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Biomedical subjects

S R Cummings

Publications and source records attributed to S R Cummings.

At least 145 records · Page 8Linked to original sources
PubMed1992

Contribution of vertebral deformities to chronic back pain and disability. The Study of Osteoporotic Fractures Research Group.

Among 2992 white women aged 65-70 years recruited from population-based listings, we measured radiographic vertebral dimensions of T5-L4 and calculated ratios of heights: anterior/posterior, mid/posterior, and posterior/posterior of either adjacent vertebra. The degree of deformity for each vertebra was analyzed in terms of the number of standard deviations (SD) that ratio differed from the mean ratio calculated for the same vertebral level in this population. We correlated the severity of each woman's worst vertebral deformity with back pain, back disability in six activities of daily living, and height loss since age 25. Only 39.4% of the cohort had no vertebral deformity; 10.2% had a deformity greater than or equal to 4 SD. Vertebral deformities less than 4 SD below the mean were not associated with increased back pain, disability, or loss of height. In contrast, women whose deformity was greater than or equal to 4 SD had a 1.9 (95% CI, 1.5-2.4) times higher risk of moderate to severe back pain and a 2.6 (95% CI, 1.7-3.9) times higher risk of disability involving the back; they were also 2.5 (95% CI, 2.0-3.2) times more likely to have lost greater than or equal to 4 cm in height. All three types of vertebral deformity (wedge, end plate, and crush) were equally associated with these outcomes. Multiple deformities less than 4 SD did not increase the likelihood of these three outcomes, but multiple deformities greater than or equal to 4 SD tended to be associated with increased back pain, disability, and height loss. This large cross-sectional study suggests that vertebral deformities cause substantial pain, disability, or loss of height only if vertebral height ratios fall 4 SD below the normal mean. Much back pain could not be attributed to vertebral deformities, suggesting other causes.

Aged↗
PubMed1992

Age-related decrements in bone mineral density in women over 65.

Age-related changes in bone density contribute to the risk of fractures. To describe the relationship between age and bone mass in elderly women, we studied a large cohort of women over age 65 years who were recruited from population-based lists in four cities in the United States. Bone density in g/cm2 was measured by single-photon absorptiometry (SPA) and dual x-ray absorptiometry (DXA) at the distal and proximal radius, the calcaneus, the lumbar spine, and the proximal femur. Centralized data collection was used to control data quality and consistency. We found a strong inverse relationship between bone density and age for most sites. Decrements in bone density between women aged 65-69 years and women 85 years and older exceeded 16% in all regions except the spine, where the difference between the two age groups was 6%. Ward's triangle and the calcaneus exhibited the largest decrements, with 26 and 21%, respectively. The estimates of annual changes in bone mineral density by linear regression at sites other than the spine ranged from -0.82% at the femoral neck and trochanter to -1.30% at Ward's triangle. Correlations between the different regions ranged from r = 0.51 between the proximal radius and Ward's triangle to r = 0.66 between the distal radius and calcaneus. We conclude that the inverse relationship between age and bone mass measured by absorptiometry techniques in white women continues into the ninth decade of life. The relationship is strongest for bone density of Ward's triangle and the calcaneus and weakest for the spine.

Absorptiometry, Photon↗
PubMed1992

Axial and appendicular bone density predict fractures in older women.

To determine whether measurement of hip and spine bone mass by dual-energy x-ray absorptiometry (DEXA) predicts fractures in women and to compare the predictive value of DEXA with that of single-photon absorptiometry (SPA) of appendicular sites, we prospectively studied 8134 nonblack women age 65 years and older who had both DEXA and SPA measurements of bone mass. A total of 208 nonspine fractures, including 37 wrist fractures, occurred during the follow-up period, which averaged 0.7 years. The risk of fracture was inversely related to bone density at all measurement sites. After adjusting for age, the relative risks per decrease of 1 standard deviation in bone density for the occurrence of any fracture was 1.40 for measurement at the proximal femur (95% confidence interval 1.20-1.63) and 1.35 (1.15-1.58) for measurement at the spine. Results were similar for all regions of the proximal femur as well as SPA measurements at the calcaneus, distal radius, and proximal radius. None of these measurements was a significantly better predictor of fractures than the others. Furthermore, measurement of the distal radius was not a better predictor of wrist fracture (relative risk 1.64: 95% CI 1.13-2.37) than other sites, such as the lumbar spine (RR 1.56; CI 1.07-2.26), the femoral neck (RR 1.65; CI 1.12-2.41), or the calcaneus (RR 1.83; CI 1.26-2.64). We conclude that the inverse relationship between bone mass and risk of fracture in older women is similar for absorptiometric measurements made at the hip, spine, and appendicular sites.

