduce the rate of fractures in women aged 55-80 years with low hip bone marrow density (< 0.68 gm/cm2 at the femoral neck). It is being conducted at 11 clinical centers around the United States with a coordinating center at UC San Francisco. The goal was to randomize 6000 women. When recruitment was completed (in May 1993), 6457 women had been randomized, amounting to 108% of goal. The women were assigned to one of two substudies. The first (Vertebral Deformity study) includes 2023 women who have at least one vertebral deformity, and will test the hypothesis that alendronate reduces the rate of new vertebral deformities during 3 years of follow-up. This substudy has a power of 0.90 to detect a 32% reduction in the incidence of new vertebral deformities, assuming a 6.5% annual incidence of new vertebral deformities in the placebo group. The second study (Clinical Fracture study) includes 4434 women without vertebral deformities at baseline and will test the hypothesis that alendronate reduces the rate of clinically recognized fractures of all types over an average of 4.25 years of follow-up. This substudy has a 0.90 power to detect a 25% reduction in the rate of all clinical fractures, assuming 4% annual incidence in the placebo group. To our knowledge, this is the largest prospective, randomized, controlled study undertaken to determine the effectiveness of a treatment in reducing the risk of fractures in postmenopausal women.

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