1,720,982 research outputs found
Loglinear spatial factor analysis: an application to diabetes mellitus complications
No full textThe investigation of spatial variation in disease rates is a
standard epidemiological practice used to describe the geographic
clustering of diseases which is helpful for making hypotheses
about the possible `factors' responsible for differences in risk.
Up to the most recent statistical and computational developments,
studies have almost entirely focused on the spatial modeling of
univariate distributions of cases, that is, on the spatial modeling
of single diseases.
However, many diseases show similar patterns of geographical
variation which may suggest the existence of common underlying
risk factors, might these be related to the environment, to particular
local food habits, or to the clustering of a particular population
(genetic origin).
In this work, for multivariate categorical data pointwise
geo-referenced in a `geostatistical' fashion, we propose a model
for the study of the joint spatial variation of more diseases.
Our approach is based on a hierarchical (generalized linear
mixed) multivariate model where the underlying latent structure is
given by a Gaussian geostatistical spatial factor model.
The methodology proposed can be seen as an extension of the
geostatistical linear model of coregionalization, and of the related
`factorial kriging analysis', to the case of geo-referenced, in
general multi-way, contingency tables.
An application of the proposed methodology is shown on an
epidemiological data set coming from an extensive survey on diabetes
mellitus patients which involved the majority of the family
practitioners of the region of Umbria in central Italy in 1990.
Attention is centered on the study of nephropathy and retinopathy,
two of the chronic diabetic complications affecting life quality
and expectancy
Hemodynamics of Neovascular Central Serous Chorioretinopathy: a Stress/Rest Optical Coherence Tomography-Angiography Study
No full textEvaluation of warm compresses and topical cyclosporine treatment in meibomian gland dysfunction by confocal scanning laser microscopy
No full textPurpose: The aim of our study is to confirm the utility of warm compresses (WC) and artificial tears (AT) in meibomian gland dysfunction (MGD) management and to understand if its association with topical cyclosporine A (CsA) improves outcomes. Methods: Patients with diagnosis of MGD-related dry eye were evaluated. In this prospective, randomized, double-masked study, patients were randomized in two treatments: AT plus WC (group A), and AT plus WC plus CsA 0.05% ophthalmic emulsion (group B). At baseline and at 1, 3, and 6 months, Ocular Surface Disease Index (OSDI) questionnaire was completed, and tear evaluation (BUT, Schirmer and osmolarity test), ocular surface evaluation (fluorescein and lissamine green staining), clinical (Shimazaki grading) and in vivo confocal microscopy (IVCM) evaluation of rete ridges (RRs) were performed. Results: A total of 40 eyes, 20 in each group, completed the study. Analysis of OSDI, tear test, ocular surface evaluation and clinical grading of MG showed significant improvement at 6 months, whereas no difference was found between the two groups at 6 months. The analysis of IVCM showed significant improvement in both groups, but significantly better results in group B were found compared to group A at 6 months. Conclusion: WC performed 3 times daily during the 1st month and once daily afterwards, in addition to AT, were useful to manage the obstruction of MG and related signs and symptoms. Additional effects of CsA were visible in IVCM only at 6 months. IVCM is an effective tool to monitor treatments in MGD
Repeatability and Reproducibility of Retinal Thickness Measurements in Diabetic Patients with Spectral Domain Optical Coherence Tomography
No full textRepeatability of Retinal Macular Thickness Measurements in Healthy Subjects and Diabetic Patients with Clinically Significant Macular Edema: Evaluation of the Follow-Up System of Spectralis Optical Coherence Tomography
No full textErratum: Repeatability and reproducibility of retinal thickness measurements in diabetic patients with spectral domain optical coherence tomography
No full textVigorous Physical Activity as a Risk Factor for Central Serous Chorioretinopathy
No full textPURPOSE: To evaluate whether frequent vigorous physical activity (PA) is significantly associated with active central serous chorioretinopathy (CSCR) and may represent a risk factor for CSCR. DESIGN: Case-control study. METHODS: This was a multicenter study. The patient population comprised consecutive patients with active CSCR and a comparable control group of healthy participants. Both groups were interrogated about their PA using a shortened version of the International Physical Activity Questionnaire. The Ainsworth Compendium of Physical Activities was taken as a reference for the activities requiring vigorous effort and to quantify the energy expended, expressed in metabolic equivalent of task (MET). As a main outcome measure, a moderate/high practice of vigorous PA was opposed to an absent/low practice of vigorous PA in the 2 groups. RESULTS: A total of 105 patients with CSCR and 105 healthy controls were included in the study. Moderate/high vigorous PA was observed in 63.5% of the patients with CSCR and in 26% of the controls (P = .0001). The MET values of vigorous PA were 2173.2 ± 2081.5 in the CSCR group and 1216.3 ± 524 in the control group (P = .029). The potential risk of disease associated with moderate/high vigorous PA was 5.58 (odds ratio; 95% confidence interval 3.01-10.69, P = .0001). CONCLUSIONS: This study demonstrates a significant association of vigorous PA with CSCR, indicating an increased probability of disease by 5.58 times. Frequent and intense PA, with the hypertensive episodes that it entails, can break the precarious hemodynamic balance in the choroid of individuals predisposed to CSCR, thereby favoring choroidal vascular decompensation and active disease
Automated Quantitative Analysis of Retinal Microvasculature in Normal Eyes on Optical Coherence Tomography Angiography
No full textRepeatability of Retinal Macular Thickness Measurements in Patients with Clinically Significant Macular Edema Using Two Different Scanning Protocols of Spectralis Optical Coherence Tomography
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