Publication bias in clinical research

Easterbrook, Philippa; Gopalan, Radha; Berlin, Jesse A.; Matthews, David R.

doi:10.1016/0140-6736(91)90201-y

Cited by 2,679 publications

(1,619 citation statements)

References 28 publications

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“…23a,30a Fourth, potential publication bias is inherent to population studies on the association between BP and dietary factors, including magnesium. 36 Twelve of 30 reports identified in our comprehensive search of the literature did not present an estimate of the association but only some unquantified differences between various subgroups. Is it possible that more studies reporting a negative, statistically significant, association might have been published in comparison with those reporting either no relation or a positive association.…”

Section: Discussionmentioning

confidence: 96%

Dietary magnesium intake and blood pressure: a qualitative overview of the observational studies

Mizushima

Cappuccio

Nichols³

et al. 1998

J Hum Hypertens

120

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Published reports of 30 separate sets of analyses from 29 observational studies relating dietary intake of magnesium to blood pressure (BP) were identified through a comprehensive search using MEDLINE and BIDS-EMBASE. Three studies were prospective, 24 crosssectional (25 reports), of which four also contained a longitudinal component, and two were obtained from baseline data in a trial. Various dietary methodologies were used: 24-h dietary recall (n = 12), food-frequency questionnaire (8), food record (7), and duplicate diet (2). Twelve reports compared magnesium intake or BP level between subgroups. Seven showed a negative association between magnesium intake and BP level, and five reported no association. From 18 of the 30 sets of analyses either a regression estimate or a Pearson correlation coefficient was reported. Many reports also allowed identification of subgroups by sex, age and race. Ninety population samples and subgroups could

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Section: Discussionmentioning

confidence: 96%

Dietary magnesium intake and blood pressure: a qualitative overview of the observational studies

Mizushima

Cappuccio

Nichols³

et al. 1998

J Hum Hypertens

120

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“…In time-lag bias, 39 studies with 'negative' results take longer time to be published, whereas enthusiastic results are published much more quickly. In publication bias, 40,41 small studies with 'negative' results are never published, whereas equally small studies with similar quality but 'positive' results would appear in the literature. We saw no evidence of such publication bias in any of the tests that we performed, but it remains one possible alternative explanation of our findings.…”

Section: Discussionmentioning

confidence: 99%

IL-10 polymorphisms and prostate cancer risk: a meta-analysis

Shao

et al. 2011

Prostate Cancer Prostatic Dis

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Evidence is accumulating that chronic inflammation may have an important role in prostate cancer (PCa). Three common polymorphisms in the promoter of interleukin-10 (IL-10) gene, À1082 A4G, À819 C4T and À592 C4A, have been implicated to alter the risk of PCa, but the results of relative studies are inconclusive or controversial. To derive a more precise estimation of the relationship, we performed an updated meta-analysis on the basis of 10 studies. A comprehensive search was conducted to examine all the eligible studies of IL-10 polymorphism and PCa risk. We used odds ratios (ORs) to assess the strength of the association, and 95% confidence intervals (CIs) give a sense of the precision of the estimate. Overall, there were no significant associations between increased risk of PCa and IL-10 À1082 A4G, À819 C4T and À592 C4A polymorphisms. However, meta-analysis suggested that IL-10 À819 C4T and À592 C4A polymorphisms might be modestly associated with PCa aggressiveness (T versus C, OR ¼ 1.162, 95% CI: 1.035-1.305, P ¼ 0.011; A versus C, OR ¼ 1.131, 95% CI: 1.012-1.264, P ¼ 0.030; respectively). IL-10 À819 C4T and À592 C4A polymorphisms might impact PCa progression. Variant alleles at both À819 and À592 were modestly associated with advanced stages of PCa. Additional well-designed studies are warranted to validate these findings.

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“…These findings are based on published data of observational studies and may be subject to various biases that may account for discrepancies found between prognostic factors and curve progression [53,54]. Relevant (and unpublished) studies hidden in unknown databases are difficult to locate and may have been missed.…”

Section: Limitationsmentioning

confidence: 99%

De novo degenerative lumbar scoliosis: a systematic review of prognostic factors for curve progression

et al. 2016

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Purpose To identify prognostic factors for curve progression in de novo degenerative lumbar scoliosis (DNDLS) by performing a systematic review of the literature. Methods Studies were selected for inclusion following a systematic search in the bibliographic databases PubMed and EMBASE prior to September 2015 and hand searches of the reference lists of retrieved articles. Two authors independently assessed methodological quality. Data were extracted and presented according to a best evidence synthesis. Results The literature search generated a total of 2696 references. After removing duplicates and articles that did not meet inclusion criteria, 12 studies were included. Due to the lack of statistical analyses, pooling of data was not possible. Strong evidence indicates that increasing intervertebral disk degeneration, lateral vertebral translation C6 mm, and an intercrest line through L5 (rather than L4) are associated with DNDLS curve progression. Moderate evidence suggests that apical vertebral rotation Grade II or III is associated with curve progression. For the majority of other prognostic factors, we found limited, conflicting, or inconclusive evidence. Osteoporosis, a coronal Cobb angle \30°, lumbar lordosis, lateral osteophytes difference of C5 mm, and degenerative spondylolisthesis have not been shown to be risk factors. Clinical risk factors for progression were not identified. Conclusions This review shows strong evidence that increased intervertebral disk degeneration, an intercrest line through L5, and apical lateral vertebral translation C6 mm are associated with DNDLS curve progression. Moderate evidence was found for apical vertebral rotation (Grade II/III) as a risk factor for curve progression. These results, however, may not be directly applicable to the individual patient.

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Publication bias in clinical research

Cited by 2,679 publications

References 28 publications

Dietary magnesium intake and blood pressure: a qualitative overview of the observational studies

Dietary magnesium intake and blood pressure: a qualitative overview of the observational studies

IL-10 polymorphisms and prostate cancer risk: a meta-analysis

De novo degenerative lumbar scoliosis: a systematic review of prognostic factors for curve progression

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