Epidemiological and statistical methods

The choice of the right method is essential in epidemiology. Which sample size is necessary to verify an association between a risk factor and a disease, taking potential statistic variations into account? To which degree do other risk factors for the examined disease distort the outcome of a study? In order to get meaningful results, these questions must be evaluated for every new scenario.



Dr. Prof. Rafael Mikolajczyk

Head of research group

Selected Publications


Akmatov MK, Kimani-Murage E, Pessler F, Guzman CA, Krause G, Kreienbrock L & Mikolajczyk RT. (2015). Evaluation of Invalid Vaccine Doses in 31 Countries of the Who African Region. Vaccine, 33(7), 892-901. doi: 10.1016/j.vaccine.2014.10.089

Akmatov MK, Rubsamen N, Schultze A, Kemmling Y, Obi N, Gunther K, Ahrens W, Pessler F, Krause G & Mikolajczyk RT. (2015). Diverse Recruitment Strategies Result in Different Participation Percentages in a Web-Based Study, but in Similar Compliance. Int J Public Health. doi: 10.1007/s00038-015-0737-0

Betran AP, Torloni MR, Zhang J, Ye J, Mikolajczyk R, Deneux-Tharaux C, Oladapo OT, Souza JP, Tuncalp O, Vogel JP & Gulmezoglu AM. (2015). What Is the Optimal Rate of Caesarean Section at Population Level? A Systematic Review of Ecologic Studies. Reprod Health, 12(1), 57. doi: 10.1186/s12978-015-0043-6

Damm O, Ultsch B, Horn J, Mikolajczyk RT, Greiner W & Wichmann O. (2015). Systematic Review of Models Assessing the Economic Value of Routine Varicella and Herpes Zoster Vaccination in High-Income Countries. BMC Public Health, 15, 533. doi: 10.1186/s12889-015-1861-8

Gross MM, Matterne A, Berlage S, Kaiser A, Lack N, Macher-Heidrich S, Misselwitz B, Bahlmann F, Falbrede J, Hillemanns P, von Kaisenberg C, von Koch FE, Schild RL, Stepan H, Devane D & Mikolajczyk R. (2015). Interinstitutional Variations in Mode of Birth after a Previous Caesarean Section: A Cross-Sectional Study in Six German Hospitals. J Perinat Med, 43(2), 177-184. doi: 10.1515/jpm-2014-0108

Karch A, Castell S, Schwab F, Geffers C, Bongartz H, Brunkhorst FM, Gastmeier P & Mikolajczyk RT. (2015). Proposing an Empirically Justified Reference Threshold for Blood Culture Sampling Rates in Intensive Care Units. J Clin Microbiol, 53(2), 648-652. doi: 10.1128/JCM.02944-14

Maier IL, Karch A, Mikolajczyk R, Bahr M & Liman J. (2015). Effect of Beta-Blocker Therapy on the Risk of Infections and Death after Acute Stroke--a Historical Cohort Study. PLoS One, 10(2), e0116836. doi: 10.1371/journal.pone.0116836

McAlaney J, Helmer SM, Stock C, Vriesacker B, Van Hal G, Dempsey RC, Akvardar Y, Salonna F, Kalina O, Guillen-Grima F, Bewick BM & Mikolajczyk R. (2015). Personal and Perceived Peer Use of and Attitudes toward Alcohol among University and College Students in Seven Eu Countries: Project Snipe. J Stud Alcohol Drugs, 76(3), 430-438.

Mikolajczyk R, Horn J, Schmedt N, Langner I, Lindemann C & Garbe E. (2015). Injury Prevention by Medication among Children with Attention-Deficit/Hyperactivity Disorder: A Case-Only Study. JAMA Pediatr, 169(4), 391-395. doi: 10.1001/jamapediatrics.2014.3275

Ohlmeier C, Hoffmann F, Giersiepen K, Rothgang H, Mikolajczyk R, Appelrat HJ, Elsasser A & Garbe E. (2015). [Linkage of Statutory Health Insurance Data with Those of a Hospital Information System: Feasible, but Also "Useful"?]. Gesundheitswesen, 77(2), e8-e14. doi: 10.1055/s-0034-1395644

