971 research outputs found
Association between diabetes, diabetes treatment and risk of developing endometrial cancer.
BackgroundA growing body of evidence suggests that diabetes is a risk factor for endometrial cancer incidence. However, most of these studies used case-control study designs and did not adjust for obesity, an established risk factor for endometrial cancer. In addition, few epidemiological studies have examined the association between diabetes treatment and endometrial cancer risk. The objective of this study was to assess the relationships among diabetes, diabetes treatment and endometrial cancer risk in postmenopausal women participating in the Women's Health Initiative (WHI).MethodsA total of 88 107 postmenopausal women aged 50-79 years who were free of cancer and had no hysterectomy at baseline were followed until date of endometrial cancer diagnosis, death, hysterectomy or loss to follow-up, whichever came first. Endometrial cancers were confirmed by central medical record and pathology report review. Multivariate Cox proportional hazards regression models were used to estimate hazard ratios (HRs) (95% confidence interval (CI)) for diagnosis of diabetes and metformin treatment as risk factors for endometrial cancer.ResultsOver a mean of 11 years of follow-up, 1241 endometrial cancers developed. In the primary analysis that focused on prevalent diabetes at enrolment, compared with women without diabetes, women with self-reported diabetes, and the subset of women with treated diabetes, had significantly higher risk of endometrial cancer without adjusting for BMI (HR=1.44, 95% CI: 1.13-1.85 for diabetes, HR=1.57, 95% CI: 1.19-2.07 for treated diabetes). However after adjusting for BMI, the associations between diabetes, diabetes treatment, diabetes duration and the risk of endometrial cancer became non-significant. Elevated risk was noted when considering combining diabetes diagnosed at baseline and during follow-up as time-dependent exposure (HR=1.31, 95% CI: 1.08-1.59) even after adjusting for BMI. No significant association was observed between metformin use and endometrial cancer risk.ConclusionsOur results suggest that the relationship observed in previous research between diabetes and endometrial cancer incidence may be largely confounded by body weight, although some modest independent elevated risk remains
Hard X-ray emission from Eta Carinae
Context : If relativistic particle acceleration takes place in colliding-wind
binaries, hard X-rays and gamma-rays are expected through inverse Compton
emission, but to date these have never been unambiguously detected.
Aims : To detect this emission, observations of Eta Carinae were performed
with INTEGRAL, leveraging its high spatial resolution.
Methods : Deep hard X-ray images of the region of Eta Car were constructed in
several energy bands.
Results : The hard X-ray emission previously detected by BeppoSax around Eta
Car originates from at least 3 different point sources. The emission of Eta Car
itself can be isolated for the first time, and its spectrum unambiguously
analyzed. The X-ray emission of Eta Car in the 22-100 keV energy range is very
hard (photon index around 1) and its luminosity is 7E33 erg/s.
Conclusions : The observed emission is in agreement with the predictions of
inverse Compton models, and corresponds to about 0.1% of the energy available
in the wind collision. Eta Car is expected to be detected in the GeV energy
range.Comment: 5 pages with 2 figures. Accepted as a Letter in Astronomy &
Astrophysic
A phase-resolved XMM-Newton Campaign on the Colliding Wind Binary HD 152248
We report the first results of an XMM-Newton monitoring campaign of the NGC
6231 open cluster in the Sco OB1 association. This first paper focuses on the
massive colliding wind binary HD 152248, which is the brightest X-ray source of
the cluster. The campaign, with a total duration of 180 ksec, was split into
six separate observations, following the orbital motion of HD 152248. The X-ray
flux from this system presents a clear, asymmetric modulation with the phase
and ranges from 0.73 to 1.18 10-12 erg s-1 cm-2 in the [0.5-10.0 keV] energy
band. The maximum of the emission is reached slightly after apastron. The EPIC
spectra are quite soft and peak around 0.8-0.9 keV. We characterize their shape
using several combinations of mekal models and power-law spectra and we detect
significant spectral variability in the [0.5-2.5 keV] energy band. We also
perform 2-D hydrodynamical simulations using different sets of parameters that
closely reproduce the physical and orbital configuration of the HD 152248
system at the time of the six XMM-Newton pointings. This allows a direct
confrontation of the model predictions with the constraints deduced from the
X-ray observations of the system. We show that the observed variation of the
flux can be explained by a variation of the X-ray emission from the colliding
wind zone, diluted by the softer X-ray contribution of the two O-type stars of
the system. Our simulations also reveal that the interaction region of HD
152248 should be highly unstable, giving rise to shells of dense gas that are
separated by low density regions. Finally, we perform a search for short-term
variability in the light curves of the system and we show that trends are
present within several of the 30 ksec exposures of our campaign. Further, most
of these trends are in good .Comment: Accepted by MNRAS; 22 pages; without figures; complete PS version
(including figures) on http://vela.astro.ulg.ac.be/Preprints/index.htm
Hormone replacement therapy after surgery for stage 1 or 2 cutaneous melanoma
A total of 206 women were followed for a minimum of 5 years after primary melanoma surgery to establish if hormone replacement therapy (HRT) adversely affected prognosis. In all, 123 had no HRT and 22 have died of melanoma; 83 had HRT for varying periods and one has died of melanoma. After controlling for known prognostic factors, we conclude that HRT after melanoma does not adversely affect prognosis
The origin of the runaway high-mass X-ray binary HD153919/4U1700-37
Based on its Hipparcos proper motion, we propose that the high-mass X-ray
binary HD153919/4U1700-37 originates in the OB association Sco OB1. At a
distance of 1.9 kpc the space velocity of 4U1700-37 with respect to Sco OB1 is
75 km/s. This runaway velocity indicates that the progenitor of the compact
X-ray source lost about 7 Msun during the (assumed symmetric) supernova
explosion. The system's kinematical age is about 2 +/- 0.5 million years which
marks the date of the supernova explosion forming the compact object. The
present age of Sco OB1 is <8 Myr; its suggested core, NGC 6231, seems to be
somewhat younger (~5 Myr). If HD153919/4U1700-37 was born as a member of Sco
OB1, this implies that the initially most massive star in the system terminated
its evolution within 30
Msun. With these parameters the evolution of the binary system can be
constrained.Comment: 6 pages, latex, 3 embedded ps figures, to appear in A&
Hard X-ray identification of Eta Carinae and steadiness close to periastron
Context: The colliding-wind binary Eta Car exhibits soft X-ray thermal
emission that varies strongly around periastron, and non-thermal emission seen
in hard X-rays and gamma-rays.
