title: A protective role for early oral exposures in the etiology of young adult Hodgkin lymphoma.
abstract: The pattern of adolescent/young adult Hodgkin lymphoma (YAHL) suggests causation by a relatively late infection with a common childhood virus, but no causal virus has been found. Susceptibility is heritable and linked to lower interleukin 12 (IL12) levels, which can also result from fewer fecal-oral microbial exposures early in life. We studied twin pairs discordant for YAHL to examine exposures capable of altering the IL12 response and T-helper type 1 (Th1)-Th2 balance. One hundred eighty-eight YAHL-discordant twin pairs from the International Twin Study returned questionnaires (70% response). Exposure history of YAHL case-twins was compared with that of their unaffected control-twins using conditional logistic regression for matched pairs to calculate odds ratios (ORs). Behaviors likely to produce oral exposure to microbes conveyed decreases in risk (univariable OR range = 0.2-0.5, P = .003-.11). Significant adjusted ORs were seen for appendectomy (OR = 4.3, P = .001), eczema (OR = 4.2, P = .025), smoking (OR = 2.2, P = .054), and relatively more frequent behaviors associated with oral exposures (OR = 0.1; P = .004). Kappa statistics for intrapair agreement were higher than 0.8 for each significant finding. Our observations support a protective role for increased early oral exposure to the microbiome, suggesting that factors associated with increased Th2 and decreased Th1 cytokines are etiologically relevant to YAHL.
authors.affiliation: Department of Preventive Medicine, Keck School of Medicine and Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California, USA. wcozen@usc.edu
authors.forename: Wendy
authors.initials: W
authors.lastname: Cozen
authors.forename: Ann S
authors.initials: AS
authors.lastname: Hamilton
authors.forename: Peng
authors.initials: P
authors.lastname: Zhao
authors.forename: Muhammad T
authors.initials: MT
authors.lastname: Salam
authors.forename: Dennis M
authors.initials: DM
authors.lastname: Deapen
authors.forename: Bharat N
authors.initials: BN
authors.lastname: Nathwani
authors.forename: Lawrence M
authors.initials: LM
authors.lastname: Weiss
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Mack
mesh_terms: D000328:Adult; D017668:Age of Onset; D016022:Case-Control Studies; D004200:Diseases in Twins / Q000209:etiology / Q000235:genetics / Q000276:immunology; D005260:Female; D006689:Hodgkin Disease / Q000209:etiology* / Q000235:genetics / Q000276:immunology; D006801:Humans; D018664:Interleukin-12 / Q000096:biosynthesis; D015850:Interleukin-6 / Q000096:biosynthesis; D008297:Male; D054892:Metagenome / Q000276:immunology; D008875:Middle Aged; D008954:Models, Biological; D012307:Risk Factors; D011795:Surveys and Questionnaires; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology; D055815:Young Adult
chemical_list: C508600:IL6 protein, human; D015850:Interleukin-6; D018664:Interleukin-12