title: Anthropometric, behavioral, and female reproductive factors and risk of multiple myeloma: a pooled analysis.
abstract: BACKGROUND
  Risk of developing multiple myeloma (MM) rises with age and is greater among men and blacks than among women and whites, respectively, and possibly increased among obese persons. Other risk factors remain poorly understood. By pooling data from two complementary epidemiologic studies, we assessed whether obesity, smoking, or alcohol consumption alters MM risk and whether female reproductive history might explain the lower occurrence of MM in females than in males.
  
  
  METHODS
  The Los Angeles County MM Case-Control Study (1985-1992) included 278 incident cases and 278 controls, matched on age, sex, race, and neighborhood of residence at case's diagnosis. We estimated MM risk using conditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs). In the prospective California Teachers Study (CTS), 152 women were diagnosed with incident MM between 1995 and 2009; we calculated hazard ratios using Cox proportional hazards analysis. Data from the two studies were pooled using a stratified, nested case-control sampling scheme (10:1 match) for the CTS; conditional logistic regression among 430 cases and 1,798 matched controls was conducted.
  
  
  RESULTS
  Obesity and smoking were not associated with MM risk in the individual or combined studies. Alcohol consumption was associated with decreased MM risk among whites only (pooled OR = 0.66, 95% CI = 0.49-0.90) for ever versus never drinking. Higher gravidity and parity were associated with increased MM risk, with pooled ORs of 1.38 (95 % CI = 1.01-1.90) for ≥3 versus 1-2 pregnancies and 1.50 (95% CI = 1.09-2.06) for ≥3 versus 1-2 live births.
  
  
  CONCLUSIONS
  Female reproductive history may modestly alter MM risk, but appears unlikely to explain the sex disparity in incidence. Further investigation in consortial efforts is warranted.
authors.affiliation: Division of Cancer Etiology, Department of Population Sciences, City of Hope and the Beckman Research Institute, Duarte, CA 91010, USA. sowang@coh.org
authors.forename: Sophia S
authors.initials: SS
authors.lastname: Wang
authors.forename: Jenna
authors.initials: J
authors.lastname: Voutsinas
authors.forename: Ellen T
authors.initials: ET
authors.lastname: Chang
authors.forename: Christina A
authors.initials: CA
authors.lastname: Clarke
authors.forename: Yani
authors.initials: Y
authors.lastname: Lu
authors.forename: Huiyan
authors.initials: H
authors.lastname: Ma
authors.forename: Dee
authors.initials: D
authors.lastname: West
authors.forename: James V
authors.initials: JV
authors.lastname: Lacey
authors.forename: Leslie
authors.initials: L
authors.lastname: Bernstein
mesh_terms: D000328:Adult; D000368:Aged; D000428:Alcohol Drinking / Q000009:adverse effects; D000886:Anthropometry; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D015141:Los Angeles; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000453:epidemiology* / Q000208:ethnology / Q000209:etiology; D009765:Obesity / Q000150:complications; D016017:Odds Ratio; D017584:Reproductive History; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors