Helping You Find Full Text Journal Articles

Search Results:

Author: Michael R Elliott (137)


Feb
2018

In May 2010, New Jersey implemented the first-in-the-nation decal provision to increase intermediate drivers' compliance with Graduated Driver Licensing restrictions and ultimately reduce young driver crashes. We previously found that the provision was associated with a 9.5% decline in crash rates.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

Patterns of symptom clustering in midlife women may suggest common underlying mechanisms or may identify women at risk of adverse health outcomes or, conversely, likely to experience healthy aging. This paper assesses symptom clustering in the Study of Women's Health Across the Nation (SWAN) longitudinally by stage of reproductive aging and estimates the probability of women experiencing specific symptom clusters. We also evaluate factors that influence the likelihood of specific symptom clusters and assess whether symptom clustering is associated with women's self-reported health status.

View Full Text PDF Listings View primary source full text article PDFs.

Mar
2018

Although motor vehicle crashes are the leading cause of death for adolescents, there is a scarcity of research addressing adolescents' lack of pre-licensure practical driving experience, which is theorized to increase their post-licensure crash risk.
Utilizing police-reported crashes and survey data from a randomized and quasi-randomized trial (n = 458 adolescents, 16 or 17 years of age at enrollment), the impact of a parent-directed supervised practice driving intervention and a comprehensive on-road driving assessment (ODA) with feedback was evaluated on adolescent drivers' motor vehicle crashes involvement.
Compared with the control condition, a nonsignificant 20% relative reduction in risk was observed for the parent-directed intervention: adjusted hazard ratio  = .

View Full Text PDF Listings View primary source full text article PDFs.

Sep
2017

As connected autonomous vehicles (CAVs) enter the fleet, there will be a long period when these vehicles will have to interact with human drivers. One of the challenges for CAVs is that human drivers do not communicate their decisions well. Fortunately, the kinematic behavior of a human-driven vehicle may be a good predictor of driver intent within a short time frame.

View Full Text PDF Listings View primary source full text article PDFs.

Aug
2017

Attention-deficit/hyperactivity disorder (ADHD) often persists into adolescence, when motor vehicle crash risk peaks. We know little about when adolescents with ADHD get licensed and, once they do, the extent to which they have increased crash risk compared with adolescents without ADHD.
To examine the association between ADHD and both driver licensing and crash involvement and whether it varies by sex, licensing age, and/or being prescribed ADHD medication at licensure.

View Full Text PDF Listings View primary source full text article PDFs.

Aug
2017

Experiencing a negative wealth shock in late middle age may cause high levels of stress and induce reductions in health-related consumption.
We used data on late middle age individuals (51-64 years) from the longitudinal US-based Health and Retirement Study (N=19 281) to examine the relationship between negative wealth shock and short-term outcomes that serve as markers of the pathways from wealth shock to health: elevated depressive symptoms, as a marker of the stress pathway and cost-related medication non-adherence (CRN), as a marker of the consumption pathway. Negative wealth shock was considered to be a loss of total net worth of 75% or more.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2017

Recent interest has been generated about reports of declining incidence in cognitive impairment among more recently born cohorts. At the same time, attained education, which is related to cognition, has increased in recent cohorts of older adults. We examined cohort differences in cognitive function in a nationally representative sample of Americans aged 25 and older followed for 25 years (1986-2011) and considered the extent to which cohort differences in education account for differences.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

Since the pioneering work of Elie Metchnikoff and the discovery of cellular immunity, the phagocytic clearance of cellular debris has been considered an integral component of resolving inflammation and restoring function of damaged and infected tissues. We now know that the phagocytic clearance of dying cells (efferocytosis), particularly by macrophages and other immune phagocytes, has profound consequences on innate and adaptive immune responses in inflamed tissues. These immunomodulatory effects result from an array of molecular signaling events between macrophages, dying cells, and other tissue-resident cells.

View Full Text PDF Listings View primary source full text article PDFs.

Mar
2017

The phagocytosis of apoptotic cells (efferocytosis) shifts macrophages to an anti-inflammatory state through a set of still poorly understood soluble and cell-bound signals. Apoptosis is a common feature of inflamed tissues, and efferocytosis by tissue macrophages is thought to promote the resolution of inflammation. However, it is not clear how the exposure of tissue macrophages to inflammatory cues (e.

