Biomedical subjects

Neil C Binkley

Publications and source records attributed to Neil C Binkley.

13 recordsLinked to original sources

PubMed2007

Circulating vitamin D3 and 25-hydroxyvitamin D in humans: An important tool to define adequate nutritional vitamin D status.

Circulating 25-hydroxyvitamin D [25(OH)D] is generally considered the means by which we define nutritional vitamin D status. There is much debate, however, with respect to what a healthy minimum level of circulation 25(OH)D should be. Recent data using various biomarkers such as intact parathyroid hormone (PTH), intestinal calcium absorption, and skeletal density measurements suggest this minimum level to be 80 nmol (32 ng/mL). Surprisingly, the relationship between circulating vitamin D(3) and its metabolic product-25(OH)D(3) has not been studied. We investigated this relationship in two separate populations: the first, individuals from Hawaii who received significant sun exposure; the second, subjects from a lactation study who received up to 6400IU vitamin D(3)/day for 6 months. Results (1) the relationship between circulating vitamin D(3) and 25(OH)D in both groups was not linear, but appeared saturable and controlled; (2) optimal nutritional vitamin D status appeared to occur when molar ratios of circulating vitamin D(3) and 25(OH)D exceeded 0.3; at this point, the V(max) of the 25-hydroxylase appeared to be achieved. This was achieved when circulating 25(OH)D exceeded 100 nmol. We hypothesize that as humans live today, the 25-hydroxylase operates well below its V(max) because of chronic substrate deficiency, namely vitamin D(3). When humans are sun (or dietary) replete, the vitamin D endocrine system will function in a fashion as do these other steroid synthetic pathways, not limited by substrate. Thus, the relationship between circulating vitamin D and 25(OH)D may represent what "normal" vitamin D status should be.

Cholecalciferol↗

PubMed2006

Between-meal risedronate does not alter bone turnover in nursing home residents.

OBJECTIVES: To assess the effect of between-meal weekly risedronate and daily calcium 630 mg and vitamin D 400 IU on bone turnover markers. DESIGN: Randomized,double-blind,placebo-controlled trial. SETTING: Skilled nursing home (NH). PARTICIPANTS: Sixty skilled-NH residents (46 men, 14 women), mean age+/-standard deviation of 76+/-6, were randomized to receive risedronate 30 mg (n=31) or matching placebo (n=29) once weekly for 12 weeks. All received 315 mg calcium with 200 IU vitamin D twice daily. MEASUREMENTS: Bone-specific alkaline phosphatase (BSAP), N-telopeptide of type 1 collagen (NTx), 25-hydroxyvitamin D (25OHD), and parathyroid hormone were measured at baseline and 6 and 12 weeks. RESULTS: Risedronate reduced BSAP significantly more than placebo (P<.05) at 6 weeks but not at 12 weeks; no treatment effect on serum NTx was observed. Defining hypovitaminosis D as a serum 25OHD concentration below 32 ng/mL, 50 of 53 (94%) study participants were low at baseline (mean 25OHD 19 ng/mL). Vitamin D levels remained insufficient in 74% of participants after 12 weeks. CONCLUSION: In this NH population, weekly risedronate administered using a between-meal dosing schedule reduced serum BSAP at 6 weeks of treatment; this effect was not observed at 12 weeks. The overall lack of change in bone turnover markers suggests that this risedronate dose and schedule would not be expected to increase bone density or reduce fracture risk in this population. Hypovitaminosis D was common and not reliably corrected by 400 IU of vitamin D daily. Despite an extremely high osteoporotic fracture risk in NH residents, additional study is required to determine under which conditions pharmacological treatment is efficacious in this population and define approaches that assure vitamin D repletion.

Aged↗

PubMed2004

Osteoporosis assessment strategies for male nursing home residents.

OBJECTIVES: Twenty-five to thirty percent of hip fractures occur in men, and nursing home residents have a 5-10-fold greater fracture risk than community-dwellers. Osteoporosis prevalence in men in long-term care, however, is poorly defined. Our objectives were to determine the prevalence of osteoporosis, as assessed by peripheral bone mineral density (BMD), in a group of institutionalized veterans, and to determine how many men with low BMD had received a prior diagnosis of osteoporosis. METHODS: Subjects were residents in a 740-bed skilled nursing facility (78% men). Male residents (n = 103) competent to give informed consent underwent bilateral calcaneal and forearm BMD by dual-energy X-ray absorptiometry (DXA). Prior osteoporosis documentation was sought in medical records. RESULTS: Twenty percent of veterans (95% confidence interval (CI) 12-28%) exhibited calcaneal osteoporosis (T-score < -2.5), and 62% (CI 52-72%) were osteoporotic at the forearm. Forearm and calcaneal BMD were correlated (r = 0.678, P < 0.001). BMD of the left and right forearm, and of left and right calcaneus, were highly correlated (r = 0.880, P < 0.001 and r = 0.931, P < 0.001, respectively). Documentation of osteoporosis existed for one of 20 men with calcaneal osteoporosis and four of 59 men with forearm osteoporosis. CONCLUSIONS: Osteoporosis was prevalent but poorly documented in institutionalized veterans. Discordance in T-scores between forearm and heel was similar to that reported in other studies. The broad range of T-scores among subjects suggests that peripheral BMD measurement may be useful for clinical fracture risk stratification. Correlation among skeletal sites indicates that measuring a single site may be practical.

