Vitamin D supplementation and breast cancer prevention : a systematic review and meta-analysis of randomized clinical trials

In recent years, the scientific evidence linking vitamin D status or supplementation to breast cancer has grown notably. To investigate the role of vitamin D supplementation on breast cancer incidence, we conducted a systematic review and meta-analysis of randomized controlled trials comparing vitamin D with placebo or no treatment. We used OVID to search MEDLINE (R), EMBASE and CENTRAL until April 2012. We screened the reference lists of included studies and used the “Related Article” feature in PubMed to identify additional articles. No language restrictions were applied. Two reviewers independently extracted data on methodological quality, participants, intervention, comparison and outcomes. Risk Ratios and 95% Confident Intervals for breast cancer were pooled using a random-effects model. Heterogeneity was assessed using the I2 test. In sensitivity analysis, we assessed the impact of vitamin D dosage and mode of administration on treatment effects. Only two randomized controlled trials fulfilled the pre-set inclusion criteria. The pooled analysis included 5372 postmenopausal women. Overall, Risk Ratios and 95% Confident Intervals were 1.11 and 0.74–1.68. We found no evidence of heterogeneity. Neither vitamin D dosage nor mode of administration significantly affected breast cancer risk. However, treatment efficacy was somewhat greater when vitamin D was administered at the highest dosage and in combination with calcium (Risk Ratio 0.58, 95% Confident Interval 0.23–1.47 and Risk Ratio 0.93, 95% Confident Interval 0.54–1.60, respectively). In conclusions, vitamin D use seems not to be associated with a reduced risk of breast cancer development in postmenopausal women. However, the available evidence is still limited and inadequate to draw firm conclusions. Study protocol code: FARM8L2B5L

Pinch modes in the SPEED2 plasma focus

Deuterium discharges in the SPEED2 plasma focus (80 kJ, 200 kV, 2 MA, 400 ns) have been found unexpectedly stable within the operational regime as a neutron source. Only at higher filling pressures (above 6 mbar) sometimes m=0 instabilities appeared in the pinch column, especially in discharges of lower efficiency (moderate dynamics and neutron yield). Enhancing the electromagnetic radiation by doping these discharges with heavy gases (e.g. neon, argon) distinctly two pinch modes are produced, the micropinch mode (MPM) or the stable column mode (SCM), with a transition regime where the initial SCM is followed by the MPM. Micropinches are local radiative collapses initiated by m=0 instabilities of low-energy- density pinch plasmas. These instabilities and the successive micropinches can be suppressed by kinetic deuterons produced during dynamical compression of high-energy-density deuterium plasma sheaths. Depending on the relaxation of this fast deuteron component the pinch column can be stabilized for several tens of nanoseconds. While the short-lived (appr. 1 ns) micropinches erratically appear as point-like successive flashes along the pinch axis with temperatures about 1 keV and about solid density the reproducible SCM, optimized with respect to the compression ratio, forms a powerful linear radiation source of temperatures and densities similar to the MPM. The SCM needs powerful (fast) drivers in order to use the kinetic ion stabilization, but not necessarily MA currents as available from the SPEED2 driver. This opens the possibility to establish the SCM also in compact experiments like SPEED3 (8 kJ, 80 kV, 0.8 MA, 300 ns) or even SPEED4 (2 kJ, 40 kV, 250 kA, 300 ns)

Mild to moderate cognitive impairment is a major risk factor for mortality and nursing home admission in the first year after hip fracture

BACKGROUND: It is not well established if and to what extent mild to moderate cognitive impairment predicts mortality and risk of nursing home admission after hip fracture. OBJECTIVE: To investigate prospectively whether and to what extent mild to moderate cognitive impairment, contributes to mortality and admission to nursing home in the first year after acute hip fracture. METHODS: We enrolled 173 patients with acute hip fracture age 65 and older who reached a Mini-Mental State Examination (MMSE) score of at least 15 during acute care after hip fracture repair. An MMSE score of 15 to 24 (median) was classified as mild to moderate cognitive impairment. Primary outcomes were mortality in all and admission to nursing home among seniors who lived at home prior to their hip fracture. Follow-up was 12 months with clinical visits at baseline, 6, and 12 months, plus monthly phone calls. We used Cox proportional hazards models controlling for age, sex, body mass index, baseline number of comorbidities and 25-hydroxyvitamin D status, and severe incident infections to assess the risk of mortality and nursing home admission. Because the study population was enrolled in a factorial design clinical trial testing high dose vitamin D and/or an exercise home program, all analyses also controlled for these treatment strategies. RESULTS: Of 173 acute hip fracture patients enrolled, 79% were women, 77% were admitted from home, and 80% were vitamin D deficient (<20ng/ml). Mean age was 84 years. 54% had mild to moderate cognitive impairment. Over the 12-month follow-up, 20 patients died (27% of 173) and 47 (35% of 134) were newly admitted to a nursing home. Mild to moderate cognitive impairment was associated with a more than 5-fold increased risk of mortality (HR=5.77; 95% CI: 1.55-21.55) and a more than 7-fold increased risk of nursing home admission (HR=7.37; 95% CI: 1.75-30.95). Additional independent risk factors of mortality were male gender (HR=3.55; 95% CI: 1.26-9.97), low BMI (HR=7.25; 95% CI: 1.61-33.74), and baseline 25-hydroxyvitamin D level (per 1ng/ml: HR=0.93; 95% CI: 0.87-0.998; p=0.04). CONCLUSIONS: Mild to moderate cognitive impairment in patients with acute hip fracture is associated with a high risk of mortality and nursing home admission during the first year after hip fracture. Female gender, a greater BMI and a higher 25-hydroxyvitamin D status may protect against mortality after hip fracture independent of cognitive function