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Biomedical subjects

R D Wasnich

Publications and source records attributed to R D Wasnich.

At least 55 records · Page 3Linked to original sources
PubMed1996

Vertebral fractures and other predictors of back pain among older women.

We examined the prevalence and predictors of back pain (BKP) among 645 postmenopausal Japanese-American women in Hawaii with a mean age of 73.9 years (ranging from 55 to 93 years) and serial spine radiographs during the preceding 12 years. The overall prevalence of BKP was 32.9% and appeared to be constant up to age 80, with an increase thereafter. At most ages, pain in the lower back was the most common, upper BKP was less so, and mid-BKP was the least common. The overall prevalence of BKP among Japanese-American women in Hawaii was about half of that reported for U.S. Caucasians. Vertebral fractures were divided into three categories based on the length of time since the fracture was identified on radiographs. BKP was only associated with recent vertebral fractures (during the previous 4 years, on average) and increased progressively with the number and severity of fractured vertebrae. A history of a single recent fracture was associated with a 2.8-fold increase in the odds of BKP; two recent fractures with a 7.8-fold increase and three recent fractures with a 21.7-fold increase in the odds of BKP. In addition, self-reported disk problems, body mass index, and the number of other painful joints also showed independent associations with BKP. Height, spine bone mineral density (BMD), calcaneus BMD, smoking, and number of live births were not significantly associated with BKP.

Age Distribution↗
PubMed1996

Blinded reading of radiographs increases the frequency of errors in vertebral fracture detection.

We examined the effect of blinding X-rays to film sequence and patient identity on vertebral fracture detection. A sample of 50 postmenopausal women with low bone density and two sets of spine X-rays 3.6 years apart was selected; based on prior morphometric studies, about half of the women had experienced new fractures after the initial film. New morphometric and semiquantitative radiologist readings were each performed twice: blinded and unblinded. For morphometry, incident fractures were defined as vertebral height decreases of more than 15% compared with the initial film. The incidence was slightly higher when blinded versus unblinded (5.6 vs. 5.3% of all vertebrae for morphometry, and 9.7 vs. 8.7% for the radiologist), but these differences were not significant. The error rate was investigated by examining the frequency of "fracture reversals"-vertebrae identified as fractured on the initial film but not on the later film. Agreement between blinded and unblinded readings was generally greater than 80% for fractures but less than 10% for "fracture reversals," suggesting that reversals are not true events but random errors. The number of reversals was higher when the radiologist was blinded (2.1% of all vertebrae vs. 0.8% when unblinded; p = 0.07). The number of vertebrae with increases greater than 15% in size over time was also greater when morphometry readings were blinded versus unblinded: 0.8 versus 0% (p < 0.05). Although these errors are small, they are similar in magnitude to the annual fracture incidence in many populations. These data show that blinding X-rays to sequence offers no advantages, increases the frequency of errors, and may inflate incidence rates. We conclude that the assessment of X-rays for vertebral fractures in clinical trials should not be performed with the evaluator blinded to the sequence of the X-rays.

Diagnostic Errors↗
PubMed1996

Body size accounts for most differences in bone density between Asian and Caucasian women. The EPIC (Early Postmenopausal Interventional Cohort) Study Group.

We compared bone mineral density (BMD) of the whole body (and subregions: arm, leg, and pelvis), hip, spine, lateral spine, wrist, and forearm among Caucasian and Asian women at four geographic centers (Honolulu, HI; Nottingham, UK; Portland, OR; Copenhagen, Denmark). Data were derived from the baseline examination of 1367 Caucasian and 162 Asian women enrolled in the 1609-subject Early Postmenopausal Interventional Cohort (EPIC) study. After adjusting for age, study site, years postmenopause, and years of estrogen use, BMD was approximately 4-6% lower (P < 0.05) among Asian women at most skeletal sites, but there was no significant difference for wrist or forearm BMD. Adding height, lean body mass, fat mass, and/or quadriceps muscle strength to the regression models reduced the racial differences at most skeletal sites; after these additional adjustments, Asian women had significantly lower BMD only for the lateral spine (-4.4%; P < 0.005), arm (-2.20%; P < 0.05) and leg (-1.65%; P < 0.05), whereas the wrist was significantly greater (4.64%; P < 0.005) for Asian women. Further research is needed to determine why racial differences in BMD persist at certain skeletal sites, but not others, after adjusting for body size.

