Population-level Outcomes Research Articles

Connecting alveolate cell biology with trophic ecology in the marine plankton using the ciliate Favella as a model.

Planktonic alveolates (ciliates and dinoflagellates), key trophic links in marine planktonic communities, exhibit complex behaviors that are underappreciated by microbiologists and ecologists. Furthermore, the physiological mechanisms underlying these behaviors are still poorly understood except in a few freshwater model ciliates, which are significantly different in cell structure and behavior than marine planktonic species. Here, we argue for an interdisciplinary research approach to connect physiological mechanisms with population-level outcomes of behaviors. Presenting the tintinnid ciliate Favella as a model alveolate, we review its population ecology, behavior, and cellular/molecular biology in the context of sensory biology and synthesize past research and current findings to construct a conceptual model describing the sensory biology of Favella. We discuss how emerging genomic information and new technical methods for integrating research across different levels of biological organization are paving the way for rapid advance. These research approaches will yield a deeper understanding of the role that planktonic alveolates may play in biogeochemical cycles, and how they may respond to future ocean conditions.

Community-based hepatitis B screening: what works?

IntroductionChronic hepatitis B (CHB) affects over 350 million people worldwide and can lead to life-threatening complications, including liver failure and hepatocellular cancer (HCC). Modern antiviral therapies could stem the rising tide of hepatitis B-related HCC, provided that individuals and populations at risk can be reliably identified through hepatitis B screening and appropriately linked to care. Opportunistic disease screening cannot deliver population-level outcomes, given the large number of undiagnosed people, but they may be achievable through well-organized and targeted community-based screening interventions.Material and methods This review summarizes the experience with community-based CHB screening programs published in the English-language literature over the last 30 years.Results They include experiences from Taiwan, the USA, The Netherlands, New Zealand, and Australia. Despite great variability in program setting and design, successful programs shared common features, including effective community engagement incorporating the target population’s cultural values and the ability to provide low-cost or free access to care, including antiviral treatment.Conclusion While many questions still remain about the best funding mechanisms to ensure program sustainability and what the most effective strategies are to ensure program reach, linkage to care, and access to treatment, the evidence suggests scope for cautious optimism. A number of successful, large-scale initiatives in the USA, Asia–Pacific, and Europe demonstrated the feasibility of community-based interventions in effectively screening large numbers of people with CHB. By providing an effective mechanism for community outreach, scaling up these interventions could deliver population-level outcomes in liver cancer prevention relevant for many countries with a large burden of disease.

A simple generative model of collective online behavior.

Human activities increasingly take place in online environments, providing novel opportunities for relating individual behaviors to population-level outcomes. In this paper, we introduce a simple generative model for the collective behavior of millions of social networking site users who are deciding between different software applications. Our model incorporates two distinct mechanisms: one is associated with recent decisions of users, and the other reflects the cumulative popularity of each application. Importantly, although various combinations of the two mechanisms yield long-time behavior that is consistent with data, the only models that reproduce the observed temporal dynamics are those that strongly emphasize the recent popularity of applications over their cumulative popularity. This demonstrates--even when using purely observational data without experimental design--that temporal data-driven modeling can effectively distinguish between competing microscopic mechanisms, allowing us to uncover previously unidentified aspects of collective online behavior.

Geographic variation in health IT and health care outcomes: A snapshot before the meaningful use incentive program began

