Biostatistics Commons^™

Extended Followup Of A Cohort Of Chromium Production Workers, Herman Jones Gibb, Peter St. John Lees, Jing Wang, Keri O'Leary

Epidemiology Faculty Publications

Background

The current study evaluates the mortality of 2,354 workers first employed at a Baltimore chromate production plant between 1950 and 1974.

Methods

The National Death Index (NDI Plus) was used to determine vital status and cause of death. Cumulative chromium (VI) exposure and nasal and skin irritation were evaluated as risk factors for lung cancer mortality.

Results

There are 91,186 person-years of observation and 217 lung cancer deaths. Cumulative chromium (VI) exposure, nasal irritation, nasal perforation, nasal ulceration, and other forms of irritation (e.g., skin irritation) were associated with lung cancer mortality.

Conclusion

Cumulative chromium (VI) exposure was a …

Sexual Networks And Hiv Risk Among Black Men Who Have Sex With Men In 6 U.S. Cities, Hong-Van Tieu, Ting-Yuan Liu, Sophia Hussen, Matthew Connor, Lei Wang, Gregory Phillips Ii, + 11 More

Epidemiology Faculty Publications

Background

Sexual networks may place U.S. Black men who have sex with men (MSM) at increased HIV risk.

Methods

Self-reported egocentric sexual network data from the prior six months were collected from 1,349 community-recruited Black MSM in HPTN 061, a multi-component HIV prevention intervention feasibility study. Sexual network composition, size, and density (extent to which members are having sex with one another) were compared by self-reported HIV serostatus and age of the men. GEE models assessed network and other factors associated with having a Black sex partner, having a partner with at least two age category difference (age difference between …

Germline Mutation Detection In Next Generation Sequencing Data And Tp53 Mutation Carrier Probability Estimation For Li-Fraumeni Syndrome, Gang Peng

Dissertations and Theses (Open Access)

Next generation sequencing technology has been widely used in genomic analysis, but its application has been compromised by the missing true variants, especially when these variants are rare. We proposed a family-based variant calling method, FamSeq, integrating Mendelian transmission information with de novo mutation and sequencing data to improve the variant calling accuracy. We investigated the factors impacting the improvement of family-based variant calling in simulation data and validated it in real sequencing data. In both simulation and real data, FamSeq works better than the single individual based method.

In FamSeq, we implemented four different methods for the Mendelian genetic …

Computerizing Efficient Estimation Of A Pathwise Differentiable Target Parameter, Mark J. Van Der Laan, Marco Carone, Alexander R. Luedtke

U.C. Berkeley Division of Biostatistics Working Paper Series

Frangakis et al. (2015) proposed a numerical method for computing the efficient influence function of a parameter in a nonparametric model at a specified distribution and observation (provided such an influence function exists). Their approach is based on the assumption that the efficient influence function is given by the directional derivative of the target parameter mapping in the direction of a perturbation of the data distribution defined as the convex line from the data distribution to a pointmass at the observation. In our discussion paper Luedtke et al. (2015) we propose a regularization of this procedure and establish the validity …

Caffeine Consumption Contributes To Skin Intrinsic Fluorescence In Type 1 Diabetes., Karen M Eny, Trevor J Orchard, Rachel Grace Miller, John Maynard, Denis M Grant, Tina Costacou, Patricia A. Cleary, Barbara H Braffett, Andrew D Paterson, Dcct/Edic Research Group

GW Biostatistics Center

Background: A variant (rs1495741) in the gene for the N-acetyltransferase 2 (NAT2) protein is associated with skin intrinsic fluorescence (SIF), a noninvasive measure of advanced glycation end products and other fluorophores in the skin. Because NAT2 is involved in caffeine metabolism, we aimed to determine whether caffeine consumption is associated with SIF and whether rs1495741 is associated with SIF independently of caffeine.