Absorptiometry, Photon↗
PubMed1992

Appendicular bone mineral and a woman's lifetime risk of hip fracture.

Appendicular bone mass is inversely related to the risk of hip fracture in short-term prospective studies, but hip fractures typically occur about 30 years after menopause. We developed a model that estimates a woman's lifetime risk of hip fracture based on measurement of radial bone mass at age 50 using short-term prospective data relating bone mass to hip fracture, the correlation between bone mass at age 50 and later years, the age-specific incidence of hip fracture and mortality, and prospective data about bone mass and mortality. We estimate that a 50-year-old white woman has a 19% lifetime risk of hip fracture if her radial bone mass is at the 10th percentile for her age and an 11% lifetime risk if her bone mass is at the 90th percentile. Improved measurement techniques that have a higher predictive value for hip fracture in short-term studies could substantially increase this gradient of lifetime risk and therefore be more clinically useful.

Aged↗
PubMed1992

Postural hypotension and postural dizziness in elderly women. The study of osteoporotic fractures. The Study of Osteoporotic Fractures Research Group.

BACKGROUND: Postural hypotension and dizziness are common findings in elderly individuals. Although postural hypotension and postural dizziness are often perceived to be strongly associated entities, evidence to support this view in sparse. In addition, there is a lack of knowledge regarding the relationship of postural hypotension and postural dizziness to potential clinical outcomes, such as falls, syncope, and restricted activity. METHODS: We utilized a cross-sectional examination to study the prevalence and correlates of postural hypotension (drop in systolic blood pressure of greater than or equal to 20 mm Hg after 1 minute of standing) and postural dizziness (self-reported dizziness on standing) in 9704 nonblack, ambulatory women aged 65 years and older enrolled in the multicenter Study of Osteoporotic Fractures. First, we examined postural hypotension and postural dizziness as outcomes of risk factors that included medical conditions, medications, and physical findings. Then, we examined falls, syncope, and impaired functional status as outcomes of postural hypotension and postural dizziness. RESULTS: Postural hypotension and postural dizziness were common findings, noted in 14% and 19% of subjects, respectively. However, they were not highly correlated with each other and did not share the same risk factors or associated outcomes. Postural dizziness was more strongly associated than was postural hypotension with history of falling (age-adjusted odds ratios, 1.32 vs 1.02), history of syncope (1.94 vs 1.35), and impaired functional status (1.95 vs 0.76). CONCLUSION: Assessment of dizziness on standing appears to be more important than measurement of postural blood pressure change in ascertaining functional status and risk of falls and syncope in elderly individuals. Future prospective studies of postural dizziness are needed to confirm its value as a predictor of clinical outcomes.

Aged↗
PubMed1991

Which fractures are associated with low appendicular bone mass in elderly women? The Study of Osteoporotic Fractures Research Group.

OBJECTIVE: To determine which types of fractures have an increased incidence in elderly women with low appendicular bone mass. DESIGN: Prospective cohort study. SETTING: Four clinical centers in the United States (Baltimore, Maryland; Minneapolis, Minnesota; Portland, Oregon; Monangehela Valley, Pennsylvania); and one coordinating center in San Francisco, California. SUBJECTS: Ambulatory, nonblack women (9704) aged 65 years or more who were recruited from population-based listings. MEASUREMENTS: We measured bone mass at the distal and proximal radius and calcaneus using single-photon absorptiometry. Fractures were verified radiographically. Associations were calculated as age-adjusted hazard ratios (with 95% Cls) per standard deviation decrease in bone mass. MAIN RESULTS: During a mean follow-up of 2.23 years, 841 nonspinal fractures occurred in 753 women. The risks for fractures of the wrist, foot, humerus, hip, rib, toe, leg, pelvis, hand, and clavicle were significantly related to reduced bone mass (P less than 0.05). These fractures represented 74% of nonspinal fractures. The overall hazard ratio for the occurrence of one or more of these fractures was 1.65 (Cl, 1.49 to 1.82) at the distal radius. In a subsample of the cohort, vertebral fractures were also related to low bone mass. Fractures of the ankle, elbow, finger, and face, however, were not associated with bone mass at any measurement site; the overall hazard ratio for these fractures was 1.12 (Cl, 0.96 to 1.30) at the distal radius. CONCLUSION: Most types of fractures have an increased incidence in elderly women with low bone mass.