BackgroundThe 2009 Health Information Technology for Economic and Clinical Health (HITECH) Act, which includes the Meaningful Use (MU) incentive program, was designed to increase the adoption of health information technology (IT) by physicians and hospitals. Policymakers hope that increased use of health IT to exchange health information will in turn enhance the quality and efficiency of health care delivery. In this study, we analyze the extent to which key outcomes vary based on the levels of health ITness among physicians and hospitals before the HITECH and MU programs led to increases in adoption and changes in use. Our findings provide an important baseline for a future evaluation of the impact of these programs on population-level outcomes. MethodsWe constructed measures of the degree of hospital and physician adoption and use (“health ITness”) at the level of the hospital referral region (HRR). We used data from the 2010 IT Supplement of the American Hospital Association (AHA) Annual Survey of Hospitals to capture hospital health ITness and data from the 2010 survey of ambulatory health care sites produced by SK&A Information Services for the physician measure. We conducted cross-sectional analyses of the relationship between market-level Medicare costs and use and three measures: (1) physician health ITness, (2) hospital health ITness, and (3) an overall measure of health ITness. ResultsIn general, greater levels of physician health ITness are associated with decreasing costs and use. Many of these relationships lose statistical significance, however, when we control for population and market characteristics such as the average age and health status of Medicare beneficiaries, mean household income, and the HMO penetration rate. Several of the relationships also change according to the level of hospital health ITness. ConclusionsOur findings suggest that greater levels of physician health ITness are associated with decreasing costs and use for a number of services, including inpatient costs and stays, imaging services, and lab tests, in 2010. Our health ITness and outcomes measures are aggregated at the HRR level; as such, these results do not suggest that the adoption and use of health IT by individual physicians or hospitals leads to decreases in costs or use for their individual patients. Nevertheless, these baseline findings provide important information to be considered in future research analyzing the impact of HITECH and the MU incentives.

Sexually transmitted disease clinics in the era of the affordable care act: is it time to tear down the walls?

Sexually transmitted disease clinics in the era of the affordable care act: is it time to tear down the walls?

Population relevance of toxicant mediated changes in sex ratio in fish: An assessment using an individual-based zebrafish (Danio rerio) model

Ecological risk assessments (ERAs) of toxicants are predominantly based on data from laboratory tests on individuals. However, the protection goal is generally at the population level. Ecological modelling has the potential to link individual-level effects to population-level outcomes. Here we developed an individual-based zebrafish population model to study the possible population-level relevance of toxicant-mediated changes in sex ratio. The model was structured with sub-models based on empirical data (e.g. growth, reproduction, mortality) derived from a combination of our own laboratory and field experiments, the literature and theoretical concepts. The outputs of the default model were validated against size distributions for wild populations of zebrafish sampled in Bangladesh. Sensitivity analysis showed that population abundance was most sensitive to changes in density-dependent survival and the availability of refugia for juveniles.The model was then used to determine the population-level relevance of changes in sex ratio caused by an androgenic (dihydrotestosterone) and oestrogenic (4-tert-octylphenol) substance. Both were investigated under acute (10 day) and chronic (1 year) exposure regimes. Acute exposures to the test chemicals had little effect on population-level endpoints at any of the concentrations tested. Chronic exposures decreased population abundance at higher concentrations for both chemicals and most strongly with DHT. However, these concentrations were far in excess of environmentally realistic levels. Our study demonstrated that ecological models can be applied to link laboratory derived ecotoxicity data at the individual level to impacts at the population level and in our study we found different modes of action and potencies caused different levels of population perturbation. Ecological models can therefore help in assessing the ecological relevance of different organism-level effects of toxicants aiding future environmental protection strategies.

Assessing the validity of using administrative data to identify patients with epilepsy

Previous validation studies assessing the use of administrative data to identify patients with epilepsy have used targeted sampling or have used a reference standard of patients in the neurologist, hospital, or emergency room setting. Therefore, the validity of using administrative data to identify patients with epilepsy in the general population has not been previously assessed. The purpose of this study was to determine the validity of using administrative data to identify patients with epilepsy in the general population. A retrospective chart abstraction study was performed using primary care physician records from 83 physicians distributed throughout Ontario and contributing data to the Electronic Medical Record Administrative data Linked Database (EMRALD) A random sample of 7,500 adult patients, from a possible 73,014 eligible, was manually chart abstracted to identify patients who had ever had epilepsy. These patients were used as a reference standard to test a variety of administrative data algorithms. An algorithm of three physician billing codes (separated by at least 30days) in 2years or one hospitalization had a sensitivity of 73.7% (95% confidence interval [CI] 64.8-82.5%), specificity of 99.8% (95% CI 99.6-99.9%), positive predictive value (PPV) of 79.5% (95% CI71.1-88.0%), and negative predictive value (NPV) of 99.7% (95% CI99.5-99.8%) for identifying patients who had ever had epilepsy. The results of our study showed that administrative data can reasonably accurately identify patients who have ever had epilepsy, allowing for a "lifetime" population prevalence determination of epilepsy in Ontario and the rest of Canada with similar administrative databases. This will facilitate future studies on population level patterns and outcomes of care for patients living with epilepsy.

