Biomedical subjects

A V Schwartz

Publications and source records attributed to A V Schwartz.

7 recordsLinked to original sources

PubMed2003

Diabetes Mellitus: Does it Affect Bone?

Both diabetes and fractures affect a large proportion of older adults. Recent cohort studies indicate that diabetes itself is associated with increased risk of fracture of the hip, proximal humerus, and foot. Observational studies and animal models suggest that decreased bone strength in diabetes may contribute to fracture risk but this remains a controversial issue. Type 1 diabetes is associated with modest reductions in bone mineral density (BMD) but type 2 diabetes is often characterized by elevated BMD. This paradox of higher BMD but increased fracture risk in type 2 diabetes may be explained by a combination of more frequent falls and poorer bone quality. Diabetes can impact bone through multiple pathways, some with contradictory effects, including obesity, changes in insulin levels, higher concentrations of advanced glycation end products in collagen, hypercalciuria associated with glycosuria, reduced renal function, lower insulin-like growth factor-I, microangiopathy, and inflammation. A better understanding of how diabetes metabolism and treatments affect bone would improve fracture prevention efforts in older diabetic adults.

Animals↗

PubMed2001

Older women with diabetes have an increased risk of fracture: a prospective study.

To determine whether type 2 diabetes is associated with fracture in older women, we analyzed data from 9654 women, age 65 yr or older, in the Study of Osteoporotic Fractures. Diabetes with age at onset 40 yr or older was reported by 657 women, of whom 106 used insulin. A total of 2624 women experienced at least one nonvertebral fracture during an average follow-up of 9.4 yr, and 388 had at least one vertebral fracture during an average interval of 3.7 yr. Although diabetes was associated with higher bone mineral density, it was also associated with a higher risk of specific fractures. Compared with nondiabetics, women with diabetes who were not using insulin had an increased risk of hip [relative risk (RR), 1.82; 95% confidence interval (CI), 1.24-2.69] and proximal humerus (RR, 1.94; 95% CI, 1.24-3.02) fractures in multivariate models controlling for age, body mass index, bone density, and other factors associated with fractures and diabetes. Insulin-treated diabetics had more than double the risk of foot (multivariate adjusted RR, 2.66; 95% CI, 1.18-6.02) fractures compared with nondiabetics. This study indicates that diabetes is a risk factor for hip, proximal humerus, and foot fractures among older women, suggesting that fracture prevention efforts should be a consideration in the treatment of diabetes.

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PubMed2000

Independent effects of peripheral nerve dysfunction on lower-extremity physical function in old age: the Women's Health and Aging Study.

OBJECTIVE: To determine the role of peripheral nerve dysfunction (PND) in the disablement pathway. RESEARCH DESIGN AND METHODS: Vibration perception threshold (VPT) was measured in 894 women aged > or = 65 years, and those with normal peripheral nerve function and with mild, moderate, and severe PND were identified. Lower-extremity impairments included quadriceps strength (kilograms) and three progressively difficult balance tasks (able/unable). Functional limitations included rising from a chair (able/unable) and usual pace and fast-paced walking speeds (meters/second). Level of PND was related to impairments and functional limitations in linear and logistic regression models that controlled for potentially confounding factors, including reported diabetes. RESULTS: Level of PND was associated with impaired balance (adjusted odds ratios: 2.21, 1.95, and 3.02 for mild, moderate, and severe PND, respectively, relative to normal, P < 0.05). PND was also associated with decrements in both usual and fast-paced walking speeds (-0.08, -0.08, and -0.15 m/s for usual pace and -0.13, -0.12, and -0.24 m/s for fast-paced walking speed for women with mild, moderate, and severe PND, respectively; P < 0.01 for all). Reported diabetes was not associated with these outcomes in the presence of PND. Some, but not all, of the association between PND and functional limitations was explained by the relationship between PND and impairments. CONCLUSIONS: PND is significantly associated with both lower-extremity impairments and functional limitations in older women, and PND appears to have independent effects on functional limitations. The independent effect of diabetes on these outcomes may be limited when PND is considered. Further research is needed to determine if PND is causally related to disability in old age.

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PubMed1999

International variation in the incidence of hip fractures: cross-national project on osteoporosis for the World Health Organization Program for Research on Aging.

