title: Factors influencing bone lead concentration in a suburban community assessed by noninvasive K x-ray fluorescence.
abstract: OBJECTIVE
  To determine the influence of demographic, exposure and medical factors on the bone lead concentration of subjects with background (nonindustrial) environmental lead exposure.
  
  
  METHODS
  Survey.
  
  
  METHODS
  Suburban residential community.
  
  
  METHODS
  A total of 101 subjects (49 males, 52 females; aged 11 to 78 years) were recruited from 49 of 123 households geographically located in a suburban residential neighborhood unexposed to any major source of industrial lead emissions.
  
  
  METHODS
  Cortical bone lead concentrations in the midshaft of the tibia were noninvasively measured by in vivo K x-ray fluorescence. Blood lead concentrations were measured by anodic stripping voltammetry. An administered questionnaire assessed potential sources of lead exposure and medical conditions affecting bone metabolism.
  
  
  RESULTS
  After the exclusion of one outlier, log-transformed bone lead concentration was highly correlated with age (r = .71; P < or = .0001). Bone lead concentration showed no significant change up to age 20 years, increased with the same slope in men and women between ages 20 and 55 years, and then increased at a faster rate in men older than 55 years. In addition to the variables age and sex, the best fitting multiple regression model for bone lead concentration (R2 = .66; P < or = .0001) revealed a positive correlation with total pack-years of cigarette smoking and a negative correlation with a history of having nursed an infant for longer than 2 weeks. Blood lead concentrations of the subjects were low (geometric mean, 0.24 mumol/L [4.9 micrograms/dL]) and after log transformation were weakly correlated with log-transformed bone lead concentration (r = .23; P = .02).
  
  
  CONCLUSIONS
  The age- and sex-related increases in bone lead concentration found by K x-ray fluorescence concur with published postmortem studies of bone lead concentration and are consistent with the kinetics of bone turnover and secular trends in lead exposure. These data help to establish a reference range for assessing the lead burden of other populations with environmental or occupational lead exposure.
authors.affiliation: Center for Occupational and Environmental Health, University of California, San Francisco 94143-0843.
authors.forename: M J
authors.initials: MJ
authors.lastname: Kosnett
authors.forename: C E
authors.initials: CE
authors.lastname: Becker
authors.forename: J D
authors.initials: JD
authors.lastname: Osterloh
authors.forename: T J
authors.initials: TJ
authors.lastname: Kelly
authors.forename: D J
authors.initials: DJ
authors.lastname: Pasta
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D001822:Body Burden; D001842:Bone and Bones / Q000737:chemistry* / Q000000981:diagnostic imaging; D002648:Child; D003710:Demography; D004781:Environmental Exposure / Q000032:analysis / Q000706:statistics & numerical data; D005260:Female; D005453:Fluorescence; D006801:Humans; D007854:Lead / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D010414:Pennsylvania; D011237:Predictive Value of Tests; D011859:Radiography / Q000379:methods; D012044:Regression Analysis; D017678:Sex Distribution; D013383:Suburban Population / Q000706:statistics & numerical data; D013977:Tibia / Q000737:chemistry / Q000000981:diagnostic imaging
chemical_list: D007854:Lead