Materials and Methods: SIF was measured in 1,181 participants with type 1 diabetes from the Epidemiology of Diabetes Interventions and Complications study. Two measures of SIF were used: SIF1, using a 375-nm excitation light-emitting diode (LED), and …

Drawing Valid Targeted Inference When Covariate-Adjusted Response-Adaptive Rct Meets Data-Adaptive Loss-Based Estimation, With An Application To The Lasso, Wenjing Zheng, Antoine Chambaz, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

Adaptive clinical trial design methods have garnered growing attention in the recent years, in large part due to their greater flexibility over their traditional counterparts. One such design is the so-called covariate-adjusted, response-adaptive (CARA) randomized controlled trial (RCT). In a CARA RCT, the treatment randomization schemes are allowed to depend on the patient’s pre-treatment covariates, and the investigators have the opportunity to adjust these schemes during the course of the trial based on accruing information (including previous responses), in order to meet a pre-specified optimality criterion, while preserving the validity of the trial in learning its primary study parameter.

In …

Negative Outcome Control For Unobserved Confounding Under A Cox Proportional Hazards Model, Eric J. Tchetgen Tchetgen, Tamar Sofer, David Richardson

Harvard University Biostatistics Working Paper Series

No abstract provided.

Survival Analysis With Functions Of Mis-Measured Covariate Histories: The Case Of Chronic Air Pollution Exposure In Relation To Mortality In The Nurses' Health Study, Xiaomei Liao, Molin Wang, Jaime E. Hart, Francine Laden, Donna Spiegelman

Harvard University Biostatistics Working Paper Series

Environmental epidemiologists are often interested in estimating the effect of functions of time-varying exposure histories, such as the 12-month moving average, in relation to chronic disease incidence or mortality. The individual exposure measurements that comprise such an exposure history are usually mis-measured, at least moderately, and, often, more substantially. To obtain unbiased estimates of Cox model hazard ratios for these complex mis-measured exposure functions, an extended risk set regression calibration (RRC) method for Cox models is developed and applied to a study of long-term exposure to the fine particulate matter ($PM_{2.5}$) component of air pollution in relation to all-cause mortality …

Nitrate And Nitrite Ingestion And Risk Of Ovarian Cancer Among Postmenopausal Women In Iowa, Maki Inoue-Choi, Rena R. Jones, Kristin E. Anderson, Kenneth P. Cantor, James R. Cerhan, Stuart Krasner, Kimberly Robien, Peter J. Weyer, Mary H. Ward

Epidemiology Faculty Publications

Nitrate and nitrite are precursors in the endogenous formation of N-nitroso compounds (NOC), potential human carcinogens. We evaluated the association of nitrate and nitrite ingestion with postmenopausal ovarian cancer risk in the Iowa Women's Health Study. Among 28,555 postmenopausal women, we identified 315 incident epithelial ovarian cancers from 1986 to 2010. Dietary nitrate and nitrite intakes were assessed at baseline using food frequency questionnaire data. Drinking water source at home was obtained in a 1989 follow-up survey. Nitrate-nitrogen (NO₃-N) and total trihalomethane (TTHM) levels for Iowa public water utilities were linked to residences and average levels were …

Size And Power Of Tests Of Hypotheses On Survival Parameters From The Lindley Distribution With Covariates, Macaulay Okwuokenye, Karl E. Peace

Biostatistics: Faculty Publications

The Lindley model is considered as an alternative model facilitating analyses of time-to-event data with covariates. Covariate information is incorporated using the Cox’s proportional hazard model with the Lindley model at the timedependent component. Simulation studies are performed to assess the size and power of tests of hypotheses on parameters arising from maximum likelihood estimators of parameters in the Lindley model. Results are contrasted with that arising from Cox’s partial maximum likelihood estimator. The Linley model is used to analyze a publicly available data set and contrasted with other models.