Ohlmeier C, Langner I, Hillebrand K, Schmedt N, Mikolajczyk R, Riedel O & Garbe E. (2015). Mortality in the German Pharmacoepidemiological Research Database (Gepard) Compared to National Data in Germany: Results from a Validation Study. BMC Public Health, 15, 570. doi: 10.1186/s12889-015-1943-7

Ohlmeier C, Mikolajczyk R, Frick J, Prutz F, Haverkamp W & Garbe E. (2015). Incidence, Prevalence and 1-Year All-Cause Mortality of Heart Failure in Germany: A Study Based on Electronic Healthcare Data of More Than Six Million Persons. Clin Res Cardiol. doi: 10.1007/s00392-015-0841-4

Pischke CR, Helmer SM, McAlaney J, Bewick BM, Vriesacker B, Van Hal G, Mikolajczyk RT, Akvardar Y, Guillen-Grima F, Salonna F, Orosova O, Dohrmann S, Dempsey RC & Zeeb H. (2015). Normative Misperceptions of Tobacco Use among University Students in Seven European Countries: Baseline Findings of the 'Social Norms Intervention for the Prevention of Polydrug Use' Study. Addict Behav, 51, 158-164. doi: 10.1016/j.addbeh.2015.07.012




Rubsamen N, Castell S, Horn J, Karch A, Ott JJ, Raupach-Rosin H, Zoch B, Krause G & Mikolajczyk RT(2015). Ebola Risk Perception in Germany, 2014. Emerg Infect Dis, 21(6), 1012-1018. doi: 10.3201/eid2106.150013

Schweitzer A, Horn J, Mikolajczyk RT, Krause G & Ott JJ(2015). Estimations of Worldwide Prevalence of Chronic Hepatitis B Virus Infection: A Systematic Review of Data Published between 1965 and 2013. Lancet. doi: 10.1016/s0140-6736(15)61412-x

Ye J, Zhang J, Mikolajczyk R, Torloni MR, Gulmezoglu AM & Betran AP. (2015). Association between Rates of Caesarean Section and Maternal and Neonatal Mortality in the 21st Century: A Worldwide Population-Based Ecological Study with Longitudinal Data. Bjog. doi: 10.1111/1471-0528.13592

Zhang J, Mikolajczyk R, Lei X, Sun L, Yu H & Cheng W. (2015). An Adjustable Fetal Weight Standard for Twins: A Statistical Modeling Study. BMC Med, 13, 159. doi: 10.1186/s12916-015-0401-9

Hechtner MC, Vogt T, Zollner Y, Schroder S, Sauer JB, Binder H, Singer S & Mikolajczyk R. (2014). Quality of Life in Parkinson's Disease Patients with Motor Fluctuations and Dyskinesias in Five European Countries. Parkinsonism Relat Disord, 20(9), 969-974. doi: 10.1016/j.parkreldis.2014.06.001

Helmer SM, Mikolajczyk RT, McAlaney J, Vriesacker B, Van Hal G, Akvardar Y, Guillen-Grima F, Salonna F, Stock C, Dempsey RC, Bewick BM & Zeeb H. (2014). Illicit Substance Use among University Students from Seven European Countries: A Comparison of Personal and Perceived Peer Use and Attitudes Towards Illicit Substance Use. Prev Med, 67, 204-209. doi: 10.1016/j.ypmed.2014.07.039

Hense S, Hillebrand K, Horn J, Mikolajczyk R, Schulze-Rath R & Garbe E. (2014). Hpv Vaccine Uptake after Introduction of the Vaccine in Germany: An Analysis of Administrative Data. Hum Vaccin Immunother, 10(6), 1729-1733. doi: 10.4161/hv.28450

Kersting C, Lindemann C, Jacobi C, Lo Baido A, Schneider A, Yurdakul M, Ziegler-Kirbach E, Mikolajczyk R & Garbe E. (2014). [Therapy Goals for Children and Adolescents with Adhd and Their Primary Caregivers. A Content Analysis and Examination of Agreement of Adhd Patients and Their Primary Caregivers.]. Gesundheitswesen. doi: 10.1055/s-0034-1387746

