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This review examines the relationship between long-term antipsychotic use and individual functioning, emphasizing clinical implications and the need for personalized care. The initial impression that antipsychotic medications may worsen long-term outcomes is critically assessed, highlighting the confounding effects of illness trajectory and individual patient characteristics. Moving beyond a focus on methodological limitations, the discussion centers on how these findings can inform clinical practice, keeping in consideration that a subset of patients with psychotic disorders are on a trajectory of long-term remission and that for a subset of patient the adverse effects of antipsychotics outweigh potential benefits. Key studies such as the OPUS study, Chicago Follow-up study, Mesifos trial, and RADAR trial are analyzed. While antipsychotics demonstrate efficacy in short-term symptom management, their long-term effects on functioning are less obvious and require careful interpretation. Research on long-term antipsychotic use and individual functioning isn't sufficient to favor antipsychotic discontinuation or dose reduction below standard doses for most patients, but it is sufficient to highlight the necessity of personalization of clinical treatment and the appropriateness of dose reduction/discontinuation in a considerable subset of patients.
In this chapter, we look at the analytic studies that are our main tools for identifying the causes of disease and evaluating health interventions. Unlike descriptive epidemiology, analytic studies involve planned comparisons between people with and without disease, or between people with and without exposures thought to cause (or prevent) disease. They try to answer the questions, ‘Why do some people develop disease?’ and ‘How strong is the association between exposure and outcome?’. This group of studies includes the intervention, cohort and case–control studies that you met briefly in Chapter 1. Together, descriptive and analytic epidemiology provide information for all stages of health planning, from the identification of problems and their causes to the design, funding and implementation of public health solutions and the evaluation of whether these solutions really work and are cost-effective in practice.
In Chapter 1 the different medical study designs are discussed and the difference between age, period and cohort effects is explained. Furthermore, some general information (e.g. prior knowledge, software used for the examples) needed to work through the book is provided. Finally, there is a short section in which the differences between the second and third edition are outlined.
The basic insight of evidence-based medicine is that randomized studies are more valid in their results than observational studies or case studies or clinical experience, in that order, because of correction for confounding bias. This concept of levels of evidence is the key to understanding EBM.
There is a case to be made for evidence-based medicine (EBM), and there is a case to be made against it. Many of the critiques of EBM are ill-founded, but some important criticisms need attention. The issues and concerns around EBM are discussed.
The controversial field of observational studies is covered, taking medicines and their possible side-effects and also lifestyle choices as an example.
Disasters have short and long-term negative effects on a large array of physical and mental health outcomes. Epidemiology offers a variety of tools and methodologies for conducting a needs assessment, surveillance, and longitudinal research aimed at identifying adverse outcomes and developing strategies for preventing disease and promoting health. The application of epidemiological methods has advanced our understanding of pervasive morbidity and mortality often experienced in the aftermath of disasters. Findings from epidemiological studies have implications for improving the allocation of resources and developing interventions targeting these adverse outcomes. In this chapter, we briefly highlight developments in the epidemiology of disasters. We present common study designs employed in disaster response and research and provide examples of applications of these methods in studying the consequences of the 1988 Spitak earthquake in Armenia. The chapter concludes with a brief discussion of recent developments in research methodology and their potential implications for disaster researchers and public health practitioners focusing on prevention and mitigation.
Achen aims to correct what he perceives as an imbalance in favor of randomized controlled trials – experiments – within contemporary social science. “The argument for experiments depends critically on emphasizing the central challenge of observational work – accounting for unobserved confounders – while ignoring entirely the central challenge of experimentation – achieving external validity,” he writes. Using the mathematics behind randomized controlled trials to make his point, he shows that once this imbalance is corrected, we are closer to Cartwright’s view (Chapter 2) than to the current belief that RCTs constitute the gold standard for good policy research. Achen concludes: “Causal inference of any kind is just plain hard. If the evidence is observational, patient consideration of plausible counterarguments, followed by the assembling of relevant evidence, can be, and often is, a painstaking process.” Well-structured qualitative case studies are one important tool; experiments, another.
Although recognised as the most effective antipsychotic for treatment-resistant schizophrenia, clozapine remains underused. One reason is the widespread concern about non-adherence to clozapine because of poor adherence before initiating clozapine.
Aims
To determine if prior poor out-patient adherence to treatmentbefore initiating clozapine predisposes to poor out-patient adherence to clozapine or to any antipsychotics (including clozapine) after its initiation.