Joint Modeling Of Treatment Effect On Time-To-Event Endpoint And Safety Covariates In Control Clinical Trial Data Analysis, Kao-Tai Tsai, Karl E. Peace

Biostatistics: Faculty Publications

It is a common practice to perform a separate analysis of efficacy and safety data from clinical trials to estimate the benefit and risk aspects of a particular treatment regimen. However, by doing so, one is likely to miss the complete picture of the treatment effect given that these data are generated from the same study subjects and therefore most likely will be correlated. Therefore, it is desirable to analyze these data jointly to obtain a more complete profile of the treatment regimen. A substantial number of statistical methodologies have been proposed in the last decade to model the time-to-event …

Fast, Accurate, And Reliable Molecular Docking With Quickvina 2, Amr Alhossary, Stephanus Daniel Handoko, Yuguang Mu, Chee-Keong Kwoh

Research Collection School Of Computing and Information Systems

Motivation: The need for efficient molecular docking tools for high-throughput screening is growing alongside the rapid growth of drug-fragment databases. AutoDock Vina ('Vina') is a widely used docking tool with parallelization for speed. QuickVina ('QVina 1') then further enhanced the speed via a heuristics, requiring high exhaustiveness. With low exhaustiveness, its accuracy was compromised. We present in this article the latest version of QuickVina ('QVina 2') that inherits both the speed of QVina 1 and the reliability of the original Vina.Results: We tested the efficacy of QVina 2 on the core set of PDBbind 2014. With the default exhaustiveness level …

Doubly Robust Estimation Of A Marginal Average Effect Of Treatment On The Treated With An Instrumental Variable, Lan Liu, Wang Miao, Baoluo Sun, James M. Robins, Eric J. Tchetgen Tchetgen

Harvard University Biostatistics Working Paper Series

No abstract provided.

One-Step Targeted Minimum Loss-Based Estimation Based On Universal Least Favorable One-Dimensional Submodels, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

Consider a study in which one observes n independent and identically distributed random variables whose probability distribution is known to be an element of a particular statistical model, and one is concerned with estimation of a particular real valued pathwise differentiable target parameter of this data probability distribution. The canonical gradient of the pathwise derivative of the target parameter, also called the efficient influence curve, defines an asymptotically efficient estimator as an estimator that is asymptotically linear with influence curve equal to the efficient influence curve.The targeted maximum likelihood estimator is a two stage estimator obtained by constructing a so …

Identification And Doubly Robust Estimation Of Data Missing Not At Random With An Ancillary Variable, Wang Miao, Eric Tchetgen Tchetgen, Zhi Geng

Harvard University Biostatistics Working Paper Series

No abstract provided.

Prehipertensi Pada Obesitas Abdominal, Lia Churniawati, Santi Martini, Catharina Umbul Wahyuni

Kesmas

Prehipertensi banyak terjadi pada penderita obesitas abdominal. Prevalensi obesitas abdominal di Kabupaten Gresik sebesar 21,5%. Kepatuhan diet penderita prehipertensi dengan obesitas abdominal diperlukan untuk mengurangi risiko terjadinya hipertensi. Prehipertensi dan hipertensi berhubungan dengan pelbagai komplikasi pada hampir seluruh organ. Penelitian ini bertujuan untuk menganalisis determinan prehipertensi pada obesitas abdominal di Kabupaten Gresik. Penelitian ini dilaksanakan di Kabupaten Gresik pada November 2013 - November 2014 dengan rancangan penelitian potong lintang. Responden adalah pasien yang datang ke unit rawat jalan puskesmas yang diambil secara konsekutif sejumlah 74 orang. Responden berusia antara 25 - 64 tahun, mengalami obesitas abdominal, tidak hamil, tidak hipertensi, …

Cemaran Mikroba Escherichia Coli Dan Total Bakteri Koliform Pada Air Minum Isi Ulang, Rolan Sudirman Pakpahan, Intje Picauly, I Nyoman W. Mahayasa