Absorptiometry, Photon↗

PubMed2004

Artifactual reduction in bone density as a result of technetium-99m MDP for bone scanning: report of two cases.

We present two patients in whom marked changes in dual-energy X-ray absorptiometry (DXA)-measured bone mineral density were found to be the result of prior administration of technetium-99m methylene diphosphonate (MDP) for bone scanning. In patient 1, an artifactual 50% decrease in lumbar spine and 19% decrease in left total hip bone density over a 14-mo period was the result of technetium-99m injection 3 h before the second bone density measurement. In patient 2, a dramatic increase in bone density at 6 mo was the result of artifactual reduction in bone density on the baseline study as a result of technetium-99m injection 2 h earlier. Clinicians and technologists should be aware that technetium-99m used for bone scanning could cause artifactual reduction in DXA-measured bone mineral density.

Absorptiometry, Photon↗

PubMed2003

Position Development Conference.

In a series of three published articles, the International Society for Clinical Densitometry has recorded the findings reached by an expert panel at the ISCD Position Development Conference held in July 2001. The key elements of those papers have been reviewed in this executive summary. It should be emphasized that the ISCD recommendations are not meant to serve as rigid guidelines or to replace clinical judgment. The recommendations will be reviewed and updated periodically as more data become available. A second Position Development Conference will be held in July 2003 in Cincinnati, OH. For information, visit the ISCD web site: http://www.iscd.org/.

Absorptiometry, Photon↗

PubMed2003

Fracture risks for women in long-term care: high prevalence of calcaneal osteoporosis and hypovitaminosis D.

STUDY OBJECTIVES: To determine the prevalence of osteoporosis as assessed by peripheral bone mineral density (BMD) in women living in a nursing home, to determine how many women with low BMD had received a diagnosis of osteoporosis, to assess the prevalence of vitamin D deficiency, and to seek reasons for vitamin D deficiency. DESIGN: Measurement of calcaneal BMD and serum 25-hydroxyvitamin D. SETTING: Skilled nursing facility. PATIENTS: Forty-nine women aged 68-100 years. MEASUREMENTS AND MAIN RESULTS: Bilateral calcaneal BMD was measured by dual-energy x-ray absorptiometry and serum 25-hydroxyvitamin D by radioimmunoassay. Medical records were reviewed to assess osteoporosis risk factors, previous documentation of osteoporosis or malabsorption, and supplemental vitamin D intake. Fifty-nine percent of the 39 women with calcaneal BMD measurements (95% confidence interval [CI] 44-74%) exhibited calcaneal osteoporosis (T score < -2.5). Sixty percent (95% CI 46-74%) had 25-hydroxyvitamin D levels of 20 ng/ml or less, which is associated with secondary hyperparathyroidism; only 4% of women had levels above 30 ng/ml, recently recommended as optimal. Vitamin D status was suboptimal even in most women taking multivitamins. Osteoporosis was documented in the records of 17% of 23 women with calcaneal osteoporosis. CONCLUSION: Osteoporosis was prevalent but poorly documented in women living in the nursing home. Peripheral BMD measurements have the potential to improve the recognition and management of osteoporosis in women in long-term care facilities. The high prevalence of vitamin D deficiency, even in those taking multivitamins, indicates that practical new approaches for vitamin D repletion in this population are urgently needed.

Aged↗

PubMed2002

A high phylloquinone intake is required to achieve maximal osteocalcin gamma-carboxylation.