Anthropometry↗
PubMed1996

Vertebral fracture epidemiology.

Vertebral fractures are the most common but least understood of all osteoporotic fractures. Their study has been hampered by the lack of a common morphometric definition, and the fact that many vertebral fractures are asymptomatic and not clinically evident. Population-based radiographic surveys are therefore required for comparative studies. Risk factors fall into five major categories: (1) age, or age-related, (2) genetic, (3) environmental, (40 endogenous hormones or chronic diseases, and (5) physical characteristics of bone. Bone density is the most clinically useful risk factor, particularly for purposes of prevention. Because vertebral fracture prevalence parallels levels of bone density, bone density is also useful for epidemiological surveys. Based on WHO diagnostic criteria, 54% of postmenopausal white women in the United States have osteopenia, and another 30% have osteoporosis. Existing fractures are also strong, independent predictors of future vertebral fracture risk, but also represent a later, and less treatable, stage of the disease.

Aged↗
PubMed1996

Determinants of vertebral fracture prevalence among native Japanese women and women of Japanese descent living in Hawaii.

Age-adjusted prevalence of vertebral fracture has been reported to be higher among native Japanese women than among women of Japanese descent living in Hawaii. In this cross-sectional population-based study, we examined a variety of potential risk factors for associations with prevalent vertebral fractures and investigated whether these factors could explain the difference in vertebral fracture prevalence between native Japanese and Japanese-American women. Spine radiographs and data on spine bone mineral density (BMD) and other potential risk factors were collected among 802 Japanese women aged 50-88 years living in Hiroshima and 840 Japanese-American women aged 52-88 years living in Hawaii. In logistic regression analysis, BMD was a major predictor of prevalent vertebral fracture. In linear regression models, weight, age, and menstrual history (age at menopause or years between menarche and menopause) were significantly associated with BMD and thus might contribute to fracture risk indirectly through their effects on BMD. However, age and menstrual history provided additional and complementary information about fracture prevalence after adjusting for BMD. These variables together explained much of the difference in vertebral fracture prevalence between the two study populations. We conclude that the observed difference in age-adjusted prevalence of spine fracture between native Japanese and Japanese-American women was accounted for primarily by the differences in BMD, duration of estrogen exposure, and/or duration of estrogen deficiency. Thus, current BMD is a major but not the sole risk factor for vertebral fractures. Age-related and menopause-related mechanisms may also play an important role in spine fracture independent of BMD.

Absorptiometry, Photon↗
PubMed1996

Clinical utility of bone mass measurements in adults: consensus of an international panel. The Society for Clinical Densitometry.

Low bone mass predicts future fracture risk as well as high cholesterol or high blood pressure can predict the risk of heart disease or stroke. Prevention of the first fracture should be a clinical goal. In patients without fractures, osteopenia and osteoporosis can be diagnosed based on the extent of reduction in bone mass below mean peak bone mass of young healthy individuals. As bone mass decreases, fracture risk increases exponentially. Clinical situations in which an assessment of bone mass and fracture risk affects therapeutic decisions include estrogen deficiency, vertebral abnormalities, radiographic osteopenia, asymptomatic primary hyperparathyroidism, and long-term corticosteroid therapy. Serial measurements can also be used to monitor the effects of osteoporosis treatments. The appropriate technique and skeletal site for bone mass measurements should be chosen based on the patient's circumstances and the precision of measurement. A clinical interpretation can enhance the value of computer-generated bone mass measurement reports and improve decision making.

Absorptiometry, Photon↗
PubMed1996

A multicenter study of the influence of fat and lean mass on bone mineral content: evidence for differences in their relative influence at major fracture sites. Early Postmenopausal Intervention Cohort (EPIC) Study Group.