The Healthy Start Partnership

This article investigates the impact of community-based interventions developed by the Healthy Start Partnership (HSP) to promote healthy body weights in families. Intercept surveys were conducted to monitor community exposure. A nonconcurrent, no treatment control design was used to assess population-level weight outcomes. Control (n = 219) and intervention (n = 276) cohorts of pregnant women were recruited and followed until 6 months postpartum. Data were collected through 2 self-administered questionnaires and medical record audits. Results indicate community residents were exposed to interventions. However, little evidence of positive effects of interventions on weight outcomes was found for mothers or infants.

Snapshot From Superstorm Sandy: American Red Cross Mental Health Risk Surveillance in Lower New York State

Disasters often cause psychological injury, as well as dramatic physical damage. Epidemiologic research has identified a set of disaster experiences and predisposing characteristics that place survivors at risk for post traumatic stress disorder (PTSD), depression, and anxiety. Rapid triage of at-risk survivors could have benefits for individual and population-level outcomes. We examine American Red Cross mental health risk surveillance data collected from October 29 to November 20, 2012, immediately after Hurricane Sandy in 8 lower New York State counties to evaluate the feasibility and utility of collecting these data. PsySTART, an evidence-based disaster mental health triage tool, was used to record survivor-reported risk factors after each survivor contact. Red Cross disaster mental health volunteers interfaced with survivors at disaster operation sites, including shelters, emergency aid stations, and mobile feeding and community outreach centers. Riskdata were called into the operations center each day and reported by county. PsySTART risk surveillance data for 18,823 disaster mental health contacts are presented for adults and children. A total of 17,979 risk factors were reported. Overall levels of risk per contact were statistically different (χ(2)(1,N=6,045)=248.1; P<.001) across the 8 counties. Survivors with high levels of risk were found in locations apartfrom the areas with the greatest physical damage. Aggregated PsySTART data in Superstorm Sandy indicate substantial population-level impact suggestive of risk for disorders that may persist chronically without treatment. Mental health triage has the potential to improve care of individual disaster survivors, as well as inform disaster management, local health providers, and public health officials.

The Human Resources for Health Program in Rwanda — A New Partnership

A global shortage of 4.3 million health professionals poses a major bottleneck to poor people worldwide with regard to benefiting from the fruits of modern medicine.1 Among existing health professionals, there are also staggering inequities in skill levels and geographic distribution.2–4 Unsurprisingly, the deepest national gaps in human resources for health run parallel to poor population-level health outcomes.1 Sub-Saharan Africa bears 24% of the global burden of disease5 but is served by only 4% of the global health workforce.1 The health graduate schools in the region face overwhelming financial, infrastructural, and personnel constraints, limiting their ability to address the . . .

A comprehensive review of mental health gatekeeper-trainings for adolescents and young adults

Mental disorders account for a larger burden of disease among adolescents and young adults than any other class of health conditions, and most of these disorders are untreated. Gatekeeper-trainings represent a potentially powerful mechanism for increasing access to treatment. This article is a comprehensive review of 21 gatekeeper-training studies conducted in schools and other youth settings around the world. Despite the widespread use of these programs, little is known about how they actually affect the abilities and actions of trained gatekeepers and the subsequent help-seeking behaviors of adolescents and young adults. Certain outcomes (knowledge, attitudes, and self-efficacy) have been commonly measured whereas others (behaviors, skills, and population-level outcomes) have rarely been assessed. The studies reviewed here also suggest that positive training effects often diminish over time. The article identifies opportunities for advancing gatekeeper-training research and practice.