BACKGROUND: Dietary vitamin K is usually inadequate to maximize serum osteocalcin gamma-carboxylation. Phylloquinone supplementation increases osteocalcin gamma-carboxylation; however, the amount required to maximize carboxylation is not known. OBJECTIVE: This study assessed the ability of various doses of phylloquinone (vitamin K(1)) to facilitate osteocalcin gamma-carboxylation. DESIGN: Healthy adults aged 19-36 y participated in 2 substudies. In an initial dose-finding study (substudy A), 6 women and 4 men received a placebo daily for 1 wk and then phylloquinone daily for 3 wk: 500, 1000, and 2000 micro g during weeks 2, 3, and 4, respectively. Osteocalcin and undercarboxylated osteocalcin were measured at baseline and after each week of supplementation. Subsequently, to further delineate the gamma-carboxylation response of osteocalcin to various doses of vitamin K, 58 women and 42 men were randomly assigned to receive placebo or phylloquinone supplementation (250, 375, 500, and 1000 micro g/d) for 2 wk (substudy B). The percentage of undercarboxylated osteocalcin (%ucOC) was measured at baseline and weeks 1 and 2. RESULTS: In substudy A, %ucOC decreased with phylloquinone supplementation (P < 0.0001); a greater reduction was observed with 1000 and 2000 micro g than with 500 micro g (P < 0.05). In substudy B, %ucOC decreased in all supplemented groups by week 1 (P for the trend < 0.0001), which was sustained through week 2. Phylloquinone supplementation decreased %ucOC dose-dependently; %ucOC was significantly different between the 250- micro g and the placebo groups and between the 1000- and 500- micro g groups but not between the 250-, 375-, and 500- micro g groups. CONCLUSION: A daily phylloquinone intake of approximately 1000 micro g is required to maximally gamma-carboxylate circulating osteocalcin.

Adult↗

PubMed2002

Short-term vitamin A supplementation does not affect bone turnover in men.

Limited data in humans and animals indicate that excess vitamin A stimulates bone resorption and inhibits bone formation, effects that over time might lead to bone loss and fracture. Thus, it is possible that vitamin A supplementation is a currently unrecognized risk factor for the development of osteoporosis. To further evaluate this possibility, a prospective, randomized, single-blind study of vitamin A supplementation was conducted in 80 healthy men age 18-58 y. One half received 7576 microg (25,000 IU) of retinol palmitate daily with their evening meal; the others took a placebo. Blood was collected from fasting subjects and serum prepared at baseline and after 2, 4 and 6 wk of supplementation. Serum bone specific alkaline phosphatase (BSAP) and N-Telopeptide of type 1 collagen (NTx) were measured at all time points. Serum osteocalcin (Oc) was measured at baseline and after 6 wk of supplementation. BSAP, NTx and Oc did not differ between the supplemented and placebo-treated groups over the course of the study. In conclusion, short-term vitamin A supplementation at this dosage in healthy men does not alter serum markers of skeletal turnover. Thus, it is unlikely that short-term administration of vitamin A would contribute to the development of osteoporosis. Whether long-term vitamin A supplementation might have adverse skeletal effects remains to be determined.

Adolescent↗

PubMed2002

Pharmacy-based bone mass measurement to assess osteoporosis risk.

OBJECTIVE: To evaluate elderly women's knowledge of their skeletal status, assess adequacy of calcium intake, determine the prevalence of low bone density, and determine whether peripheral bone density testing led to medical interventions in a group of rural, elderly Wisconsin women recruited in community pharmacies. DESIGN: Recruiting notices were posted in each pharmacy, and eligible women were enrolled in the order in which they volunteered. Each completed a fracture-risk questionnaire. Calcaneal bone density was measured within the following 6 weeks, using peripheral dual-energy X-ray absorptiometry. Mail surveys were used to assess interventions subsequent to the womens' study participation. SETTING: The study was conducted at 5 community pharmacies in rural Wisconsin. RESULTS: Of 133 women, 20% had calcaneal osteoporosis, defined as a T score < or =2.5 (calcaneal bone density <2.5 SDs below the young reference database). Thirty percent of women met National Osteoporosis Foundation (NOF) treatment criteria based on heel bone density and NOF-designated risk factors. Of those meeting treatment criteria, 75% were unaware of their low bone mass. Half of the women received <1200 mg/d of calcium, the recommended dose for osteoporosis prevention. Those who were taking a calcium supplement were much more likely to receive the recommended amount. Women who had discussed bone density test results with their physicians were more likely to receive central dual energy X-ray absorptiometry (DXA) measurements and/or start antiresorptive therapy than women who did not. CONCLUSIONS: Rural, elderly Wisconsin women are at substantial risk for osteoporosis, based on calcaneal bone density, but most are unaware of their risk. Compounding this risk is low calcium intake. Community screening of rural, elderly women by peripheral bone density measurement can lead to medical interventions in such individuals.

Absorptiometry, Photon↗

PubMed2002

Executive summary International Society for Clinical Densitometry position development conference Denver, Colorado July 20-22, 2001.

Bone densitometry is routinely used to assess the skeleton in patients who have diseases or conditions that can cause low bone mass. However, there are some areas of controversy related to the interpretation of bone densitometry results. To address these issues, the International Society for Clinical Densitometry (ISCD) convened a Position Development Conference in Denver, Colorado, July 20-22, 2001. The ISCD is a not-for-profit multidisciplinary society whose main mission is to promote quality in the performance and interpretation of bone densitometry examinations.

