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

Selective citation in human literature on phthalates

This folder describes the citation network analysis on the human literature on phthalates. Goal of the research is to identify determinants of selective citation in this field of research

Enforcement of the nutrition and health claim regulation

The nutrition and health claim regulation (NHCR) aims to protect consumers against false or incorrect nutrition and health claims by requesting scientific substantiation. It also aims to establish a level playing field in the internal market for all food producers. European regulations such as the NHCR require national authorities to enforce these acts. Regulation (EC) No 882/2004 requires national authorities to adopt a risk-based enforcement approach for controls on compliance with feed and food law requirements. Our analysis shows fragment- ed national enforcement practices. So, 18 Member States have developed 13 different guidance documents on the flexibility of wording and/or compliance with the NHCR, whilst the Member State authorities have also taken diverging actions. The NHCR is therefore current- ly unable to establish a level playing field. An EU-wide approach in enforcement should be developed to ensure such fair competition in the internal market

Active ingredients leading in health claims on functional foods

Defining and characterising the active ingredient is the first criterion in reviewing scientific substantiation of health claims by the European Food Safety Authority under the Nutrition and Health Claim Regulation. This study analyses three health claim dossiers where the active ingredient is directly connected to the food item containing the bioactive. Since this bioactive itself is held responsible for the effect, the association of the food item and the bioactive is not always justifiable. This association is shown to be influenced by both the type of claim and the substantiating evidence. We argue that it would be preferable to more precisely chemically define the active ingredients. Claims could then be based on a bioactive constituent without the necessity to connect the claim to a specific matrix, becoming more transparent and relevant to both the industry and consumers. Characterisation and defining the bioactive should therefore be central in the health claim

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