Mikolajczyk RT, Horn J, Prins M, Wiessing L & Kretzschmar M. (2014). Trajectories of Injecting Behavior in the Amsterdam Cohort Study among Drug Users. Drug Alcohol Depend. doi: 10.1016/j.drugalcdep.2014.08.020

Ohlmeier C, Frick J, Prutz F, Lampert T, Ziese T, Mikolajczyk R & Garbe E. (2014). [Use of Routine Data from Statutory Health Insurances for Federal Health Monitoring Purposes]. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz, 57(4), 464-472. doi: 10.1007/s00103-013-1912-1

Ohlmeier C, Linder R, Enders D, Mikolajczyk R, Haverkamp W, Horenkamp-Sonntag D & Garbe E. (2014). Evaluating Methods for Intersectoral Comparison of Quality of Care. A Routine Data Analysis of Elective Percutaneous Coronary Interventions. Methods Inf Med, 53(4), 269-277. doi: 10.3414/ME13-01-0132

Stich HL, Kramer A & Mikolajczyk RT. (2014). Clustering of Developmental Delays in Bavarian Preschool Children - a Repeated Cross-Sectional Survey over a Period of 12 Years. BMC Pediatr, 14, 18. doi: 10.1186/1471-2431-14-18



Helmer S, Sebena R, McAlaney J, Petkeviciene J, Urban R & Mikolajczyk RT(2013). Misperceptions of Peer Drinking Behaviour and Personal Alcohol Consumption among Students in Central and Eastern Europe. Paper presented at the Eur J Epidemiol. [Abstract] retrieved from

Horn J, Damm O, Kretzschmar ME, Delere Y, Wichmann O, Kaufmann AM, Garbe E, Kramer A, Greiner W & Mikolajczyk RT. (2013). Estimating the Long-Term Effects of Hpv Vaccination in Germany. Vaccine, 31(19), 2372-2380. doi: 10.1016/j.vaccine.2013.03.006

Kraut AA, Langner I, Lindemann C, Banaschewski T, Petermann U, Petermann F, Mikolajczyk RT & Garbe E. (2013). Comorbidities in Adhd Children Treated with Methylphenidate: A Database Study. BMC Psychiatry, 13, 11. doi: 10.1186/1471-244X-13-11

Langner I, Garbe E, Banaschewski T & Mikolajczyk RT(2013). Twin and Sibling Studies Using Health Insurance Data: The Example of Attention Deficit/Hyperactivity Disorder (Adhd). PLoS One, 8(4), e62177. doi: 10.1371/journal.pone.0062177

Mikolajczyk R, Kraut A & Garbe E. (2013). Evaluation of Pregnancy Outcome Records in the German Pharmacoepidemiological Research Database (Gepard). Pharmacoepidemiol Drug Saf, 22(8), 873-880. doi: 10.1002/pds.3467

Mikolajczyk RT, Helmer S, Wörmann T, Bhopal R, Rey G, Juel J, Regidor E, Deboosere P, Mackenbach JP & Kunst AE. (2013). Infectious Diseases Mortality among Migrants and Host Population in Five European Countries. Paper presented at the Eur J Epidemiol. [Abstract] retrieved from

Mikolajczyk RT, Kraut AA, Horn J, Schulze-Rath R & Garbe E. (2013). Changes in Incidence of Anogenital Warts Diagnoses after the Introduction of Human Papillomavirus Vaccination in Germany-an Ecologic Study. Sex Transm Dis, 40(1), 28-31. doi: 10.1097/OLQ.0b013e3182756efd

Mikolajczyk RT, Prins M, Wiessing L & Kretzschmar M. (2013). Trajectories of Injecting Behaviour in the Amsterdam Cohort Study among Drug Users. Eur J Epidemiol, 28(Suppl 1), S13-14.

