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Biomedical subjects

Michael C Nevitt

Publications and source records attributed to Michael C Nevitt.

48 records · Page 3Linked to original sources
PubMed2003

Walking performance and cardiovascular response: associations with age and morbidity--the Health, Aging and Body Composition Study.

BACKGROUND: The long-distance corridor walk is a timed 400-meter walk test used to assess walking endurance in well-functioning men and women aged 70-79 in the Health, Aging and Body Composition Study. METHODS: We examined walking time along with heart rate and blood pressure response in relationship to prevalent chronic conditions, weight, physical activity, and markers of subclinical disease. Of 3075 participants, 2324 (76%) completed the test with heart rate and blood pressure responses in the range expected for a moderate level of exertion. RESULTS: Slower walking time was influenced by both clinical and subclinical disease, and also was strongly related to both low and high body weight and low self-reported physical activity. Heart rate and blood pressure responses were higher with several clinical and subclinical diseases, but heart rate response and recovery were more strongly related to walking time than to disease. Higher body mass index and lower physical activity were associated with greater heart rate response and recovery. CONCLUSIONS: The independent contribution of both clinical and subclinical disease to walking time supports the use of walking tests as a summary measure of disease in older adults. The independent association of walking time with physical activity suggests that it is sensitive to levels of fitness as well. Together these findings show that walking performance is a valid indicator of physiologic reserve in older adults.

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PubMed2003

BMD at multiple sites and risk of fracture of multiple types: long-term results from the Study of Osteoporotic Fractures.

UNLABELLED: In a large cohort of U.S. women aged 65 and older, we report the relationships of BMD measured at several sites, and subsequent fracture risk at multiple sites over > 8 years of follow-up. Although we found almost all fracture types to be related to low BMD, the overall proportion of fractures attributable to low BMD is modest. INTRODUCTION: Although several studies have reported the relationship between bone mineral density (BMD) and subsequent fracture risk, most have been limited by short follow-up time, BMD measures at only one or two sites, or availability of data for only select fracture types. MATERIALS AND METHODS: In the multicenter Study of Osteoporotic Fractures (SOF), we studied the relationship of several different BMD measures to fracture risk of multiple types in 9704 non-black women aged 65 and older. We previously reported on the relationship of peripheral BMD measures to risk of several types of fracture during an average 2.2-year follow-up period. In this expanded analysis, we present results of the relationship of both peripheral and central BMD measures and fractures of multiple types during 10.4 and 8.5 years of follow-up, respectively. We also report population attributable risk (PAR) estimates for osteoporosis and risk of several types of fracture. RESULTS: Our results show that almost all types of fractures have an increased incidence in women with low BMD. However, hip BMD is somewhat more strongly related to most of the fracture types studied than spine or peripheral BMD measures. Nonetheless, the proportion of fractures attributable to osteoporosis (based on a standard definition of osteoporosis) is modest, ranging from < 10% to 44% based on the most commonly used definition of osteoporosis (BMD T-score < -2.5). CONCLUSION: Finding effective prevention strategies for fractures in older women will require additional interventions beside preventions for bone loss, such as prevention of falls and other fracture risk factors.

Aged↗
PubMed2002

QDR 4500A DXA overestimates fat-free mass compared with criterion methods.

This study evaluated the accuracy with which the dual-energy X-ray absorptiometer (Hologic QDR 4500A) measured fat-free mass (FFM), fat mass (FM), and hydration of FFM. In a study of 58 men and women (ages 70-79 yr), the QDR 4500A was found to provide a systematically higher estimate of FFM and lower estimate of FM than a four-component model of body composition. A correction factor from this study was developed and applied to two other samples (n = 13 and 37). We found mean corrected levels of FFM and FM to be equivalent to that obtained by the four-component model or total body water. In addition, the hydration of the corrected FFM was closer to the established hydration level in adult samples and that obtained from the four-component model. These findings suggest that the current calibration of the fan-beam system of the Hologic QDR 4500A provides an overestimate of FFM and underestimate of FM compared with reference methods.

Absorptiometry, Photon↗
PubMed2002

High prevalence of lateral knee osteoarthritis in Beijing Chinese compared with Framingham Caucasian subjects.

