bias epidemiology


Summary: Any deviation of results or inferences from the truth, or processes leading to such deviation. Bias can result from several sources: one-sided or systematic variations in measurement from the true value (systematic error); flaws in study design; deviation of inferences, interpretations, or analyses based on flawed data or data collection; etc. There is no sense of prejudice or subjectivity implied in the assessment of bias under these conditions.

Top Publications

  1. Hook E, Regal R. Capture-recapture methods in epidemiology: methods and limitations. Epidemiol Rev. 1995;17:243-64 pubmed
  2. Lachin J. Statistical considerations in the intent-to-treat principle. Control Clin Trials. 2000;21:167-89 pubmed
    ..In such cases, a landmark analysis using the observations from the last patient evaluation is likely to prove more powerful than life-table or longitudinal analyses. Examples are described. ..
  3. . Capture-recapture and multiple-record systems estimation I: History and theoretical development. International Working Group for Disease Monitoring and Forecasting. Am J Epidemiol. 1995;142:1047-58 pubmed
    ..The final section of the paper discusses techniques for model selection in the context of models for estimating the size of populations. ..
  4. Richards B, Whittle S, Buchbinder R. Muscle relaxants for pain management in rheumatoid arthritis. Cochrane Database Syst Rev. 2012;1:CD008922 pubmed publisher
    ..However, even short term muscle relaxant use (24 hours to 2 weeks) is associated with significant adverse events, predominantly drowsiness and dizziness. ..
  5. Shabanzadeh D. New determinants for gallstone disease??. Dan Med J. 2018;65: pubmed
  6. Schwingshackl L, Hoffmann G, Buijsse B, Mittag T, Stelmach Mardas M, Boeing H, et al. Dietary supplements and risk of cause-specific death, cardiovascular disease, and cancer: a protocol for a systematic review and network meta-analysis of primary prevention trials. Syst Rev. 2015;4:34 pubmed publisher
    ..Results and conclusions are pending completion of this study. Our systematic review will be of great value to consumers of supplements, healthcare providers, and policy-makers, regarding the use of dietary supplements. CRD42014014801 . ..
  7. Jaturapatporn D, Isaac M, McCleery J, Tabet N. Aspirin, steroidal and non-steroidal anti-inflammatory drugs for the treatment of Alzheimer's disease. Cochrane Database Syst Rev. 2012;:CD006378 pubmed publisher
    ..Based on the studies carried out so far, the efficacy of aspirin, steroid and NSAIDs (traditional NSAIDs and COX-2 inhibitors) is not proven. Therefore, these drugs cannot be recommended for the treatment of AD. ..
  8. Carter C, Blizard R. Autism genes are selectively targeted by environmental pollutants including pesticides, heavy metals, bisphenol A, phthalates and many others in food, cosmetics or household products. Neurochem Int. 2016;: pubmed publisher
  9. Van Zuuren E, Albusta A, Fedorowicz Z, Carter B, Pijl H. Selenium supplementation for Hashimoto's thyroiditis. Cochrane Database Syst Rev. 2013;:CD010223 pubmed publisher
    ..This review highlights the need for randomised placebo-controlled trials to evaluate the effects of selenium in people with Hashimoto's thyroiditis and can ultimately provide reliable evidence to help inform clinical decision making. ..

