title: Living near a freeway is associated with lower bone mineral density among Mexican Americans.
abstract: We hypothesized that chronic exposures to traffic combustion products may lower bone mineral density (BMD). We found that proximity to freeways was associated with reduced BMD. Our findings suggest that traffic-related pollution may contribute to the occurrence of osteopenia and osteoporosis.
  
  
  BACKGROUND
  Adults residing in rural areas have been linked with higher BMD. We aimed to determine if this difference is due in part to air pollution by examining the relationships between traffic metrics and ambient air pollution with total body and pelvic BMD.
  
  
  METHODS
  Mexican American adults (n = 1,175; mean 34 years; 72 % female) who had participated in the BetaGene study of air pollution, obesity, and insulin resistance were included in this analysis. Total body and pelvic BMD were estimated using dual-energy X-ray absorptiometry. Traffic and ambient air pollutant exposures were estimated at residences using location and ambient monitoring data. Variance component models were used to analyze the associations between residential distance to the nearest freeway and ambient air pollutants with BMD.
  
  
  RESULTS
  Residential proximity to a freeway was associated with lower total body BMD (p-trend = 0.01) and pelvic BMD (p-trend = 0.03) after adjustment for age, sex, weight, and height. The adjusted mean total body and pelvic BMD in participants living within 500 m of a freeway were 0.02 and 0.03 g/cm(2) lower than participants living greater than 1,500 m from a freeway. These associations did not differ significantly by age, sex, or obesity status. Results were similar after further adjustment for body fat and weekly physical activity minutes. Ambient air pollutants (NO2, O3, and PM2.5) were not significantly associated with BMD.
  
  
  CONCLUSIONS
  Traffic-related exposures in overweight and obese Mexican Americans may adversely affect BMD. Our findings indicate that long-term exposures to traffic may contribute to the occurrence of osteoporosis and its consequences.
authors: Southern California Environmental Health Sciences Center, Division of Environmental Health, Department of Preventive Medicine, Keck School of Medicine, University of Southern California, 2001 N. Soto Street, Los Angeles, CA, 90032, USA.
authors: Z
authors: Z
authors: Chen
authors: Southern California Environmental Health Sciences Center, Division of Environmental Health, Department of Preventive Medicine, Keck School of Medicine, University of Southern California, 2001 N. Soto Street, Los Angeles, CA, 90032, USA.
authors: M T
authors: MT
authors: Salam
authors: Division of Biostatistics, Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.|Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
authors: R
authors: R
authors: Karim
authors: Southern California Environmental Health Sciences Center, Division of Environmental Health, Department of Preventive Medicine, Keck School of Medicine, University of Southern California, 2001 N. Soto Street, Los Angeles, CA, 90032, USA.|Department of Public Health, California State University, Los Angeles, CA, USA.
authors: C M
authors: CM
authors: Toledo-Corral
authors: Division of Biostatistics, Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
authors: R M
authors: RM
authors: Watanabe
authors: Department of Research & Evaluation, Kaiser Permanente Southern California, Pasadena, CA, USA.
authors: A H
authors: AH
authors: Xiang
authors: Division of Diabetes and Endocrinology, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
authors: T A
authors: TA
authors: Buchanan
authors: Southern California Environmental Health Sciences Center, Division of Environmental Health, Department of Preventive Medicine, Keck School of Medicine, University of Southern California, 2001 N. Soto Street, Los Angeles, CA, 90032, USA.
authors: R
authors: R
authors: Habre
authors: Southern California Environmental Health Sciences Center, Division of Environmental Health, Department of Preventive Medicine, Keck School of Medicine, University of Southern California, 2001 N. Soto Street, Los Angeles, CA, 90032, USA.
authors: T M
authors: TM
authors: Bastain
authors: Sonoma Technology, Inc., Petaluma, CA, USA.
authors: F
authors: F
authors: Lurmann
authors: Spatial Sciences Institute, University of Southern California, Los Angeles, CA, USA.
authors: M
authors: M
authors: Taher
authors: Spatial Sciences Institute, University of Southern California, Los Angeles, CA, USA.
authors: J P
authors: JP
authors: Wilson
authors: Division of Diabetes and Endocrinology, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
authors: E
authors: E
authors: Trigo
authors: Southern California Environmental Health Sciences Center, Division of Environmental Health, Department of Preventive Medicine, Keck School of Medicine, University of Southern California, 2001 N. Soto Street, Los Angeles, CA, 90032, USA. gillilan@usc.edu.
authors: F D
authors: FD
authors: Gilliland
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D000328:Adult; D000397:Air Pollution / Q000009:adverse effects* / Q000032:analysis; D000886:Anthropometry / Q000379:methods; D015519:Bone Density / Q000502:physiology; D002140:California / Q000453:epidemiology; D004781:Environmental Exposure / Q000009:adverse effects / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D017058:Mexican Americans / Q000706:statistics & numerical data; D018986:Motor Vehicles; D010024:Osteoporosis / Q000208:ethnology / Q000209:etiology* / Q000503:physiopathology; D050177:Overweight / Q000150:complications / Q000208:ethnology; D010384:Pelvic Bones / Q000503:physiopathology; D012111:Residence Characteristics / Q000706:statistics & numerical data; D012959:Socioeconomic Factors; D001335:Vehicle Emissions / Q000032:analysis / Q000633:toxicity*
chemical_list: D001335:Vehicle Emissions
keywords: Air pollution; BMD; Bone mineral density; Osteopenia; Osteoporosis; Traffic-related pollution