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Full-Text Articles in Public Health

Stochastic Variation In Network Epidemic Models: Implications For The Design Of Community Level Hiv Prevention Trials, David Boren, Patrick Sullivan, Chris Beyrer, Stefan Baral, Linda-Gail Becker, Ron Brookmeyer Sep 2014

Stochastic Variation In Network Epidemic Models: Implications For The Design Of Community Level Hiv Prevention Trials, David Boren, Patrick Sullivan, Chris Beyrer, Stefan Baral, Linda-Gail Becker, Ron Brookmeyer

Ron Brookmeyer

Important sources of variation in the spread of HIV in communities arise from overlapping sexual networks and heterogeneity in biological and behavioral risk factors in populations. These sources of variation are not routinely accounted for in the design of HIV prevention trials. In this paper, we use agent based models to account for these sources of variation. We illustrate the approach with an agent based model for the spread of HIV infection among men who have sex with men (MSM) in South Africa. We find that traditional sample size approaches that rely on binomial (or Poisson) models are inadequate and …


Cluster Randomized Trials And Statistical Power, Stephen A. Lauer, Nicholas G. Reich Sep 2014

Cluster Randomized Trials And Statistical Power, Stephen A. Lauer, Nicholas G. Reich

Nicholas G Reich

The cluster-randomized trial (CRT) is a common study design in public health research. In situations where dividing a group of individuals into treatment and controls is unethical or impossible, a CRT design maintains the strengths of a randomized study design. By comparing the outcomes of small populations (clusters), we can observe the impacts of interventions on the community as a whole. Public health researchers around the world have utilized CRTs to measure the effect of, for example, de-worming medication on school attendance, financial incentives on doctor absenteeism, and providing chlorine to waterholes. The CRT can be a potent tool, however …


Depicting Estimates Using The Intercept In Meta-Regression Models: The Moving Constant Technique, Blair T. Johnson Dr., Tania B. Huedo-Medina Dr. Aug 2014

Depicting Estimates Using The Intercept In Meta-Regression Models: The Moving Constant Technique, Blair T. Johnson Dr., Tania B. Huedo-Medina Dr.

Blair T. Johnson

In any scientific discipline, the ability to portray research patterns graphically often aids greatly in interpreting a phenomenon. In part to depict phenomena, the statistics and capabilities of meta-analytic models have grown increasingly sophisticated. Accordingly, this article details how to move the constant in weighted meta-analysis regression models (viz. “meta-regression”) to illuminate the patterns in such models across a range of complexities. Although it is commonly ignored in practice, the constant (or intercept) in such models can be indispensible when it is not relegated to its usual static role. The moving constant technique makes possible estimates and confidence intervals at …


Adaptive Pair-Matching In The Search Trial And Estimation Of The Intervention Effect, Laura Balzer, Maya L. Petersen, Mark J. Van Der Laan Jan 2014

Adaptive Pair-Matching In The Search Trial And Estimation Of The Intervention Effect, Laura Balzer, Maya L. Petersen, Mark J. Van Der Laan

Laura B. Balzer

In randomized trials, pair-matching is an intuitive design strategy to protect study validity and to potentially increase study power. In a common design, candidate units are identified, and their baseline characteristics used to create the best n/2 matched pairs. Within the resulting pairs, the intervention is randomized, and the outcomes measured at the end of follow-up. We consider this design to be adaptive, because the construction of the matched pairs depends on the baseline covariates of all candidate units. As consequence, the observed data cannot be considered as n/2 independent, identically distributed (i.i.d.) pairs of units, as current practice assumes. …


Causal Models And Learning From Data: Integrating Causal Modeling And Statistical Estimation, Maya Petersen, M J. Van Der Laan Jan 2014

Causal Models And Learning From Data: Integrating Causal Modeling And Statistical Estimation, Maya Petersen, M J. Van Der Laan

Maya Petersen

No abstract provided.


Lung Flute Improves Symptoms And Health Status In Copd With Chronic Bronchitis: A 26 Week Randomized Controlled Trial, Sanjay Sethi, Jingjing Yin, Pamela K. Anderson Jan 2014

Lung Flute Improves Symptoms And Health Status In Copd With Chronic Bronchitis: A 26 Week Randomized Controlled Trial, Sanjay Sethi, Jingjing Yin, Pamela K. Anderson

Jingjing Yin

Background: Chronic obstructive pulmonary disease (COPD) is characterized by mucus hypersecretion that contributes to disease related morbidity and is associated with increased mortality. The Lung Flute® is a new respiratory device that produces a low frequency acoustic wave with moderately vigorous exhalation to increase mucus clearance. We hypothesized that the Lung Flute, used on a twice daily basis will provide clinical benefit to patients with COPD with chronic bronchitis.

