title: Family history of hematopoietic malignancy and risk of lymphoma.
abstract: BACKGROUND
  A family history of hematopoietic malignancy is associated with an increased risk of non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL), although the magnitude of the relative risk is unclear. We estimated the association between familial hematopoietic cancer and risk of lymphoma using validated, registry-based family data, and we also investigated whether associations between some environmental exposures and risk of lymphoma vary between individuals with and without such a family history.
  
  
  METHODS
  In a population-based case-control study of malignant lymphoma, 1506 case patients and 1229 control subjects were linked to the Swedish Multi-Generation Register and then to the Swedish Cancer Register to ascertain history of cancer in first-degree relatives of patients with malignant lymphoma. Multiple logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for associations with the risk of lymphoma.
  
  
  RESULTS
  A history of hematopoietic malignancy in any first-degree relative was associated with an increased risk of all NHL (OR = 1.8, 95% CI = 1.2 to 2.5), common B-cell NHL subtypes, and HL. Relative risks were generally stronger in association with sibling hematopoietic cancer (OR for all NHL = 3.2, 95% CI = 1.3 to 7.6) than with parental hematopoietic cancer (OR = 1.6, 95% CI = 1.1 to 2.3). A family history of NHL or chronic lymphocytic leukemia (CLL) was associated with an increased risk of several NHL subtypes and HL, whereas familial multiple myeloma was associated with a higher risk of follicular lymphoma. There was no statistically significant heterogeneity in NHL risk associations with environmental factors between individuals with and without familial hematopoietic malignancy.
  
  
  CONCLUSIONS
  The increased risk of NHL and HL among individuals with a family history of hematopoietic malignancy was approximately twofold for both lymphoma types. There was no evidence that etiologic associations varied between familial NHL and nonfamilial NHL.
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden. ellen.chang@meb.ki.se
authors.forename: Ellen T
authors.initials: ET
authors.lastname: Chang
authors.forename: Karin Ekström
authors.initials: KE
authors.lastname: Smedby
authors.forename: Henrik
authors.initials: H
authors.lastname: Hjalgrim
authors.forename: Anna
authors.initials: A
authors.lastname: Porwit-MacDonald
authors.forename: Göran
authors.initials: G
authors.lastname: Roos
authors.forename: Bengt
authors.initials: B
authors.lastname: Glimelius
authors.forename: Hans-Olov
authors.initials: HO
authors.lastname: Adami
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D016001:Confidence Intervals; D004781:Environmental Exposure / Q000009:adverse effects; D005260:Female; D020022:Genetic Predisposition to Disease; D019337:Hematologic Neoplasms / Q000235:genetics*; D006689:Hodgkin Disease / Q000453:epidemiology* / Q000209:etiology / Q000235:genetics*; D006801:Humans; D015994:Incidence; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics; D016015:Logistic Models; D008224:Lymphoma, Follicular / Q000235:genetics; D008228:Lymphoma, Non-Hodgkin / Q000453:epidemiology* / Q000209:etiology / Q000235:genetics*; D008297:Male; D008498:Medical Record Linkage; D008875:Middle Aged; D009101:Multiple Myeloma / Q000235:genetics; D016017:Odds Ratio; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology