title: Space-time clustering of non-hodgkin lymphoma using residential histories in a Danish case-control study.
abstract: Non-Hodgkin lymphoma (NHL) is a frequent cancer and incidence rates have increased markedly during the second half of the 20(th) century; however, the few established risk factors cannot explain this rise and still little is known about the aetiology of NHL. Spatial analyses have been applied in an attempt to identify environmental risk factors, but most studies do not take human mobility into account. The aim of this study was to identify clustering of NHL in space and time in Denmark, using 33 years of residential addresses. We utilised the nation-wide Danish registers and unique personal identification number that all Danish citizens have to conduct a register-based case-control study of 3210 NHL cases and two independent control groups of 3210 each. Cases were identified in the Danish Cancer Registry and controls were matched by age and sex and randomly selected from the Civil Registration System. Residential addresses of cases and controls from 1971 to 2003 were collected from the Civil Registration System and geocoded. Data on pervious hospital diagnoses and operations were obtained from the National Patient Register. We applied the methods of the newly developed Q-statistics to identify space-time clustering of NHL. All analyses were conducted with each of the two control groups, and we adjusted for previous history of autoimmune disease, HIV/AIDS or organ transplantation. Some areas with statistically significant clustering were identified; however, results were not consistent across the two control groups; thus we interpret the results as chance findings. We found no evidence for clustering of NHL in space and time using 33 years of residential histories, suggesting that if the rise in incidence of NHL is a result of risk factors that vary across space and time, the spatio-temporal variation of such factors in Denmark is too small to be detected with the applied method.
authors.affiliation: Danish Cancer Society Research Center, Copenhagen, Denmark. baastrup@cancer.dk
authors.forename: Rikke
authors.initials: R
authors.lastname: Baastrup Nordsborg
authors.forename: Jaymie R
authors.initials: JR
authors.lastname: Meliker
authors.forename: Annette
authors.initials: A
authors.lastname: Kjær Ersbøll
authors.forename: Geoffrey M
authors.initials: GM
authors.lastname: Jacquez
authors.forename: Ole
authors.initials: O
authors.lastname: Raaschou-Nielsen
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D016000:Cluster Analysis; D003718:Denmark / Q000453:epidemiology; D004777:Environment; D005260:Female; D006798:Housing; D006801:Humans; D015994:Incidence; D008228:Lymphoma, Non-Hodgkin / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D012042:Registries; D012307:Risk Factors
references.citation: Br J Cancer. 2000 May;82(9):1571-6
references.pmid: 10789727
references.citation: Scand J Public Health. 2011 Jul;39(7 Suppl):42-5
references.pmid: 21775350
references.citation: Spat Spatiotemporal Epidemiol. 2012 Dec;3(4):297-310
references.pmid: 23149326
references.citation: Int J Health Geogr. 2006 Aug 03;5:32
references.pmid: 16887016
references.citation: Stat Med. 2006 Nov 30;25(22):3929-43
references.pmid: 16435334
references.citation: BMJ. 1994 Aug 20-27;309(6953):501-5
references.pmid: 8086902
references.citation: Int J Cancer. 2007;120 Suppl 12:1-39
references.pmid: 17405121
references.citation: Scand J Public Health. 2011 Jul;39(7 Suppl):22-5
references.pmid: 21775345
references.citation: Scand J Public Health. 2011 Jul;39(7 Suppl):30-3
references.pmid: 21775347
references.citation: Br J Cancer. 1992 Apr;65(4):583-8
references.pmid: 1562467
references.citation: Oncogene. 2004 Aug 23;23(38):6524-34
references.pmid: 15322522
references.citation: Eur J Cancer. 2001 Oct;37 Suppl 8:S4-66
references.pmid: 11602373
references.citation: Am J Epidemiol. 2003 Dec 15;158(12):1182-92
references.pmid: 14652303
references.citation: Environ Health. 2005 Mar 22;4(1):4
references.pmid: 15784151
references.citation: Dan Med Bull. 1999 Jun;46(3):263-8
references.pmid: 10421985
references.citation: Dan Med Bull. 1997 Nov;44(5):535-9
references.pmid: 9408738
references.citation: Stoch Environ Res Risk Assess. 2007 Aug;21(5):625-634
references.pmid: 18560470
references.citation: Haematologica. 2005 Dec;90(12):1709-10
references.pmid: 16330453
references.citation: Cancer Epidemiol Biomarkers Prev. 2006 Jul;15(7):1295-300
references.pmid: 16835326
references.citation: Am J Epidemiol. 2000 Jul 1;152(1):13-9
references.pmid: 10901325
references.citation: Int J Cancer. 1999 Mar 15;80(6):827-41
references.pmid: 10074914
references.citation: Acta Oncol. 2006;45(3):258-71
references.pmid: 16644568
references.citation: Environ Health. 2011 Jun 30;10:63
references.pmid: 21718483
references.citation: Eur J Epidemiol. 2000;16(12):1111-6
references.pmid: 11484799
references.citation: Commun Stat Theory Methods. 1997 Jan 1;26(3):
references.pmid: 24363487
references.citation: Int J Cancer. 1996 Oct 9;68(2):156-9
references.pmid: 8900420