Aims: To definitively identify Eta Car as the source of the hard X-ray
emission, to examine how changes in the 2-10 keV band influence changes in the
hard X-ray band, and to understand more clearly the mechanisms producing the
non-thermal emission using new INTEGRAL observations obtained close to
periastron.
Methods: A Chandra observation encompassing the ISGRI error circle was
analysed, and all other soft X-ray sources (including the outer shell of Eta
Car itself) were discarded as likely counter-parts. New hard X-ray images of
Eta Car were studied close to periastron, and compared to previous observations
far from periastron.
Results: The INTEGRAL component, when represented by a power law (with a
photon index of 1.8), would produce more emission in the Chandra band than
observed from any point source in the ISGRI error circle apart from Eta Car, as
long as the hydrogen column density to the ISGRI source is lower than 1E24
cm^{-2}. Such sources are rare, thus the ISGRI emission is very likely to be
associated with Eta Car. The eventual contribution of the outer shell to the
non-thermal component also remains fairly limited. Close to periastron, a
3-sigma detection is achieved for the hard X-ray emission of Eta Car, with a
flux similar to the average value far from periastron.
Conclusions: Assuming a single absorption component for both the thermal and
non-thermal sources, this detection can be explained with a hydrogen column
density that does not exceed 6E23 cm^{-2} without resorting to an intrinsic
increase in the hard X-ray emission. The energy injected in hard X-rays
(averaged over a month) appears rather constant as close as a few stellar
radii, well within the acceleration region of the wind.Comment: 9 pages with 5 figures. Accepted for publication in Astronomy &
Astrophysic
Insulin Resistance and Cancer-Specific and All-Cause Mortality in Postmenopausal Women: The Women\u27s Health Initiative
© The Author(s) 2019. Published by Oxford University Press. All rights reserved. For permissions, please email: [email protected]. BACKGROUND: Insulin resistance has been proposed as a mediator of the increased cancer incidence and mortality associated with obesity. However, prior studies included limited cancer deaths and had inconsistent findings. Therefore, we evaluated insulin resistance and cancer-specific and all-cause mortality in postmenopausal women participating in the Women\u27s Health Initiative (WHI). METHODS: Eligible were a subsample of 22 837 WHI participants aged 50-79 years enrolled at 40 US clinical centers from 1993 to 1998 who had baseline fasting glucose and insulin levels. Baseline insulin resistance was measured by the homeostasis model assessment of insulin resistance (HOMA-IR). Cancers were verified by central medical record review and deaths verified by medical record and death certificate review enhanced by National Death Index queries. Cox proportional hazards regression models were used to calculate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for cancer-specific and all-cause mortality. All statistical tests were two-sided. RESULTS: During a median of 18.9 years of follow-up, 1820 cancer deaths and 7415 total deaths occurred. Higher HOMA-IR quartile was associated with higher cancer-specific mortality (Q4 vs Q1, HR = 1.26, 95% CI = 1.09 to 1.47; Ptrend = .003) and all-cause mortality (Q4 vs Q1, HR = 1.63, 95% CI = 1.51 to 1.76; Ptrend \u3c .001). A sensitivity analysis for diabetes status did not change findings. Among women with body mass index less than 25 kg/m2, higher HOMA-IR quartile was associated with higher cancer mortality (Fine and Gray, P = .004). CONCLUSIONS: High insulin resistance, as measured by HOMA-IR, identifies postmenopausal women at higher risk for cancer-specific and all-cause mortality who could potentially benefit from early intervention
Quasi-simultaneous XMM-Newton and VLA observation of the non-thermal radio emitter HD\168112 (O5.5III(f^+))
We report the results of a multiwavelength study of the non-thermal radio
emitter HD168112 (O5.5III(f^+)). The detailed analysis of two
quasi-simultaneous XMM-Newton and VLA observations reveals strong variability
of this star both in the X-ray and radio ranges. The X-ray observations
separated by five months reveal a decrease of the X-ray flux of ~30%. The radio
emission on the other hand increases by a factor 5-7 between the two
observations obtained roughly simultaneously with the XMM-Newton pointings. The
X-ray data reveal a hard emission that is most likely produced by a thermal
plasma at kT ~2-3 keV while the VLA data confirm the non-thermal status of this
star in the radio waveband. Comparison with archive X-ray and radio data
confirms the variability of this source in both wavelength ranges over a yet
ill defined time scale. The properties of HD168112 in the X-ray and radio
domain point towards a binary system with a significant eccentricity and an
orbital period of a few years. However, our optical spectra reveal no
significant changes of the star's radial velocity suggesting that if HD168112
is indeed a binary, it must be seen under a fairly low inclination.Comment: 17 pages, 11 figures (10 postscript + 1 gif
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