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In addition to low BMD, AA have impaired bone microarchitecture compared with EA and nonathletes. These are the first data to show abnormal bone microarchitecture in AA.

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METHODS.One hundred ninety-eight healthy men, ages 20-50, received goserelin acetate, which suppresses endogenous gonadal steroid production, and were randomized to treatment with 0, 1.25, 2.5, 5, or 10 grams of testosterone gel daily for 16 weeks. An additional cohort of 202 men was randomized to receive these treatments plus anastrozole, which suppresses conversion of androgens to estrogens. Thirty-seven men served as controls and received placebos for goserelin and testosterone. Changes in bone turnover markers, bone mineral density (BMD) by dual-energy x-ray absorptiometry (DXA), and BMD by quantitative computed tomography (QCT) were assessed in all men. Bone microarchitecture was assessed in 100 men. RESULTS.As testosterone dosage decreased, the percent change in C-telopeptide increased. These increases were considerably greater when aromatization of testosterone to estradiol was also suppressed, suggesting effects of both testosterone and estradiol deficiency. Decreases in DXA BMD were observed when aromatization was suppressed but were modest in most groups. QCT spine BMD fell substantially in all testosterone-dose groups in which aromatization was also suppressed, and this decline was independent of testosterone dose. Estradiol deficiency disrupted cortical microarchitecture at peripheral sites. Estradiol levels above 10 pg/ml and testosterone levels above 200 ng/dl were generally sufficient to prevent increases in bone resorption and decreases in BMD in men. CONCLUSIONS.Estrogens primarily regulate bone homeostasis in adult men, and testosterone and estradiol levels must decline substantially to impact the skeleton. TRIAL REGISTRATION. ClinicalTrials.gov, NCT00114114.FUNDING. AbbVie Inc., AstraZeneca Pharmaceuticals LP, NIH.

CONTEXT Lower bone density in young amenorrheic athletes (AA) compared to eumenorrheic athletes (EA) and non-athletes may increase fracture risk during a critical time of bone accrual. Finite element analysis (FEA) is a unique tool to estimate bone strength in vivo, and the contribution of cortical microstructure to bone strength in young athletes is not well understood. OBJECTIVE We hypothesized that FEA-estimated stiffness and failure load are impaired in AA at the distal radius and tibia compared to EA and non-athletes despite weight-bearing exercise. DESIGN AND SETTING Cross-sectional study; Clinical Research Center SUBJECTS 34 female endurance athletes involved in weight-bearing sports (17 AA, 17 EA) and 16 non-athletes (14-21y) of comparable age, maturity and BMI OUTCOME MEASURES We used HR-pQCT images to assess cortical microarchitecture and FEA to estimate bone stiffness and failure load. RESULTS Cortical perimeter, porosity and trabecular area at the weight-bearing tibia were greater in both groups of athletes than non-athletes, whereas the ratio (%) of cortical to total area was lowest in AA. Despite greater cortical porosity in EA, estimated tibial stiffness and failure load was higher than in non-athletes. However, this advantage was lost in AA. At the non-weight-bearing radius, failure load and stiffness were lower in AA than non-athletes. After controlling for lean mass and menarchal age, athletic status accounted for 5-9% of the variability in stiffness and failure load, menarchal age for 8-23%, and lean mass for 12-37%. CONCLUSION AA have lower FEA-estimated bone strength at the distal radius than non-athletes, and lose the advantage of weight-bearing exercise seen in EA at the distal tibia.

We studied 108 cases of sudden coronary death at autopsy. Any calcification was present in 55% of men and women under 40 years; all hearts showed some calcification by age 50 in men, and by age 60 in women. The only risk factor independently associated with increased calcification was diabetes mellitus, in women only. The degree of calcification was greatest for acute and healed plaque ruptures, and the least for plaque erosion. Calcification in coronary atherosclerosis appears to be delayed in women, is greatest in women diabetics, and is associated with one type of plaque instability, namely plaque rupture.

African-American women have a lower risk of fracture than Caucasian women, and this difference is only partially explained by differences in DXA areal bone mineral density (aBMD). Little is known about racial differences in skeletal microarchitecture and the consequences for bone strength. To evaluate potential factors underlying this racial difference in fracture rates, we used high-resolution peripheral quantitative computed tomography (HR-pQCT) to assess cortical and trabecular bone microarchitecture and estimate bone strength using micro-finite element analysis in African-American (n=100) and Caucasian (n=173) women participating in the Study of Women's Health Across the Nation (SWAN). African-American women had larger and denser bones than Caucasians, with greater total area, aBMD, and total volumetric BMD (vBMD) at the radius and tibia metaphysis (p<0.05 for all). African-Americans had greater trabecular vBMD at the radius, but higher cortical vBMD at the tibia. Cortical microarchitecture tended to show the most pronounced racial differences, with higher cortical area, thickness, and volumes in African-Americans at both skeletal sites (p<0.05 for all), and lower cortical porosity in African-Americans at the tibia (p<0.05). African-American women also had greater estimated bone stiffness and failure load at both the radius and tibia. Differences in skeletal microarchitecture and estimated stiffness and failure load persisted even after adjustment for DXA aBMD. The densitometric and microarchitectural predictors of failure load at the radius and tibia were the same in African-American and Caucasian women. In conclusion, differences in bone microarchitecture and density contribute to greater estimated bone strength in African-Americans and probably explain, at least in part, the lower fracture risk of African-American women.