Age Factors↗
PubMed1991

Evaluating the benefits and risks of postmenopausal hormone therapy.

The evidence that estrogen protects against coronary heart disease is biologically plausible, consistent, and strong. These benefits have not been established by a randomized trial, however, so that the degree of protection against heart disease might have been overestimated because estrogen users tend to be healthier than nonusers. A randomized trial to determine whether estrogen alone or in combination with progestin protects against coronary heart disease should be given a high priority. Progestins generally attenuate the effects of estrogen on the concentrations of HDLC. It is not known whether this effect also limits the beneficial effects of estrogen on the risk of coronary heart disease. Recent studies suggest that estrogen may protect against coronary heart disease in other ways besides favorably altering serum concentrations of lipoproteins and that progestins might not have adverse effects on the risk of heart disease. Currently, theoretical concerns that progestins might be harmful seem outweighed by the evidence that they protect against endometrial cancer in women who have a uterus. For these women, some may find the side effects of progestins to be so bothersome that they prefer to take estrogen alone. This approach is reasonable so long as the patient has periodic endometrial biopsies for early detection of pre-malignant or malignant endometrial changes. Women without a uterus should take estrogen alone. Women who take long-term estrogen therapy appear to have about a 30% greater chance of developing breast cancer. On the other hand, breast cancer that develops while taking estrogen therapy might have a slightly better prognosis. Quantitative comparisons of fatal conditions suggest that the benefits of long-term therapy outweigh the risks. But these comparisons assume that all causes of deaths are equally important and do not adequately take account of other psychologic and physical effects of hormone therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Density↗
PubMed1991

Non-trauma mortality in elderly women with low bone mineral density. Study of Osteoporotic Fractures Research Group.

9704 ambulatory women aged 65 years or older were prospectively studied to determine whether low bone mineral density (osteopenia) was associated with mortality. Bone mineral density was measured at entry to the study by single-photon absorptiometry. 299 women died during a mean of 2.8 years' follow-up. Osteopenia was associated with increased non-trauma mortality, probably because it is a marker for several other adverse factors. Each standard deviation decrease in proximal radius bone mineral density (0.104 g/cm2) was associated with a 1.19-fold increase in mortality (95% confidence interval 1.04-1.36), adjusted for age and duration of follow-up. Diminished bone mineral density at the proximal radius was strongly associated with deaths from stroke (relative risk = 1.74; 95% CI 1.12-2.70), an association that was not confounded by history of previous stroke, hypertension, postmenopausal use of oestrogen, thiazide diuretic treatment, diabetes mellitus, and smoking. Most deaths in women with low bone mineral density are unrelated to the occurrence of fractures-an observation that should be taken into account when estimating the need for and cost-effectiveness of bone-density screening and fracture prevention programmes.

Aged↗
PubMed1991

A comparison of morphometric definitions of vertebral fracture.

To compare the accuracy of several approaches for defining prevalent vertebral fractures from measurements of vertebral dimensions (morphometry), we measured the lateral dimensions of vertebral bodies of 115 normal premenopausal and 100 postmenopausal women. Of the postmenopausal women two observers agreed that 49 had definite vertebral fractures and 38 were definitely normal. Using these classifications as an independent reference, women were then classified as fractured or normal by several definitions based on vertebral morphometry. No morphometric definition of vertebral fracture agreed perfectly with the consensus classifications. In general, definitions that involved combinations of measurements of anterior (Ha), middle (Hm), and posterior (Hp) vertebral height classified women more accurately than did definitions based on a single measurement or ratio. The Ha/Hp ratio produced many false positives unless it was adjusted for normal variations in the shapes of different vertebral bodies. Definitions of fracture based on a greater than 15% reduction in heights or ratios had higher sensitivity but more false positives than definitions that used a more stringent (greater than 20%) criterion. All morphometric definitions of vertebral fracture separated the post-menopausal women into two groups (fractured and normal) that had significantly (P less than 0.001) different mean spine bone density by quantitative computed tomography. Definitions that had the lowest rates of false positives also produced the largest differences in bone density between those defined as fractured and those defined as normal.