Method
This cohort study included 3228 patients with schizophrenia living in Quebec (Canada) initiating (with a 2-year clearance period) oral clozapine (index date) between 2009 and 2016. Using pharmacy data, out-patient adherence to treatment was measured by the medication possession ratio (MPR), over a 1-year period preceding and following the index date. Five groups of patients were formed based on their prior MPR level (independent variable). Two dependent variables were defined after clozapine initiation (good out-patient adherence to any antipsychotics and to clozapine only). Along with multiple logistic regressions, state sequence analysis was used as a visual representation of antipsychotic-use trajectories over time, before and after clozapine initiation.
Results
Although prior poor adherence to antipsychotics was associated with poor adherence after clozapine initiation, the absolute risk of subsequent poor adherence remained low, regardless of previous adherence level. Most patients adhered to their treatment after initiating clozapine (>68% to clozapine and >84% to any antipsychotics).
Conclusions
Despite the fact that poor adherence prior to initiating clozapine is widely recognised by clinicians as a barrier for the prescription of clozapine, the current study supports the initiation of clozapine in all eligible patients.
Depression is a mental disorder triggered by the interaction of social, psychological and biological factors that have an important impact on an individual’s life. Despite being a well-studied disease with several established forms of treatment, its prevalence is increasing, especially among older adults. New forms of treatment and prevention are encouraged, and some researchers have been discussing the effects of vitamin D (VitD) on depression; however, the exact mechanism by which VitD exerts its effects is not yet conclusive. In this study, we aimed to discuss the possible mechanisms underlying the association between VitD and depression in older adults. Therefore, we conducted a systematic search of databases for indexed articles published until 30 April 2021. The primary focus was on both observational studies documenting the association between VitD and depression/depressive symptoms, and clinical trials documenting the effects of VitD supplementation on depression/depressive symptoms, especially in older adults. Based on pre-clinical, clinical and observational studies, it is suggested that the maintenance of adequate VitD concentrations is an important issue, especially in older adults, which are a risk population for both VitD deficiency and depression. Nevertheless, it is necessary to carry out more studies using longitudinal approaches in low- and middle-income countries to develop a strong source of evidence to formulate guidelines and interventions.
Numerous animal models and epidemiological and observational studies have demonstrated that enterovirus (EV) infection could be involved in the development of clinical type 1 diabetes mellitus (T1DM), but its aetiology is not fully understood. Therefore, we reviewed the association between EV infection and clinical T1DM. We searched PubMed and Embase from inception to April 2021 and reference lists of included studies without any language restrictions in only human studies. The correlation between EV infection and clinical T1DM was calculated as the pooled odds ratio (OR) and 95% confidence intervals (CIs), analysed using random-effects models. Subgroup and sensitivity analyses were performed to evaluate the robustness of the associations. A total of 25 articles (22 case–control studies and three nested case–control studies) met the inclusion criterion including 4854 participants (2948 cases and 1906 controls) with a high level of statistical heterogeneity (I2 = 80%, P < 0.001) mainly attributable to methods of EV detection, study type, age distribution, source of EV sample and control subjects. Meta-analysis showed a significant association between EV infection and clinical T1DM (OR 5.75, 95% CI 3.61–9.61). There is a clinically significant association between clinical T1DM and EV infection.
There remain inconclusive findings from previous observational epidemiological studies on whether consumption of artificially sweetened soft drinks (ASSD) increases the risk of gastrointestinal (GI) cancer. We investigated the associations between the consumption of ASSD and the risk of GI cancer using a meta-analysis.
Design:
Systematic review and meta-analysis.
Setting:
PubMed and EMBASE were searched using keywords until May 2020 to identify observational epidemiological studies on the association between the consumption of ASSD and the risk of GI cancer.
Subjects:
Twenty-one case–control studies and seventeen cohort studies with 12 397 cancer cases and 2 474 452 controls.
Results:
In the random-effects meta-analysis of all the studies, consumption of ASSD was not significantly associated with the risk of overall GI cancer (OR/relative risk (RR), 1·02; 95 % CI, 0·92, 1·14). There was no significant association between the consumption of ASSD and the risk of overall GI cancer in the subgroup meta-analyses by study design (case–control studies: OR, 0·95; 95 % CI, 0·82, 1·11; cohort studies: RR, 1·14; 95 % CI, 0·97, 1·33). In the subgroup meta-analysis by type of cancer, consumption of ASSD was significantly associated with the increased risk of liver cancer (OR/RR, 1·28; 95 % CI, 1·03, 1·58).
Conclusions:
The current meta-analysis of observational epidemiological studies suggests that overall, there is no significant association between the consumption of ASSD and the risk of GI cancer.
