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R D Wasnich

Publications and source records attributed to R D Wasnich.

At least 109 records · Page 6Linked to original sources
PubMed1988

The clinical relevance of calcaneus bone mineral measurements: a review.

The use of bone mineral content (BMC) measurements to assist in the management of osteoporosis has received increasing emphasis in recent years. Although the calcaneus, an essentially trabecular bone (90-95%), has been used extensively in the NASA experiments, few data relating to primary osteoporosis have appeared in the literature until recently. This paper is a review of the methods of measurement, their precision and methods of calibration, and the relationship of calcaneal mineral content to age, height, weight, other bone sites, degree of spinal osteoporosis, metabolic bone disease and the effects of therapeutic drugs. Prospectively, calcaneal BMC relates as well as spinal BMC to osteoporotic fracture risk. It is this use of BMC measurements which has the most promise for the future. The data indicate that osteoporosis is a systemic disease and trabecular bone losses are reflected in the calcaneus as well as in the spine itself.

Absorptiometry, Photon↗
PubMed1988

A model for estimating the potential costs and savings of osteoporosis prevention strategies.

A model was developed which estimates the costs of osteoporosis risk evaluation and treatment, and the resulting savings in terms of reduced fracture frequency, for the adult female population of the United States. In the absence of treatment, the model predicts 1.44 million fractures will occur annually from non-violent causes. Treatment of all women beginning at age 50 with an agent that slows bone loss by 50% would reduce the number of these fractures by 0.59 million. Selective treatment of the 47% of women at the greatest fracture risk would reduce the number of fractures by 0.45 million, but would only cost 47% as much as treating all women. Additional data are required before the model can be used to evaluate specific treatment regimens. However, it appears that selective treatment of those at highest risk would yield the greatest benefit to cost ratio, if only benefits related to reduced fracture frequency are considered.

Age Factors↗
PubMed1988

Sequential dose injections. A new technique for technetium-99m colloid gastrointestinal bleeding studies.

For Tc-99m colloid bleeding studies to be positive, the patient must be actively bleeding while the colloid is circulating in the blood pool. A simple technique of sequential dose injections (SDI) is presented where five injections of 2 mCi each are made at 5-minute intervals. Image acquisition is performed after each injection. This technique results in an increase in the effective plasma residence time of the colloidal particles from 10-15 minutes to 35-40 minutes. A case report is presented in which the bleeding site was identified only after the fifth serial injection of a fractionated dose of Tc-99m microaggregated albumin colloid.

Aged↗
PubMed1988

Precision error in dual-photon absorptiometry related to source age.

An average, variable precision error of up to 6% related to source age was observed for dual-photon absorptiometry of the spine in a longitudinal study of bone mineral content involving 393 women. Application of a software correction for source decay compensated for only a portion of this error. The authors conclude that measurement of bone-loss rates using serial dual-photon bone mineral measurements must be interpreted with caution.

Adult↗
PubMed1987

Definition of a spine fracture threshold based upon prospective fracture risk.

Assessment of fracture threshold (FT) could have important clinical application in determining which individuals should be treated preventively, and what level of therapy to prescribe, if suitable treatment regimens can be developed. We propose that FT be defined as the bone mineral content (BMC) at which the risk of fracture doubles, relative to premenopausal women, as determined by logistic regression analysis of spine fracture incidence in a prospective study of 408 postmenopausal women. The observed values for the FT agree well with those reported by others, based upon more arbitrary definitions. More than 90% of individuals with new nonviolent spine fractures have BMC below the fracture threshold, while fewer than 10% of younger women (age 30-45) are below this value. Although not all women with BMC below the FT have had fractures, they are at increased risk of fracture. Women with BMC equivalent to the FT have at least a 5% chance of fracture over a 10-year period, and the probability of fracture rises rapidly as BMC decreases. BMC appears to be a much stronger predictor of fracture risk than age or body size (height or weight). Thus, use of a BMC fracture threshold to categorize individual risk could provide a more objective basis for clinical decision making.

Adult↗
PubMed1987

Selection of the optimal skeletal site for fracture risk prediction.

Commonly known risk factors have been shown to correlate with mean bone mass in populations, but none of these risk factors, either alone or in combination, have been shown to be predictive of future fracture risk in an individual. In order to evaluate the predictive power of bone mineral measurements at various sites, bone mineral content (BMC) has been measured at four skeletal sites and compared to subsequent fracture incidence at all skeletal locations, including spine and appendicular sites. Os calcis BMC has the most consistent monotonic relationship to unadjusted fracture incidence rates; os calcis BMC also has the strongest (p = 0.009) relation to levels of relative risk, after adjustment for age, height, and weight. Based on actual ability to predict fracture risk prospectively, along with such secondary criteria as cost, ease of performance, precision, and radiation exposure, the os calcis appears to be an optimal BMC measurement site for routine screening of perimenopausal women.

Adult↗
PubMed1986

Differential effects of thiazide and estrogen upon bone mineral content and fracture prevalence.

