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Biomedical subjects

Michael Kleerekoper

Publications and source records attributed to Michael Kleerekoper.

23 records · Page 2Linked to original sources
PubMedDate not supplied

Differential associations for menopause and age in measures of vitamin K, osteocalcin, and bone density: a cross-sectional exploratory study in healthy volunteers.

OBJECTIVE: To distinguish the effects of midlife aging from early postmenopause on vitamin K measures, bone formation biomarkers, and bone density. DESIGN: Cycling older volunteers (CO; 40-52 years, n = 19) were compared to cycling young (CY; 20-30 years, n = 21) and untreated, age-matched women in the early postmenopause years (EPM; 40-52 years, mean years PM = 2.8 +/- 0.5, n = 19). We assessed sex steroids, vitamin status (phylloquinone, 25-hydroxyvitamin D, retinol), osteocalcin (OC), percentage of undercarboxylated osteocalcin (%ucOC), and bone mineral density (BMD) at the spine and hip with dual-energy x-ray absorptiometry. RESULTS: CO women had similar estradiol and vitamin status as CY women, but lower OC (0.64 +/- 0.04 vs 0.97 +/- 0.08 nmol/L, P = 0.01) and BMD at the total hip (1.0038 +/- 0.032 vs 1.1126 +/- 0.030 g/cm2, P = 0.02). In the two older groups, BMD was similar at all sites, but OC was elevated in the EPM women (1.10 +/- 0.10 vs 0.64 +/- 0.04 nmol/L, EPM vs CO, P = 0.001). Although phylloquinone was highest in the EPM women, %ucOC was also higher when compared with all cycling women (21.9 +/- 1.7% vs 17.4 +/- 0.9%, n = 40; P = 0.02). CONCLUSIONS: Premenopausal women show reduced BMD despite normal estrogen profiles. %ucOC may be a specific bone marker of the early postmenopause in healthy women.

Absorptiometry, Photon↗
PubMedDate not supplied

Secondary osteoporosis: a review of the recent evidence.

OBJECTIVE: To review several causes of secondary osteoporosis as well as screening recommendations for underlying disorders. METHODS: We conducted a review of the literature on many of the causes of osteoporosis that have been published during the past 15 years, focusing on those sources available from 2000 through the present. Indeed, more than two-thirds of the articles that we reviewed were printed during the past 6 years. These reports examined secondary osteoporosis in general, as well as many of the specific causes. RESULTS: Secondary osteoporosis occurs in almost two-thirds of men, more than half of premenopausal and perimenopausal women, and about one-fifth of postmenopausal women. Its causes are vast, and they include hypogonadism, medications, hyperthyroidism, vitamin D deficiency, primary hyperparathyroidism, solid organ transplantation, gastrointestinal diseases, hematologic diseases, Cushing's syndrome, and idiopathic hypercalciuria. These causes have their own pathogenesis, epidemiologic features, and effect on the skeleton. CONCLUSION: The causes of secondary osteoporosis are numerous, and an understanding of their characteristics with respect to bone density and potential fracture risk is essential in the management of osteoporosis. A heightened awareness of the possibility of their existence is necessary to provide optimal care.

Adrenal Cortex Hormones↗
PubMedDate not supplied

Is BMD testing appropriate for all menopausal women?

The United States Preventive Services Task Force has provided an evidence-based guideline indicating that bone mineral density (BMD) testing is appropriate for all women aged 65 or older. This does not preclude BMD testing in younger postmenopausal women but places the onus on the treating physician to justify the procedure to the patient and often the patient's insurance carrier. There are very few circumstances in which BMD testing is appropriate for healthy premenopausal women, but BMD testing in younger postmenopausal women is often appropriate: when there is a family history of osteoporosis with fracture, a personal history of fracture as an adult, and a medical, surgical or therapeutic history that might be associated with accelerated bone loss or increased risk of fracture. Medical conditions include intestinal diseases associated with malabsorption, such as non-tropical sprue, or primary hyperparathyroidism. Women who have neurologic conditions that increase the risk of falling should also be tested. There are data to suggest that patients with hemoglobinopathy are at increased risk for osteoporosis. Surgical conditions include the increasingly performed surgery for obesity and other surgery resulting in bowel resection (e.g., for inflammatory bowel disease). The major medication-related concern is corticosteroid therapy, but chronic or over-treatment with thyroxine, and chronic heparin therapy, should also be considered risk factors for osteoporosis. When performing a BMD test for the first time, it is essential to remember that 50% of women at menopause will have a negative T-score, but this does not imply that the patient has indeed lost any bone from her peak bone mass.

Absorptiometry, Photon↗