Bone Density↗

PubMed2002

What are the criteria by which a densitometric diagnosis of osteoporosis can be made in males and non-Caucasians?

Osteoporotic fractures are not rare in men or non-Caucasian women. However, for these groups, there is no consensus densitometric definition of osteoporosis. As is the case in Caucasian women, low bone mineral density (BMD) is associated with increased fracture risk among men and non-Caucasian women; thus, a densitometric definition of osteoporosis seems feasible. Reaching agreement on criteria for diagnosing osteoporosis in men and non-Caucasians was among the goals of the International Society for Clinical Densitometry Position Development Conference held in July 2001. To this end, the conference recommendation for males is that osteoporosis be defined as a BMD T-score of -2.5 or below the young normal mean for men. Since the relationship between BMD and fracture risk may differ between men and women, it is recommended that T scores in men continue to be derived using a male normative database. Similarly, for non-Caucasians, the recommendation is to diagnose osteoporosis at or below a T-score of -2.5. However, given the difficulty in defining race or ethnic groups, a dearth of data, and their conflicting nature correlating BMD with fracture risk in different ethnicities, it is recommended that a uniform normative database (not adjusted for race) be utilized in the United States for T-score derivation in non-Caucasians. Note that these are current clinical recommendations, which may change as additional data accumulate. Furthermore, there was agreement that the following individuals should have their bone density measured: anyone (male or female, regardless of race) with prior fragility fractures or with conditions widely recognized to increase the risk of bone loss and fracture (such as hypogonadism, corticosteroid treatment, hyperparathyroidism, alcohol abuse, anticonvulsant use, and prior gastrectomy); women on long-term hormone replacement therapy; and in the absence of these conditions, women age 65 and older (regardless of race) and men age 70 and older.

Absorptiometry, Photon↗

PubMedDate not supplied

Acceptability of pharmacy-based bone density measurement by women and primary healthcare providers.

OBJECTIVES: To assess women's information sources regarding, and monetary value placed on, pharmacy-based bone density screening. In addition, we evaluated clinicians' response to peripheral bone mass measurements. DESIGN: We recruited 197 women 50 years of age or older in four rural Midwestern community pharmacies. Each woman completed a questionnaire and underwent calcaneal bone density testing. Results were sent to participants' primary care providers. These providers, and others practicing within a 50-mile radius, were surveyed anonymously to evaluate usefulness of bone density data provided by this program or pharmacy-based osteoporosis screening in general. In addition, clinicians were asked how they would manage a woman with a calcaneal T-score of -1.3. RESULTS: Fifty-six percent of participants [95% CI, 49%-63%] became interested in screening through the media, and only 6% (CI, 3%-9%) became interested through contact with their primary care provider. Women were willing to pay a median of $25 for screening. Of 18 responding clinicians with patients in this study, 72% (CI, 47%-90%) found the results useful. Of the 67 responding clinicians, 51% (CI, 39%-63%) supported pharmacy-based bone mass measurement. For a case scenario of a woman with a calcaneal T-score of -1.3, 57% (CI, 46%-68%) of clinicians indicated that they would have ordered central dual-energy x-ray absorptiometry, and 20% (CI, 11%-29%) would have prescribed antiresorptive therapy. CONCLUSIONS: This study suggests that (1) women are an important force in obtaining bone density testing outside the clinic setting, both by self-education and willingness to pay, and (2) primary care clinicians receiving such results find them useful and indicate willingness to use them in decision-making.

Aged↗

PubMedDate not supplied

Osteoporosis screening by community pharmacists: use of National Osteoporosis Foundation resources.

OBJECTIVES: To assess the feasibility of establishing an osteoporosis screening program in rural community pharmacies based on information and resources provided by the National Osteoporosis Foundation (NOF), to survey primary care providers regarding the usefulness of this screening program, and to recommend strategies for pharmacists interested in working with patients at risk for osteoporosis. DESIGN AND PARTICIPANTS: Pharmacists and/or nurses enrolled women 65 years of age and older into the study, measured calcaneal bone density, administered a questionnaire to ascertain subjects' osteoporosis risk factors, and provided NOF literature to subjects. With their agreement, women's bone mass data and risk factor assessments were provided to primary care providers along with NOF's Physician's Guide to Prevention and Treatment of Osteoporosis. These providers were surveyed as to whether they found this information useful. SETTING: Five independent community pharmacies in rural Wisconsin. RESULTS: We enrolled and tested 133 women. Of these, 122 (92%) agreed to have information mailed to their primary health care providers. These 57 providers were surveyed and 24 (42%) responded; of these 24, 20 (83%) found the information they received useful. CONCLUSION: A community pharmacy-based osteoporosis screening program using NOF materials was well accepted by physicians. NOF resources and recommendations can provide a strong foundation for such programs.

Absorptiometry, Photon↗