View Full Text PDF Listings View primary source full text article PDFs.

Mar
2017

Newly licensed adolescent drivers have skill deficits that increase risk for motor vehicle crashes. Development of programs targeted to prelicensed adolescents has been hindered by concerns about encouraging overconfidence and early licensure. The study had 2 primary objectives: (a) determine whether an Internet-based intervention designed to improve parent-supervised practice (TeenDrivingPlan [TDP]) influenced adolescents' time to licensure and parents' perceptions of adolescents' driving skill, expertise, and safety and (b) evaluate the association of these perceptions and practice diversity (number of different environments where practiced occurred) with time to licensure.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

The phagocytic clearance of host cells is important for eliminating dying cells and for the therapeutic clearance of antibody-targeted cells. As ubiquitous, motile and highly phagocytic immune cells, macrophages are principal players in the phagocytic removal of host cells throughout the body. In recent years, great strides have been made in identifying the molecular mechanisms that control the recognition and phagocytosis of cells by macrophages.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2017

Graduated Driver Licensing (GDL) is the most effective strategy to reduce the burden of young driver crashes, but the extent to which young intermediate (newly licensed) drivers comply with, and police enforce, important GDL passenger and night-time restrictions is largely unknown. Population-level rates of intermediate drivers' compliance were estimated as well as police enforcement among crash-involved drivers who were noncompliant.
New Jersey's statewide driver licensing and crash databases were individually linked.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

The phagocytic clearance of dying cells in a tissue is a highly orchestrated series of intercellular events coordinated by a complex signaling network. Recent data from genetic, biochemical, and live-imaging approaches have greatly enhanced our understanding of the dynamics of cell clearance and how the process is orchestrated at the cellular and tissue levels. We discuss how networks regulating apoptotic cell clearance are integrated to enable a rapid, efficient, and high-capacity clearance system within tissues.

View Full Text PDF Listings View primary source full text article PDFs.

Jun
2016

Multistage sampling is often employed in survey samples for cost and convenience. However, accounting for clustering features when generating datasets for multiple imputation is a nontrivial task, particularly when, as is often the case, cluster sampling is accompanied by unequal probabilities of selection, necessitating case weights. Thus, multiple imputation often ignores complex sample designs and assumes simple random sampling when generating imputations, even though failing to account for complex sample design features is known to yield biased estimates and confidence intervals that have incorrect nominal coverage.

View Full Text PDF Listings View primary source full text article PDFs.

Jun
2016

When analyzing data sampled with unequal inclusion probabilities, correlations between the probability of selection and the sampled data can induce bias if the inclusion probabilities are ignored in the analysis. Weights equal to the inverse of the probability of inclusion are commonly used to correct possible bias. When weights are uncorrelated with the descriptive or model estimators of interest, highly disproportional sample designs resulting in large weights can introduce unnecessary variability, leading to an overall larger mean square error compared to unweighted methods.

View Full Text PDF Listings View primary source full text article PDFs.

Apr
2016

The growth of nonresponse rates for social science surveys has led to increased concern about the risk of nonresponse bias. Unfortunately, the nonresponse rate is a poor indicator of when nonresponse bias is likely to occur. We consider in this paper a set of alternative indicators.

View Full Text PDF Listings View primary source full text article PDFs.

Mar
2016

Multiple imputation (MI) is commonly used when item-level missing data are present. However, MI requires that survey design information be built into the imputation models. For multistage stratified clustered designs, this requires dummy variables to represent strata as well as primary sampling units (PSUs) nested within each stratum in the imputation model.

View Full Text PDF Listings View primary source full text article PDFs.

Apr
2015

4-6 million people die of enteric infections each year. After invading intestinal epithelial cells, enteric bacteria encounter phagocytes. However, little is known about how phagocytes internalize the bacteria to generate host responses.

View Full Text PDF Listings View primary source full text article PDFs.

Nov
2015

The Penn Ovarian Aging Study tracked a population-based sample of 436 women aged 35-47 years to determine associations between reproductive hormone levels and menopausal symptoms. We develop a joint modeling method that uses the individual-level longitudinal measurements of follicle stimulating hormone (FSH) to predict the risk of severe hot flashes in a manner that distinguishes long-term trends of the mean trajectory, cumulative changes captured by the derivative of mean trajectory, and short-term residual variability. Our method allows the potential effects of longitudinal trajectories on the health risks to vary and accumulate over time.

