title: Association of lead and cadmium exposure with frailty in US older adults.
abstract: BACKGROUND
  Environmental lead and cadmium exposure is associated with higher risk of several age-related chronic diseases, including cardiovascular disease, chronic kidney disease and osteoporosis. These diseases may lead to frailty, a geriatric syndrome characterized by diminished physiologic reserve in multiple systems with decreased ability to cope with acute stressors. However, no previous study has evaluated the association between lead or cadmium exposure and frailty.
  
  
  METHODS
  Cross-sectional study among individuals aged ≥ 60 years who participated in the third U.S. National Health and Nutrition Examination Survey and had either blood lead (N=5272) or urine cadmium (N=4887) determinations. Frailty was ascertained with a slight modification of the Fried criteria, so that individuals meeting ≥ 3 of 5 pre-defined criteria (exhaustion, low body weight, low physical activity, weakness and slow walking speed), were considered as frail. The association between lead and cadmium with frailty was evaluated using logistic regression with adjustment for relevant confounders.
  
  
  RESULTS
  Median (intertertile range) concentrations of blood lead and urine cadmium were 3.9 µg/dl (2.9-4.9) and 0.62 µg/l (0.41-0.91), respectively. The prevalence of frailty was 7.1%. The adjusted odds ratios (95% confidence interval) of frailty comparing the second and third to the lowest tertile of blood lead were, respectively, 1.40 (0.96-2.04) and 1.75 (1.33-2.31). Lead concentrations were also associated with the frequency of exhaustion, weakness and slowness. The corresponding odds ratios (95% confidence interval) for cadmium were, respectively, 0.97 (0.68-1.39) and 1.55 (1.03-2.32), but this association did not hold after excluding participants with reduced glomerular filtration rate: 0.70 (0.43-1.14) and 1.09 (0.56-2.11), respectively.
  
  
  CONCLUSIONS
  In the US older adult population, blood lead but not urine cadmium concentrations showed a direct dose-response relationship with frailty. These findings support that lead exposure increases frailty in older adults.
authors.affiliation: Department of Preventive Medicine and Public Health, School of Medicine, Universidad Autónoma de Madrid/ IdiPAZ, Madrid, Spain; CIBER of Epidemiology and Public Health (CIBERESP), Madrid, Spain; Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA. Electronic address: esthergge@gmail.com.
authors.forename: Esther
authors.initials: E
authors.lastname: García-Esquinas
authors.affiliation: Department of Environmental Health Sciences, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA; Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA; Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: Ana
authors.initials: A
authors.lastname: Navas-Acien
authors.affiliation: CIBER of Epidemiology and Public Health (CIBERESP), Madrid, Spain; Environmental Epidemiology and Cancer Unit, National Center for Epidemiology, Carlos III Institute of Health, Madrid, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Pérez-Gómez
authors.affiliation: Department of Preventive Medicine and Public Health, School of Medicine, Universidad Autónoma de Madrid/ IdiPAZ, Madrid, Spain; CIBER of Epidemiology and Public Health (CIBERESP), Madrid, Spain.
authors.forename: Fernando Rodríguez
authors.initials: FR
authors.lastname: Artalejo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002104:Cadmium / Q000652:urine*; D003430:Cross-Sectional Studies; D005260:Female; D016330:Frail Elderly / Q000706:statistics & numerical data; D006801:Humans; D007854:Lead / Q000097:blood*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D016017:Odds Ratio; D015995:Prevalence; D014481:United States / Q000453:epidemiology
chemical_list: D002104:Cadmium; D007854:Lead
keywords: Cadmium; Frailty; Lead; Muscle strength