Adult↗
PubMed1991

A new approach to defining normal vertebral dimensions.

We developed a method for estimating the mean and standard deviation of ratios of normal vertebral heights from a sample that includes people with and without vertebral fractures. This method assumes that the measurements in normal vertebrae have a Gaussian distribution and that, for any vertebral level, the prevalence of abnormal measurements is less than 10%. Under these assumptions, normal values for nonfractured vertebrae can be estimated from several statistical properties of Gaussian distributions. We applied these methods to the lateral spinal radiographs of 2992 women aged 65-70 years who were recruited from population-based listings. The estimated means and standard deviations for ratios of dimensions in nonfractured vertebrae were very similar to those based on studies of premenopausal women. Our method may be useful for defining normal values from large populations that include normal and abnormal women, does not require x-rays of normal premenopausal women, avoids the potential biases of defining normality based on qualitative judgment, and can be applied to other types of physical and biochemical measurements.

Aged↗
PubMed1991

Epidemiologic studies of osteoporotic fractures: methodologic issues.

Cross-sectional and case-control studies are efficient and inexpensive approaches to the study of osteoporosis; their validity depends primarily on how the subjects are sampled. Retrospective studies of fractures may be biased if measurements change as a result of the fracture. Prospective cohort studies are less prone to such biases but are expensive. Randomized blinded trials are ideal for assessing studying single factors but trials are sometimes flawed by avoidable problems. Patient reports about risk factors are imperfect but sufficiently accurate to detect most strong associations between risk factors and osteoporosis. Noise in the measurement of risk factors will cause studies to underestimate the effect of these factors. About one-sixth of recalls of falls and fractures are incorrect. Self-report of vertebral fractures is unreliable and biased and there is controversy about how to define vertebral fractures on lateral X-ray film. Clinical and epidemiological research in osteoporosis would be advanced by greater care in the design of studies and methods of measurement.

Bias↗
PubMed1991

Occupational exposure to HIV: frequency and rates of underreporting of percutaneous and mucocutaneous exposures by medical housestaff.

PURPOSE: To study the frequency of work-related exposures to human immunodeficiency virus (HIV)-infected blood and reporting of exposures among medical housestaff. SETTINGS: Three teaching hospitals where HIV infection is prevalent among patients. SUBJECTS: Internal medicine interns and residents in training in 1988-1989. METHODS: In a cross-sectional survey, house officers were asked to complete anonymously a questionnaire reviewing their past percutaneous and mucocutaneous exposure to blood products. RESULTS: Nineteen percent of the respondents (16 of 86) recalled accidental exposure to HIV-infected blood, and 36% (31 of 86) recalled exposure to blood from patients at high risk for having HIV infection. Of the exposures recalled in the 12 months prior to the survey, 81% (47 of 58) of all needlestick injuries and all (nine of nine) needlestick injuries from HIV-infected blood occurred in postgraduate year 1 or 2 trainees. Only 30% (31 of 103) of the needlestick injuries recalled by subjects were reported. The principal reasons for not reporting were time constraints, perception that the percutaneous injury did not represent a significant exposure, lack of knowledge about the reporting mechanism, and concern about confidentiality and professional discrimination. CONCLUSIONS: Medical housestaff are at substantial risk for occupational infection with HIV. A large proportion of internal medicine housestaff recall accidental exposure to blood during medical school and residency, and the majority of exposures were not reported. Hospitals may be able to increase rates of reporting of percutaneous exposures to HIV by developing programs that are easy to access, efficient, and strictly confidential.

Adult↗
PubMed1991

The index of radiographic area (IRA): a new approach to estimating the severity of vertebral deformity.