The democratic peace—the idea that democracies rarely fight one another—has been called “the closest thing we have to an empirical law in the study of international relations.” Yet, some contend that this relationship is spurious and suggest alternative explanations. Unfortunately, in the absence of randomized experiments, we can never rule out the possible existence of such confounding biases. Rather than commonly used regression-based approaches, we apply a nonparametric sensitivity analysis. We show that overturning the negative association between democracy and conflict would require a confounder that is forty-seven times more prevalent in democratic dyads than in other dyads. To put this number in context, the relationship between democracy and peace is at least five times as robust as that between smoking and lung cancer. To explain away the democratic peace, therefore, scholars would have to find far more powerful confounders than those already identified in the literature.
This article offers a description and discussion of “shadowing” as a data collection and analytic tool, highlighting potential research opportunities related to the direct observation of individuals—principally political elites—in their normal daily routine for an extended period of time, often between one day and one week. In contrast with large-scale data collection methods, including surveys, shadowing enables researchers to develop detailed observations of political behavior that are not limited by the availability of administrative data or the constraints of a questionnaire or an interview guide. Unlike more in-depth qualitative methods, such as ethnography, shadowing is scalable in a manner that allows for larger sample sizes and the potential for medium-N inference. I provide a detailed account of how to design and conduct a shadowing study, including sampling strategies, techniques for coding shadowing data, and processes for drawing inferences about the behavior of shadowed subjects, drawing on examples from a completed shadowing-based study. I also discuss ways to mitigate selection and observer biases, presenting results that suggest these can be no more pronounced when shadowing political elites than in other forms of observational research.
The Paleolithic diet (PaleoDiet) is an allegedly healthy dietary pattern inspired by the consumption of wild foods and animals assumed to be consumed in the Paleolithic era. Despite gaining popularity in the media, different operational definitions of this Paleolithic nutritional intake have been used in research. Our hypothesis is that specific components used to define the PaleoDiet may modulate the association of this diet with several health outcomes. We comprehensively reviewed currently applied PaleoDiet scores and suggested a new score based on the food composition of current PaleoDiet definitions and the theoretical food content of a staple dietary pattern in the Paleolithic age. In a PubMed search up to December 2019, fourteen different PaleoDiet definitions were found. We observed some common components of the PaleoDiet among these definitions although we also found high heterogeneity in the list of specific foods that should be encouraged or banned within the PaleoDiet. Most studies suggest that the PaleoDiet may have beneficial effects in the prevention of cardiometabolic diseases (type 2 diabetes, overweight/obesity, CVD and hyperlipidaemias) but the level of evidence is still weak because of the limited number of studies with a large sample size, hard outcomes instead of surrogate outcomes and long-term follow-up. Finally, we propose a new PaleoDiet score composed of eleven food items, based on a high consumption of fruits, nuts, vegetables, fish, eggs and unprocessed meats (lean meats); and a minimum content of dairy products, grains and cereals, and legumes and practical absence of processed (or ultra-processed) foods or culinary ingredients.
Amidst rising concern about publication bias, pre-registration and results-blind review have grown rapidly in use. Yet discussion of both the problem of publication bias and of potential solutions has been remarkably narrow in scope: publication bias has been understood largely as a problem afflicting quantitative studies, while pre-registration and results-blind review have been almost exclusively applied to experimental or otherwise prospective research. This chapter examines the potential contributions of pre-registration and results-blind review to qualitative and quantitative retrospective research. First, the chapter provides an empirical assessment of the degree of publication bias in qualitative political science research. Second, it elaborates a general analytic framework for evaluating the feasbility and utility of pre-registration and results-blind review for confirmatory studies. Third, through a review of published studies, the paper demonstrates that much observational—and, especially, qualitative—political science research displays features that would make for credible pre-registration. The paper concludes that pre-registration and results-blind review have the potential to enhance the validity of confirmatory research across a range of empirical methods, while elevating exploratory work by making it harder to disguise discovery as testing.