We examined the relative influence of fat and lean mass on bone mineral content (BMC) among 1600 early postmenopausal women aged 45-59 y from four geographical locations (Nottingham, United Kingdom; Portland, OR; Honolulu; and Copenhagen). Bone sites investigated included the major fracture sites: hip, spine, and radius. Body weight had strong associations at all skeletal sites examined [BMC differences of 4-6% per interquartile range (IQR) of weight]. Associations with the fat and lean components of weight were more variable. The BMC differences per IQR of lean mass were 5-7% at the hip sites, 3% at the spine, and 2% at the radial sites. The greater differences for lean mass at the hip may reflect the high physical mobility and muscular activity of this site. The BMC differences per IQR of fat mass were 4-6% at the hip sites, 4% at the spine, and 5% at the ultradistal radius. These results suggest that low fat mass or low lean mass, particularly at the extremes, may adversely affect the major fracture sites. The bone sites with the greatest differences for fat mass were the most highly trabecular sites. With only a few exceptions, the associations of BMC with fat mass and lean mass were similar in direction and comparable in magnitude across the four geographic locations. We conclude that both fat and lean mass have independent influences on bone mass, but that their relative influence may vary by bone site depending on the trabecular content, physical mobility, and muscularity of the site.

Adipose Tissue↗
PubMed1996

Anthropometric, lifestyle and menstrual factors influencing size-adjusted bone mineral content in a multiethnic population of premenopausal women.

We report associations of anthropometric, lifestyle and menstrual characteristics with peak bone mass in a multiethnic population of premenopausal women, ages 25-34 y. Four bone sites were examined: the spine, calcaneus, and distal and proximal radius. Body mass index (BMI) was positively associated with bone mass at the spine and calcaneus, the two most trabecular sites. The calcaneus, in addition, was positively associated with an index of calf muscle mass. The distal radius was associated with an arm muscle index, grip strength and the intensity of menstrual flow (light, moderate or heavy). Menstrual flow was also associated with spine bone mass in models not adjusted for BMI; light flow was an indicator of low distal radius or spine bone mass. We hypothesize that light flow may indicate a lack of regular ovulation. The cortical proximal radius was positively associated with milk consumption and height. The magnitude of associations varied by exposure and bone site. Among the strongest associations were BMI at the spine and calcaneus (4 and 7% differences in bone mass per standard deviation), and menstrual flow at the distal radius (a 7% difference between light and heavy menstrual flow). Ethnicity was not statistically significant in multivariable models at any of the four bone sites. However, the prevalence of exposures associated with bone mass varied substantially among the ethnic groups. Ethnic differences in bone mass may have derived indirectly through differences in exposure histories. Other influences of skeletal development may also occur indirectly. Sports activity during adolescence, for instance, was not an independent predictor of bone mass, but sports activity was associated with both strength and muscle mass. Our results suggest that many factors influence peak bone mass, and that the factors vary in importance by skeletal region, possibly related to bone composition and the local intensity of exposure.

Adult↗
PubMed1996

A new, standardized approach to fracture risk interpretation.

Screening for osteoporosis has been hampered by the absence of a standard approach to the interpretation of bone density and other risk factors. A consensus conference of international experts has now recommended a report which is based upon two concepts: (1) comparison of an individual's bone density to the mean value for 30 year old women, and (2) estimation of Remaining Lifetime Fracture Probability (RLFP), based upon current age and bone density, life expectancy, future bone loss, and other risk factors. This model is dynamic and can be perfected as new risk factors become established. It also allows for estimation of therapeutic impact, and thus improves and individualizes clinical decision making.

Adult↗
PubMed1995

A longitudinal study of estrogen and calcium supplement use among Japanese women living in Hawaii.

BACKGROUND: Estrogen and calcium supplements represent accepted treatments for the prevention of osteoporosis in the United States. The effectiveness of these treatments, however, will depend upon the extent that they are utilized, which may vary over time. METHODS: We report a longitudinal study of estrogen and calcium use among a cohort of Japanese-American women living in Hawaii. Their mean age at the baseline examination in 1981 was 63.9 (age range 45 to 81). Between 1981 and 1992 the same women were repeatedly surveyed regarding their estrogen and calcium supplement use. RESULTS: During the decade of follow-up the prevalence of estrogen use doubled, with 25 to 30% of the women reporting estrogen use in the later years. The prevalence of calcium supplement use (500 mg/day or more) quadrupled over the same interval, with 20% of the women reporting calcium supplement use in the later years. The increases in estrogen and calcium supplement use derived from complex patterns of use. For estrogen, less than half of the users in 1981 were still using 5 years later; the number of women stopping estrogen, however, were more than replaced by new estrogen users. For calcium supplements, fewer than half of the women initiating use continued for as long as 5 years. Women beginning estrogen were younger, had more often used estrogen in the past, had a lower body mass index, had dietary calcium intakes of 400 mg/day or greater, and were more likely to have regularly used alcohol. Women initiating calcium supplements exhibited several of the same characteristics as women initiating estrogen use (younger age, past estrogen use, and regular alcohol use). CONCLUSIONS: The changes in use over the past decade may reduce the risk of osteoporotic fractures among our cohort. Benefits from the changes, however, could be limited by the inconsistent use by many of the cohort women. Also of concern are the weak associations observed between estrogen and calcium supplement use and bone mass measurements, which are strong indicators of fracture risk. It appears that treatment in our cohort has failed to reach many of the women with the greatest fracture risks.

