The Founder’s Lecture 2009: advances in imaging of osteoporosis and osteoarthritis

The objective of this review article is to provide an update on new developments in imaging of osteoporosis and osteoarthritis over the past three decades. A literature review is presented that summarizes the highlights in the development of bone mineral density measurements, bone structure imaging, and vertebral fracture assessment in osteoporosis as well as MR-based semiquantitative assessment of osteoarthritis and quantitative cartilage matrix imaging. This review focuses on techniques that have impacted patient management and therapeutic decision making or that potentially will affect patient care in the near future. Results of pertinent studies are presented and used for illustration. In summary, novel developments have significantly impacted imaging of osteoporosis and osteoarthritis over the past three decades

Teknik Demografi

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Sex hormone levels and risks of estrogen receptor-negative and estrogen receptor-positive breast cancers

BackgroundEndogenous sex hormone levels are associated with risks of breast cancer overall and estrogen receptor (ER)-positive breast tumors; however, their associations with ER-negative tumors remain unclear.MethodsIn a case-cohort study within the Women's Health Initiative Observational Study among postmenopausal women aged 50-79 years, we examined associations between endogenous testosterone and estradiol levels and the risks of ER-negative and ER-positive breast cancers. Serum levels of bioavailable testosterone and estradiol were assessed at the baseline visit in 317 invasive breast cancer case subjects and in a subcohort of 594 women. Bioavailable sex hormone levels were calculated using the total hormone level and the sex hormone-binding globulin concentration (measured by radioimmunoassays and a chemiluminescent immunoassay, respectively). Cox proportional hazards regression was used for statistical analysis. All statistical tests were two-sided.ResultThe unadjusted absolute rates of ER-negative breast cancer for testosterone quartiles 1-4 were 0.34, 0.20, 0.23, and 0.21 per 10000 person-years, respectively. Compared with women in the lowest quartile of testosterone level, those in quartile 2 had a 56% lower risk of ER-negative cancer (hazard ratio [HR] = 0.44, 95% confidence interval [CI] = 0.23 to 0.85), those in quartile 3 had a 45% lower risk (HR = 0.55, 95% CI = 0.30 to 1.01), and those in quartile 4 had a 49% lower risk (HR = 0.51, 95% CI = 0.28 to 0.94), independent of other risk factors. Estradiol level was not associated with ER-negative breast cancer. ER-positive breast cancer risk increased with higher testosterone levels (Ptrend =. 04), but this trend was not statistically significant after adjustment for estradiol (Ptrend =. 15). ER-positive cancer risk was approximately twofold higher in women with estradiol levels in quartiles 2-4 compared with women in quartile 1, independent of risk factors.ConclusionHigher serum levels of bioavailable testosterone are associated with lower risks of ER-negative breast cancer in postmenopausal women. © 2011 The Author

Systemic bone loss following myocardial infarction in mice

Myocardial infarction (MI) and osteoporotic fracture are leading causes of morbidity and mortality, and epidemiological evidence linking their incidence suggests possible crosstalk. MI can exacerbate atherosclerosis through the sympathetic nervous system (SNS) activation and β(3) adrenoreceptor-mediated release of hematopoietic stem cells, leading to monocytosis. We hypothesized that this same pathway initiates systemic bone loss following MI, since osteoclasts differentiate from monocytes. In this study, MI was created with left anterior descending artery ligation in 12-week-old male mice (n = 24) randomized to β(3)-adrenergic receptor (AR) antagonist (SR 59230A) treatment or no treatment for 10 days postoperatively. Additional mice (n = 21, treated and untreated) served as unoperated controls. Bone mineral density (BMD), bone mineral content (BMC), and body composition were quantified at baseline and 10 days post-MI using dual-energy x-ray absorptiometry; circulating monocyte levels were quantified and the L5 vertebral body and femur were analyzed with microcomputed tomography 10 days post-MI. We found that MI led to circulating monocyte levels increases, BMD and BMC decreases at the femur and lumbar spine in MI mice (−6.9% femur BMD, −3.5% lumbar BMD), and trabecular bone volume decreases in MI mice compared with control mice. β(3)-AR antagonist treatment appeared to diminish the bone loss response (−5.3% femur BMD, −1.2% lumbar BMD), though these results were somewhat inconsistent. Clinical significance: These results suggest that MI leads to systemic bone loss, but that the SNS may not be a primary modulator of this response; bone loss and increased fracture risk may be important clinical comorbidities following MI or other ischemic injuries