Zhen Chen

In many diagnostic accuracy studies, a priori orders may be available on multiple receiver operating characteristic curves. For example, being closer to delivery, fetal ultrasound measures in the third trimester should be no less accurate t…

Endometriosis is a commonly encountered gynecological disease in women, which seriously affects the life quality of patients. In Chinese traditional medicine, Four Agents Decoction is utilized in the clinical treatment of endometriosis for …

Endometriosis is a hormone-responsive gynecologic disease, signifying its connotations across a woman's life span. Previous studies suggested that endocrine disrupting chemicals were risk factors for endometriosis. Nevertheless, little is k…

In application of diagnostic accuracy, it is possible that a priori information may exist regarding the test score distributions, either between different disease populations for a single test or between multiple correlated tests. Few have …

In analysis of diagnostic data with multiple tests, it is often the case that these tests are correlated. Modeling the correlation explicitly not only produces valid inference results but also enables borrowing of information. Motivated by …

Background: Body mass index (BMI) and endometriosis have been inversely associated. To address gaps in this research, we examined associations among body composition, endometriosis, and physical activity. Materials and Methods: Women from 1…

Published findings from the Longitudinal Investigation of Fertility and the Environment (LIFE) Study regarding the relation between environmental chemicals and couple fecundity, as measured by time-to-pregnancy (TTP), are reviewed with a pa…

STUDY QUESTION: Is sexual and/or physical abuse history associated with incident endometriosis diagnosis or other gynecologic disorders among premenopausal women undergoing diagnostic and/or therapeutic laparoscopy or laparotomy regardless …

BACKGROUND: Endometriosis is a gynecologic disease reported to be associated with infertility and, possibly, adverse pregnancy outcomes. While considerable research focuses on pregnancy outcomes following diagnosis and/or treatment, few dat…

constraints may exist, either between the healthy and diseased populations within a test or between tests within a population. In this paper, we proposed an integrated modeling approach for ROC curves that jointly accounts for stochastic an…

Bisphenol A, benzophenone-type UV filters, and phthalates are chemicals in high production and use including in a range of personal care products. Exposure of humans to these chemicals has been shown to affect endocrine function. Although s…

OBJECTIVE: To determine agreement on endometriosis diagnosis between real-time laparoscopy and subsequent expert review of digital images, operative reports, magnetic resonance imaging (MRI), and histopathology, viewed sequentially. DESIGN:…

STUDY QUESTION: What are the pain characteristics among women, with no prior endometriosis diagnosis, undergoing laparoscopy or laparotomy regardless of clinical indication? SUMMARY ANSWER: Women with surgically visualized endometriosis rep…

ObjectiveTo assess benzophenone-type ultraviolet (UV) filter concentrations, chemicals used in sunscreen and personal care products, and semen endpoints.DesignCohort.SettingNot applicable.Patient(s)A total of 413 men provided semen and urin…

Multiple trace elements have estrogen receptor activity, but the association of these elements with uterine leiomyoma has not been defined. A cohort of 473 women aged 18-44 undergoing surgery for benign gynecologic indications provided whol…

To evaluate the association between persistent organic pollutants (POPs) and uterine fibroids, we used previously collected data from a cohort of women aged 18-44 years undergoing laparoscopy or laparotomy at 14 participating hospital surgi…

In diagnostic studies without a gold standard, the assumption on the dependence structure of the multiple tests or raters plays an important role in model performance. In case of binary disease status, both conditional independence and cros…

ObjectiveTo explore the relation between bisphenol A and 14 phthalate metabolites and endometriosis.DesignMatched cohort design.SettingFourteen clinical centers.Patient(s)The operative cohort comprised 495 women undergoing laparoscopy/lapar…

ObjectiveWe sought to identify risk factors for endometriosis and their consistency across study populations in the Endometriosis: Natural History, Diagnosis, and Outcomes (ENDO) Study.Study designIn this prospective matched, exposure cohor…

Inter-rater reliability is usually assessed by means of the intraclass correlation coefficient. Using two-way analysis of variance to model raters and subjects as random effects, we derive group sequential testing procedures for the design …

Analysis of human urine is commonly used in biomonitoring studies to assess exposure to essential (e.g., Cu, Zn, Se) and non-essential (Pb, Cd, Pt) trace elements. These data are also used in epidemiological studies to evaluate potential as…

There has been limited study of trace elements and endometriosis. Using a matched cohort design, 473 women aged 18-44 years were recruited into an operative cohort, along with 131 similarly aged women recruited into a population cohort. End…

BackgroundObesity is a growing public health problem among reproductive-aged women, with consequences for chronic disease risk and reproductive and obstetric morbidities. Evidence also suggests that body shape (i.e., regional fat distributi…

In diagnostic medicine, estimating the diagnostic accuracy of a group of raters or medical tests relative to the gold standard is often the primary goal. When a gold standard is absent, latent class models where the unknown gold standard te…