title: Case-control studies on the relationship between onchocerciasis and epilepsy: systematic review and meta-analysis.
abstract: OBJECTIVE
  A systematic review and meta-analysis of all available case-control studies on the relationship between onchocerciasis and epilepsy. Because age and level of onchocerciasis endemicity in the area of residence are major determinants for infection, an additional analysis was performed, restricted to studies achieving control of these confounding factors.
  
  
  METHODS
  Medical databases, the "African Neurology Database, Institute of Neuroepidemiology and Tropical Neurology, Limoges," reference lists of relevant articles, commercial search engines, up to May 2012.
  
  
  METHODS
  We searched for studies examining infection status with Onchocerca volvulus in persons with epilepsy (PWE) and without epilepsy (PWOE) providing data suitable for the calculation of pooled odds ratios (ORp) and/or standardized mean differences (SMD) using random-effects models.
  
  
  RESULTS
  Eleven studies providing data of qualitative skin biopsies for diagnosis of onchocerciasis were identified. Combined analysis on the total sample of 876 PWE and 4712 PWOE resulted in an ORp of 2.49 (95% confidence interval (95%CI): 1.61-3.86, p<0.001). When this analysis was restricted to those studies achieving control for age, residence and sex (367 PWE, 624 PWOE), an ORp of 1.29 (95% CI: 0.93-1.79; p = 0.139) was found. Presence of nodules for diagnosis of onchocerciasis was analyzed in four studies (225 PWE, 189 PWOE; ORp 1.74; 95%CI: 0.94-3.20; p<0.076), including two studies of the restricted analysis (106 PWE, 106 PWOE; ORp 2.81; 95%CI: 1.57-5.00; p<0.001). One study examined quantitative microfilariae counts in patients without preceding microfilaricidal treatment and demonstrated significantly higher counts in PWE than in PWOE.
  