Kesmas

Jumlah layanan air minum melalui depot air minum di Kota Kupang meningkat dengan rata-rata 1,44 setiap tahun sejak 2010, sementara tidakterdapat jaminan kualitas air minum isi ulang memenuhi syarat setiap saat. Hasil pemeriksaan sampel air minum isi ulang di Kota Kupang tahun 2013 menunjukkan 37,5% tercemar mikroba. Tujuan penelitian ini adalah menganalisis cemaran mikroba dan mengetahui determinan cemaran Escherichia coli (E. coli) dan total koliform pada air minum isi ulang. Penelitian ini menggunakan desain studi potong lintang periode Januari Maret 2015. Populasi penelitian berjumlah 51 depot air minum yang ditentukan menggunakan teknik total sampling. Analisis data dilakukan secara univariat, analisis …

Akses Jaminan Kesehatan Nasional Pada Pekerja Seks Perempuan, Ni Made Sri Nopiyani, Putu Ayu Indrayathi, Rina Listyowati, I Ketut Suarjana, Pande Putu Januraga

Kesmas

Pekerja seks perempuan (PSP) merupakan kelompok yang termarginalkan secara sosial dan memiliki kerentanan yang tinggi terhadap masalah kesehatan. Upaya perluasan Jaminan Kesehatan Nasional (JKN) pada PSP masih terbatas sehingga penting dilakukan untuk mendukung pencapaian universal health coverage. Penelitian ini bertujuan untuk memperoleh gambaran mengenai akses JKN pada PSP di Denpasar. Penelitian ini merupakan studi kualitatif. Data dikumpulkan melalui wawancara mendalam terhadap 15 orang PSP dan empat orang mucikari di Denpasar pada Agustus hingga Oktober 2014. Hasil wawancara diolah dengan analisis tematik. Kerangka analisis yang digunakan adalah The Health Access Livelihood Framework. Kepemilikan JKN pada PSP di Denpasar masih rendah, meskipun …

Pengaruh Teknik Marmet Terhadap Kelancaran Air Susu Ibu Dan Kenaikan Berat Badan Bayi, Anita Widiastuti, Siti Arifah, Wiwin Renny Rachmawati

Kesmas

Bayi lahir cukup bulan memiliki naluri menyusu 20 - 30 menit setelah dilahirkan. Namun, fakta menunjukkan produksi dan ejeksi air susu ibu (ASI) yang sedikit di hari-hari pertama menyebabkan banyak ibu yang mengalami ketidakefektifan proses menyusui. Tidak terproduksinya ASI diakibatkan karena kurangnya rangsangan hormon prolaktin. Teknik marmet merupakan perpaduan memerah dan memijat payudara pada ibu nifas yang dapat merangsang hormon pada proses menyusui. Penelitian ini bertujuan untuk mengetahui perbedaan pengaruh teknik marmet dengan masase payudara pada ibu nifas tiga hari postpartum terhadap kelancaran ASI dan kenaikan berat badan bayi. Penelitian ini menggunakan desain pre-experimental bentuk perbandingan kelompok statistik yang dilakukan …

Asma Pada Anak Indonesia: Penyebab Dan Pencetus, Ika Dharmayanti, Dwi Hapsari, Khadijah Azhar

Kesmas

Asma merupakan penyakit kronis yang dapat mengganggu kualitas hidup. Hingga saat ini, jumlah penderita asma semakin meningkat termasuk di Indonesia. Penelitian ini bertujuan untuk mengidentifikasi faktor-faktor yang berhubungan dengan kejadian asma dan pencetus asma pada anak usia 6 - 14 tahun di Indonesia. Metode penelitian adalah desain potong lintang dengan menggunakan data Riset Kesehatan Dasar tahun 2013 di 33 provinsi di Indonesia. Variabel bebas adalah karakteristik responden, faktor lingkungan, dan perilaku merokok anak dan orangtua. Hasil analisis menunjukkan bahwa jenis kelamin laki-laki, kondisi sosial ekonomi rendah, riwayat asma pada orangtua, anak yang merokok atau pernah merokok, dan orangtua yang merokok …