Matching for causal inference is a well-studied problem, but standard methods fail when the units to match are text documents: the high-dimensional and rich nature of the data renders exact matching infeasible, causes propensity scores to produce incomparable matches, and makes assessing match quality difficult. In this paper, we characterize a framework for matching text documents that decomposes existing methods into (1) the choice of text representation and (2) the choice of distance metric. We investigate how different choices within this framework affect both the quantity and quality of matches identified through a systematic multifactor evaluation experiment using human subjects. Altogether, we evaluate over 100 unique text-matching methods along with 5 comparison methods taken from the literature. Our experimental results identify methods that generate matches with higher subjective match quality than current state-of-the-art techniques. We enhance the precision of these results by developing a predictive model to estimate the match quality of pairs of text documents as a function of our various distance scores. This model, which we find successfully mimics human judgment, also allows for approximate and unsupervised evaluation of new procedures in our context. We then employ the identified best method to illustrate the utility of text matching in two applications. First, we engage with a substantive debate in the study of media bias by using text matching to control for topic selection when comparing news articles from thirteen news sources. We then show how conditioning on text data leads to more precise causal inferences in an observational study examining the effects of a medical intervention.
High-quality data are critical to the entire scientific enterprise, yet the complexity and effort involved in data curation are vastly under-appreciated. This is especially true for large observational, clinical studies because of the amount of multimodal data that is captured and the opportunity for addressing numerous research questions through analysis, either alone or in combination with other data sets. However, a lack of details concerning data curation methods can result in unresolved questions about the robustness of the data, its utility for addressing specific research questions or hypotheses and how to interpret the results. We aimed to develop a framework for the design, documentation and reporting of data curation methods in order to advance the scientific rigour, reproducibility and analysis of the data.
Methods:
Forty-six experts participated in a modified Delphi process to reach consensus on indicators of data curation that could be used in the design and reporting of studies.
Results:
We identified 46 indicators that are applicable to the design, training/testing, run time and post-collection phases of studies.
Conclusion:
The Data Acquisition, Quality and Curation for Observational Research Designs (DAQCORD) Guidelines are the first comprehensive set of data quality indicators for large observational studies. They were developed around the needs of neuroscience projects, but we believe they are relevant and generalisable, in whole or in part, to other fields of health research, and also to smaller observational studies and preclinical research. The DAQCORD Guidelines provide a framework for achieving high-quality data; a cornerstone of health research.
We investigated how initial conflicts in adolescent romantic relationships escalate into serious forms of conflict, including intimate partner violence (IPV). We focused on whether adolescents’ micro-level interaction patterns, i.e., coercion and positive engagement, mediated between conflict and future IPV. The sample consisted of 91 heterosexual couples, aged 13 to 18 years (M = 16.5, SD = 0.99) from a diverse background (42% Hispanic/Latino, 42% White). Participants completed surveys about conflict at Time 1, and they participated in videotaped conflict and jealousy discussions. At Time 2, participants completed surveys about conflict and IPV, and an average daily conflict score was calculated from ecological momentary assessments. Multilevel hazard models revealed that we did not find support for dyadic coercion as a risk process leading to escalations in conflict. However, a higher likelihood of ending dyadic positive behaviors mediated between earlier levels of conflict and a latent construct of female conflict and IPV. Classic coercive dynamics may not apply to adolescent romantic relationships. Instead, not being able to reinforce levels of positivity during conflict predicted conflict and IPV as reported by females. The implications of these findings for understanding coercion in the escalation from conflict to IPV in adolescent romantic relationships are discussed.
Dietary acid load (DAL) might contribute to change the levels of cardiometabolic risk factors; however, the results are conflicting. The present review was conducted to determine the relationship between DAL and cardiometabolic risk factors.
Design:
Systematic review and meta-analysis.
Setting:
A systematic search was conducted in electronic databases including ISI Web of Science, PubMed/MEDLINE, Scopus and Google Scholar for observational studies which assessed cardiometabolic risk factors across DAL. Outcomes were lipid profile, glycaemic factors and anthropometric indices. Effect sizes were derived using a fixed- or random-effect model (DerSimonian–Laird). Also, subgroup analysis was performed to find the probable source of heterogeneity. Egger’s test was performed for finding any publication bias.
Results:
Thirty-one studies were included in the current review with overall sample size of 92 478. There was a significant relationship between systolic blood pressure (SBP; weighted mean difference (WMD) = 1·74 (95 % CI 0·25, 3·24) mmHg; P = 0·022; I2 = 95·3 %), diastolic blood pressure (DBP; WMD = 0·75 (95 % CI 0·07, 1·42) mmHg; P = 0·030; I2 = 80·8 %) and DAL in cross-sectional studies. Serum lipids, glycaemic parameters including fasting blood sugar, glycated Hb, serum insulin, homeostatic model assessment of insulin resistance and waist circumference had no significant relationship with DAL. No publication bias was found. BMI was not associated with DAL in both cross-sectional and cohort studies.
Conclusions:
Higher DAL is associated with increased SBP and DBP. More studies are needed to find any relationship of DAL with lipid profile and glycaemic factors.