Selective citation in the literature on the hygiene hypothesis:A citation analysis on the association between infections and rhinitis

Objective Our objective was to assess the occurrence and determinants of selective citation in scientific publications on Strachan's original hygiene hypothesis. His hypothesis states that lack of exposure to infections in early childhood increases the risk of rhinitis. Setting Web of Science Core Collection. Participants We identified 110 publications in this network, consisting of 5551 potential citations. Primary and secondary outcome measures Whether a citation occurs or not, measured and analysed according to the preregistered protocol. Results We found evidence for citation bias in this field: publications supportive of the hypothesis were cited more often than non-supportive publications (OR adjusted for study design [adjOR] 2.2, 95% CI 1.6 to 3.1), and the same was the case for publications with mixed findings (adjOR 3.1, 95% CI 2.2 to 4.5). Other relevant determinants for citation were type of exposure, specificity, journal impact factor, authority and self-citation. Surprisingly, prospective cohort studies were cited less often than other empirical studies. Conclusions There is clear evidence for selective citation in this research field, and particularly for citation bias

Determinants of Citation in Epidemiological Studies on Phthalates:A Citation Analysis

Citing of previous publications is an important factor in knowledge development. Because of the great amount of publications available, only a selection of studies gets cited, for varying reasons. If the selection of citations is associated with study outcome this is called citation bias. We will study determinants of citation in a broader sense, including e.g. study design, journal impact factor or the funding source of the publication. As a case study we assess which factors drive citation in the human literature on phthalates, specifically the metabolite mono(2-ethylhexyl) phthalate (MEHP). A systematic literature search identified all relevant publications on human health effect of MEHP. Data on potential determinants of citation were extracted in duplo. Specialized software was used to create a citation network, including all potential citation pathways. Random effect logistic regression was used to assess whether these determinants influence the likelihood of citation. 112 Publications on MEHP were identified, with 5684 potential citation pathways of which 551 were actual citations. Reporting of a harmful point estimate, journal impact factor, authority of the author, a male corresponding author, research performed in North America and self-citation were positively associated with the likelihood of being cited. In the literature on MEHP, citation is mostly driven by a number of factors that are not related to study outcome. Although the identified determinants do not necessarily give strong indications of bias, it shows selective use of published literature for a variety of reasons

Identifying unmet clinical need in hypertrophic cardiomyopathy using national electronic health records

Introduction: To evaluate unmet clinical need in unselected hypertrophic cardiomyopathy (HCM) patients to determine the risk of a wide range of subsequent cardiovascular disease endpoints and safety endpoints relevant for trial design. Methods: Population based cohort (CALIBER, linked primary care, hospital and mortality records in England, period 1997–2010), all people diagnosed with HCM were identified and matched by age, sex and general practice with ten randomly selected people without HCM. Random-effects Poisson models were used to assess the associations between HCM and cardiovascular diseases and bleeding. Results: Among 3,290,455 eligible people a diagnosis of hypertrophic cardiomyopathy was found in 4 per 10,000. Forty-one percent of the 1,160 individuals with hypertrophic cardiomyopathy were women and the median age was 57 years. The median follow-up was 4.0 years. Compared to general population controls, people with HCM had higher risk of ventricular arrhythmia (incidence rate ratio = 23.53, [95% confidence interval 12.67–43.72]), cardiac arrest or sudden cardiac death (6.33 [3.69–10.85]), heart failure (4.31, [3.30–5.62]), and atrial fibrillation (3.80 [3.04–4.75]). HCM was also associated with a higher incidence of myocardial infarction ([MI] 1.90 [1.27–2.84]) and coronary revascularisation (2.32 [1.46–3.69]).The absolute Kaplan-Meier risks at 3 years were 8.8% for the composite endpoint of cardiovascular death or heart failure, 8.4% for the composite of cardiovascular death, stroke or myocardial infarction, and 1.5% for major bleeding. Conclusions: Our study identified major unmet need in HCM and highlighted the importance of implementing improved cardiovascular prevention strategies to increase life-expectancy of the contemporary HCM population. They also show that national electronic health records provide an effective method for identifying outcomes and clinically relevant estimates of composite efficacy and safety endpoints essential for trial design in rare diseases

Abstract Reporting Bias

This research project aims to study the occurrence of abstract reporting bias

Standing on one shoulder: citation bias in the epidemiological literature

Newton once wrote: “If I have seen further, it is by standing on the shoulders of giants.” Science can make progress by building on earlier research. Citation analyses can show which research is being built on. If only positive studies that confirm a hypothesis are quoted, and negative studies that undermine the same hypothesis are ignored, we experience citation bias. This bias can lead to the development of knowledge being distorted, unnecessary research being carried out and incorrect decisions being made. This dissertation investigated whether there is selective quoting within the epidemiological literature, and specifically whether there is citation bias. This appears to be the case; in particular, positive studies seem to prefer to cite other positive studies, while negative studies have no publications for positive or negative studies

Miscellaneous

Publications on Sound Science that do not fit in any of the other research projects registered here on DataVers

Evaluating Registered Reports with P-curves

Research project on Registered Reports, aiming to evaluate their evidential value with the help of p curves. Is the evidential value from Registered better than from regular publications

Evaluating Registered Reports with P-curves

Research project on Registered Reports, aiming to evaluate their evidential value with the help of p curves. Is the evidential value from Registered better than from regular publications

Citation analysis of the published literature on the association between swimming in chlorinated water and childhood asthma

Citation analysis of the published literature on the association between swimming in chlorinated water and childhood asthm