Mikolajczyk RT, Schmedt N, Zhang J, Lindemann C, Langner I & Garbe E. (2013). Regional Variation in Caesarean Deliveries in Germany and Its Causes. BMC Pregnancy Childbirth, 13, 99. doi: 10.1186/1471-2393-13-99

Ohlmeier C, Mikolajczyk R, Haverkamp W & Garbe E. (2013). Incidence, Prevalence, and Antithrombotic Management of Atrial Fibrillation in Elderly Germans. Europace. doi: 10.1093/europace/eut048

Samkange-Zeeb F, Mikolajczyk RT & Zeeb H. (2013). Awareness and Knowledge of Sexually Transmitted Diseases among Secondary School Students in Two German Cities. J Community Health, 38(2), 293-300. doi: 10.1007/s10900-012-9614-4

Zakar R, Zakar MZ, Mikolajczyk R & Kraemer A. (2013). Spousal Violence against Women and Its Association with Women's Mental Health in Pakistan. Health Care Women Int, 34(9), 795-813. doi: 10.1080/07399332.2013.794462




Akmatov M, Mikolajczyk R, Krumkamp R, Wörmann T, Chu J, Paetzelt G, Reintjes R, Pessler F & Krämer A. (2012). Availability of Indicators of Migration in the Surveillance of Hiv, Tuberculosis and Hepatitis B in the European Union – a Short Note. Journal of Public Health, 20(5), 483-486. doi: 10.1007/s10389-011-0488-1

Akmatov MK & Mikolajczyk RT. (2012). Timeliness of Childhood Vaccinations in 31 Low and Middle-Income Countries. J Epidemiol Community Health, 66(7), e14. doi: 10.1136/jech.2010.124651

El Ansari W, Stock C & Mikolajczyk RT. (2012). Relationships between Food Consumption and Living Arrangements among University Students in Four European Countries - a Cross-Sectional Study. Nutr J, 11, 28. doi: 10.1186/1475-2891-11-28

Garbe E, Mikolajczyk RT, Banaschewski T, Petermann U, Petermann F, Kraut AA & Langner I. (2012). Drug Treatment Patterns of Attention-Deficit/Hyperactivity Disorder in Children and Adolescents in Germany: Results from a Large Population-Based Cohort Study. J Child Adolesc Psychopharmacol, 22(6), 452-458. doi: 10.1089/cap.2012.0022

Helmer SM, Kramer A & Mikolajczyk RT. (2012). Health-Related Locus of Control and Health Behaviour among University Students in North Rhine Westphalia, Germany. BMC Res Notes, 5, 703. doi: 10.1186/1756-0500-5-703

Lindemann C, Langner I, Kraut AA, Banaschewski T, Schad-Hansjosten T, Petermann U, Petermann F, Schreyer-Mehlhop I, Garbe E & Mikolajczyk RT(2012). Age-Specific Prevalence, Incidence of New Diagnoses, and Drug Treatment of Attention-Deficit/Hyperactivity Disorder in Germany. J Child Adolesc Psychopharmacol, 22(4), 307-314. doi: 10.1089/cap.2011.0064

Lopez-del Burgo C, Mikolajczyk RT, Osorio A, Carlos S, Errasti T & de Irala J. (2012). Knowledge and Beliefs About Mechanism of Action of Birth Control Methods among European Women. Contraception, 85(1), 69-77. doi: 10.1016/j.contraception.2011.04.007

Mikolajczyk RT, Horn J, Damm O, Kaufmann AM & Kretzschmar ME. (2012). Re: Epidemiological Study of Anti-Hpv-16/18 Seropositivity and Subsequent Risk of Hpv-16 and -18 Infections. J Natl Cancer Inst, 104(2), 163; author reply 163-164. doi: 10.1093/jnci/djr517

Mikolajczyk RT, Iannotti RJ, Farhat T & Thomas V. (2012). Ethnic Differences in Perceptions of Body Satisfaction and Body Appearance among U.S. Schoolchildren: A Cross-Sectional Study. BMC Public Health, 12, 425. doi: 10.1186/1471-2458-12-425

Mikolajczyk RT, Kraut AA, Horn J, Schulze-Rath R & Garbe E. (2012). Auswirkungen Der Hpv-Impfung Auf Die Inzidenz Von Anogenitalen Warzen – Eine Auswertung Von Abrechnungsdaten Einer Krankenkasse. Paper presented at the DGEpi 2012, Regensburg 26.-29.09.