Randomized Controlled Trial of Universal Postnatal Nurse Home Visiting: Impact on Emergency Care

Although nurse home visiting has proven efficacious with small samples, scaling up to community populations with diverse families has not yet proven effective. The Durham Connects program was developed in collaboration with community leaders as a brief, universal, postnatal nurse home visiting intervention designed to screen for risk, provide brief intervention, and connect families with more intensive evidence-based services as needed. This study tested program effectiveness in reducing infant emergency medical care between birth and age 12 months. All 4777 resident births in Durham, North Carolina across 18 months were randomly assigned, with even birth date families to intervention and odd birth date families to control. Intervention families were offered 3 to 7 contacts between 3 and 12 weeks after birth to assess family needs and connect parents with community resources to improve infant health and well-being. Hospital records were analyzed by using an intent-to-treat design to evaluate impact among a representative subset of 549 families. After demographic factors (ie, birth risk, Medicaid status, ethnicity, and single parenthood) were covaried, relative to control families, families assigned to intervention had 50% less total emergency medical care use (mean [M] emergency department visits and hospital overnights) (M(intervention) = 0.78 and M(control) = 1.57; P < .001, effect size = 0.28) across the first 12 months of life. This brief, universal, postnatal nurse home visiting program improves population-level infant health care outcomes for the first 12 months of life. Nurse home visiting can be implemented universally at high fidelity with positive impacts on infant emergency health care that are similar to those of longer, more intensive home visiting programs. This approach offers a novel solution to the paradox of targeting by offering individually tailored intervention while achieving population-level impact.

Differences in Treatment, Outcomes, and Quality of Life Among Patients With Heart Failure in Canada and the United States

The aim of this study was to compare clinical outcomes, resource utilization, and health-related quality of life between Canadian and U.S. patients enrolled in ASCEND-HF (Acute Study of Clinical Effectiveness of Nesiritide in Decompensated Heart Failure). A further aim was to supplement the within-trial analysis with a contemporaneous population-based comparison of all patients hospitalized with primary diagnoses of heart failure (HF) in the 2 countries. Little is known about intercountry differences in outcomes of patients with HF in Canada and the United States. Trial patients consisted of 465 Canadian and 2,684 U.S. patients enrolled in ASCEND-HF. Population-level cohorts consisted of 1.9 million U.S. and 81,016 Canadians hospitalized for HF in 2007 and2008. Canadian patients in ASCEND-HF were older, were more likely to be white, and had lower body weights and blood pressures than U.S. patients. Canadians also had lower baseline-adjusted odds of 30-day mortality (odds ratio: 0.46; 95% confidence interval: 0.23 to 0.92) and better health-related quality of life than U.S. patients. In both countries, trial patients differed significantly from population-level cohorts. In contrast to ASCEND-HF, unadjusted in-hospital mortality at the population level was significantly lower in the United States (3.4%) compared with Canada (11.1%) (p< 0.01). Intercountry differences in outcomes of patients hospitalized with HF differed significantly between trial and population cohorts. Further study on how cardiac care is delivered in the 2 countries and how it influences the results of clinical trials and population-level outcomes, especially in the long term, is warranted. (A Study Testing the Effectiveness of Nesiritide in Patients With Acute Decompensated Heart Failure; NCT00475852).

Advancing impact prediction and hypothesis testing in invasion ecology using a comparative functional response approach