View Full Text PDF Listings View primary source full text article PDFs.

Mar
2016

Multiple imputation (MI) is a well-established method to handle item-nonresponse in sample surveys. Survey data obtained from complex sampling designs often involve features that include unequal probability of selection. MI requires imputation to be congenial, that is, for the imputations to come from a Bayesian predictive distribution and for the observed and complete data estimator to equal the posterior mean given the observed or complete data, and similarly for the observed and complete variance estimator to equal the posterior variance given the observed or complete data; more colloquially, the analyst and imputer make similar modeling assumptions.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

Young driver studies have applied quasi-induced exposure (QIE) methods to assess relationships between demographic and behavioral factors and at-fault crash involvement, but QIE's primary assumption of representativeness has not yet been validated among young drivers. Determining whether nonresponsible young drivers in clean (i.e.

View Full Text PDF Listings View primary source full text article PDFs.

Sep
2015

There has been recent dramatic increase in the use of sensors affixed to the heads or helmets of athletes to measure the biomechanics of head impacts that lead to concussion. The relationship between injury and linear or rotational head acceleration measured by such sensors can be quantified with an injury risk curve. The utility of the injury risk curve relies on the accuracy of both the clinical diagnosis and the biomechanical measure.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
2015

New Jersey (NJ) implemented the first-in-the-US Graduated Driver Licensing (GDL) decal provision in May 2010 for young drivers with learner's permits or intermediate licenses. Previous analyses found an association between the provision and crash reduction among intermediate drivers. The aim of this study is to examine the association between NJ's provision and GDL citation and crash rates among drivers aged <21 years with learner's permits.

View Full Text PDF Listings View primary source full text article PDFs.

Jul
2015

Few studies have concurrently assessed the influence of age and experience on young driver crashes, in particular in the post-Graduated Driver Licensing (GDL) era. Further, little attention is given to the transition from intermediate to full licensure. We examined the independent and joint contributions of licensing age, driving experience, and GDL license phase on crash rates among the population of young New Jersey (NJ) drivers.

View Full Text PDF Listings View primary source full text article PDFs.

View Full Text PDF Listings View primary source full text article PDFs.

Jun
2015

Joint modeling methods have become popular tools to link important features extracted from longitudinal data to a primary event. While most modeling strategies have focused on the association between the longitudinal mean trajectories and risk of an event, we consider joint models that incorporate information from both long-term trends and short-term variability in a longitudinal submodel. We also consider both shared random effect and latent class (LC) approaches in the primary-outcome model to predict a binary outcome of interest.

View Full Text PDF Listings View primary source full text article PDFs.

Mar
2015

Recent surveys have provided insight on the primary reasons why US teens delay licensure but are limited in their ability to estimate licensing rates and trends. State administrative licensing data are the ideal source to provide this information but have not yet been analyzed for this purpose. Our objective was to analyze New Jersey's (NJ) licensing database to: (1) describe population-based rates of licensure among 17- to 20-year-olds, overall and by gender and zip code level indicators of household income, population density, and race/ethnicity; and (2) examine recent trends in licensure.

View Full Text PDF Listings View primary source full text article PDFs.

May
2015

To measure the explanatory role of behavioural factors to educational and income disparities in mortality among US adults (ages 25+).
Data were from four waves of the American Changing Lives Study (N=3617). There were 1832 deaths between 1986 and 2011.

View Full Text PDF Listings View primary source full text article PDFs.

Aug
2015

The validation of intermediate markers as surrogate markers (S) for the true outcome of interest (T) in clinical trials offers the possibility for trials to be run more quickly and cheaply by using the surrogate endpoint in place of the true endpoint.
Working within a principal stratification framework, we propose causal quantities to evaluate surrogacy using a Gaussian copula model for an ordinal surrogate and time-to-event final outcome. The methods are applied to data from four colorectal cancer clinical trials, where S is tumor response and T is overall survival.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
2014

This manuscript describes the use of multiple imputation to combine information from multiple surveys of the same underlying population. We use a newly developed method to generate synthetic populations nonparametrically using a finite population Bayesian bootstrap that automatically accounting for complex sample designs. We then analyze each synthetic population with standard complete-data software for simple random samples and obtain valid inference by combining the point and variance estimates using extensions of existing combining rules for synthetic data.