Pischke CR, Zeeb H, van Hal G, Vriesacker B, McAlaney J, Bewick BM, Akvardar Y, Guillen-Grima F, Orosova O, Salonna F, Kalina O, Stock C, Helmer SM & Mikolajczyk RT(2012). A Feasibility Trial to Examine the Social Norms Approach for the Prevention and Reduction of Licit and Illicit Drug Use in European University and College Students. BMC Public Health, 12, 882. doi: 10.1186/1471-2458-12-882

Sagel U, Kramer A & Mikolajczyk RT. (2012). "Blind Periods" in Screening for Toxoplasmosis in Pregnancy in Austria - a Debate. BMC Infect Dis, 12, 118. doi: 10.1186/1471-2334-12-118

Samkange-Zeeb F, Mikolajczyk RT & Zeeb H. (2012). Awareness and Knowledge of Sexually Transmitted Diseases among Secondary School Students in Two German Cities. J Community Health. doi: 10.1007/s10900-012-9614-4

Sebena R, El Ansari W, Stock C, Orosova O & Mikolajczyk RT. (2012). Are Perceived Stress, Depressive Symptoms and Religiosity Associated with Alcohol Consumption? A Survey of Freshmen University Students across Five European Countries. Subst Abuse Treat Prev Policy, 7, 21. doi: 10.1186/1747-597X-7-21

Stich HL, Baune BT, Caniato RN, Mikolajczyk RT & Kramer A. (2012). Individual Development of Preschool Children-Prevalences and Determinants of Delays in Germany: A Cross-Sectional Study in Southern Bavaria. BMC Pediatr, 12, 188. doi: 10.1186/1471-2431-12-188

Zakar R, Zakar MZ, Mikolajczyk R & Kramer A. (2012). Intimate Partner Violence and Its Association with Women's Reproductive Health in Pakistan. Int J Gynaecol Obstet, 117(1), 10-14. doi: 10.1016/j.ijgo.2011.10.032



Akmatov MK, Mikolajczyk RT, Meier S & Kramer A. (2011). Alcohol Consumption among University Students in North Rhine-Westphalia, Germany--Results from a Multicenter Cross-Sectional Study. J Am Coll Health, 59(7), 620-626. doi: 10.1080/07448481.2010.520176

Langner I, Mikolajczyk R & Garbe E. (2011). Regional and Temporal Variations in Coding of Hospital Diagnoses Referring to Upper Gastrointestinal and Oesophageal Bleeding in Germany. BMC Health Serv Res, 11, 193. doi: 10.1186/1472-6963-11-193

Mikolajczyk RT, Zhang J, Betran AP, Souza JP, Mori R, Gulmezoglu AM & Merialdi M. (2011). A Global Reference for Fetal-Weight and Birthweight Percentiles. Lancet, 377(9780), 1855-1861. doi: 10.1016/S0140-6736(11)60364-4

Neta G, Grewal J, Mikolajczyk R, Klebanoff M & Zhang J. (2011). Does the Individualized Reference Outperform a Simple Ultrasound-Based Reference Applied to Birth Weight in Predicting Child Neurodevelopment? Ultrasound Obstet Gynecol, 38(1), 62-66. doi: 10.1002/uog.8902

Sagel U, Kramer A & Mikolajczyk RT. (2011). Incidence of Maternal Toxoplasma Infections in Pregnancy in Upper Austria, 2000-2007. BMC Infect Dis, 11, 348. doi: 10.1186/1471-2334-11-348

Sebena R, Orosova O, Mikolajczyk RT & van Dijk JP. (2011). Selected Sociodemographic Factors and Related Differences in Patterns of Alcohol Use among University Students in Slovakia. BMC Public Health, 11, 849. doi: 10.1186/1471-2458-11-849

Zhang J, Mikolajczyk R, Grewal J, Neta G & Klebanoff M. (2011). Prenatal Application of the Individualized Fetal Growth Reference. Am J Epidemiol, 173(5), 539-543. doi: 10.1093/aje/kwq411


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