To assess the overall severity of vertebral deformity for an individual, we developed the index of radiographic area (IRA), a computerized method for analyzing vertebral dimensions from lateral radiographs of the spine. Six coordinates for each vertebral body are recorded in a computer by means of a digitizer. A computer program identifies all abnormal vertebrae, computes the radiographic area of the remaining normal vertebrae, and then estimates the expected normal radiographic area for the abnormal vertebrae in that individual. Differences between the expected and observed radiographic area of all abnormal vertebrae are summed to produce the IRA score. The score correlated well with the quantitative score of vertebral deformity of an experienced radiologist (r = 0.85), and with the vertebral bone density by quantitative computed tomography (QCT) (r = 0.66). The IRA is a practical, standardized method for quantitating the overall severity of vertebral deformity in individuals who have vertebral fractures. Its reproducibility for longitudinal studies and clinical trials needs further study.

Aged↗
PubMed1991

Risk factors for injurious falls: a prospective study.

We conducted a prospective study of the consequences of falls in 325 elderly community-dwelling persons, all of whom had fallen in the previous year. We contacted subjects every week for one year to ascertain falls and to determine the circumstances and consequences of falls. Only 6% of 539 falls resulted in a major injury (fracture, dislocation, or laceration requiring suture), but over half (55%) resulted in minor soft tissue injury. One in ten falls left the faller unable to get up for at least 5 minutes, and one in four falls caused subjects to limit their activities. The risk of injury per fall was about the same regardless of the number of falls a person had during follow-up. The risk of major injury was increased (age- and sex-adjusted odds ratio: 5.9, 95% confidence interval: 2.3-14.9) in falls associated with loss of consciousness compared to nonsyncopal falls. In multivariate analyses of nonsyncopal falls, the risk of major injury per fall was higher in persons having a previous fall with fracture (6.7; 2.1-21.5), a slower Trail Making B time (1.9; 1.1-3.2), and in Whites (18.4; 7.5-44.6). The risk that a nonsyncopal fall would result in minor injury (versus no injury) was increased in persons with a slower hand reaction time (1.8; 1.0-3.2) decreased grip strength (1.5; 1.0-2.3), in Whites (2.0; 1.0-3.7), in falls while using stairs and steps (2.2; 1.0-5.0), and turning around or reaching (3.5; 1.7-7.3). Our findings suggest that neuromuscular and cognitive impairment, as well as the circumstances of falls, affect the risk of injury when a fall occurs.

Accidental Falls↗
PubMed1991

Staff involvement and special follow-up time increase physicians' counseling about smoking cessation: a controlled trial.

We compared the counseling behaviors of two groups of health maintenance organization physicians: one group received training about smoking cessation counseling; the other group received the same training plus staff support and appointment time specially designated for follow-up of smokers. We interviewed patients after their office visits to measure smoking counseling. The group receiving staff support and designated follow-up time counseled more and made more follow-up appointments about smoking.

Attitude of Health Personnel↗
PubMed1990

High blood cholesterol in elderly men and the excess risk for coronary heart disease.

OBJECTIVE: To determine whether high blood cholesterol is an important risk factor for mortality from coronary heart disease in elderly men. DESIGN: Cohort study with a mean follow-up of 10.1 years. SETTING: A health maintenance organization. PATIENTS: The cohort included 2746 white men 60 to 79 years of age who had no self-reported history of coronary heart disease. MEASUREMENT AND MAIN RESULTS: A total of 260 deaths occurred during 27,842 person-years of follow-up. The relative risk for mortality from coronary heart disease in men 60 to 79 years of age in the highest serum cholesterol quartile was 1.5 (95% CI, 1.2 to 2.0) compared with those in the three lower quartiles combined. The relative risk did not change greatly with age, ranging from 1.4 in men 60 to 64 years of age to 1.7 in men 75 to 79 years of age. However, because mortality from coronary heart disease increased with age, the excess risk for such mortality attributable to elevated serum cholesterol levels increased fivefold over these 20 years, from 2.2 deaths per 1000 person-years to 11.3 deaths per 1000 person-years. CONCLUSIONS: Our results support those of other observational studies in elderly men. If treatment of high blood cholesterol is as effective in reducing cholesterol-related risk for coronary heart disease after 65 years of age as it is in middle-aged men, it might actually produce greater reductions in mortality due to coronary heart disease. A clinical trial is needed to confirm this extrapolation.

Age Factors↗