More Information


  1. Koretz R, Avenell A, Lipman T. Nutritional support for liver disease. Cochrane Database Syst Rev. 2012;:CD008344 pubmed publisher
    ..Future trials have to be powered adequately to see small, but clinically important, differences. ..
  2. Perugi G, Quaranta G, Belletti S, Casalini F, Mosti N, Toni C, et al. General medical conditions in 347 bipolar disorder patients: clinical correlates of metabolic and autoimmune-allergic diseases. J Affect Disord. 2015;170:95-103 pubmed publisher
    ..If the link with autoimmune-allergic diathesis will be confirmed, it could provide an interesting new paradigm for the study of the "systemic" nature of mood disorders and a promising target for future treatment options. ..
  3. Fogarty M, Osborn D, Askie L, Seidler A, Hunter K, Lui K, et al. Delayed vs early umbilical cord clamping for preterm infants: a systematic review and meta-analysis. Am J Obstet Gynecol. 2018;218:1-18 pubmed publisher
    ..Analyses of individual patient data in these and other randomized controlled trials will be critically important in reliably evaluating important secondary outcomes. ..
  4. Boghossian T, Rashid F, Thompson W, Welch V, Moayyedi P, Rojas Fernandez C, et al. Deprescribing versus continuation of chronic proton pump inhibitor use in adults. Cochrane Database Syst Rev. 2017;3:CD011969 pubmed publisher
  5. Golubovsky J, Ilyas H, Chen J, Tanenbaum J, Mroz T, Steinmetz M. Risk factors and associated complications for postoperative urinary retention after lumbar surgery for lumbar spinal stenosis. Spine J. 2018;18:1533-1539 pubmed publisher
    ..Surgeons and anesthesiologists should take preventative measures against POUR in individuals with increased age, BPH, AKI, and UTI within 90 days before surgery, as these factors were found to significantly increase the risk of POUR. ..
  6. Hulshof C, Colosio C, Daams J, Ivanov I, Prakash K, Kuijer P, et al. WHO/ILO work-related burden of disease and injury: Protocol for systematic reviews of exposure to occupational ergonomic risk factors and of the effect of exposure to occupational ergonomic risk factors on osteoarthritis of hip or knee and selected o. Environ Int. 2019;125:554-566 pubmed publisher
    ..PROSPERO registration number: CRD42018102631. ..
  7. Moreno I, Cicinelli E, Garcia Grau I, Gonzalez Monfort M, Baù D, Vilella F, et al. The diagnosis of chronic endometritis in infertile asymptomatic women: a comparative study of histology, microbial cultures, hysteroscopy, and molecular microbiology. Am J Obstet Gynecol. 2018;218:602.e1-602.e16 pubmed publisher
    ..92% providing an opportunity to improve the clinical management of infertile patients with a risk of experiencing this ghost endometrial pathology. ..
  8. Hart R, Doherty D, McLachlan R, Walls M, Keelan J, Dickinson J, et al. Testicular function in a birth cohort of young men. Hum Reprod. 2015;30:2713-24 pubmed publisher
  9. Frampton G, Jones J, Rose M, Payne L. Placental growth factor (alone or in combination with soluble fms-like tyrosine kinase 1) as an aid to the assessment of women with suspected pre-eclampsia: systematic review and economic analysis. Health Technol Assess. 2016;20:1-160 pubmed
    ..This study is registered as PROSPERO CRD42015017670. The National Institute for Health Research Health Technology Assessment programme. ..
  10. Agabio R, Trogu E, Pani P. Antidepressants for the treatment of people with co-occurring depression and alcohol dependence. Cochrane Database Syst Rev. 2018;4:CD008581 pubmed publisher
    ..According to these results, in people with co-occurring depression and alcohol dependence, antidepressants may be useful for the treatment of depression, alcohol dependence, or both, although the clinical relevance may be modest. ..
  11. Norman G, Christie J, Liu Z, Westby M, Jefferies J, Hudson T, et al. Antiseptics for burns. Cochrane Database Syst Rev. 2017;7:CD011821 pubmed publisher
    ..Reporting was poor, to the extent that we are not confident that most trials are free from risk of bias. ..
  12. Strike K, Mulder K, Michael R. Exercise for haemophilia. Cochrane Database Syst Rev. 2016;12:CD011180 pubmed publisher
    ..However, some groups used prophylactic factor prior to exercise and other groups studied only subjects with moderate haemophilia. Therefore, the safety of these techniques for persons with severe haemophilia remains unclear. ..
  13. Manders M, McLindon L, Schulze B, Beckmann M, Kremer J, Farquhar C. Timed intercourse for couples trying to conceive. Cochrane Database Syst Rev. 2015;:CD011345 pubmed publisher
    ..Further research is required, reporting clinically relevant outcomes (live birth, clinical pregnancy rates and adverse effects), to determine if timed intercourse is safe and effective in couples trying to conceive. ..
  14. Naderpoor N, Shorakae S, de Courten B, Misso M, Moran L, Teede H. Metformin and lifestyle modification in polycystic ovary syndrome: systematic review and meta-analysis. Hum Reprod Update. 2015;21:560-74 pubmed publisher
  15. Hoyt A, Canfield M, Romitti P, Botto L, Anderka M, Krikov S, et al. Associations between maternal periconceptional exposure to secondhand tobacco smoke and major birth defects. Am J Obstet Gynecol. 2016;215:613.e1-613.e11 pubmed publisher
    ..Increased odds ratios resulting from chance (eg, multiple comparisons) or recall bias cannot be ruled out. ..
  16. Eslami L, Merat S, Malekzadeh R, Nasseri Moghaddam S, Aramin H. Statins for non-alcoholic fatty liver disease and non-alcoholic steatohepatitis. Cochrane Database Syst Rev. 2013;:CD008623 pubmed publisher
  17. Koretz R, Pleguezuelo M, Arvaniti V, Barrera Baena P, Ciria R, Gurusamy K, et al. Interferon for interferon nonresponding and relapsing patients with chronic hepatitis C. Cochrane Database Syst Rev. 2013;:CD003617 pubmed publisher