OBJECTIVE: We recently reported that, despite their thinness, elderly subjects in Beijing, China had an equal prevalence (in men) or higher prevalence (in women) of both radiographic and symptomatic knee osteoarthritis (OA) compared with that in the Framingham, Massachusetts cohort of elderly subjects. Our objective was to evaluate whether Chinese subjects might have more medial disease than do Caucasians, given a report of varus alignment in the knee joints of Chinese elderly. METHODS: We compared the prevalence of medial and lateral radiographic knee OA and measured anatomic alignment in the knees of elderly subjects from the Beijing and Framingham cohorts. Both studies recruited a random sample of the population. The Beijing OA Study used the Framingham OA Study protocol for radiographs. Anteroposterior weight-bearing films were read for Kellgren and Lawrence (K/L) grade and joint space narrowing (JSN; 0-3 scale) in each compartment. Medial disease was defined when radiographs showed a K/L grade >or=2 and medial JSN >or=1, and lateral disease was assessed in a comparable manner. Using knee-specific analyses, we compared the prevalence of medial and lateral knee OA after adjusting for age, body mass index, and the correlation between the 2 knees. Restricting the analyses to knees with JSN >or=2 and comparing the proportion of OA knees with medial disease and lateral disease yielded similar results. We assessed alignment in knees from 100 persons without OA, measuring the angle subtended by the femoral and tibial anatomic axes. RESULTS: We studied 1,781 Chinese subjects ages 60-88 years, and 1,084 Framingham subjects ages 63-93 years. Whereas medial OA was less prevalent among the Beijing men, lateral OA was more than twice as prevalent among the Beijing men and women, compared with that in the Framingham elderly. For example, of all knees with radiographic OA, 28.5% of Beijing women's knees had lateral OA versus 11% of Framingham women's knees (P < 0.001), and among men, 32.3% of Beijing men's knees versus 8.8% of Framingham men's knees (P < 0.001) had lateral OA. Alignment was more valgus in the Beijing men than in the Framingham men (mean 4.5 degrees versus 2.7 degrees valgus, respectively; P < 0.001), but no differences in alignment were evident in the women. CONCLUSION: In this first attempt to compare the characteristics of OA in different racial groups, we conclude that, opposite to expectations, Chinese subjects have much more lateral OA than do Caucasian subjects in the Framingham cohort, a predilection possibly explained in the men by differences in anatomic alignment.

Aged↗
PubMed2002

Very low prevalence of hip osteoarthritis among Chinese elderly in Beijing, China, compared with whites in the United States: the Beijing osteoarthritis study.

OBJECTIVE: To compare the prevalence of osteoarthritis (OA) of the hip among elderly persons in China and the US. METHODS: We recruited a population-based sample of 1,506 persons (82% of those enumerated) ages > or = 60 years living in Beijing, China. Subjects answered questions about joint symptoms and underwent radiography of the pelvis. Radiographs of the Beijing subjects were intermingled with hip radiographs of white women ages > or = 65 years from the Study of Osteoporotic Fractures (SOF) and white men and women ages 60-74 years from the First National Health and Nutrition Examination Survey (NHANES-I) and were then interpreted. Radiographic hip OA was defined as the presence of 1 of the following 3 findings in either hip: minimum joint space of < or = 1.5 mm, definite osteophytes and joint space narrowing, or > or = 3 radiographic features of OA. Symptomatic hip OA was defined as both radiographic OA and hip pain. RESULTS: The crude prevalence of radiographic hip OA in Chinese ages 60-89 years was 0.9% in women and 1.1% in men; it did not increase with age. Chinese women had a lower age-standardized prevalence of radiographic hip OA compared with white women in the SOF (age-standardized prevalence ratio 0.07) and the NHANES-I (prevalence ratio 0.22). Chinese men had a lower prevalence of radiographic hip OA compared with white men of the same age in the NHANES-I (prevalence ratio 0.19). There were no cases of symptomatic hip OA in the Chinese men and only 1 case in the Chinese women; 35 cases were expected in both sexes. CONCLUSION: This is the first population-based study of hip OA in China to use standardized radiographic methods and definitions. We found that hip OA was 80-90% less frequent than in white persons in the US. Identification of the genetic and environmental factors that underlie these differences may help elucidate the etiology and prevention of hip OA.

Aged↗
PubMed2002

Central nervous system-active medications and risk for falls in older women.