A cross-national study of hip fracture incidence was carried out in five geographic areas--Beijing, China; Budapest, Hungary; Hong Kong; Porto Alegre, Brazil; and Reykjavik, Iceland--during the years 1990-1992. Cases of hip fracture among women and men of age 20 years and older were identified using hospital discharge data in conjunction with medical records, operating room logs, and radiology logs. Estimated incidence rates varied widely, with Beijing reporting the lowest rates (age-adjusted rate per 100,000 population for men 20 years and older = 45.4; women = 39.6) and Reykjavik the highest rates (man = 141.3; women = 274.1). Rates were higher for women than for men in every area except Beijing. In every area except Budapest, review of the operating room or radiology logs identified additional cases that were not reported in the discharge list, increasing the estimated number of hip fractures by 11% to 62%, depending on the area. Review of medical records identified miscoding of hip fractures (ICD 9820) as 'shaft of femur and other femur fractures' (ICD 9821) in the discharge lists of every area except Budapest, increasing the estimated number of hip fractures by 1% to 30%. The final estimates of hip fracture incidence taking into account all investigated sources of undercount and overcount ranged from 15% lower to 89% higher than an estimate based on the discharge diagnoses alone. Although these results indicate substantial limitations in relying on hospital discharge data alone to estimate hip fracture incidence rates, the extent of errors found in the discharge lists is smaller than the large international variation found here and previously reported in incidence rates. The findings support the conclusion that the differences reported among countries mainly reflect genuine variation in the hip fracture incidence rates.

Adult↗

PubMed1999

Falls in older Mexican-American women.

OBJECTIVE: To determine the frequency of falls and identify risk factors for falls among older Mexican-American women. DESIGN: A prospective cohort study with an average follow-up of 2.7 years. SETTING: A clinical center at the Palo Alto Veterans Affairs Medical Center, California. PARTICIPANTS: 152 community-dwelling Mexican-American Caucasian women aged 59 years or older. OUTCOME MEASURES: Falls and injurious falls, as determined by monthly telephone interviews. RESULTS: The rate of falls was 508 per 1000 person-years (95% confidence interval (CI), 440-577). Injurious falls requiring medical attention occurred at a rate of 79 per 1000 person-years (95% CI, 52-107). Factors that were associated independently with an increased risk of falling were older age, a history of arthritis or rheumatism, a history of high thyroid, having fainted at least once in the year before baseline, current use of psychotropic medications, and walking fewer than 5 blocks a day. Those persons with an average time for the chair stand test had a lower risk of falling than those with the slowest times or the fastest times. CONCLUSIONS: The frequency of falls and injurious falls in this cohort of 152 relatively acculturated, healthy, older Mexican-American women was similar or slightly higher than previously reported rates for non-Hispanic Caucasian(s). Many of the factors associated with falls in this study were similar to those reported for non-Hispanic Caucasian women, suggesting that fall prevention measures tested mainly among non-Hispanic Caucasian women would also be appropriate for Mexican-American women.

Accidental Falls↗

PubMed1998

Characteristics of falls and risk of hip fracture in elderly men.

The steep rise in hip fracture incidence rates with age is not fully explained by an increase in the frequency of falls or by reduction in bone mineral density, suggesting that circumstances of falls may also affect the risk of hip fracture. Previous studies conducted mainly among women have identified the importance of the orientation of a fall in the etiology of hip fracture. In this case-control study among men of 45 years and older, we evaluated how the circumstances of falls affect the risk of hip fracture. We compared 214 cases with hip fracture due to a fall with 86 controls who had fallen within the past year but did not sustain a hip fracture. As expected, in multivariable age-adjusted analyses men who reported hitting the hip/thigh in a fall had a markedly elevated risk of hip fracture (OR = 97.8; 95% CI = 31.7-302). Hitting the knee in a fall was associated with reduced risk (OR = 0.24; 95% CI = 0.09-0.67). Other factors that were associated with reduced risk of hip fracture among men who fell were more hours of physical activity in the past year (OR = 0.84; 95% CI = 0.73-0.97, for each additional 4 h per week), a greater body mass index (OR = 0.60; 95% CI = 0.40-0.90, for each additional 4 kg/m2), and a history of a fracture when age 45 years or older (OR = 0.26; 95% CI = 0.10-0.69). Reported lower limb dysfunction was associated with increased risk of hip fracture (OR = 6.41; 95% CI = 2.09-19.6) among fallers. The increased risk associated with hitting the hip/thigh in a fall and the reduced risk associated with high body mass index suggest that preventive efforts for older men at high risk might include protective hip pads to reduce the force on the hip in a fall. Exercise and strength training programs may also reduce the risk of hip fracture among men who fall.

Accidental Falls↗

PubMed1998

Relationship of neurological function and age in older women. The study of osteoporotic fractures.

The decline of neurological and neuromuscular function with age in older women and in subgroups of older women with selected risk factors for poor function is described using cross- sectional analyses of data on 8,080 women from the multicenter Study of Osteoporotic Fractures. All twelve performance-based tests of muscle strength, balance, gait, somatosensory discrimination and reaction time declined with increasing age. On a percentage scale, vibration threshold declined the most rapidly with age. Participants who were smokers, physically inactive, nonconsumers of alcohol, diabetics and more frequent fallers had poorer age-adjusted performance than those without these attributes. However, with a few exceptions, the rate of decline in performance with age for those with and without these characteristics did not differ significantly.

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