View Full Text PDF Listings View primary source full text article PDFs.

Feb
2015

New Jersey (NJ) implemented the first Graduated Driver Licensing (GDL) decal provision in the U.S. in May 2010.

View Full Text PDF Listings View primary source full text article PDFs.

Apr
2015

Because of the time and expense required to obtain clinical outcomes of interest, such as functional limitations or death, clinical trials often focus the effects of treatment on earlier and more easily obtained surrogate markers. Preliminary work to define surrogates focused on the fraction of a treatment effect "explained" by a marker in a regression model, but as notions of causality have been formalized in the statistical setting, formal definitions of high-quality surrogate markers have been developed in the causal inference framework, using either the "causal effect" or "causal association" settings. In the causal effect setting, high-quality surrogate markers have a large fraction of the total treatment effect explained by the effect of the treatment on the marker net of the treatment on the outcome.

View Full Text PDF Listings View primary source full text article PDFs.

Feb
2015

Few studies have evaluated factors that influence menstrual cycle length (MCL) during the menopausal transition (MT), a life stage during which very long cycles become more likely to occur. The objective of this article was to assess how body mass index and race/ethnicity--factors associated with MCL in young women--influence MCL during the MT.
Study of Women's Health Across the Nation menstrual calendar substudy data of African-American, white, Chinese, and Japanese women were available for three sites (southeastern Michigan, Los Angeles, and northern California).

View Full Text PDF Listings View primary source full text article PDFs.

Aug
2014

Many studies have failed to show an effect of parent-supervised practice driving on the driving performance of teenagers; nevertheless, most Graduated Driver Licensing programs have provisions that require supervised practice.
To determine whether a web-based intervention, the Teen Driving Plan (TDP), can improve the driving performance of teenagers before licensure as measured by the Teen On-road Driving Assessment (tODA).
Randomized, single-blind, clinical trial among 217 dyads (1 parent: 1 teenaged learner's-permit holder) to test TDP effectiveness on increasing the quantity and diversity of supervised practice and improving the teenagers' prelicensed driving performance.

View Full Text PDF Listings View primary source full text article PDFs.

Feb
2015

Inexperienced, less-skilled driving characterises many newly licensed drivers and contributes to high crash rates. A randomised trial of TeenDrivingPlan (TDP), a new learner driver phase internet-based intervention, demonstrated effectiveness in improving safety relevant, on-road driving behaviour, primarily through greater driving practice diversity. To inform future learner driver interventions, this analysis examined TDP use and its association with practice diversity.

View Full Text PDF Listings View primary source full text article PDFs.

Jun
2014

Outside of the survey sampling literature, samples are often assumed to be generated by a simple random sampling process that produces independent and identically distributed (IID) samples. Many statistical methods are developed largely in this IID world. Application of these methods to data from complex sample surveys without making allowance for the survey design features can lead to erroneous inferences.

View Full Text PDF Listings View primary source full text article PDFs.

Jun
2014

Elmo1 and Elmo2 are highly homologous cytoplasmic adaptor proteins that interact with Dock family guanine nucleotide exchange factors to promote activation of the small GTPase Rac. In T lymphocytes, Dock2 is essential for CCR7- and CXCR4-dependent Rac activation and chemotaxis, but the role of Elmo proteins in regulating Dock2 function in primary T cells is not known. In this article, we show that endogenous Elmo1, but not Elmo2, interacts constitutively with Dock2 in mouse and human primary T cells.

View Full Text PDF Listings View primary source full text article PDFs.

Apr
2014

As women approach menopause, the patterns of their menstrual cycle lengths change. To study these changes, we need to jointly model both the mean and variability of cycle length. Our proposed model incorporates separate mean and variance change points for each woman and a hierarchical model to link them together, along with regression components to include predictors of menopausal onset such as age at menarche and parity.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2014

Over the last two decades, research has assessed the relationship between neighborhood socioeconomic factors and individual health. However, existing research is based almost exclusively on cross-sectional data, ignoring the complexity in health transitions that may be shaped by long-term residential exposures. We address these limitations by specifying distinct health transitions over multiple waves of a 15-year study of American adults.