Individual and combined effects of thiazides and estrogens upon bone mineral content at four sites (proximal radius, distal radius, os calcis, lumbar spine) and fracture prevalence were assessed retrospectively in 993 postmenopausal women. Compared with untreated women, use of thiazide alone was associated with significantly higher bone mineral content (P less than or equal to .01); nonspine fracture prevalence in this group was reduced by one-half (P = .07). Estrogen alone also was associated with significantly higher bone mineral content (P less than or equal to .0001); nonspine fracture prevalence was reduced by almost one-half (P = .07). The users of both estrogen and thiazide had the highest bone mineral content levels, which were significantly different than the thiazide-only group at four bone sites (P less than or equal to .001), and the estrogen-only group for three bone sites (P less than or equal to .05). Nonspine fracture prevalence for the users of both drugs was 17% that of the untreated group (P = .02). The relationships with spine fracture prevalence were less consistent; however, estrogen users appeared to have a lower spine fracture prevalence rate and higher spinal bone mineral content than thiazide users. These findings suggest a potential role for thiazides in the prevention of osteoporosis.

Adult↗
PubMed1985

Prediction of postmenopausal fracture risk with use of bone mineral measurements.

In a study of 1098 women (mean age, 63.3 years) nonspine fracture incidence and prevalence rates and spine fracture prevalence rates were compared by quintile of bone mineral content at the proximal radius, distal radius, os calcis, and lumbar spine. The risk of fracture associated with varying bone mineral content levels was explored with use of estimated odds ratios. Risk of fracture is significantly increased with diminishing quintiles of bone mineral content. Subjects in the lowest quintile of os calcis bone mineral content have a nonspine fracture risk 10 times greater than subjects in the highest bone mineral content quintile. The os calcis bone mineral content measurement is the best predictor of nonspine fracture risk and is also the best overall indicator of spine fracture risk. Therefore measurement of os calcis bone mineral content may be useful for routine risk evaluation of perimenopausal women. The ability to predict individual risk should allow for more rational preventive regimens.

Adult↗
PubMed1985

The relationship between diet and bone mineral content of multiple skeletal sites in elderly Japanese-American men and women living in Hawaii.

The relationship of dietary intake of nutrients assessed by 24-h recalls and supplementary intake of selected minerals and vitamins to the bone mineral content (BMC) of the radius, ulna, and os calcis measured by the photon absorption technique was cross-sectionally studied in a sample of elderly Japanese residents (1208 men and 912 women) in Hawaii. Dietary intakes of milk, calcium, and vitamin D were significantly and positively associated with BMC in both sexes after adjusting for age, weight, height, strenuous exercise (men), history of nonviolent fracture, thiazide use, and estrogen use (women). However, independent contributions of milk or nutrients to BMC were only modest as compared with those of major confounders. No consistent result was obtained concerning the effects of supplementary minerals and vitamins upon BMC.

Adult↗
PubMed1984

Bone mineral measurements among middle-aged and elderly Japanese residents in Hawaii.

Cross-sectional data of bone mineral content measured at five skeletal sites (distal radius and ulna, proximal radius and ulna, and os calcis) with single photon absorptiometry were obtained from a population of Japanese-Americans living in Hawaii, comprising 1368 men (aged 61-81 years) and 1098 women (aged 43-80 years). Age-specific mean values of bone mineral content for all skeletal sites were much greater for men than for women and decreased steadily with advancing age in both sexes. The decrease in bone mineral content with age across a 15-year age range was two to four times (depending on skeletal site) greater for women than for men. In multiple regression analyses, age, weight, and postmenopausal estrogen use were potent determinants of bone mineral content for all skeletal sites. Weight was more strongly related to bone mineral content of the os calcis than age in both sexes. Height was significantly related only to the forearm bones. Strenuous exercise was significantly related to bone mineral content of the os calcis and the distal ulna only in men. When compared with US Caucasians of comparable sex and age, the Japanese in Hawaii have lower bone mineral content of the radius. This may partly be explained by the difference in body size. Significant correlations were found between bone mineral content of appendicular bones and radiographically determined vertebral osteoporosis.

Adult↗
PubMed1983

Thiazide effect on the mineral content of bone.

The thiazide diuretics are known to cause calcium retention. In order to study the effect of thiazides on bone mineralization, we have measured the mineral content of bone at five sites (the distal radius, the distal ulna, the proximal radius, the proximal ulna, and the os calcis) in 1368 men with a mean age of 68 years, including 323 who were taking thiazides for hypertension. The results were adjusted for age and body-mass index. Thiazide users had significantly more bone mineral content at all five sites than did non-users. Untreated hypertensive patients and persons without hypertension had comparable bone mineral content, indicating that the higher mineral content found among thiazide users is related to the drug and not to the underlying hypertension. These findings suggest the possibility of a preventive or therapeutic role for thiazides in osteoporosis.

Aged↗
PubMed1982

Presence of hepatitis B surface antigen before primary hepatocellular carcinoma.

In a study of 7,498 men of Japanese ancestry in Hawaii, 18 incident cases of primary hepatocellular carcinoma were identified after the follow-up period of 13 years. Sixteen of the 18 patients had stored serum specimens available for analysis. Ten of the 16 had positive serum test results for hepatitis B surface antigen in their original specimens. None of 48 matched controls subjects, whose stored serum specimens were also analyzed, had similar positive test results. This finding indicates that hepatitis B surface antigenemia preceded primary hepatocellular carcinoma in many patients.

Aged↗