title: Urinary benzene metabolite and insulin resistance in elderly adults.
abstract: BACKGROUND
  Benzene is a volatile organic compound present in traffic-related and indoor air pollution. It is of particular concern since it is known to induce oxidative stress, which can affect insulin resistance (IR). We therefore examined the association between exposure to environmental benzene and IR in the elderly.
  
  
  METHODS
  Between 2008 and 2010, benzene metabolite levels (urinary trans,trans-muconic acid (t,t-MA)) and homeostatic model assessment index (HOMA-IR) were repeatedly measured in 505 adults aged ≥60 years. Linear mixed-effect models and marginal logistic models were used to evaluate associations of t,t-MA concentration with HOMA-IR score and elevated IR, defined as HOMA-IR ≥2.6.
  
  
  RESULTS
  After adjustment for sociodemographic and behavioral factors, environmental co-exposures, and metabolic conditions, quartile levels of urinary t,t-MA demonstrated a dose-dependent association with elevated IR (p-trend<0.001) and the level of oxidative stress estimated by urinary malondialdehyde (p-trend<0.001). As compared to the lowest quartile, the upper quartiles of t,t-MA (t,t-MA concentration >0.017mg/g CR) were associated with elevated IR [odds ratio=Q2: 2.00 (95% confidence interval (CI): 1.16-3.46); Q3: 3.33 (95% CI: 1.90-5.84); Q4: 2.07 (95% CI: 1.02-4.22)].
  
  
  CONCLUSIONS
  Urinary benzene at levels currently observed in the urban elderly population is associated with IR, independent of traditional risk factors. Reduction of community-level exposure to benzene is therefore important for the effective prevention of IR in older adults.
authors.affiliation: Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; Institute of Environmental Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.
authors.forename: Yoon-Hyeong
authors.initials: YH
authors.lastname: Choi
authors.affiliation: Institute of Environmental Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea; Environmental Health Center, Seoul National University Medical Research Center, Seoul, Republic of Korea.
authors.forename: Jin Hee
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Environmental Health Research Division, National Institute of Environmental Research, Incheon, Republic of Korea.
authors.forename: Bo-Eun
authors.initials: BE
authors.lastname: Lee
authors.affiliation: Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; Institute of Environmental Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea; Environmental Health Center, Seoul National University Medical Research Center, Seoul, Republic of Korea. Electronic address: ychong1@snu.ac.kr.
authors.forename: Yun-Chul
authors.initials: YC
authors.lastname: Hong
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000393:Air Pollutants / Q000652:urine*; D016902:Air Pollution, Indoor / Q000032:analysis / Q000706:statistics & numerical data; D001554:Benzene / Q000378:metabolism*; D015415:Biomarkers / Q000652:urine; D004781:Environmental Exposure / Q000032:analysis* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D008315:Malondialdehyde / Q000652:urine; D008875:Middle Aged; D013011:Sorbic Acid / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D000393:Air Pollutants; D015415:Biomarkers; C005939:muconic acid; D008315:Malondialdehyde; D001554:Benzene; D013011:Sorbic Acid
keywords: Benzene; Elderly; Epidemiology; Insulin resistance