Qingzhao Yu

Prof. Qingzhao Yu

orcid

Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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29 March 2019 in BMC Women's Health
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Journal Article
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JYJunko Yano
Junko Yano
JSJack Sobel
Jack Sobel
PNPaul Nyirjesy
Paul Nyirjesy
RSRyan Sobel
Ryan Sobel
VWValerie L. Williams
Valerie L. Williams
PJPaul L. Fidel, Jr.
Paul L. Fidel, Jr.
Vulvovaginal candidiasis (VVC) is a common infection affecting women worldwide. Reports of patterns/risk factors/trends for episodic/recurrent VVC (RVVC) are largely outdated. The purpose of this study was to obtain current patient perspectives of several aspects of VVC/RVVC. Business cards containing on-line survey information were distributed to healthy volunteers and patients seeking standard, elective, or referral gynecologic care in university-affiliated Obstetrics/Gynecology clinics. The internet-based questionnaire was completed by 284 non-pregnant women (78% Caucasian, 14% African American, 8% Asian). The majority of the participants (78%) indicated a history of VVC with 34% defined as having RVVC. The most common signs/symptoms experienced were itching, burning and redness with similar ranking of symptoms among VVC and RVVC patients. Among risk factors, antibiotic use ranked highest followed by intercourse, humid weather and use of feminine hygiene products. A high number of respondents noted ‘no known cause’ (idiopathic episodes) that was surprisingly similar among women with a history of either VVC or RVVC. VVC/RVVC episodes reported were primarily physician-diagnosed (73%) with the remainder mostly reporting self-diagnosis and treating with over-the-counter (OTC) medications. Most physician-diagnosed attacks utilized a combination of pelvic examination and laboratory tests followed by prescribed antifungals. Physician-treated cases achieved a higher level of symptom relief (84%) compared to those who self-medicated (57%). The majority of women with RVVC (71%) required continual or long-term antifungal medication as maintenance therapy to control symptoms. Current patient perspectives closely reflect historically documented estimates of VVC/RVVC prevalence and trends regarding symptomatology, disease management and post-treatment outcomes.

9 January 2017 in Journal of Open Research Software
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Journal Article
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QYQingzhao Yu
Qingzhao Yu
BLBin Li
Bin Li
Mediation refers to the effect transmitted by mediators that intervene in the relationship between an exposure and a response variable. Mediation analysis has been broadly studied in many fields. However, it remains a challenge for researchers to consider complicated associations among variables and to differentiate individual effects from multiple mediators. [1] proposed general definitions of mediation effects that were adaptable to all different types of response (categorical or continuous), exposure, or mediation variables. With these definitions, multiple mediators of different types can be considered simultaneously, and the indirect effects carried by individual mediators can be separated from the total effect. Moreover, the derived mediation analysis can be performed with general predictive models. That is, the relationships among variables can be modeled using not only generalized linear models but also nonparametric models such as the Multiple Additive Regression Trees. Therefore, more complicated variable transformations and interactions can be considered in analyzing the mediation effects. The proposed method is realized by the R package 'mma'. We illustrate in this paper the proposed method and how to use 'mma' to estimate mediation effects and make inferences

25 September 2018 in Statistics in Medicine
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Journal Article
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QYQingzhao Yu
Qingzhao Yu
XWXiaocheng Wu
Xiaocheng Wu
BLBin Li
Bin Li
RSRichard A. Scribner
Richard A. Scribner

1 May 2008 in Geospatial Health
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Journal Article
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QYQingzhao Yu
Qingzhao Yu
RSRichard Scribner
Richard Scribner
BCBrad Carlin
Brad Carlin
KTKatherine Theall
Katherine Theall
NSNeal Simonsen
Neal Simonsen
KMKaren Mason
Karen Mason
Many previous studies have suggested a link between alcohol outlets and assaultive violence. In this paper, we evaluate the impact of the “1992 Civil Unrest” in Los Angeles (which followed the “Rodney King incident”), in which many alcohol outlets were damaged leading to a decrease in alcohol outlet density, on crime. We leverage the natural experiment created by the closure of alcohol outlets in certain areas and not others to explore the effects of alcohol availability on assault crimes at the census tract level. We develop a hierarchical model that controls for important covariates (such as race and socio-economic status) and accounts for unexplained spatial and temporal variability. While our model is somewhat complex, its hierarchical Bayesian analysis is accessible via the WinBUGS software. Our results show that, keeping other effects fixed, the reduction in alcohol availability within a census tract was associated with a drop in the assaultive violence rate at the census tract level. Comparing several dual candidate changepoint models using the Deviance Information Criterion, the drop in assaultive violence rate is best seen as having occurred one year after the reduction in alcohol availability, with the effect lasting roughly five years. We also create maps of the fitted assault rates in Los Angeles, as well as spatial residual maps that suggest various spatially-varying covariates are still missing from our model.

1 June 2017 in Spatial and Spatio-temporal Epidemiology
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Journal Article
Closed access
QYQingzhao Yu
Qingzhao Yu
RSRichard A. Scribner
Richard A. Scribner
CLClaudia Leonardi
Claudia Leonardi
LZLu Zhang
Lu Zhang
CPChi Park
Chi Park
NSNeal R. Simonsen
Neal R. Simonsen

1 December 2018 in Journal of Dentistry
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Journal Article
Closed access
MPMathilde C. Peters
Mathilde C. Peters
AHAubrey R. Hopkins
Aubrey R. Hopkins
QYQingzhao Yu
Qingzhao Yu