{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,24]],"date-time":"2026-01-24T08:05:54Z","timestamp":1769241954623,"version":"3.49.0"},"reference-count":16,"publisher":"Wiley","issue":"4","license":[{"start":{"date-parts":[[2019,7,26]],"date-time":"2019-07-26T00:00:00Z","timestamp":1564099200000},"content-version":"vor","delay-in-days":25,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"funder":[{"DOI":"10.13039\/100009633","name":"Eunice Kennedy Shriver National Institute of Child Health and Human Development","doi-asserted-by":"publisher","award":["DP2-HD084070"],"award-info":[{"award-number":["DP2-HD084070"]}],"id":[{"id":"10.13039\/100009633","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Paediatric Perinatal Epid"],"published-print":{"date-parts":[[2019,7]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Background<\/jats:title><jats:p>Several health agencies define microcephaly for surveillance purposes using a single criterion, a percentile or Z\u2010score cut\u2010off for newborn head circumference. This definition, however, conflicts with the reported prevalence of microcephaly even in populations with endemic Zika virus.<\/jats:p><\/jats:sec><jats:sec><jats:title>Objective<\/jats:title><jats:p>We explored possible reasons for this conflict, hypothesising that the definition of microcephaly used in some studies may be incompletely described, lacking the additional clinical criteria that clinicians use to make a formal diagnosis. We also explored the potential for misclassification that can result from differences in these definitions, especially when applying a percentile cut\u2010off definition in the presence of the much lower observed prevalence estimates that we believe to be valid.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>We conducted simulations under a theoretical bimodal distribution of head circumference. For different definitions of microcephaly, we calculated the sensitivity and specificity using varying cut\u2010offs of head circumference. We then calculated and plotted the positive predictive value for each of these definitions by prevalence of microcephaly.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Simple simulations suggest that if the true prevalence of microcephaly is approximately what is reported in peer\u2010reviewed literature, then relying on cut\u2010off\u2010based definitions may lead to very poor positive predictive value under realistic conditions.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions<\/jats:title><jats:p>While a simple head circumference criterion may be used in practice as a screening or surveillance tool, the definition lacks clarification as to what constitutes true pathological microcephaly and may lead to confusion about the true prevalence of microcephaly in Zika\u2010endemic areas, as well as bias in aetiologic studies.<\/jats:p><\/jats:sec>","DOI":"10.1111\/ppe.12561","type":"journal-article","created":{"date-parts":[[2019,7,26]],"date-time":"2019-07-26T09:12:43Z","timestamp":1564132363000},"page":"286-290","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Misclassification in defining and diagnosing microcephaly"],"prefix":"10.1111","volume":"33","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7329-8931","authenticated-orcid":false,"given":"Mariah M.","family":"Kalmin","sequence":"first","affiliation":[{"name":"Department of Epidemiology UNC\u2010Chapel Hill Chapel Hill North Carolina"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Emily W.","family":"Gower","sequence":"additional","affiliation":[{"name":"Department of Epidemiology UNC\u2010Chapel Hill Chapel Hill North Carolina"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Elizabeth M.","family":"Stringer","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynecology UNC\u2010Chapel Hill Chapel Hill North Carolina"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Natalie M.","family":"Bowman","sequence":"additional","affiliation":[{"name":"Department of Medicine UNC\u2010Chapel Hill Chapel Hill North Carolina"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Elizabeth T.","family":"Rogawski McQuade","sequence":"additional","affiliation":[{"name":"Department of Public Health Sciences University of Virginia Charlottesville Virginia"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Daniel","family":"Westreich","sequence":"additional","affiliation":[{"name":"Department of Epidemiology UNC\u2010Chapel Hill Chapel Hill North Carolina"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2019,7,26]]},"reference":[{"key":"e_1_2_10_2_1","first-page":"e20163692","article-title":"Microcephaly in Piaui, Brazil: descriptive study during the Zika virus epidemic, 2015\u20132016","volume":"27","author":"Ribeiro IG","year":"2018","journal-title":"Epidemiol Serv Saude"},{"key":"e_1_2_10_3_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jped.2016.02.009"},{"key":"e_1_2_10_4_1","doi-asserted-by":"publisher","DOI":"10.1126\/science.247.4939.198"},{"key":"e_1_2_10_5_1","doi-asserted-by":"publisher","DOI":"10.1080\/17550870903271363"},{"key":"e_1_2_10_6_1","volume-title":"Facts about Microcephaly","author":"Centers for Disease Control and Prevention","year":"2016"},{"key":"e_1_2_10_7_1","volume-title":"Microcephaly Fact Sheet","author":"World Health Organization","year":"2016"},{"key":"e_1_2_10_8_1","volume-title":"Microcephaly Information Page","author":"National Institute of Neurological Disorders and Stroke","year":"2017"},{"key":"e_1_2_10_9_1","volume-title":"American Academy of Pediatrics Textbook of Pediatric Care","author":"American Academy of Pediatrics","year":"2017"},{"key":"e_1_2_10_10_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.ajog.2016.02.043"},{"key":"e_1_2_10_11_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.hal.2017.02.004"},{"key":"e_1_2_10_12_1","doi-asserted-by":"publisher","DOI":"10.1111\/ele.13138"},{"key":"e_1_2_10_13_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.tmaid.2016.09.006"},{"key":"e_1_2_10_14_1","doi-asserted-by":"publisher","DOI":"10.1002\/bdr2.1347"},{"key":"e_1_2_10_15_1","doi-asserted-by":"publisher","DOI":"10.1002\/bdra.23587"},{"key":"e_1_2_10_16_1","doi-asserted-by":"publisher","DOI":"10.15585\/mmwr.mm6703a2"},{"key":"e_1_2_10_17_1","doi-asserted-by":"publisher","DOI":"10.15585\/mmwr.mm6731e1"}],"container-title":["Paediatric and Perinatal 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