OBJECTIVES: To determine whether current use of central nervous system (CNS)-active medications, including benzodiazepines, antidepressants, anticonvulsants, and narcotics, increases the risk for subsequent falls. DESIGN: Prospective cohort study. SETTING: Four clinical centers in Baltimore, Maryland; Portland, Oregon; Minneapolis, Minnesota; and the Monongahela Valley, Pennsylvania. PARTICIPANTS: Eight thousand one hundred twenty-seven women aged 65 and older participating in the fourth examination of the Study of Osteoporotic Fractures between 1992 and 1994. MEASUREMENTS: Current use of CNS-active medications was assessed with an interviewer-administered questionnaire with verification of use from medication containers. A computerized dictionary was used to categorize type of medication from product brand and generic names. Incident falls were reported every 4 months for 1 year after the fourth examination. RESULTS: During an average follow-up of 12 months, 2,241 women (28%) reported falling at least once, including 917 women (11%) who experienced two or more (frequent) falls. Compared with nonusers, women using benzodiazepines (multivariate odds ratio (MOR) = 1.51, 95% confidence interval (CI) = 1.14-2.01), those taking antidepressants (MOR = 1.54, 95% CI = 1.14-2.07), and those using anticonvulsants (MOR = 2.56, 95% CI = 1.49-4.41) were at increased risk of experiencing frequent falls during the subsequent year. We found no evidence of an independent association between narcotic use and falls (MOR = 0.99 for frequent falling, 95% CI = 0.68-1.43). Among benzodiazepine users, both women using short-acting benzodiazepines (MOR = 1.42, 95% CI = 0.98-2.04) and those using long-acting benzodiazepines (MOR = 1.56, 95% CI = 1.00-2.43) appeared to be at greater risk of frequent falls than nonusers, although the CIs overlapped 1.0. We found no evidence to suggest that women using selective serotonin-reuptake inhibitors (MOR = 3.45, 95% CI = 1.89-6.30) had a lower risk of frequent falls than those using tricyclic antidepressants (MOR 1.28, 95% CI = 0.90-1.84). CONCLUSIONS: Community-dwelling older women taking CNS-active medications, including those taking benzodiazepines, antidepressants, and anticonvulsants, are at increased risk of frequent falls. Minimizing use of these CNS-active medications may decrease risk of future falls. Our results suggest that fall risk in women taking benzodiazepines is at best marginally decreased by use of short-acting preparations. Similarly, our findings indicate that preferential use of selective serotonin-reuptake inhibitors is unlikely to reduce fall risk in older women taking antidepressants.

Accidental Falls↗
PubMed2002

Diabetes and incidence of functional disability in older women.

OBJECTIVE: To examine the relationship between diabetes and the incidence of functional disability and to determine the predictors of functional disability among older women with diabetes. RESEARCH DESIGN AND METHODS: We analyzed data from 8,344 women enrolled in the Study of Osteoporotic Fractures, a prospective cohort of women aged > or =65 years. Diabetes (n = 527, 6.3% prevalence) and comorbidities (coronary heart disease, stroke, arthritis, depression, and visual impairment) were assessed by questionnaire and physical examination. Incident disability, defined as onset of inability to do one or more major functional tasks (walking 0.25 mile, climbing 10 steps, performing household chores, shopping, and cooking meals), was assessed by questionnaire over 12 years. RESULTS: The yearly incidence of any functional disability was 9.8% among women with diabetes and 4.8% among women without diabetes. The age-adjusted hazard rate ratio (HRR) of disability for specific tasks associated with diabetes ranged from 2.12 (1.82-2.48) for doing housework to 2.50 (2.05-3.04) for walking two to three blocks. After adjustment for potential confounders at baseline (BMI, physical activity, estrogen use, baseline functional status, visual impairment, and marital status) and comorbidities (heart disease, stroke, depression, and arthritis), diabetes remained associated with a 42% increased risk of any incident disability and a 53-98% increased risk of disability for specific tasks. Among women with diabetes, older age, higher BMI, coronary heart disease, arthritis, physical inactivity, and severe visual impairment at baseline were each independently associated with disability. CONCLUSIONS: Diabetes is associated with an increased incidence of functional disability, which is likely to further erode health status and quality of life.

Age of Onset↗
PubMed2002

Older women with diabetes have a higher risk of falls: a prospective study.