View Full Text PDF Listings View primary source full text article PDFs.

View Full Text PDF Listings View primary source full text article PDFs.

Apr
2014

Traditional methods for determining crash responsibility - most commonly moving violation citations - may not accurately characterize at-fault status among crash-involved drivers given that: (1) issuance may vary by factors that are independent of fault (e.g., driver age, gender), and (2) these methods do not capture driver behaviors that are not illegal but still indicative of fault.

View Full Text PDF Listings View primary source full text article PDFs.

Apr
2014

In clinical trials, a surrogate outcome variable (S) can be measured before the outcome of interest (T) and may provide early information regarding the treatment (Z) effect on T. Using the principal surrogacy framework introduced by Frangakis and Rubin (2002. Principal stratification in causal inference.

View Full Text PDF Listings View primary source full text article PDFs.

View Full Text PDF Listings View primary source full text article PDFs.

Sep
2013

Prior longitudinal studies of negative working conditions and depression generally have used a single exposure indicator, such as job strain, and have required consistent availability of the measure across waves and selection of only those working at all measurement points.
Up to four waves of the Americans' Changing Lives study (1986 to 2001/2) and item-response theory (IRT) models were used to generate wave-specific measures of negative working conditions. Random-intercept linear mixed models assessed the association between the score and depressive symptoms.

View Full Text PDF Listings View primary source full text article PDFs.

Oct
2013

Zhang et al. respond.

Am J Public Health 2013 Oct 15;103(10):e10. Epub 2013 Aug 15.
Nanhua Zhang, Harolyn W Baker, Michael R Elliott

View Full Text PDF Listings View primary source full text article PDFs.

Aug
2013

Extant observational studies generally support the existence of a link between neighborhood context and health. However, estimating the causal impact of neighborhood effects from observational data has proven to be a challenge. Omission of relevant factors may lead to overestimating the effects of neighborhoods on health while inclusion of time-varying confounders that may also be mediators (e.

View Full Text PDF Listings View primary source full text article PDFs.

Sep
2014

This article discusses joint modeling of compliance and outcome for longitudinal studies when noncompliance is present. We focus on two-arm randomized longitudinal studies in which subjects are randomized at baseline, treatment is applied repeatedly over time, and compliance behaviors and clinical outcomes are measured and recorded repeatedly over time. In the proposed Markov compliance and outcome model, we use the potential outcome framework to define pre-randomization principal strata from the joint distribution of compliance under treatment and control arms, and estimate the effect of treatment within each principal strata.

View Full Text PDF Listings View primary source full text article PDFs.

May
2013

To obtain a probability sample of pregnancies, the National Children's Study conducted door-to-door recruitment in randomly selected neighbourhoods in randomly selected counties in 2009-10. In 2011, an experiment was conducted in 10 US counties, in which the two-stage geographic sample was maintained, but participants were recruited in prenatal care provider offices. We describe our experience recruiting pregnant women this way in Wayne County, Michigan, a county where geographically eligible women attended 147 prenatal care settings, and comprised just 2% of total county pregnancies.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
1969

When an outcome of interest in a clinical trial is late-occurring or difficult to obtain, surrogate markers can extract information about the effect of the treatment on the outcome of interest. Understanding associations between the causal effect (CE) of treatment on the outcome and the causal effect of treatment on the surrogate is critical to understanding the value of a surrogate from a clinical perspective.
Traditional regression approaches to determine the proportion of the treatment effect explained by surrogate markers suffer from several shortcomings: they can be unstable and can lie outside the 0-1 range.

View Full Text PDF Listings View primary source full text article PDFs.

Jul
2013

This study aims to assess the agreement between the menopausal transition stages defined by annual interviews or annual follicle-stimulating hormone levels and the menopausal transition stages defined by monthly menstrual calendars, as well as factors associated with discordance.
These analyses used daily self-recorded menstrual calendar data from 1996 to 2006, annual interviews, and annual follicle-stimulating hormone levels. Participants were recruited from four study sites of the Study of Women's Health Across the Nation (Boston, southeastern Michigan, Oakland, and Los Angeles) and four racial/ethnic groups (African American, white, Chinese, and Japanese).

View Full Text PDF Listings View primary source full text article PDFs.

Back to top