AbstractInvasion ecology urgently requires predictive methodologies that can forecast the ecological impacts of existing, emerging and potential invasive species. We argue that many ecologically damaging invaders are characterised by their more efficient use of resources. Consequently, comparison of the classical ‘functional response’ (relationship between resource use and availability) between invasive and trophically analogous native species may allow prediction of invader ecological impact. We review the utility of species trait comparisons and the history and context of the use of functional responses in invasion ecology, then present our framework for the use of comparative functional responses. We show that functional response analyses, by describing the resource use of species over a range of resource availabilities, avoids many pitfalls of ‘snapshot’ assessments of resource use. Our framework demonstrates how comparisons of invader and native functional responses, within and between Type II and III functional responses, allow testing of the likely population-level outcomes of invasions for affected species. Furthermore, we describe how recent studies support the predictive capacity of this method; for example, the invasive ‘bloody red shrimp’Hemimysis anomalashows higher Type II functional responses than native mysids and this corroborates, and could have predicted, actual invader impacts in the field. The comparative functional response method can also be used to examine differences in the impact of two or more invaders, two or more populations of the same invader, and the abiotic (e.g. temperature) and biotic (e.g. parasitism) context-dependencies of invader impacts. Our framework may also address the previous lack of rigour in testing major hypotheses in invasion ecology, such as the ‘enemy release’ and ‘biotic resistance’ hypotheses, as our approach explicitly considers demographic consequences for impacted resources, such as native and invasive prey species. We also identify potential challenges in the application of comparative functional responses in invasion ecology. These include incorporation of numerical responses, multiple predator effects and trait-mediated indirect interactions, replacement versus non-replacement study designs and the inclusion of functional responses in risk assessment frameworks. In future, the generation of sufficient case studies for a meta-analysis could test the overall hypothesis that comparative functional responses can indeed predict invasive species impacts.

A qualitative study into the development of a physical activity legacy from the London 2012 Olympic Games

Olympic Games have sometimes been considered as public health interventions capable of improving population health by encouraging increased physical activity levels. However, the evidence base does not appear to support this and is of poor quality, focussing on population level outcomes, usually related only to participation in organised sports. A new approach to research into the effects of such events is required focussing on the processes and mechanisms by which population physical activity levels might be increased enabling more effective use of such events in the future. Two separate processes, the 'demonstration effect' and 'festival effect,' have been proposed in Government guidance and are explored using qualitative methods in eight inactive people and four physical activity promotion specialists in Brighton & Hove. The findings appear to support the idea that watching elite athletes compete is unlikely to inspire participation among inactive people and may even discourage it by reducing self-efficacy as a result of the perceived competence gap. Despite this, positive attitudes towards the London Olympics were observed among inactive members of the public and a desire to become actively involved in the event. Examples of intention to continue participating in community events and physical activities as a result of positive experiences of Olympic related events were also observed.

Context‐dependent amphibian host population response to an invading pathogen

Amphibian chytridiomycosis, caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), is an emerging infectious disease that widely threatens amphibian biodiversity. However, population-level outcomes following the introduction of the pathogen are highly context dependent and are mediated by a broad suite of biotic and abiotic variables. Here, we examine the effect of the introduction of Bd on native island populations of the IUCN red-listed amphibian species Alytes muletensis, the Mallorcan midwife toad. We show that the outcome of pathogen introduction is not only dependent on biotic factors, but is also dependent on environmental factors that vary across local scales. Our experimental infections confirm that the genotype of Bd occurring on Mallorca is hypovirulent in A. muletensis when compared against the lineage found occurring on mainland Iberia. Long-term population data show that A. muletensis populations on the island are increasing overall, but trends in highly infected populations are conflicting. We use mathematical models and field data to demonstrate that this divergence in population response to infection can be explained by local environmental differences between infected sites, whereas pathogen genetics, host genetics, and intrinsic epidemiological dynamics driven by fungal load are less likely to be the cause of these differing population trajectories. Our results illustrate the need to take into account the appropriate environmental scale and context when assessing the risk that an emerging pathogen presents to a naive population or species.

Comprehensive and integrated district health systems strengthening: the Rwanda Population Health Implementation and Training (PHIT) Partnership

