J Neurosurg Pediatrics 3:000–000, 2009 534 J. Neurosurg.: Pediatrics / Volume 3 / June 2009 E ncEphalocElEs are congenital malformations char- acterized by a protrusion of the brain tissue and/or meninges through a skull defect 1,3 and reportedly occur in 0.8–5.6 per 10,000 live births. 4,7,11 In patients in Western countries encephaloceles are most frequently located in the occipital region, whereas in Russian and Southeast Asian patients frontoethmoidal encephaloceles predominate. 8,13 The origin of the encephalocele is con- sidered to be complex, and any associated risk factors have remained mostly elusive. 13 There is some evidence that encephaloceles are associated with speciic environ- mental exposures such as hyperthermia and alatoxin. 1,13 Genetic background, maternal nutritional deiciencies, or other environmental factors may facilitate the develop- ment of an encephalocele. 8 Despite the known protective effect of folate against the occurrence of a myelomenin- gocele, the relationship between maternal folate levels and the incidence of an encephalocele is not evident. 1,9 We conducted the present study to further evaluate important risk factors associated with encephaloceles in 31 affected children and to compare the data with those in an equal number of controls. Methods This hospital-based case-control study was conduct- ed between August 2006 and August 2007 at the Chil- dren’s Hospital Medical Center in Tehran. We studied various risk factors in 31 children with encephaloceles, whose ages ranged from 1 month to 7 years. All patients were visited in our outpatient clinic either at their irst visit or during their follow-up. The control group con- sisted of 31 age-matched children who had been selected among the patients referred to other clinics for nonneural congenital anomalies. Choosing controls from the same hospital and among children with other congenital anom- alies was done to decrease the chance of recall bias; we based this decision on a conclusion that patients in the case group overstate past exposures but those in the con- trol group do not remember past exposures well. All data were collected using a structured question- naire during face-to-face interviews with the mothers. The same interviewer and questionnaire were used for both cohorts. Information was gleaned from the child’s birth certiicate, mother’s sociodemographic characteristics and lifestyle behaviors during pregnancy as well as her re- productive history, previous miscarriages, consanguinity of the child’s parents, and family history of NTDs. Peri- J Neurosurg Pediatrics 3:534–537, 2009 Risk factors associated with occipital encephalocele: a case-control study Clinical article Majid dadMehr, M.d., 1 F arideh Nejat , M.d., M.P.h., 1 MostaFa el Khashab, M.d., Ph.d., 2 saeed aNsari, M.d., 1 NiMa baradaraN, M.d., 1 abolhasaN ertiaei, M.d., 1 aNd F arzad bateNi, M.d. 3 1 Department of Neurosurgery, Children’s Hospital Medical Center, Tehran University of Medical Sciences, Tehran; 3 Department of Neurosurgery, Mashad University of Medical Sciences, Mashad, Iran; and 2 Hackensack University Medical Center, Hackensack, New Jersey Object. An encephalocele is characterized by congenital herniation of the brain tissue and/or meninges through a skull defect. The underlying cause is complex and not fully understood, but environmental agents are suspected. The authors aimed to determine the known risk factors for encephaloceles. Methods. Potential risk factors were studied in 31 children with encephaloceles who had been referred to the out- patient clinic. At the same time, 31 children with non-CNS anomalies were randomly selected from the same hospital as a control group. Both cohorts were assessed in person through interviews with the mothers. Results. Most children with encephaloceles were female. There was no signiicant risk factor in the case group as compared with controls, although the families of patients with encephaloceles had a better economic status (p = 0.03) and the fathers had a higher mean age. Conclusions. Although the authors of this study could not identify any signiicant risk factors for encephalo- celes, environmental factors can still be mentioned as probable etiological elements. Additional studies with larger sample sizes and more comprehensive evaluations are required to conirm the role of environmental or genetic factors to prevent the occurrence of encephaloceles. (DOI: 10.3171/2009.2.PEDS08436) Key Words • encephalocele • risk factor • economic status Abbreviation used in this paper: NTD = neural tube defect.