  18. Hutton B, Yazdi F, Bordeleau L, Morgan S, Cameron C, Kanji S, et al. Comparison of physical interventions, behavioral interventions, natural health products, and pharmacologics to manage hot flashes in patients with breast or prostate cancer: protocol for a systematic review incorporating network meta-analyses. Syst Rev. 2015;4:114 pubmed publisher
    ..Our findings will be shared with Cancer Care Ontario for consideration in the development of guidance related to supportive care in these patients. CRD42015024286. ..
  19. Radner H, Ramiro S, Buchbinder R, Landewe R, van der Heijde D, Aletaha D. Pain management for inflammatory arthritis (rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis and other spondylarthritis) and gastrointestinal or liver comorbidity. Cochrane Database Syst Rev. 2012;1:CD008951 pubmed publisher
  20. Saenz de Juano M, Billooye K, Smitz J, Anckaert E. The loss of imprinted DNA methylation in mouse blastocysts is inflicted to a similar extent by in vitro follicle culture and ovulation induction. Mol Hum Reprod. 2016;22:427-41 pubmed publisher
    ..N/A. This study received funding by Strategic Research Programs-Groeiers (OZR/2014/97), IWT/TBM/110680 and by UZ Brussel Fonds Willy Gepts (WFWG 2013). There is no conflict of interest. ..
  21. Sisay M, Weldegebreal F, Tesfa T, Ataro Z, Marami D, Mitiku H, et al. Resistance profile of clinically relevant bacterial isolates against fluoroquinolone in Ethiopia: a systematic review and meta-analysis. BMC Pharmacol Toxicol. 2018;19:86 pubmed publisher
    ..Within gram-negative bacteria, nearly half of isolates in N. gonorrhoea were found ciprofloxacin resistant. From enterobacteriaceae isolates, K. pneumonia and E. coli showed higher estimates of ciprofloxacin resistance. ..
  22. Simon L, Murphy K, Shamsi M, Liu L, Emery B, Aston K, et al. Paternal influence of sperm DNA integrity on early embryonic development. Hum Reprod. 2014;29:2402-12 pubmed publisher
    ..This work was supported by the University of Utah internal funds. The authors declare no competing interests. N/A. ..
  23. Cheuk D, Sieswerda E, van Dalen E, Postma A, Kremer L. Medical interventions for treating anthracycline-induced symptomatic and asymptomatic cardiotoxicity during and after treatment for childhood cancer. Cochrane Database Syst Rev. 2016;:CD008011 pubmed publisher
    ..We did not identify any RCTs or CCTs studying other medical interventions for symptomatic or asymptomatic cardiotoxicity in childhood cancer patients or survivors.High-quality studies should be performed. ..
  24. van Sonsbeek S, Pullens B, van Benthem P. Positive pressure therapy for Ménière's disease or syndrome. Cochrane Database Syst Rev. 2015;:CD008419 pubmed publisher
    ..Notwithstanding these comments, no complications or adverse effects were noted in any of the included studies. ..
  25. Boyles A, Blain R, Rochester J, Avanasi R, Goldhaber S, McComb S, et al. Systematic review of community health impacts of mountaintop removal mining. Environ Int. 2017;107:163-172 pubmed publisher
    ..Without such work, uncertainty will remain regarding the impact of these practices on the health of the people who breathe the air and drink the water affected by MTR mining. ..
  26. Yarrington C, Cantonwine D, Seely E, McElrath T, Zera C. The association of early unexplained elevated alanine aminotransferase with large-for-gestational-age birthweight. Am J Obstet Gynecol. 2016;215:474.e1-5 pubmed publisher
    ..This may represent the impact of maternal nonalcoholic fatty liver on the fetal developmental milieu. ..
  27. Jakobsen J, Nielsen E, Feinberg J, Katakam K, Fobian K, Hauser G, et al. Direct-acting antivirals for chronic hepatitis C. Cochrane Database Syst Rev. 2017;6:CD012143 pubmed publisher
    ..All trials and outcome results were at high risk of bias, so our results presumably overestimate benefit and underestimate harm. The quality of the evidence was very low. ..
  28. Simoes E, Bouras A, Cortez Escalante J, Malta D, Porto D, Mokdad A, et al. A priority health index identifies the top six priority risk and related factors for non-communicable diseases in Brazilian cities. BMC Public Health. 2015;15:443 pubmed publisher
    ..PHI can be used to track NCD prevention and health promotion actions at the local and national level in Brazil and in countries with similar public health surveillance systems. ..
  29. Bighelli I, Castellazzi M, Cipriani A, Girlanda F, Guaiana G, Koesters M, et al. Antidepressants versus placebo for panic disorder in adults. Cochrane Database Syst Rev. 2018;4:CD010676 pubmed publisher
    ..Data from the present review will be included in a network meta-analysis of psychopharmacological treatment in panic disorder, which will hopefully provide further useful information on this issue. ..
  30. Larun L, Brurberg K, Odgaard Jensen J, Price J. Exercise therapy for chronic fatigue syndrome. Cochrane Database Syst Rev. 2015;:CD003200 pubmed publisher
    ..Randomised trials with low risk of bias are needed to investigate the type, duration and intensity of the most beneficial exercise intervention. ..
  31. Levato R, Webb W, Otto I, Mensinga A, Zhang Y, van Rijen M, et al. The bio in the ink: cartilage regeneration with bioprintable hydrogels and articular cartilage-derived progenitor cells. Acta Biomater. 2017;61:41-53 pubmed publisher
    ..This study provides important cues on ACPCs, indicating they represent a promising cell source for the next generation of cartilage constructs with increased biomimicry. ..
  32. Li J, Eriksson M, Czene K, Hall P, Rodriguez Wallberg K. Common diseases as determinants of menopausal age. Hum Reprod. 2016;31:2856-2864 pubmed
    ..J.L. is a recipient of an Alex and Eva Wallström Foundation award. The authors declare that there is no conflict of interest regarding the publication of this paper. ..