  
  CONCLUSIONS
  Our results strengthen the hypothesis that, in onchocerciasis foci, epilepsy and infection with O. volvulus are associated. Analysis of indicators giving information on infection intensity, namely nodule palpation and quantitative microfilaria count in untreated patients, support the hypothesis that intensity of infection with O. volvulus is involved in the etiology of epilepsy.
authors.affiliation: Basic Health Services Kabarole & Bundibugyo Districts, Fort Portal, Uganda. drchkaiser@web.de
authors.forename: Christoph
authors.initials: C
authors.lastname: Kaiser
authors.forename: Sébastien D S
authors.initials: SD
authors.lastname: Pion
authors.forename: Michel
authors.initials: M
authors.lastname: Boussinesq
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D004827:Epilepsy / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017181:Onchocerca volvulus / Q000472:pathogenicity; D009855:Onchocerciasis / Q000150:complications*; D055815:Young Adult
references.citation: Lancet. 1994 Jan 15;343(8890):183-4
references.pmid: 7904037
references.citation: Stat Med. 1996 Mar 30;15(6):619-29
references.pmid: 8731004
references.citation: Epilepsia. 2003 Jul;44(7):950-5
references.pmid: 12823579
references.citation: Epilepsia. 2009 Oct;50(10):2325-6
references.pmid: 19785668
references.citation: Tropenmed Parasitol. 1976 Jun;27(2):123-32
references.pmid: 941247
references.citation: Epilepsy Res. 1998 May;30(3):247-51
references.pmid: 9657652
references.citation: Bull World Health Organ. 1962;27(4-5):629-32
references.pmid: 20604134
references.citation: Trans R Soc Trop Med Hyg. 1983;77(6):857-61
references.pmid: 6665840
references.citation: Bull World Health Organ. 1962;27:609-15
references.pmid: 13960828
references.citation: Arch Neurol. 2007 Dec;64(12):1696-700
references.pmid: 18071032
references.citation: Bull World Health Organ. 1986;64(5):667-81
references.pmid: 3492300
references.citation: PLoS Negl Trop Dis. 2009 Jun 16;3(6):e461
references.pmid: 19529767
references.citation: PLoS Med. 2009 Jul 21;6(7):e1000097
references.pmid: 19621072
references.citation: Hum Pathol. 1970 Dec;1(4):581-94
references.pmid: 5535426
references.citation: Epilepsia. 2010 May;51(5):830-7
references.pmid: 19919664
references.citation: Trop Geogr Med. 1986 Sep;38(3):203-8
references.pmid: 3018970
references.citation: Lancet. 1996 Mar 23;347(9004):836
references.pmid: 8622372
references.citation: Am J Trop Med Hyg. 2002 Dec;67(6):669-79
references.pmid: 12518860
references.citation: Tropenmed Parasitol. 1976 Jun;27(2):133-44
references.pmid: 941248
references.citation: Ann Trop Med Parasitol. 1959 Apr;53(1):97-102
references.pmid: 13650495
references.citation: Trans R Soc Trop Med Hyg. 1997 Sep-Oct;91(5):525-7
references.pmid: 9463656
references.citation: Bull Soc Pathol Exot. 2000 Nov;93(4):255-9
references.pmid: 11204726
references.citation: MMWR Morb Mortal Wkly Rep. 2012 Jan 27;61(3):52-4
references.pmid: 22278159
references.citation: Am J Trop Med Hyg. 2008 Nov;79(5):643-4; author reply 644-5
references.pmid: 18981494
references.citation: Trans R Soc Trop Med Hyg. 2007 Jan;101(1):48-55
references.pmid: 16905166
references.citation: Bull Soc Pathol Exot. 1995 Mar;88(4):164-9
references.pmid: 8640078
references.citation: Trans R Soc Trop Med Hyg. 1974;68(3):190-208
references.pmid: 4421166
references.citation: Epilepsy Res. 2008 Dec;82(2-3):200-10
references.pmid: 18976884
references.citation: Epilepsia. 1987 May-Jun;28(3):272-9
references.pmid: 3582291
references.citation: Trans R Soc Trop Med Hyg. 2002 Sep-Oct;96(5):537-41
references.pmid: 12474484
references.citation: Br J Ophthalmol. 1958 Jan;42(1):21-37
references.pmid: 13499854
references.citation: Ann Trop Med Parasitol. 2002 Apr;96(3):297-307
references.pmid: 12061976
references.citation: Trans R Soc Trop Med Hyg. 2008 Feb;102(2):148-54
references.pmid: 18082234
references.citation: Int J Parasitol. 2004 Mar 29;34(4):463-73
references.pmid: 15013736
references.citation: Am J Trop Med Hyg. 1996 Jan;54(1):80-3
references.pmid: 8651377
references.citation: Stat Med. 1999 Feb 15;18(3):321-59
references.pmid: 10070677
references.citation: Lancet Neurol. 2005 Jan;4(1):21-31
references.pmid: 15620854
references.citation: Invest Ophthalmol Vis Sci. 1993 Sep;34(10):2888-902
references.pmid: 8360022
references.citation: Trop Med Parasitol. 1993 Jun;44(2):61-8
references.pmid: 8367667
references.citation: Filaria J. 2003 Mar 24;2(1):8
references.pmid: 12769825
references.citation: Am J Epidemiol. 1999 Mar 15;149(6):565-70
references.pmid: 10084246
references.citation: Bull World Health Organ. 1979;57(4):655-62
references.pmid: 316743
references.citation: Am J Trop Med Hyg. 2012 Mar;86(3):557
references.pmid: 22403337
references.citation: Trop Med Int Health. 2004 Jan;9(1):92-5
references.pmid: 14728612
references.citation: Epilepsia. 1992 Nov-Dec;33(6):1051-6
references.pmid: 1464263
references.citation: East Afr Med J. 1950 Sep;27(9):339-59
references.pmid: 14793447
references.citation: Lancet Neurol. 2003 Dec;2(12):714
references.pmid: 14649236
references.citation: Trends Parasitol. 2006 Jan;22(1):17-20
references.pmid: 16307906
references.citation: Epilepsia. 2008 Dec;49(12):2008-15
references.pmid: 18503562
references.citation: Am J Trop Med Hyg. 2008 Mar;78(3):400-1
references.pmid: 18337333
references.citation: Trop Doct. 1998 Apr;28(2):73-7
references.pmid: 9594671
references.citation: Lancet. 1998 May 2;351(9112):1341-6
references.pmid: 9643811
references.citation: Am J Trop Med Hyg. 2011 Aug;85(2):225-8
references.pmid: 21813839
references.citation: Med Trop (Mars). 2000;60(2):151-5
references.pmid: 11100441
references.citation: Bull Soc Pathol Exot. 1990;83(2):263-74
references.pmid: 2208456
references.citation: Parasitology. 2010 Sep;137(10):1559-68
references.pmid: 20388236
references.citation: Trans R Soc Trop Med Hyg. 1998 Mar-Apr;92(2):236
references.pmid: 9764344
references.citation: Epilepsia. 1979 Dec;20(6):613-22
references.pmid: 499114
references.citation: Neuroepidemiology. 2004 May-Jun;23(3):144-9
references.pmid: 15084784
references.citation: Lancet. 2012 Sep 29;380(9848):1193-201
references.pmid: 23021288
references.citation: Trans R Soc Trop Med Hyg. 1959 Mar;53(2):138-41
references.pmid: 13647617
references.citation: East Afr Med J. 1992 Oct;69(10):554-6
references.pmid: 1473507
references.citation: Bull World Health Organ. 1996;74(4):361-7
references.pmid: 8823957
references.citation: Trans R Soc Trop Med Hyg. 1950 Jan;43(4):362
references.pmid: 15404734
references.citation: Philos Trans R Soc Lond B Biol Sci. 1999 Apr 29;354(1384):809-26
references.pmid: 10365406
references.citation: Lancet Neurol. 2013 Feb;12(2):166-74
references.pmid: 23305742