Age Factors↗
PubMed1995

Users of low-dose glucocorticoids have increased bone loss rates: a longitudinal study.

Although high doses of glucocorticoids are believed to cause bone loss, the effects of low glucocorticoid doses are still controversial. Our study examined the effects of low-dose glucocorticoids on the rate of bone loss at three appendicular bone sites. The study population was a cohort of elderly Japanese-Americans, 1094 women and 1378 men. The women were all postmenopausal. At the baseline examination the mean age of the women was 64 years (range 45-81), and the mean age of the men was 68 years (range 61-82). Glucocorticoid users (19 women and 21 men) had used oral systemic or inhaled glucocorticoids on a regular schedule for more than 1 month (mean use was 2.1 years for the women and 1.9 years for the men). The most common dose was equivalent to 5 mg/day of prednisone; fewer than 15% of users had taken doses equivalent to 10 mg/day or more. Changes in bone mass at the calcaneus, distal radius, and proximal radius were documented using bone densitometry at 1 to 2-year intervals over an 8-year period. The initial bone mass of the glucocorticoid users and controls was similar at the baseline examination. The subsequent loss rates among females during glucocorticoid use, however, were approximately double that of the controls. Among males, bone loss rates during glucocorticoid use were 2-3 times that of controls for the calcaneus and radius sites. The differences between glucocorticoid users and controls persisted after adjusting for confounding variables such as age and use of thiazides and estrogens.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Relation of height and weight to the regional variations in bone mass among Japanese-American men and women.

We examined the magnitude of regional variations in bone mass among elderly, Japanese-American men and women. All subjects had bone measurements at the calcaneus, and at the distal and proximal radius sites. A subset of the women had, in addition, spine bone mass measurements. To provide a common measurement scale, the bone measurements were converted to age- and sex-specific Z-scores. The Z-scores between pairs of bone sites were then subtracted to yield the differences in bone mass between bone sites (expressed in Z-score units). For most individuals the differences were less than 1.0 Z-score; however, 12%-20% of the differences were at least 1 Z-score apart. The most similar sites were the distal and proximal radius: different regions within the same bone. Among the other bone pairs, the calcaneus and spine were the most similar to one another. The magnitudes of the differences in bone mass were associated with height and weight. Heavier subjects, for instance, had greater calcaneus than radius bone mass measurements, and greater spine than radius measurements. The spine and calcaneus are more weight-bearing than the radius sites. Associations were observed up to 0.25 Z-score per 10 kg difference in weight. Height was associated with bone mass differences in an opposite direction to weight. Taller subjects had greater bone mass at the radius sites than expected from their calcaneus or spine bone measurements (0.1 to 0.2 Z-score difference per 5 cm difference in height). Bone width partly explained the associations with height; that is, adjusting the radius widths reduced the associations with height. Overall, our results indicate that small to moderate differences between bone sites were common among our study population, and that the magnitudes of the differences were associated with height and weight.

Adult↗
PubMed1995

A randomized, double-masked, placebo-controlled trial of chlorthalidone and bone loss in elderly women.

Employing a double-masked, prospective design, bone loss at three skeletal sites has been monitored among 113 postmenopausal women participating in a placebo-controlled trial of the thiazide-like diuretic chlorthalidone for treatment of systolic hypertension. The mean duration of chlorthalidone use was 2.6 years, at doses of 12.5-25 mg/day. Compared with placebo use, chlorthalidone use was associated with significant reductions in annual bone loss rates. Non-use of chlorthalidone was associated with bone loss at the calcaneus (-0.56% per year) and the proximal radius (-0.91% per year); borderline bone gain was observed at the distal radius (+0.39%). In contrast, chlorthalidone use was associated with bone gain at the calcaneus (+0.44% per year) and the distal radius (+1.51% per year); proximal radius bone loss was significantly reduced to -0.32% per year. The average increment for three appendicular sites was +0.9% per year. These data support a causal relationship between chlorthalidone use and reduced bone loss.