Methods: We performed a 26 week randomized, non-intervention controlled, single center, open label trial in 69 patients with COPD and Chronic Bronchitis. The primary endpoint was change in respiratory …


Spatial Epidemiology And Climatic Predictors Of Paediatric Dengue Infections Captured Via Sentinel Site Surveillance, Phnom Penh Cambodia 2011–2012, Andrew A. Lover, Philippe Buchy, Anne Rachline, Duch Moniboth, Rekol Huy, Chour Y. Meng, Yee Sin Leo, Kdan Yuvatha, Ung Sophal, Ngan Chantha, Bunthin Y, Veasna Duong, Sophie Goyet, Jeremy Brett, Arnaud Tarantola, Philippe Cavailler Dec 2013

Spatial Epidemiology And Climatic Predictors Of Paediatric Dengue Infections Captured Via Sentinel Site Surveillance, Phnom Penh Cambodia 2011–2012, Andrew A. Lover, Philippe Buchy, Anne Rachline, Duch Moniboth, Rekol Huy, Chour Y. Meng, Yee Sin Leo, Kdan Yuvatha, Ung Sophal, Ngan Chantha, Bunthin Y, Veasna Duong, Sophie Goyet, Jeremy Brett, Arnaud Tarantola, Philippe Cavailler

Andrew Lover

Background
Dengue is a major contributor to morbidity in children aged twelve and below throughout Cambodia; the 2012 epidemic season was the most severe in the country since 2007, with more than 42,000 reported (suspect or confirmed) cases.
Methods
We report basic epidemiological characteristics in a series of 701 patients at the National Paediatric Hospital in Cambodia, recruited during a prospective clinical study (2011–2012). To more fully explore this cohort, we examined climatic factors using multivariate negative binomial models and spatial clustering of cases using spatial scan statistics to place the clinical study within a larger epidemiological framework.
Results
We …


Retention And Risk Factors For Attrition In A Large Public Health Art Program In Myanmar: A Retrospective Cohort Analysis, Aye Thida, Sai Thein Than Tun, Sai Ko Ko Zaw, Andrew A. Lover, Philippe Cavailler, Jennifer Chunn, Mar Mar Aye, Par Par, Kyaw Win Naing, Kaung Nyunt Zan, Myint Shwe Shwe, Thar Tun Kyaw, Zaw Htoon Waing, Philippe Clevenbergh Dec 2013

Retention And Risk Factors For Attrition In A Large Public Health Art Program In Myanmar: A Retrospective Cohort Analysis, Aye Thida, Sai Thein Than Tun, Sai Ko Ko Zaw, Andrew A. Lover, Philippe Cavailler, Jennifer Chunn, Mar Mar Aye, Par Par, Kyaw Win Naing, Kaung Nyunt Zan, Myint Shwe Shwe, Thar Tun Kyaw, Zaw Htoon Waing, Philippe Clevenbergh

Andrew Lover

Background

The outcomes from an antiretroviral treatment (ART) program within the public sector in Myanmar have not been reported. This study documents retention and the risk factors for attrition in a large ART public health program in Myanmar.

Methods

A retrospective analysis of a cohort of adult patients enrolled in the Integrated HIV Care (IHC) Program between June 2005 and October 2011 and followed up until April 2012 is presented. The primary outcome was attrition (death or loss-follow up); a total of 10,223 patients were included in the 5-year cumulative survival analysis. Overall 5,718 patients were analyzed for the risk …


Note On The Origin Of The Madagascar Strain Of Plasmodium Vivax, Andrew A. Lover Dec 2013

Note On The Origin Of The Madagascar Strain Of Plasmodium Vivax, Andrew A. Lover

Andrew Lover

Dear Sir:
Recent studies have established the potential for strains of Plasmodium vivax in Madagascar to infect Duffy-negative populations,1 and polymerase chain reaction (PCR)-based screening suggests a previously unrecognized burden of this parasite in sub-Saharan Africa.2
There is a dearth of data concerning any P. vivax parasites from Africa; however, one of the most widely studied strains used during the malariotherapy era was the Madagascar strain, used at the Horton Hospital research site in the UK from 1923 to ca. 1970. This isolate has been the subject of extensive studies,3,4 but there has been considerable …


Demographic And Spatial Predictors Of Anemia In Women Of Reproductive Age In Timor-Leste: Implications For Health Program Prioritization, Andrew A. Lover, Mikael Hartman, Kee Seng Chia, David L. Heymann Dec 2013

Demographic And Spatial Predictors Of Anemia In Women Of Reproductive Age In Timor-Leste: Implications For Health Program Prioritization, Andrew A. Lover, Mikael Hartman, Kee Seng Chia, David L. Heymann

Andrew Lover

Anemia is a significant risk factor for poor health outcomes for both the mother and neonate; however, the determinants of anemia in many epidemiological settings are poorly understood. Using a subset of a nationally representative cluster survey (2010 Demographic and Health Survey) in combination with other non-contemporaneous survey data, the epidemiology of anemia among women of reproductive age in Timor-Leste has been explored. Logistic regression was used to identify risk factors, population-level impacts were estimated as population attributable fractions and spatial analytics were used to identify regions of highest risk. The DHS survey found that ∼21% of adult women in …


The Distribution Of Incubation And Relapse Times In Experimental Human Infections With The Malaria Parasite Plasmodium Vivax, Andrew A. Lover, Xiahong Zhao, Zheng Gao, Richard J. Coker, Alex R. Cook Dec 2013

The Distribution Of Incubation And Relapse Times In Experimental Human Infections With The Malaria Parasite Plasmodium Vivax, Andrew A. Lover, Xiahong Zhao, Zheng Gao, Richard J. Coker, Alex R. Cook

Andrew Lover

Background
The distributions of incubation and relapse periods are key components of infectious disease models for the malaria parasite Plasmodium vivax; however, detailed distributions based upon experimental data are lacking.
Methods
Using a range of historical, experimental mosquito-transmitted human infections, Bayesian estimation with non-informative priors was used to determine parametric distributions that can be readily implemented for the incubation period and time-to-first relapse in P. vivax infections, including global subregions by parasite source. These analyses were complemented with a pooled analysis of observational human infection data with infections that included malaria chemoprophylaxis and long-latencies. The epidemiological impact of these …