title: Polycyclic aromatic hydrocarbons and postmenopausal breast cancer: An evaluation of effect measure modification by body mass index and weight change.
abstract: BACKGROUND
  Polycyclic aromatic hydrocarbons (PAHs) have been linked to breast cancer in many, but not all, previous studies. PAHs are lipophilic and stored in fat tissue, which we hypothesized may result in constant low-dose exposure to these carcinogens. No previous studies have evaluated whether obesity modifies associations between multiple measures of PAHs and breast cancer incidence.
  
  
  METHODS
  This population-based study included 1,006 postmenopausal women with first primary in situ or invasive breast cancer and 990 age-frequency matched controls. To evaluate effect modification by obesity (adult body mass index (BMI, kg/m2) and weight change) on multiple PAH measures (the biomarker PAH-DNA adducts, and long-term sources active cigarette smoking, living with a smoking spouse, grilled/smoked meat intake, residential synthetic log burning, and vehicular traffic), interaction contrast ratios (ICRs) for the additive scale, and ratio of odds ratios (RORs) with log-likelihood ratio tests (LRT) for the multiplicative scale, were determined using unconditional logistic regression.
  
  
  RESULTS
  BMI modified the PAH-DNA adduct and postmenopausal breast cancer association on the additive (ICR: 0.49; 95% CI: 0.01, 0.96) and multiplicative (ROR: 1.56; 95% CI: 0.91, 2.68) scales. The odds ratio for detectable vs. non-detectable adducts was increased among women with BMI ≥25 (OR=1.34; 95% CI: 0.94, 1.92), but not in those with BMI <25 (OR=0.86; 95% CI: 0.57, 1.28) (LRT p=0.1). For most other PAH measures, the pattern of modification by BMI/weight gain was similar, but estimates were imprecise.
  
  
  CONCLUSIONS
  The association between PAH-DNA adducts and breast cancer incidence may be elevated among overweight/obese women.
authors.affiliation: Department of Epidemiology, University of North Carolina, Chapel Hill, NC, USA. Electronic address: nicolen@live.unc.edu.
authors.forename: Nicole
authors.initials: N
authors.lastname: Niehoff
authors.affiliation: Epidemiology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA.
authors.forename: Alexandra J
authors.initials: AJ
authors.lastname: White
authors.affiliation: Department of Epidemiology, Emory University, Atlanta, GA, USA.
authors.forename: Lauren E
authors.initials: LE
authors.lastname: McCullough
authors.affiliation: Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC, USA.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Steck
authors.affiliation: Department of Consulting in the Public Interest (CIPI), Lambertville, NJ, USA.
authors.forename: Jan
authors.initials: J
authors.lastname: Beyea
authors.affiliation: Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA.
authors.forename: Irina
authors.initials: I
authors.lastname: Mordukhovich
authors.affiliation: Department of Environmental Health Sciences, Columbia University, New York, NY, USA.
authors.forename: Jing
authors.initials: J
authors.lastname: Shen
authors.affiliation: Department of Epidemiology, Columbia University, New York, NY, USA; Departments of Medicine, Columbia University, New York, NY, USA.
authors.forename: Alfred I
authors.initials: AI
authors.lastname: Neugut
authors.affiliation: Department of Epidemiology, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Conway
authors.affiliation: Department of Environmental Health Sciences, Columbia University, New York, NY, USA.
authors.forename: Regina M
authors.initials: RM
authors.lastname: Santella
authors.affiliation: Department of Epidemiology, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: Marilie D
authors.initials: MD
authors.lastname: Gammon
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D049628:Body Size; D001943:Breast Neoplasms / Q000139:chemically induced / Q000453:epidemiology*; D016022:Case-Control Studies; D004781:Environmental Exposure; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000633:toxicity*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009518:New York / Q000453:epidemiology; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity*; D017698:Postmenopause; D012307:Risk Factors; D015430:Weight Gain; D055815:Young Adult
chemical_list: D004785:Environmental Pollutants; D011084:Polycyclic Aromatic Hydrocarbons
keywords: Adducts; Breast cancer; Obesity; Polycyclic aromatic hydrocarbons; Weight gain