BackgroundNationally, health in Rwanda has been improving since 2000, with considerable improvement since 2005. Despite improvements, rural areas continue to lag behind urban sectors with regard to key health outcomes. Partners In Health (PIH) has been supporting the Rwanda Ministry of Health (MOH) in two rural districts in Rwanda since 2005. Since 2009, the MOH and PIH have spearheaded a health systems strengthening (HSS) intervention in these districts as part of the Rwanda Population Health Implementation and Training (PHIT) Partnership. The partnership is guided by the belief that HSS interventions should be comprehensive, integrated, responsive to local conditions, and address health care access, cost, and quality. The PHIT Partnership represents a collaboration between the MOH and PIH, with support from the National University of Rwanda School of Public Health, the National Institute of Statistics, Harvard Medical School, and Brigham and Women’s Hospital.Description of interventionThe PHIT Partnership’s health systems support aligns with the World Health Organization’s six health systems building blocks. HSS activities focus across all levels of the health system — community, health center, hospital, and district leadership — to improve health care access, quality, delivery, and health outcomes. Interventions are concentrated on three main areas: targeted support for health facilities, quality improvement initiatives, and a strengthened network of community health workers.Evaluation designThe impact of activities will be assessed using population-level outcomes data collected through oversampling of the demographic and health survey (DHS) in the intervention districts. The overall impact evaluation is complemented by an analysis of trends in facility health care utilization. A comprehensive costing project captures the total expenditures and financial inputs of the health care system to determine the cost of systems improvement. Targeted evaluations and operational research pieces focus on specific programmatic components, supported by partnership-supported work to build in-country research capacity.DiscussionBuilding on early successes, the work of the Rwanda PHIT Partnership approach to HSS has already seen noticeable increases in facility capacity and quality of care. The rigorous planned evaluation of the Partnership’s HSS activities will contribute to global knowledge about intervention methodology, cost, and population health impact.

A dental public health approach based on computational mathematics: Monte Carlo simulation of childhood dental decay

This study developed a Monte Carlo simulation approach to examining the prevalence and incidence of dental decay using Australian children as a test environment. Monte Carlo simulation has been used for a half a century in particle physics (and elsewhere); put simply, it is the probability for various population-level outcomes seeded randomly to drive the production of individual level data. A total of five runs of the simulation model for all 275,000 12-year-olds in Australia were completed based on 2005-2006 data. Measured on average decayed/missing/filled teeth (DMFT) and DMFT of highest 10% of sample (Sic10) the runs did not differ from each other by more than 2% and the outcome was within 5% of the reported sampled population data. The simulations rested on the population probabilities that are known to be strongly linked to dental decay, namely, socio-economic status and Indigenous heritage. Testing the simulated population found DMFT of all cases where DMFT<>0 was 2.3 (n=128,609) and DMFT for Indigenous cases only was 1.9 (n=13,749). In the simulation population the Sic25 was 3.3 (n=68,750). Monte Carlo simulations were created in particle physics as a computational mathematical approach to unknown individual-level effects by resting a simulation on known population-level probabilities. In this study a Monte Carlo simulation approach to childhood dental decay was built, tested and validated.

Individual and population level effects of partner notification for Chlamydia trachomatis.

Partner notification (PN or contact tracing) is an important aspect of treating bacterial sexually transmitted infections (STIs), such as Chlamydia trachomatis. It facilitates the identification of new infected cases that can be treated through individual case management. PN also acts indirectly by limiting onward transmission in the general population. However, the impact of PN, both at the level of individuals and the population, remains unclear. Since it is difficult to study the effects of PN empirically, mathematical and computational models are useful tools for investigating its potential as a public health intervention. To this end, we developed an individual-based modeling framework called Rstisim. It allows the implementation of different models of STI transmission with various levels of complexity and the reconstruction of the complete dynamic sexual partnership network over any time period. A key feature of this framework is that we can trace an individual’s partnership history in detail and investigate the outcome of different PN strategies for C. trachomatis. For individual case management, the results suggest that notifying three or more partners from the preceding 18 months yields substantial numbers of new cases. In contrast, the successful treatment of current partners is most important for preventing re-infection of index cases and reducing further transmission of C. trachomatis at the population level. The findings of this study demonstrate the difference between individual and population level outcomes of public health interventions for STIs.

Bicyclists' violations—automobile drivers' fault? simultaneous increases in population-level bicycle violation and safety in a complex adaptive system of social traffic behaviour

BackgroundBicyclists famously flout traffic rules, sometimes causing collisions with automobiles. Some research suggests that road users adapt to each other's behaviour, reducing conflicts. However, few bicycle safety studies investigate potential...