Aged↗
PubMed1995

Vertebral dimension measurements improve prediction of vertebral fracture incidence.

We investigated the independent contributions of vertebral size and shape, bone density, and existing fractures for predicting the risk of new vertebral fractures among postmenopausal Japanese-American women in Hawaii. Baseline measurements of bone density at the distal and proximal radius and the calcaneus were obtained in 1981, and at the lumbar spine in 1984. Incident fractures were documented on serial radiographs during an average of 8.0 years of follow up of 840 women. A positive difference of 1 standard deviation in vertebral depth increased the risk of new vertebral fractures by approximately 1.3-fold (95% confidence interval = 1.03, 1.66) after controlling for bone density and prevalent fractures. A combination of large vertebral depth (above the 66th percentile) and low bone density (below the 33rd percentile) increased fracture risk approximately six times compared to women with high bone density (above the 66th percentile) and small vertebral depth (below the 33rd percentile). We conclude that combining information about vertebral depth, bone density, and prevalent fracture appears to be better for predicting new fractures than any single variable alone.

Absorptiometry, Photon↗
PubMed1995

Estrogen and calcium supplement use among Japanese-American women: effects upon bone loss when used singly and in combination.

We examined the effects of estrogen and calcium supplementation upon bone loss among a cohort of Japanese-American women. The women averaged 64 years of age (age range 45-81) and 14 years postmenopause at their initial examination in 1981. They returned at 1-3-year intervals for subsequent examinations, most recently in 1992-1994. At each examination, bone mass was measured at the calcaneus and distal and proximal radius. The women had low average dietary calcium intakes (median intake 384 mg/day). Women taking calcium supplements reported a median supplement intake of 355 mg/day; over 75% of the women taking estrogen took the equivalent of 0.6 mg/day or more of conjugated estrogens. Women taking estrogen had uniformly slower bone loss at all three sites. Compared to women not taking estrogen, whose bone loss averaged about 1% per year, women taking estrogen had 0.75-0.85% per year decreased bone loss at the three bone sites. By contrast, women who stopped estrogen had greater than average loss rates (0.35-0.65% per year greater). Calcium supplementation also reduced bone loss, but to a lesser extent than estrogen: bone loss decreased 0.25% per year at the radius sites, but was not slowed at the calcaneus. The calcaneus is more trabecular than the radius sites, which may explain the lack of response. We also examined combined estrogen and calcium supplement use.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Vertebral fracture prevalence in women in Hiroshima compared to Caucasians or Japanese in the US.

BACKGROUND: Although vertebral fractures are very common among elderly Caucasian women, no studies have compared the prevalence to that among Asian populations. Any observed differences in prevalence might lead to the identification of important environmental and/or genetic factors. We therefore compared the prevalence of vertebral fractures among US Caucasians to native Japanese and Japanese immigrants in Hawaii using a standardized approach. METHODS: Spinal radiographs of women aged > 50 years were obtained from native Japanese in Hiroshima, Japanese-Americans in Hawaii, and North American Caucasians in Minnesota between 1982 and 1991. Fractures were defined as vertebral heights > 3 standard deviations (SD) below the vertebra-specific mean. RESULTS: Compared to Japanese-Americans, odds ratios (OR) and 95% confidence intervals (CI) for prevalent vertebral fractures were 1.8 (95% CI: 1.3-2.5) for native Japanese women and 1.5 (95% CI: 1.1-2.1) for Minnesota Caucasians. The OR tended to be higher when comparing the prevalence of two or more fractures per person: OR = 3.2 (95% CI: 2.0-5.3) for native Japanese and OR = 1.9 (95% CI: 1.2-3.2) for Minnesota Caucasians. Similar results were observed for native Japanese using a fracture definition of > or = 4 SD below the mean, but the OR for Caucasians was reduced to 1.2 (95% CI: 0.6-2.3). CONCLUSION: The observation that, among these three populations, hip fracture incidence is lowest but spine fracture prevalence is greatest among native Japanese suggests that different risk factors may be responsible.

Age Factors↗