OBJECTIVE: To determine whether older women with diabetes have an increased risk of falls and whether known risk factors for falls account for any increased risk. RESEARCH DESIGN AND METHODS: This prospective cohort study included 9,249 women > or =67 years of age enrolled in the Study of Osteoporotic Fractures. Diabetes was determined by questionnaire at baseline. Physical performance was measured at the second examination. Subsequently, falls were ascertained every 4 months by postcard. RESULTS: A total of 629 (6.8%) women had diabetes, including 99 who used insulin. During an average of 7.2 years, 1,640 women (18%) fell more than once a year. Diabetes, stratified by insulin use, was associated with an increased risk of falling more than once a year (age-adjusted odds ratio [OR] 1.68 [95% CI 1.37-2.07] for non-insulin-treated diabetes; age-adjusted OR 2.78 [1.82-4.24] for insulin-treated diabetes). In the first 2 years of follow-up, women with diabetes were not more likely to fall than women without diabetes (44 vs. 42%; P = 0.26), but they had more falls (3.1 vs. 2.4; P < 0.01). Women with diabetes were more likely to have other risk factors for falls, which appeared to account for the increased risk of falls associated with non-insulin-treated diabetes (adjusted OR 1.18 [0.87-1.60]) but not insulin-treated diabetes (adjusted OR 2.76 [1.52-5.01]). CONCLUSIONS: Older women with diabetes have an increased risk of falling, partly because of the increased rates of known fall risk factors, and may benefit from interventions to prevent falls. Further research is needed to determine whether diabetes treatment reduces fall risk.

Accidental Falls↗
PubMedDate not supplied

Lumbar spine listhesis in older African American women.

BACKGROUND CONTEXT: Degenerative changes in the lumbar spine may result in a loss of spinal stability and subluxation of one vertebra relative to another. Cadaveric studies and clinical case series have suggested that listhesis may be much more common in African Americans than in whites. PURPOSE: To determine the prevalence of lumbar spine listhesis (anterolisthesis and retrolisthesis) among African American women aged 65 years and older and the relationship of listhesis to low back pain, physical function and quality of life. STUDY DESIGN/SETTING: Cross-sectional study. PATIENT SAMPLE: A total of 481 African American women aged 65 years and older who were enrolled in the Study of Osteoporotic Fractures. These women were recruited from population-based listings in Baltimore, MD, Minneapolis, MN, Pittsburgh, PA, and Portland, OR. OUTCOME MEASURES: Not applicable. METHODS: Lateral radiographs of the lumbar spine were digitized, and listhesis (anterolisthesis and retrolisthesis) was assessed at spinal levels L3-L4, L4-L5 and L5-S1. Usable data were obtained for 470 women. Listhesis was defined as present when the subluxation (antero or retro) was 3 mm or more. RESULTS: The overall prevalence of anterolisthesis was 58.3% and varied by spinal level (13.2% at L3-L4, 36.5% at L4-L5 and 29.6% at L5-S1). The prevalence increased with age but was lower among oophorectomized women and those currently on estrogen replacement therapy. Anterolisthesis was not associated (p>.05) with disc height nor was it related to back function. Retrolisthesis occurred in 4% of women and was associated with decreased disc height and an increased prevalence of spinal problems and walking problems. CONCLUSIONS: The prevalence of anterolisthesis among older African American women living in the community was two to three times greater than that found in white women of a similar age. This condition was not related to an increased frequency of back problems nor did it adversely affect general physical function. Retrolisthesis was relatively rare but was associated with decreased back function.

Black or African American↗
PubMedDate not supplied

Neck and shoulder pain in 70- to 79-year-old men and women: findings from the Health, Aging and Body Composition Study.

BACKGROUND CONTEXT: Musculoskeletal pain in the cervicobrachial region is considered a major health problem among adults of working age, but little is known about the impact of this pain in the elderly. PURPOSE: Determine the prevalence of neck and shoulder pain in a well-functioning cohort, identify factors associated with this pain, assess the pattern of coexisting joint pain and evaluate the impact of this pain on physical functioning. STUDY DESIGN: Cross-sectional study. PATIENT SAMPLE: Black and white men and women, aged 70 to 79 years, participating in the Health, Aging and Body Composition (Health ABC) study. OUTCOME MEASURES: Not applicable. METHODS: Between April 1997 and June 1998, 3,075 men and women participating in Health ABC study completed the initial home interview and clinical examination. Information was collected on musculoskeletal pain, medical history, depressive symptomatology and physical function. Physical performance measures were obtained. RESULTS: A total of 11.9% of participants reported neck pain of one month or more in duration and 18.9% reported shoulder pain. White women had the highest prevalence of neck pain (15.4%) and black women the highest prevalence of shoulder pain (24.3%). The correlates of both neck and shoulder pain were female gender, no education beyond high school, poorer self-rated health, depressive symptomatology and a medical history of arthritis, heart attack, angina. Increasing severity of both neck and shoulder pain was associated with an increased prevalence of joint pain at other body sites and with poor functional capacity. Measures of physical performance involving the upper extremity were also decreased. CONCLUSIONS: Neck and shoulder pain, either alone or in conjunction with pain in other joints, has a substantial impact on the function and well-being of the older adults in this cohort.

Age Distribution↗